X-Git-Url: https://git.hcoop.net/hcoop/debian/exim4.git/blobdiff_plain/420a0d19af455b8c65ca20e08b500bd9c4995860..2813c06e9d6e591298239bc7dac3fb1b5c778a7c:/src/pdkim/pdkim.c diff --git a/src/pdkim/pdkim.c b/src/pdkim/pdkim.c dissimilarity index 88% index 4f0da3f..4c93de7 100644 --- a/src/pdkim/pdkim.c +++ b/src/pdkim/pdkim.c @@ -1,1773 +1,1789 @@ -/* - * PDKIM - a RFC4871 (DKIM) implementation - * - * Copyright (C) 2009 - 2012 Tom Kistner - * - * http://duncanthrax.net/pdkim/ - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License along - * with this program; if not, write to the Free Software Foundation, Inc., - * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. - */ - -#include -#include -#include -#include - -#include "pdkim.h" - -#include "sha1.h" -#include "sha2.h" -#include "rsa.h" -#include "base64.h" - -#define PDKIM_SIGNATURE_VERSION "1" -#define PDKIM_PUB_RECORD_VERSION "DKIM1" - -#define PDKIM_MAX_HEADER_LEN 65536 -#define PDKIM_MAX_HEADERS 512 -#define PDKIM_MAX_BODY_LINE_LEN 16384 -#define PDKIM_DNS_TXT_MAX_NAMELEN 1024 -#define PDKIM_DEFAULT_SIGN_HEADERS "From:Sender:Reply-To:Subject:Date:"\ - "Message-ID:To:Cc:MIME-Version:Content-Type:"\ - "Content-Transfer-Encoding:Content-ID:"\ - "Content-Description:Resent-Date:Resent-From:"\ - "Resent-Sender:Resent-To:Resent-Cc:"\ - "Resent-Message-ID:In-Reply-To:References:"\ - "List-Id:List-Help:List-Unsubscribe:"\ - "List-Subscribe:List-Post:List-Owner:List-Archive" - -/* -------------------------------------------------------------------------- */ -struct pdkim_stringlist { - char *value; - int tag; - void *next; -}; - -#define PDKIM_STR_ALLOC_FRAG 256 -struct pdkim_str { - char *str; - unsigned int len; - unsigned int allocated; -}; - -/* -------------------------------------------------------------------------- */ -/* A bunch of list constants */ -const char *pdkim_querymethods[] = { - "dns/txt", - NULL -}; -const char *pdkim_algos[] = { - "rsa-sha256", - "rsa-sha1", - NULL -}; -const char *pdkim_canons[] = { - "simple", - "relaxed", - NULL -}; -const char *pdkim_hashes[] = { - "sha256", - "sha1", - NULL -}; -const char *pdkim_keytypes[] = { - "rsa", - NULL -}; - -typedef struct pdkim_combined_canon_entry { - const char *str; - int canon_headers; - int canon_body; -} pdkim_combined_canon_entry; -pdkim_combined_canon_entry pdkim_combined_canons[] = { - { "simple/simple", PDKIM_CANON_SIMPLE, PDKIM_CANON_SIMPLE }, - { "simple/relaxed", PDKIM_CANON_SIMPLE, PDKIM_CANON_RELAXED }, - { "relaxed/simple", PDKIM_CANON_RELAXED, PDKIM_CANON_SIMPLE }, - { "relaxed/relaxed", PDKIM_CANON_RELAXED, PDKIM_CANON_RELAXED }, - { "simple", PDKIM_CANON_SIMPLE, PDKIM_CANON_SIMPLE }, - { "relaxed", PDKIM_CANON_RELAXED, PDKIM_CANON_SIMPLE }, - { NULL, 0, 0 } -}; - - -const char *pdkim_verify_status_str(int status) { - switch(status) { - case PDKIM_VERIFY_NONE: return "PDKIM_VERIFY_NONE"; - case PDKIM_VERIFY_INVALID: return "PDKIM_VERIFY_INVALID"; - case PDKIM_VERIFY_FAIL: return "PDKIM_VERIFY_FAIL"; - case PDKIM_VERIFY_PASS: return "PDKIM_VERIFY_PASS"; - default: return "PDKIM_VERIFY_UNKNOWN"; - } -} -const char *pdkim_verify_ext_status_str(int ext_status) { - switch(ext_status) { - case PDKIM_VERIFY_FAIL_BODY: return "PDKIM_VERIFY_FAIL_BODY"; - case PDKIM_VERIFY_FAIL_MESSAGE: return "PDKIM_VERIFY_FAIL_MESSAGE"; - case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: return "PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE"; - case PDKIM_VERIFY_INVALID_BUFFER_SIZE: return "PDKIM_VERIFY_INVALID_BUFFER_SIZE"; - case PDKIM_VERIFY_INVALID_PUBKEY_PARSING: return "PDKIM_VERIFY_INVALID_PUBKEY_PARSING"; - default: return "PDKIM_VERIFY_UNKNOWN"; - } -} - - -/* -------------------------------------------------------------------------- */ -/* Print debugging functions */ -#ifdef PDKIM_DEBUG -void pdkim_quoteprint(FILE *stream, const char *data, int len, int lf) { - int i; - const unsigned char *p = (const unsigned char *)data; - - for (i=0;i 127) ) - fprintf(stream,"{%02x}",c); - else - fputc(c,stream); - break; - } - } - if (lf) - fputc('\n',stream); -} -void pdkim_hexprint(FILE *stream, const char *data, int len, int lf) { - int i; - const unsigned char *p = (const unsigned char *)data; - - for (i=0;ivalue = strdup(str); - if (new_entry->value == NULL) return NULL; - if (base != NULL) { - pdkim_stringlist *last = base; - while (last->next != NULL) { last = last->next; } - last->next = new_entry; - return base; - } - else return new_entry; -} -pdkim_stringlist *pdkim_prepend_stringlist(pdkim_stringlist *base, char *str) { - pdkim_stringlist *new_entry = malloc(sizeof(pdkim_stringlist)); - if (new_entry == NULL) return NULL; - memset(new_entry,0,sizeof(pdkim_stringlist)); - new_entry->value = strdup(str); - if (new_entry->value == NULL) return NULL; - if (base != NULL) { - new_entry->next = base; - } - return new_entry; -} - - -/* -------------------------------------------------------------------------- */ -/* A small "growing string" implementation to escape malloc/realloc hell */ -pdkim_str *pdkim_strnew (const char *cstr) { - unsigned int len = cstr?strlen(cstr):0; - pdkim_str *p = malloc(sizeof(pdkim_str)); - if (p == NULL) return NULL; - memset(p,0,sizeof(pdkim_str)); - p->str = malloc(len+1); - if (p->str == NULL) { - free(p); - return NULL; - } - p->allocated=(len+1); - p->len=len; - if (cstr) strcpy(p->str,cstr); - else p->str[p->len] = '\0'; - return p; -} -char *pdkim_strncat(pdkim_str *str, const char *data, int len) { - if ((str->allocated - str->len) < (len+1)) { - /* Extend the buffer */ - int num_frags = ((len+1)/PDKIM_STR_ALLOC_FRAG)+1; - char *n = realloc(str->str, - (str->allocated+(num_frags*PDKIM_STR_ALLOC_FRAG))); - if (n == NULL) return NULL; - str->str = n; - str->allocated += (num_frags*PDKIM_STR_ALLOC_FRAG); - } - strncpy(&(str->str[str->len]),data,len); - str->len+=len; - str->str[str->len] = '\0'; - return str->str; -} -char *pdkim_strcat(pdkim_str *str, const char *cstr) { - return pdkim_strncat(str, cstr, strlen(cstr)); -} -char *pdkim_numcat(pdkim_str *str, unsigned long num) { - char minibuf[20]; - snprintf(minibuf,20,"%lu",num); - return pdkim_strcat(str,minibuf); -} -char *pdkim_strtrim(pdkim_str *str) { - char *p = str->str; - char *q = str->str; - while ( (*p != '\0') && ((*p == '\t') || (*p == ' ')) ) p++; - while (*p != '\0') {*q = *p; q++; p++;} - *q = '\0'; - while ( (q != str->str) && ( (*q == '\0') || (*q == '\t') || (*q == ' ') ) ) { - *q = '\0'; - q--; - } - str->len = strlen(str->str); - return str->str; -} -char *pdkim_strclear(pdkim_str *str) { - str->str[0] = '\0'; - str->len = 0; - return str->str; -} -void pdkim_strfree(pdkim_str *str) { - if (str == NULL) return; - if (str->str != NULL) free(str->str); - free(str); -} - - - -/* -------------------------------------------------------------------------- */ -void pdkim_free_pubkey(pdkim_pubkey *pub) { - if (pub) { - if (pub->version != NULL) free(pub->version); - if (pub->granularity != NULL) free(pub->granularity); - if (pub->hashes != NULL) free(pub->hashes); - if (pub->keytype != NULL) free(pub->keytype); - if (pub->srvtype != NULL) free(pub->srvtype); - if (pub->notes != NULL) free(pub->notes); - if (pub->key != NULL) free(pub->key); - free(pub); - } -} - - -/* -------------------------------------------------------------------------- */ -void pdkim_free_sig(pdkim_signature *sig) { - if (sig) { - pdkim_signature *next = (pdkim_signature *)sig->next; - - pdkim_stringlist *e = sig->headers; - while(e != NULL) { - pdkim_stringlist *c = e; - if (e->value != NULL) free(e->value); - e = e->next; - free(c); - } - - if (sig->sigdata != NULL) free(sig->sigdata); - if (sig->bodyhash != NULL) free(sig->bodyhash); - if (sig->selector != NULL) free(sig->selector); - if (sig->domain != NULL) free(sig->domain); - if (sig->identity != NULL) free(sig->identity); - if (sig->headernames != NULL) free(sig->headernames); - if (sig->copiedheaders != NULL) free(sig->copiedheaders); - if (sig->rsa_privkey != NULL) free(sig->rsa_privkey); - if (sig->sign_headers != NULL) free(sig->sign_headers); - if (sig->signature_header != NULL) free(sig->signature_header); - if (sig->sha1_body != NULL) free(sig->sha1_body); - if (sig->sha2_body != NULL) free(sig->sha2_body); - - if (sig->pubkey != NULL) pdkim_free_pubkey(sig->pubkey); - - free(sig); - if (next != NULL) pdkim_free_sig(next); - } -} - - -/* -------------------------------------------------------------------------- */ -DLLEXPORT void pdkim_free_ctx(pdkim_ctx *ctx) { - if (ctx) { - pdkim_stringlist *e = ctx->headers; - while(e != NULL) { - pdkim_stringlist *c = e; - if (e->value != NULL) free(e->value); - e = e->next; - free(c); - } - pdkim_free_sig(ctx->sig); - pdkim_strfree(ctx->cur_header); - free(ctx); - } -} - - -/* -------------------------------------------------------------------------- */ -/* Matches the name of the passed raw "header" against - the passed colon-separated "list", starting at entry - "start". Returns the position of the header name in - the list. */ -int header_name_match(const char *header, - char *tick, - int do_tick) { - char *hname; - char *lcopy; - char *p; - char *q; - int rc = PDKIM_FAIL; - - /* Get header name */ - char *hcolon = strchr(header,':'); - if (hcolon == NULL) return rc; /* This isn't a header */ - hname = malloc((hcolon-header)+1); - if (hname == NULL) return PDKIM_ERR_OOM; - memset(hname,0,(hcolon-header)+1); - strncpy(hname,header,(hcolon-header)); - - /* Copy tick-off list locally, so we can punch zeroes into it */ - lcopy = strdup(tick); - if (lcopy == NULL) { - free(hname); - return PDKIM_ERR_OOM; - } - p = lcopy; - q = strchr(p,':'); - while (q != NULL) { - *q = '\0'; - - if (strcasecmp(p,hname) == 0) { - rc = PDKIM_OK; - /* Invalidate header name instance in tick-off list */ - if (do_tick) tick[p-lcopy] = '_'; - goto BAIL; - } - - p = q+1; - q = strchr(p,':'); - } - - if (strcasecmp(p,hname) == 0) { - rc = PDKIM_OK; - /* Invalidate header name instance in tick-off list */ - if (do_tick) tick[p-lcopy] = '_'; - } - - BAIL: - free(hname); - free(lcopy); - return rc; -} - - -/* -------------------------------------------------------------------------- */ -/* Performs "relaxed" canonicalization of a header. The returned pointer needs - to be free()d. */ -char *pdkim_relax_header (char *header, int crlf) { - int past_field_name = 0; - int seen_wsp = 0; - char *p = header; - char *q; - char *relaxed = malloc(strlen(header)+3); - if (relaxed == NULL) return NULL; - q = relaxed; - while (*p != '\0') { - int c = *p; - /* Ignore CR & LF */ - if ( (c == '\r') || (c == '\n') ) { - p++; - continue; - } - if ( (c == '\t') || (c == ' ') ) { - c = ' '; /* Turns WSP into SP */ - if (seen_wsp) { - p++; - continue; - } - else seen_wsp = 1; - } - else { - if ( (!past_field_name) && (c == ':') ) { - if (seen_wsp) q--; /* This removes WSP before the colon */ - seen_wsp = 1; /* This removes WSP after the colon */ - past_field_name = 1; - } - else seen_wsp = 0; - } - /* Lowercase header name */ - if (!past_field_name) c = tolower(c); - *q = c; - p++; - q++; - } - if ((q>relaxed) && (*(q-1) == ' ')) q--; /* Squash eventual trailing SP */ - *q = '\0'; - if (crlf) strcat(relaxed,"\r\n"); - return relaxed; -} - - -/* -------------------------------------------------------------------------- */ -#define PDKIM_QP_ERROR_DECODE -1 -char *pdkim_decode_qp_char(char *qp_p, int *c) { - char *initial_pos = qp_p; - - /* Advance one char */ - qp_p++; - - /* Check for two hex digits and decode them */ - if (isxdigit(*qp_p) && isxdigit(qp_p[1])) { - /* Do hex conversion */ - if (isdigit(*qp_p)) {*c = *qp_p - '0';} - else {*c = toupper(*qp_p) - 'A' + 10;} - *c <<= 4; - if (isdigit(qp_p[1])) {*c |= qp_p[1] - '0';} - else {*c |= toupper(qp_p[1]) - 'A' + 10;} - return qp_p + 2; - } - - /* Illegal char here */ - *c = PDKIM_QP_ERROR_DECODE; - return initial_pos; -} - - -/* -------------------------------------------------------------------------- */ -char *pdkim_decode_qp(char *str) { - int nchar = 0; - char *q; - char *p = str; - char *n = malloc(strlen(p)+1); - if (n == NULL) return NULL; - *n = '\0'; - q = n; - while (*p != '\0') { - if (*p == '=') { - p = pdkim_decode_qp_char(p,&nchar); - if (nchar >= 0) { - *q = nchar; - q++; - continue; - } - } - else { - *q = *p; - q++; - } - p++; - } - *q = '\0'; - return n; -} - - -/* -------------------------------------------------------------------------- */ -char *pdkim_decode_base64(char *str, int *num_decoded) { - int dlen = 0; - char *res; - - base64_decode(NULL, &dlen, (unsigned char *)str, strlen(str)); - res = malloc(dlen+1); - if (res == NULL) return NULL; - if (base64_decode((unsigned char *)res,&dlen,(unsigned char *)str,strlen(str)) != 0) { - free(res); - return NULL; - } - if (num_decoded != NULL) *num_decoded = dlen; - return res; -} - -/* -------------------------------------------------------------------------- */ -char *pdkim_encode_base64(char *str, int num) { - int dlen = 0; - char *res; - - base64_encode(NULL, &dlen, (unsigned char *)str, num); - res = malloc(dlen+1); - if (res == NULL) return NULL; - if (base64_encode((unsigned char *)res,&dlen,(unsigned char *)str,num) != 0) { - free(res); - return NULL; - } - return res; -} - - -/* -------------------------------------------------------------------------- */ -#define PDKIM_HDR_LIMBO 0 -#define PDKIM_HDR_TAG 1 -#define PDKIM_HDR_VALUE 2 -pdkim_signature *pdkim_parse_sig_header(pdkim_ctx *ctx, char *raw_hdr) { - pdkim_signature *sig ; - char *p,*q; - pdkim_str *cur_tag = NULL; - pdkim_str *cur_val = NULL; - int past_hname = 0; - int in_b_val = 0; - int where = PDKIM_HDR_LIMBO; - int i; - - sig = malloc(sizeof(pdkim_signature)); - if (sig == NULL) return NULL; - memset(sig,0,sizeof(pdkim_signature)); - sig->bodylength = -1; - - sig->rawsig_no_b_val = malloc(strlen(raw_hdr)+1); - if (sig->rawsig_no_b_val == NULL) { - free(sig); - return NULL; - } - - p = raw_hdr; - q = sig->rawsig_no_b_val; - - while (1) { - - /* Ignore FWS */ - if ( (*p == '\r') || (*p == '\n') ) - goto NEXT_CHAR; - - /* Fast-forward through header name */ - if (!past_hname) { - if (*p == ':') past_hname = 1; - goto NEXT_CHAR; - } - - if (where == PDKIM_HDR_LIMBO) { - /* In limbo, just wait for a tag-char to appear */ - if (!((*p >= 'a') && (*p <= 'z'))) - goto NEXT_CHAR; - - where = PDKIM_HDR_TAG; - } - - if (where == PDKIM_HDR_TAG) { - if (cur_tag == NULL) - cur_tag = pdkim_strnew(NULL); - - if ((*p >= 'a') && (*p <= 'z')) - pdkim_strncat(cur_tag,p,1); - - if (*p == '=') { - if (strcmp(cur_tag->str,"b") == 0) { - *q = '='; q++; - in_b_val = 1; - } - where = PDKIM_HDR_VALUE; - goto NEXT_CHAR; - } - } - - if (where == PDKIM_HDR_VALUE) { - if (cur_val == NULL) - cur_val = pdkim_strnew(NULL); - - if ( (*p == '\r') || (*p == '\n') || (*p == ' ') || (*p == '\t') ) - goto NEXT_CHAR; - - if ( (*p == ';') || (*p == '\0') ) { - if (cur_tag->len > 0) { - pdkim_strtrim(cur_val); - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) - fprintf(ctx->debug_stream, "%s=%s\n", cur_tag->str, cur_val->str); - #endif - switch (cur_tag->str[0]) { - case 'b': - switch (cur_tag->str[1]) { - case 'h': - sig->bodyhash = pdkim_decode_base64(cur_val->str,&(sig->bodyhash_len)); - break; - default: - sig->sigdata = pdkim_decode_base64(cur_val->str,&(sig->sigdata_len)); - break; - } - break; - case 'v': - if (strcmp(cur_val->str,PDKIM_SIGNATURE_VERSION) == 0) { - /* We only support version 1, and that is currently the - only version there is. */ - sig->version = 1; - } - break; - case 'a': - i = 0; - while (pdkim_algos[i] != NULL) { - if (strcmp(cur_val->str,pdkim_algos[i]) == 0 ) { - sig->algo = i; - break; - } - i++; - } - break; - case 'c': - i = 0; - while (pdkim_combined_canons[i].str != NULL) { - if (strcmp(cur_val->str,pdkim_combined_canons[i].str) == 0 ) { - sig->canon_headers = pdkim_combined_canons[i].canon_headers; - sig->canon_body = pdkim_combined_canons[i].canon_body; - break; - } - i++; - } - break; - case 'q': - i = 0; - while (pdkim_querymethods[i] != NULL) { - if (strcmp(cur_val->str,pdkim_querymethods[i]) == 0 ) { - sig->querymethod = i; - break; - } - i++; - } - break; - case 's': - sig->selector = strdup(cur_val->str); - break; - case 'd': - sig->domain = strdup(cur_val->str); - break; - case 'i': - sig->identity = pdkim_decode_qp(cur_val->str); - break; - case 't': - sig->created = strtoul(cur_val->str,NULL,10); - break; - case 'x': - sig->expires = strtoul(cur_val->str,NULL,10); - break; - case 'l': - sig->bodylength = strtol(cur_val->str,NULL,10); - break; - case 'h': - sig->headernames = strdup(cur_val->str); - break; - case 'z': - sig->copiedheaders = pdkim_decode_qp(cur_val->str); - break; - default: - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) - fprintf(ctx->debug_stream, "Unknown tag encountered\n"); - #endif - break; - } - } - pdkim_strclear(cur_tag); - pdkim_strclear(cur_val); - in_b_val = 0; - where = PDKIM_HDR_LIMBO; - goto NEXT_CHAR; - } - else pdkim_strncat(cur_val,p,1); - } - - NEXT_CHAR: - if (*p == '\0') break; - - if (!in_b_val) { - *q = *p; - q++; - } - p++; - } - - /* Make sure the most important bits are there. */ - if (!(sig->domain && (*(sig->domain) != '\0') && - sig->selector && (*(sig->selector) != '\0') && - sig->headernames && (*(sig->headernames) != '\0') && - sig->bodyhash && - sig->sigdata && - sig->version)) { - pdkim_free_sig(sig); - return NULL; - } - - *q = '\0'; - /* Chomp raw header. The final newline must not be added to the signature. */ - q--; - while( (q > sig->rawsig_no_b_val) && ((*q == '\r') || (*q == '\n')) ) { - *q = '\0'; q--; - } - - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) { - fprintf(ctx->debug_stream, - "PDKIM >> Raw signature w/o b= tag value >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); - pdkim_quoteprint(ctx->debug_stream, - sig->rawsig_no_b_val, - strlen(sig->rawsig_no_b_val), 1); - fprintf(ctx->debug_stream, - "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); - } - #endif - - sig->sha1_body = malloc(sizeof(sha1_context)); - if (sig->sha1_body == NULL) { - pdkim_free_sig(sig); - return NULL; - } - sig->sha2_body = malloc(sizeof(sha2_context)); - if (sig->sha2_body == NULL) { - pdkim_free_sig(sig); - return NULL; - } - - sha1_starts(sig->sha1_body); - sha2_starts(sig->sha2_body,0); - - return sig; -} - - -/* -------------------------------------------------------------------------- */ -pdkim_pubkey *pdkim_parse_pubkey_record(pdkim_ctx *ctx, char *raw_record) { - pdkim_pubkey *pub ; - char *p; - pdkim_str *cur_tag = NULL; - pdkim_str *cur_val = NULL; - int where = PDKIM_HDR_LIMBO; - - pub = malloc(sizeof(pdkim_pubkey)); - if (pub == NULL) return NULL; - memset(pub,0,sizeof(pdkim_pubkey)); - - p = raw_record; - - while (1) { - - /* Ignore FWS */ - if ( (*p == '\r') || (*p == '\n') ) - goto NEXT_CHAR; - - if (where == PDKIM_HDR_LIMBO) { - /* In limbo, just wait for a tag-char to appear */ - if (!((*p >= 'a') && (*p <= 'z'))) - goto NEXT_CHAR; - - where = PDKIM_HDR_TAG; - } - - if (where == PDKIM_HDR_TAG) { - if (cur_tag == NULL) - cur_tag = pdkim_strnew(NULL); - - if ((*p >= 'a') && (*p <= 'z')) - pdkim_strncat(cur_tag,p,1); - - if (*p == '=') { - where = PDKIM_HDR_VALUE; - goto NEXT_CHAR; - } - } - - if (where == PDKIM_HDR_VALUE) { - if (cur_val == NULL) - cur_val = pdkim_strnew(NULL); - - if ( (*p == '\r') || (*p == '\n') ) - goto NEXT_CHAR; - - if ( (*p == ';') || (*p == '\0') ) { - if (cur_tag->len > 0) { - pdkim_strtrim(cur_val); - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) - fprintf(ctx->debug_stream, "%s=%s\n", cur_tag->str, cur_val->str); - #endif - switch (cur_tag->str[0]) { - case 'v': - /* This tag isn't evaluated because: - - We only support version DKIM1. - - Which is the default for this value (set below) - - Other versions are currently not specified. */ - break; - case 'h': - pub->hashes = strdup(cur_val->str); - break; - case 'g': - pub->granularity = strdup(cur_val->str); - break; - case 'n': - pub->notes = pdkim_decode_qp(cur_val->str); - break; - case 'p': - pub->key = pdkim_decode_base64(cur_val->str,&(pub->key_len)); - break; - case 'k': - pub->hashes = strdup(cur_val->str); - break; - case 's': - pub->srvtype = strdup(cur_val->str); - break; - case 't': - if (strchr(cur_val->str,'y') != NULL) pub->testing = 1; - if (strchr(cur_val->str,'s') != NULL) pub->no_subdomaining = 1; - break; - default: - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) - fprintf(ctx->debug_stream, "Unknown tag encountered\n"); - #endif - break; - } - } - pdkim_strclear(cur_tag); - pdkim_strclear(cur_val); - where = PDKIM_HDR_LIMBO; - goto NEXT_CHAR; - } - else pdkim_strncat(cur_val,p,1); - } - - NEXT_CHAR: - if (*p == '\0') break; - p++; - } - - /* Set fallback defaults */ - if (pub->version == NULL) pub->version = strdup(PDKIM_PUB_RECORD_VERSION); - if (pub->granularity == NULL) pub->granularity = strdup("*"); - if (pub->keytype == NULL) pub->keytype = strdup("rsa"); - if (pub->srvtype == NULL) pub->srvtype = strdup("*"); - - /* p= is required */ - if (pub->key == NULL) { - pdkim_free_pubkey(pub); - return NULL; - } - - return pub; -} - - -/* -------------------------------------------------------------------------- */ -int pdkim_update_bodyhash(pdkim_ctx *ctx, const char *data, int len) { - pdkim_signature *sig = ctx->sig; - /* Cache relaxed version of data */ - char *relaxed_data = NULL; - int relaxed_len = 0; - - /* Traverse all signatures, updating their hashes. */ - while (sig != NULL) { - /* Defaults to simple canon (no further treatment necessary) */ - const char *canon_data = data; - int canon_len = len; - - if (sig->canon_body == PDKIM_CANON_RELAXED) { - /* Relax the line if not done already */ - if (relaxed_data == NULL) { - int seen_wsp = 0; - const char *p = data; - int q = 0; - relaxed_data = malloc(len+1); - if (relaxed_data == NULL) return PDKIM_ERR_OOM; - while (*p != '\0') { - char c = *p; - if (c == '\r') { - if ( (q > 0) && (relaxed_data[q-1] == ' ') ) q--; - } - else if ( (c == '\t') || (c == ' ') ) { - c = ' '; /* Turns WSP into SP */ - if (seen_wsp) { - p++; - continue; - } - else seen_wsp = 1; - } - else seen_wsp = 0; - relaxed_data[q++] = c; - p++; - } - relaxed_data[q] = '\0'; - relaxed_len = q; - } - canon_data = relaxed_data; - canon_len = relaxed_len; - } - - /* Make sure we don't exceed the to-be-signed body length */ - if ((sig->bodylength >= 0) && - ((sig->signed_body_bytes+(unsigned long)canon_len) > sig->bodylength)) - canon_len = (sig->bodylength - sig->signed_body_bytes); - - if (canon_len > 0) { - if (sig->algo == PDKIM_ALGO_RSA_SHA1) - sha1_update(sig->sha1_body,(unsigned char *)canon_data,canon_len); - else - sha2_update(sig->sha2_body,(unsigned char *)canon_data,canon_len); - sig->signed_body_bytes += canon_len; -#ifdef PDKIM_DEBUG - if (ctx->debug_stream!=NULL) - pdkim_quoteprint(ctx->debug_stream,canon_data,canon_len,0); -#endif - } - - sig = sig->next; - } - - if (relaxed_data != NULL) free(relaxed_data); - return PDKIM_OK; -} - - -/* -------------------------------------------------------------------------- */ -int pdkim_finish_bodyhash(pdkim_ctx *ctx) { - pdkim_signature *sig = ctx->sig; - - /* Traverse all signatures */ - while (sig != NULL) { - - /* Finish hashes */ - unsigned char bh[32]; /* SHA-256 = 32 Bytes, SHA-1 = 20 Bytes */ - if (sig->algo == PDKIM_ALGO_RSA_SHA1) - sha1_finish(sig->sha1_body,bh); - else - sha2_finish(sig->sha2_body,bh); - - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) { - fprintf(ctx->debug_stream, "PDKIM [%s] Body bytes hashed: %lu\n", - sig->domain, sig->signed_body_bytes); - fprintf(ctx->debug_stream, "PDKIM [%s] bh computed: ", sig->domain); - pdkim_hexprint(ctx->debug_stream, (char *)bh, - (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32,1); - } - #endif - - /* SIGNING -------------------------------------------------------------- */ - if (ctx->mode == PDKIM_MODE_SIGN) { - sig->bodyhash_len = (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32; - sig->bodyhash = malloc(sig->bodyhash_len); - if (sig->bodyhash == NULL) return PDKIM_ERR_OOM; - memcpy(sig->bodyhash,bh,sig->bodyhash_len); - - /* If bodylength limit is set, and we have received less bytes - than the requested amount, effectively remove the limit tag. */ - if (sig->signed_body_bytes < sig->bodylength) sig->bodylength = -1; - } - /* VERIFICATION --------------------------------------------------------- */ - else { - /* Compare bodyhash */ - if (memcmp(bh,sig->bodyhash, - (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32) == 0) { - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) - fprintf(ctx->debug_stream, "PDKIM [%s] Body hash verified OK\n", - sig->domain); - #endif - } - else { - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) { - fprintf(ctx->debug_stream, "PDKIM [%s] Body hash did NOT verify\n", - sig->domain); - fprintf(ctx->debug_stream, "PDKIM [%s] bh signature: ", sig->domain); - pdkim_hexprint(ctx->debug_stream, sig->bodyhash, - (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32,1); - } - #endif - sig->verify_status = PDKIM_VERIFY_FAIL; - sig->verify_ext_status = PDKIM_VERIFY_FAIL_BODY; - } - } - - sig = sig->next; - } - - return PDKIM_OK; -} - - - -/* -------------------------------------------------------------------------- */ -/* Callback from pdkim_feed below for processing complete body lines */ -int pdkim_bodyline_complete(pdkim_ctx *ctx) { - char *p = ctx->linebuf; - int n = ctx->linebuf_offset; - - /* Ignore extra data if we've seen the end-of-data marker */ - if (ctx->seen_eod) goto BAIL; - - /* We've always got one extra byte to stuff a zero ... */ - ctx->linebuf[(ctx->linebuf_offset)] = '\0'; - - if (ctx->input_mode == PDKIM_INPUT_SMTP) { - /* Terminate on EOD marker */ - if (memcmp(p,".\r\n",3) == 0) { - ctx->seen_eod = 1; - goto BAIL; - } - /* Unstuff dots */ - if (memcmp(p,"..",2) == 0) { - p++; - n--; - } - } - - /* Empty lines need to be buffered until we find a non-empty line */ - if (memcmp(p,"\r\n",2) == 0) { - ctx->num_buffered_crlf++; - goto BAIL; - } - - /* At this point, we have a non-empty line, so release the buffered ones. */ - while (ctx->num_buffered_crlf) { - pdkim_update_bodyhash(ctx,"\r\n",2); - ctx->num_buffered_crlf--; - } - - pdkim_update_bodyhash(ctx,p,n); - - BAIL: - ctx->linebuf_offset = 0; - return PDKIM_OK; -} - - -/* -------------------------------------------------------------------------- */ -/* Callback from pdkim_feed below for processing complete headers */ -#define DKIM_SIGNATURE_HEADERNAME "DKIM-Signature:" -int pdkim_header_complete(pdkim_ctx *ctx) { - pdkim_signature *sig = ctx->sig; - - /* Special case: The last header can have an extra \r appended */ - if ( (ctx->cur_header->len > 1) && - (ctx->cur_header->str[(ctx->cur_header->len)-1] == '\r') ) { - ctx->cur_header->str[(ctx->cur_header->len)-1] = '\0'; - ctx->cur_header->len--; - } - - ctx->num_headers++; - if (ctx->num_headers > PDKIM_MAX_HEADERS) goto BAIL; - - /* SIGNING -------------------------------------------------------------- */ - if (ctx->mode == PDKIM_MODE_SIGN) { - /* Traverse all signatures */ - while (sig != NULL) { - pdkim_stringlist *list; - - if (header_name_match(ctx->cur_header->str, - sig->sign_headers? - sig->sign_headers: - PDKIM_DEFAULT_SIGN_HEADERS, 0) != PDKIM_OK) goto NEXT_SIG; - - /* Add header to the signed headers list (in reverse order) */ - list = pdkim_prepend_stringlist(sig->headers, - ctx->cur_header->str); - if (list == NULL) return PDKIM_ERR_OOM; - sig->headers = list; - - NEXT_SIG: - sig = sig->next; - } - } - - /* DKIM-Signature: headers are added to the verification list */ - if (ctx->mode == PDKIM_MODE_VERIFY) { - if (strncasecmp(ctx->cur_header->str, - DKIM_SIGNATURE_HEADERNAME, - strlen(DKIM_SIGNATURE_HEADERNAME)) == 0) { - pdkim_signature *new_sig; - /* Create and chain new signature block */ - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) - fprintf(ctx->debug_stream, - "PDKIM >> Found sig, trying to parse >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); - #endif - new_sig = pdkim_parse_sig_header(ctx, ctx->cur_header->str); - if (new_sig != NULL) { - pdkim_signature *last_sig = ctx->sig; - if (last_sig == NULL) { - ctx->sig = new_sig; - } - else { - while (last_sig->next != NULL) { last_sig = last_sig->next; } - last_sig->next = new_sig; - } - } - else { - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) { - fprintf(ctx->debug_stream,"Error while parsing signature header\n"); - fprintf(ctx->debug_stream, - "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); - } - #endif - } - } - /* every other header is stored for signature verification */ - else { - pdkim_stringlist *list; - - list = pdkim_prepend_stringlist(ctx->headers, - ctx->cur_header->str); - if (list == NULL) return PDKIM_ERR_OOM; - ctx->headers = list; - } - } - - BAIL: - pdkim_strclear(ctx->cur_header); /* Re-use existing pdkim_str */ - return PDKIM_OK; -} - - - -/* -------------------------------------------------------------------------- */ -#define HEADER_BUFFER_FRAG_SIZE 256 -DLLEXPORT int pdkim_feed (pdkim_ctx *ctx, - char *data, - int len) { - int p; - for (p=0;ppast_headers) { - /* Processing body byte */ - ctx->linebuf[(ctx->linebuf_offset)++] = c; - if (c == '\n') { - int rc = pdkim_bodyline_complete(ctx); /* End of line */ - if (rc != PDKIM_OK) return rc; - } - if (ctx->linebuf_offset == (PDKIM_MAX_BODY_LINE_LEN-1)) - return PDKIM_ERR_LONG_LINE; - } - else { - /* Processing header byte */ - if (c != '\r') { - if (c == '\n') { - if (ctx->seen_lf) { - int rc = pdkim_header_complete(ctx); /* Seen last header line */ - if (rc != PDKIM_OK) return rc; - ctx->past_headers = 1; - ctx->seen_lf = 0; -#ifdef PDKIM_DEBUG - if (ctx->debug_stream) - fprintf(ctx->debug_stream, - "PDKIM >> Hashed body data, canonicalized >>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); -#endif - continue; - } - else ctx->seen_lf = 1; - } - else if (ctx->seen_lf) { - if (! ((c == '\t') || (c == ' '))) { - int rc = pdkim_header_complete(ctx); /* End of header */ - if (rc != PDKIM_OK) return rc; - } - ctx->seen_lf = 0; - } - } - if (ctx->cur_header == NULL) { - ctx->cur_header = pdkim_strnew(NULL); - if (ctx->cur_header == NULL) return PDKIM_ERR_OOM; - } - if (ctx->cur_header->len < PDKIM_MAX_HEADER_LEN) - if (pdkim_strncat(ctx->cur_header,&data[p],1) == NULL) - return PDKIM_ERR_OOM; - } - } - return PDKIM_OK; -} - - -/* -------------------------------------------------------------------------- */ -char *pdkim_create_header(pdkim_signature *sig, int final) { - char *rc = NULL; - char *base64_bh = NULL; - char *base64_b = NULL; - pdkim_str *hdr = pdkim_strnew("DKIM-Signature: v="PDKIM_SIGNATURE_VERSION); - if (hdr == NULL) return NULL; - - base64_bh = pdkim_encode_base64(sig->bodyhash, sig->bodyhash_len); - if (base64_bh == NULL) goto BAIL; - - /* Required and static bits */ - if ( - pdkim_strcat(hdr,"; a=") && - pdkim_strcat(hdr,pdkim_algos[sig->algo]) && - pdkim_strcat(hdr,"; q=") && - pdkim_strcat(hdr,pdkim_querymethods[sig->querymethod]) && - pdkim_strcat(hdr,"; c=") && - pdkim_strcat(hdr,pdkim_canons[sig->canon_headers]) && - pdkim_strcat(hdr,"/") && - pdkim_strcat(hdr,pdkim_canons[sig->canon_body]) && - pdkim_strcat(hdr,"; d=") && - pdkim_strcat(hdr,sig->domain) && - pdkim_strcat(hdr,"; s=") && - pdkim_strcat(hdr,sig->selector) && - pdkim_strcat(hdr,";\r\n\th=") && - pdkim_strcat(hdr,sig->headernames) && - pdkim_strcat(hdr,"; bh=") && - pdkim_strcat(hdr,base64_bh) && - pdkim_strcat(hdr,";\r\n\t") - ) { - /* Optional bits */ - if (sig->identity != NULL) { - if (!( pdkim_strcat(hdr,"i=") && - pdkim_strcat(hdr,sig->identity) && - pdkim_strcat(hdr,";") ) ) { - goto BAIL; - } - } - if (sig->created > 0) { - if (!( pdkim_strcat(hdr,"t=") && - pdkim_numcat(hdr,sig->created) && - pdkim_strcat(hdr,";") ) ) { - goto BAIL; - } - } - if (sig->expires > 0) { - if (!( pdkim_strcat(hdr,"x=") && - pdkim_numcat(hdr,sig->expires) && - pdkim_strcat(hdr,";") ) ) { - goto BAIL; - } - } - if (sig->bodylength >= 0) { - if (!( pdkim_strcat(hdr,"l=") && - pdkim_numcat(hdr,sig->bodylength) && - pdkim_strcat(hdr,";") ) ) { - goto BAIL; - } - } - /* Extra linebreak */ - if (hdr->str[(hdr->len)-1] == ';') { - if (!pdkim_strcat(hdr," \r\n\t")) goto BAIL; - } - /* Preliminary or final version? */ - if (final) { - base64_b = pdkim_encode_base64(sig->sigdata, sig->sigdata_len); - if (base64_b == NULL) goto BAIL; - if ( - pdkim_strcat(hdr,"b=") && - pdkim_strcat(hdr,base64_b) && - pdkim_strcat(hdr,";") - ) goto DONE; - } - else { - if (pdkim_strcat(hdr,"b=;")) goto DONE; - } - - goto BAIL; - } - - DONE: - rc = strdup(hdr->str); - - BAIL: - pdkim_strfree(hdr); - if (base64_bh != NULL) free(base64_bh); - if (base64_b != NULL) free(base64_b); - return rc; -} - - -/* -------------------------------------------------------------------------- */ -DLLEXPORT int pdkim_feed_finish(pdkim_ctx *ctx, pdkim_signature **return_signatures) { - pdkim_signature *sig = ctx->sig; - pdkim_str *headernames = NULL; /* Collected signed header names */ - - /* Check if we must still flush a (partial) header. If that is the - case, the message has no body, and we must compute a body hash - out of '' */ - if (ctx->cur_header && ctx->cur_header->len) { - int rc = pdkim_header_complete(ctx); - if (rc != PDKIM_OK) return rc; - pdkim_update_bodyhash(ctx,"\r\n",2); - } - else { - /* For non-smtp input, check if there's an unfinished line in the - body line buffer. If that is the case, we must add a CRLF to the - hash to properly terminate the message. */ - if ((ctx->input_mode == PDKIM_INPUT_NORMAL) && ctx->linebuf_offset) { - pdkim_update_bodyhash(ctx, ctx->linebuf, ctx->linebuf_offset); - pdkim_update_bodyhash(ctx,"\r\n",2); - } - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) - fprintf(ctx->debug_stream, - "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); - #endif - } - - /* Build (and/or evaluate) body hash */ - if (pdkim_finish_bodyhash(ctx) != PDKIM_OK) return PDKIM_ERR_OOM; - - /* SIGNING -------------------------------------------------------------- */ - if (ctx->mode == PDKIM_MODE_SIGN) { - headernames = pdkim_strnew(NULL); - if (headernames == NULL) return PDKIM_ERR_OOM; - } - /* ---------------------------------------------------------------------- */ - - while (sig != NULL) { - sha1_context sha1_headers; - sha2_context sha2_headers; - char *sig_hdr; - char headerhash[32]; - - if (sig->algo == PDKIM_ALGO_RSA_SHA1) - sha1_starts(&sha1_headers); - else - sha2_starts(&sha2_headers,0); - - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) - fprintf(ctx->debug_stream, - "PDKIM >> Hashed header data, canonicalized, in sequence >>>>>>>>>>>>>>\n"); - #endif - - /* SIGNING ---------------------------------------------------------------- */ - /* When signing, walk through our header list and add them to the hash. As we - go, construct a list of the header's names to use for the h= parameter. */ - if (ctx->mode == PDKIM_MODE_SIGN) { - pdkim_stringlist *p = sig->headers; - while (p != NULL) { - char *rh = NULL; - /* Collect header names (Note: colon presence is guaranteed here) */ - char *q = strchr(p->value,':'); - if (pdkim_strncat(headernames, p->value, - (q-(p->value))+((p->next==NULL)?0:1)) == NULL) - return PDKIM_ERR_OOM; - - if (sig->canon_headers == PDKIM_CANON_RELAXED) - rh = pdkim_relax_header(p->value,1); /* cook header for relaxed canon */ - else - rh = strdup(p->value); /* just copy it for simple canon */ - - if (rh == NULL) return PDKIM_ERR_OOM; - - /* Feed header to the hash algorithm */ - if (sig->algo == PDKIM_ALGO_RSA_SHA1) - sha1_update(&(sha1_headers),(unsigned char *)rh,strlen(rh)); - else - sha2_update(&(sha2_headers),(unsigned char *)rh,strlen(rh)); - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) - pdkim_quoteprint(ctx->debug_stream, rh, strlen(rh), 1); - #endif - free(rh); - p = p->next; - } - } - /* VERIFICATION ----------------------------------------------------------- */ - /* When verifying, walk through the header name list in the h= parameter and - add the headers to the hash in that order. */ - else { - char *b = strdup(sig->headernames); - char *p = b; - char *q = NULL; - pdkim_stringlist *hdrs = ctx->headers; - - if (b == NULL) return PDKIM_ERR_OOM; - - /* clear tags */ - while (hdrs != NULL) { - hdrs->tag = 0; - hdrs = hdrs->next; - } - - while(1) { - hdrs = ctx->headers; - q = strchr(p,':'); - if (q != NULL) *q = '\0'; - while (hdrs != NULL) { - if ( (hdrs->tag == 0) && - (strncasecmp(hdrs->value,p,strlen(p)) == 0) && - ((hdrs->value)[strlen(p)] == ':') ) { - char *rh = NULL; - if (sig->canon_headers == PDKIM_CANON_RELAXED) - rh = pdkim_relax_header(hdrs->value,1); /* cook header for relaxed canon */ - else - rh = strdup(hdrs->value); /* just copy it for simple canon */ - if (rh == NULL) return PDKIM_ERR_OOM; - /* Feed header to the hash algorithm */ - if (sig->algo == PDKIM_ALGO_RSA_SHA1) - sha1_update(&(sha1_headers),(unsigned char *)rh,strlen(rh)); - else - sha2_update(&(sha2_headers),(unsigned char *)rh,strlen(rh)); - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) - pdkim_quoteprint(ctx->debug_stream, rh, strlen(rh), 1); - #endif - free(rh); - hdrs->tag = 1; - break; - } - hdrs = hdrs->next; - } - if (q == NULL) break; - p = q+1; - } - free(b); - } - - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) - fprintf(ctx->debug_stream, - "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); - #endif - - /* SIGNING ---------------------------------------------------------------- */ - if (ctx->mode == PDKIM_MODE_SIGN) { - /* Copy headernames to signature struct */ - sig->headernames = strdup(headernames->str); - pdkim_strfree(headernames); - - /* Create signature header with b= omitted */ - sig_hdr = pdkim_create_header(ctx->sig,0); - } - /* VERIFICATION ----------------------------------------------------------- */ - else { - sig_hdr = strdup(sig->rawsig_no_b_val); - } - /* ------------------------------------------------------------------------ */ - - if (sig_hdr == NULL) return PDKIM_ERR_OOM; - - /* Relax header if necessary */ - if (sig->canon_headers == PDKIM_CANON_RELAXED) { - char *relaxed_hdr = pdkim_relax_header(sig_hdr,0); - free(sig_hdr); - if (relaxed_hdr == NULL) return PDKIM_ERR_OOM; - sig_hdr = relaxed_hdr; - } - - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) { - fprintf(ctx->debug_stream, - "PDKIM >> Signed DKIM-Signature header, canonicalized >>>>>>>>>>>>>>>>>\n"); - pdkim_quoteprint(ctx->debug_stream, sig_hdr, strlen(sig_hdr), 1); - fprintf(ctx->debug_stream, - "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); - } - #endif - - /* Finalize header hash */ - if (sig->algo == PDKIM_ALGO_RSA_SHA1) { - sha1_update(&(sha1_headers),(unsigned char *)sig_hdr,strlen(sig_hdr)); - sha1_finish(&(sha1_headers),(unsigned char *)headerhash); - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) { - fprintf(ctx->debug_stream, "PDKIM [%s] hh computed: ", sig->domain); - pdkim_hexprint(ctx->debug_stream, headerhash, 20, 1); - } - #endif - } - else { - sha2_update(&(sha2_headers),(unsigned char *)sig_hdr,strlen(sig_hdr)); - sha2_finish(&(sha2_headers),(unsigned char *)headerhash); - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) { - fprintf(ctx->debug_stream, "PDKIM [%s] hh computed: ", sig->domain); - pdkim_hexprint(ctx->debug_stream, headerhash, 32, 1); - } - #endif - } - - free(sig_hdr); - - /* SIGNING ---------------------------------------------------------------- */ - if (ctx->mode == PDKIM_MODE_SIGN) { - rsa_context rsa; - - rsa_init(&rsa,RSA_PKCS_V15,0); - - /* Perform private key operation */ - if (rsa_parse_key(&rsa, (unsigned char *)sig->rsa_privkey, - strlen(sig->rsa_privkey), NULL, 0) != 0) { - return PDKIM_ERR_RSA_PRIVKEY; - } - - sig->sigdata_len = mpi_size(&(rsa.N)); - sig->sigdata = malloc(sig->sigdata_len); - if (sig->sigdata == NULL) return PDKIM_ERR_OOM; - - if (rsa_pkcs1_sign( &rsa, RSA_PRIVATE, - ((sig->algo == PDKIM_ALGO_RSA_SHA1)? - SIG_RSA_SHA1:SIG_RSA_SHA256), - 0, - (unsigned char *)headerhash, - (unsigned char *)sig->sigdata ) != 0) { - return PDKIM_ERR_RSA_SIGNING; - } - - rsa_free(&rsa); - - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) { - fprintf(ctx->debug_stream, "PDKIM [%s] b computed: ", - sig->domain); - pdkim_hexprint(ctx->debug_stream, sig->sigdata, sig->sigdata_len, 1); - } - #endif - - sig->signature_header = pdkim_create_header(ctx->sig,1); - if (sig->signature_header == NULL) return PDKIM_ERR_OOM; - } - /* VERIFICATION ----------------------------------------------------------- */ - else { - rsa_context rsa; - char *dns_txt_name, *dns_txt_reply; - - rsa_init(&rsa,RSA_PKCS_V15,0); - - dns_txt_name = malloc(PDKIM_DNS_TXT_MAX_NAMELEN); - if (dns_txt_name == NULL) return PDKIM_ERR_OOM; - dns_txt_reply = malloc(PDKIM_DNS_TXT_MAX_RECLEN); - if (dns_txt_reply == NULL) { - free(dns_txt_name); - return PDKIM_ERR_OOM; - } - memset(dns_txt_reply,0,PDKIM_DNS_TXT_MAX_RECLEN); - memset(dns_txt_name ,0,PDKIM_DNS_TXT_MAX_NAMELEN); - - if (snprintf(dns_txt_name,PDKIM_DNS_TXT_MAX_NAMELEN, - "%s._domainkey.%s.", - sig->selector,sig->domain) >= PDKIM_DNS_TXT_MAX_NAMELEN) { - sig->verify_status = PDKIM_VERIFY_INVALID; - sig->verify_ext_status = PDKIM_VERIFY_INVALID_BUFFER_SIZE; - goto NEXT_VERIFY; - } - - if ((ctx->dns_txt_callback(dns_txt_name, dns_txt_reply) != PDKIM_OK) || - (dns_txt_reply[0] == '\0')) { - sig->verify_status = PDKIM_VERIFY_INVALID; - sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE; - goto NEXT_VERIFY; - } - - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) { - fprintf(ctx->debug_stream, - "PDKIM >> Parsing public key record >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); - fprintf(ctx->debug_stream,"Raw record: "); - pdkim_quoteprint(ctx->debug_stream, dns_txt_reply, strlen(dns_txt_reply), 1); - } - #endif - - sig->pubkey = pdkim_parse_pubkey_record(ctx,dns_txt_reply); - if (sig->pubkey == NULL) { - sig->verify_status = PDKIM_VERIFY_INVALID; - sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_PARSING; - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) { - fprintf(ctx->debug_stream,"Error while parsing public key record\n"); - fprintf(ctx->debug_stream, - "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); - } - #endif - goto NEXT_VERIFY; - } - - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) { - fprintf(ctx->debug_stream, - "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); - } - #endif - - if (rsa_parse_public_key(&rsa, - (unsigned char *)sig->pubkey->key, - sig->pubkey->key_len) != 0) { - sig->verify_status = PDKIM_VERIFY_INVALID; - sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_PARSING; - goto NEXT_VERIFY; - } - - /* Check the signature */ - if (rsa_pkcs1_verify(&rsa, - RSA_PUBLIC, - ((sig->algo == PDKIM_ALGO_RSA_SHA1)? - SIG_RSA_SHA1:SIG_RSA_SHA256), - 0, - (unsigned char *)headerhash, - (unsigned char *)sig->sigdata) != 0) { - sig->verify_status = PDKIM_VERIFY_FAIL; - sig->verify_ext_status = PDKIM_VERIFY_FAIL_MESSAGE; - goto NEXT_VERIFY; - } - - /* We have a winner! (if bodydhash was correct earlier) */ - if (sig->verify_status == PDKIM_VERIFY_NONE) { - sig->verify_status = PDKIM_VERIFY_PASS; - } - - NEXT_VERIFY: - - #ifdef PDKIM_DEBUG - if (ctx->debug_stream) { - fprintf(ctx->debug_stream, "PDKIM [%s] signature status: %s", - sig->domain, pdkim_verify_status_str(sig->verify_status)); - if (sig->verify_ext_status > 0) { - fprintf(ctx->debug_stream, " (%s)\n", - pdkim_verify_ext_status_str(sig->verify_ext_status)); - } - else { - fprintf(ctx->debug_stream, "\n"); - } - } - #endif - - rsa_free(&rsa); - free(dns_txt_name); - free(dns_txt_reply); - } - - sig = sig->next; - } - - /* If requested, set return pointer to signature(s) */ - if (return_signatures != NULL) { - *return_signatures = ctx->sig; - } - - return PDKIM_OK; -} - - -/* -------------------------------------------------------------------------- */ -DLLEXPORT pdkim_ctx *pdkim_init_verify(int input_mode, - int(*dns_txt_callback)(char *, char *) - ) { - pdkim_ctx *ctx = malloc(sizeof(pdkim_ctx)); - if (ctx == NULL) return NULL; - memset(ctx,0,sizeof(pdkim_ctx)); - - ctx->linebuf = malloc(PDKIM_MAX_BODY_LINE_LEN); - if (ctx->linebuf == NULL) { - free(ctx); - return NULL; - } - - ctx->mode = PDKIM_MODE_VERIFY; - ctx->input_mode = input_mode; - ctx->dns_txt_callback = dns_txt_callback; - - return ctx; -} - - -/* -------------------------------------------------------------------------- */ -DLLEXPORT pdkim_ctx *pdkim_init_sign(int input_mode, - char *domain, - char *selector, - char *rsa_privkey) { - pdkim_ctx *ctx; - pdkim_signature *sig; - - if (!domain || !selector || !rsa_privkey) return NULL; - - ctx = malloc(sizeof(pdkim_ctx)); - if (ctx == NULL) return NULL; - memset(ctx,0,sizeof(pdkim_ctx)); - - ctx->linebuf = malloc(PDKIM_MAX_BODY_LINE_LEN); - if (ctx->linebuf == NULL) { - free(ctx); - return NULL; - } - - sig = malloc(sizeof(pdkim_signature)); - if (sig == NULL) { - free(ctx->linebuf); - free(ctx); - return NULL; - } - memset(sig,0,sizeof(pdkim_signature)); - sig->bodylength = -1; - - ctx->mode = PDKIM_MODE_SIGN; - ctx->input_mode = input_mode; - ctx->sig = sig; - - ctx->sig->domain = strdup(domain); - ctx->sig->selector = strdup(selector); - ctx->sig->rsa_privkey = strdup(rsa_privkey); - - if (!ctx->sig->domain || !ctx->sig->selector || !ctx->sig->rsa_privkey) { - pdkim_free_ctx(ctx); - return NULL; - } - - ctx->sig->sha1_body = malloc(sizeof(sha1_context)); - if (ctx->sig->sha1_body == NULL) { - pdkim_free_ctx(ctx); - return NULL; - } - sha1_starts(ctx->sig->sha1_body); - - ctx->sig->sha2_body = malloc(sizeof(sha2_context)); - if (ctx->sig->sha2_body == NULL) { - pdkim_free_ctx(ctx); - return NULL; - } - sha2_starts(ctx->sig->sha2_body,0); - - return ctx; -} - -#ifdef PDKIM_DEBUG -/* -------------------------------------------------------------------------- */ -DLLEXPORT void pdkim_set_debug_stream(pdkim_ctx *ctx, - FILE *debug_stream) { - ctx->debug_stream = debug_stream; -} -#endif - -/* -------------------------------------------------------------------------- */ -DLLEXPORT int pdkim_set_optional(pdkim_ctx *ctx, - char *sign_headers, - char *identity, - int canon_headers, - int canon_body, - long bodylength, - int algo, - unsigned long created, - unsigned long expires) { - - if (identity != NULL) { - ctx->sig->identity = strdup(identity); - if (ctx->sig->identity == NULL) return PDKIM_ERR_OOM; - } - - if (sign_headers != NULL) { - ctx->sig->sign_headers = strdup(sign_headers); - if (ctx->sig->sign_headers == NULL) return PDKIM_ERR_OOM; - } - - ctx->sig->canon_headers = canon_headers; - ctx->sig->canon_body = canon_body; - ctx->sig->bodylength = bodylength; - ctx->sig->algo = algo; - ctx->sig->created = created; - ctx->sig->expires = expires; - - return PDKIM_OK; -} +/* + * PDKIM - a RFC4871 (DKIM) implementation + * + * Copyright (C) 2009 - 2016 Tom Kistner + * Copyright (C) 2016 - 2017 Jeremy Harris + * + * http://duncanthrax.net/pdkim/ + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include "../exim.h" + + +#ifndef DISABLE_DKIM /* entire file */ + +#ifndef SUPPORT_TLS +# error Need SUPPORT_TLS for DKIM +#endif + +#include "crypt_ver.h" + +#ifdef RSA_OPENSSL +# include +# include +# include +#elif defined(RSA_GNUTLS) +# include +# include +#endif + +#include "pdkim.h" +#include "rsa.h" + +#define PDKIM_SIGNATURE_VERSION "1" +#define PDKIM_PUB_RECORD_VERSION US "DKIM1" + +#define PDKIM_MAX_HEADER_LEN 65536 +#define PDKIM_MAX_HEADERS 512 +#define PDKIM_MAX_BODY_LINE_LEN 16384 +#define PDKIM_DNS_TXT_MAX_NAMELEN 1024 +#define PDKIM_DEFAULT_SIGN_HEADERS "From:Sender:Reply-To:Subject:Date:"\ + "Message-ID:To:Cc:MIME-Version:Content-Type:"\ + "Content-Transfer-Encoding:Content-ID:"\ + "Content-Description:Resent-Date:Resent-From:"\ + "Resent-Sender:Resent-To:Resent-Cc:"\ + "Resent-Message-ID:In-Reply-To:References:"\ + "List-Id:List-Help:List-Unsubscribe:"\ + "List-Subscribe:List-Post:List-Owner:List-Archive" + +/* -------------------------------------------------------------------------- */ +struct pdkim_stringlist { + uschar * value; + int tag; + void * next; +}; + +/* -------------------------------------------------------------------------- */ +/* A bunch of list constants */ +const uschar * pdkim_querymethods[] = { + US"dns/txt", + NULL +}; +const uschar * pdkim_algos[] = { + US"rsa-sha256", + US"rsa-sha1", + NULL +}; +const uschar * pdkim_canons[] = { + US"simple", + US"relaxed", + NULL +}; +const uschar * pdkim_hashes[] = { + US"sha256", + US"sha1", + NULL +}; +const uschar * pdkim_keytypes[] = { + US"rsa", + NULL +}; + +typedef struct pdkim_combined_canon_entry { + const uschar * str; + int canon_headers; + int canon_body; +} pdkim_combined_canon_entry; + +pdkim_combined_canon_entry pdkim_combined_canons[] = { + { US"simple/simple", PDKIM_CANON_SIMPLE, PDKIM_CANON_SIMPLE }, + { US"simple/relaxed", PDKIM_CANON_SIMPLE, PDKIM_CANON_RELAXED }, + { US"relaxed/simple", PDKIM_CANON_RELAXED, PDKIM_CANON_SIMPLE }, + { US"relaxed/relaxed", PDKIM_CANON_RELAXED, PDKIM_CANON_RELAXED }, + { US"simple", PDKIM_CANON_SIMPLE, PDKIM_CANON_SIMPLE }, + { US"relaxed", PDKIM_CANON_RELAXED, PDKIM_CANON_SIMPLE }, + { NULL, 0, 0 } +}; + + +/* -------------------------------------------------------------------------- */ + +const char * +pdkim_verify_status_str(int status) +{ +switch(status) + { + case PDKIM_VERIFY_NONE: return "PDKIM_VERIFY_NONE"; + case PDKIM_VERIFY_INVALID: return "PDKIM_VERIFY_INVALID"; + case PDKIM_VERIFY_FAIL: return "PDKIM_VERIFY_FAIL"; + case PDKIM_VERIFY_PASS: return "PDKIM_VERIFY_PASS"; + default: return "PDKIM_VERIFY_UNKNOWN"; + } +} + +const char * +pdkim_verify_ext_status_str(int ext_status) +{ +switch(ext_status) + { + case PDKIM_VERIFY_FAIL_BODY: return "PDKIM_VERIFY_FAIL_BODY"; + case PDKIM_VERIFY_FAIL_MESSAGE: return "PDKIM_VERIFY_FAIL_MESSAGE"; + case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: return "PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE"; + case PDKIM_VERIFY_INVALID_BUFFER_SIZE: return "PDKIM_VERIFY_INVALID_BUFFER_SIZE"; + case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: return "PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD"; + case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: return "PDKIM_VERIFY_INVALID_PUBKEY_IMPORT"; + case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: return "PDKIM_VERIFY_INVALID_SIGNATURE_ERROR"; + case PDKIM_VERIFY_INVALID_DKIM_VERSION: return "PDKIM_VERIFY_INVALID_DKIM_VERSION"; + default: return "PDKIM_VERIFY_UNKNOWN"; + } +} + +const char * +pdkim_errstr(int status) +{ +switch(status) + { + case PDKIM_OK: return "OK"; + case PDKIM_FAIL: return "FAIL"; + case PDKIM_ERR_RSA_PRIVKEY: return "RSA_PRIVKEY"; + case PDKIM_ERR_RSA_SIGNING: return "RSA SIGNING"; + case PDKIM_ERR_LONG_LINE: return "RSA_LONG_LINE"; + case PDKIM_ERR_BUFFER_TOO_SMALL: return "BUFFER_TOO_SMALL"; + case PDKIM_SIGN_PRIVKEY_WRAP: return "PRIVKEY_WRAP"; + case PDKIM_SIGN_PRIVKEY_B64D: return "PRIVKEY_B64D"; + default: return "(unknown)"; + } +} + + +/* -------------------------------------------------------------------------- */ +/* Print debugging functions */ +static void +pdkim_quoteprint(const uschar *data, int len) +{ +int i; +for (i = 0; i < len; i++) + { + const int c = data[i]; + switch (c) + { + case ' ' : debug_printf("{SP}"); break; + case '\t': debug_printf("{TB}"); break; + case '\r': debug_printf("{CR}"); break; + case '\n': debug_printf("{LF}"); break; + case '{' : debug_printf("{BO}"); break; + case '}' : debug_printf("{BC}"); break; + default: + if ( (c < 32) || (c > 127) ) + debug_printf("{%02x}", c); + else + debug_printf("%c", c); + break; + } + } +debug_printf("\n"); +} + +static void +pdkim_hexprint(const uschar *data, int len) +{ +int i; +if (data) for (i = 0 ; i < len; i++) debug_printf("%02x", data[i]); +else debug_printf(""); +debug_printf("\n"); +} + + + +static pdkim_stringlist * +pdkim_prepend_stringlist(pdkim_stringlist * base, const uschar * str) +{ +pdkim_stringlist * new_entry = store_get(sizeof(pdkim_stringlist)); + +memset(new_entry, 0, sizeof(pdkim_stringlist)); +new_entry->value = string_copy(str); +if (base) new_entry->next = base; +return new_entry; +} + + + +/* Trim whitespace fore & aft */ + +static void +pdkim_strtrim(uschar * str) +{ +uschar * p = str; +uschar * q = str; +while (*p == '\t' || *p == ' ') p++; /* skip whitespace */ +while (*p) {*q = *p; q++; p++;} /* dump the leading whitespace */ +*q = '\0'; +while (q != str && ( (*q == '\0') || (*q == '\t') || (*q == ' ') ) ) + { /* dump trailing whitespace */ + *q = '\0'; + q--; + } +} + + + +/* -------------------------------------------------------------------------- */ + +DLLEXPORT void +pdkim_free_ctx(pdkim_ctx *ctx) +{ +} + + +/* -------------------------------------------------------------------------- */ +/* Matches the name of the passed raw "header" against + the passed colon-separated "tick", and invalidates + the entry in tick. Returns OK or fail-code */ +/*XXX might be safer done using a pdkim_stringlist for "tick" */ + +static int +header_name_match(const uschar * header, uschar * tick) +{ +uschar * hname; +uschar * lcopy; +uschar * p; +uschar * q; +uschar * hcolon = Ustrchr(header, ':'); /* Get header name */ + +if (!hcolon) + return PDKIM_FAIL; /* This isn't a header */ + +/* if we had strncmpic() we wouldn't need this copy */ +hname = string_copyn(header, hcolon-header); + +/* Copy tick-off list locally, so we can punch zeroes into it */ +p = lcopy = string_copy(tick); + +for (q = Ustrchr(p, ':'); q; q = Ustrchr(p, ':')) + { + *q = '\0'; + if (strcmpic(p, hname) == 0) + goto found; + + p = q+1; + } + +if (strcmpic(p, hname) == 0) + goto found; + +return PDKIM_FAIL; + +found: + /* Invalidate header name instance in tick-off list */ + tick[p-lcopy] = '_'; + return PDKIM_OK; +} + + +/* -------------------------------------------------------------------------- */ +/* Performs "relaxed" canonicalization of a header. */ + +static uschar * +pdkim_relax_header(const uschar * header, int crlf) +{ +BOOL past_field_name = FALSE; +BOOL seen_wsp = FALSE; +const uschar * p; +uschar * relaxed = store_get(Ustrlen(header)+3); +uschar * q = relaxed; + +for (p = header; *p; p++) + { + uschar c = *p; + /* Ignore CR & LF */ + if (c == '\r' || c == '\n') + continue; + if (c == '\t' || c == ' ') + { + if (seen_wsp) + continue; + c = ' '; /* Turns WSP into SP */ + seen_wsp = TRUE; + } + else + if (!past_field_name && c == ':') + { + if (seen_wsp) q--; /* This removes WSP before the colon */ + seen_wsp = TRUE; /* This removes WSP after the colon */ + past_field_name = TRUE; + } + else + seen_wsp = FALSE; + + /* Lowercase header name */ + if (!past_field_name) c = tolower(c); + *q++ = c; + } + +if (q > relaxed && q[-1] == ' ') q--; /* Squash eventual trailing SP */ + +if (crlf) { *q++ = '\r'; *q++ = '\n'; } +*q = '\0'; +return relaxed; +} + + +/* -------------------------------------------------------------------------- */ +#define PDKIM_QP_ERROR_DECODE -1 + +static uschar * +pdkim_decode_qp_char(uschar *qp_p, int *c) +{ +uschar *initial_pos = qp_p; + +/* Advance one char */ +qp_p++; + +/* Check for two hex digits and decode them */ +if (isxdigit(*qp_p) && isxdigit(qp_p[1])) + { + /* Do hex conversion */ + *c = (isdigit(*qp_p) ? *qp_p - '0' : toupper(*qp_p) - 'A' + 10) << 4; + *c |= isdigit(qp_p[1]) ? qp_p[1] - '0' : toupper(qp_p[1]) - 'A' + 10; + return qp_p + 2; + } + +/* Illegal char here */ +*c = PDKIM_QP_ERROR_DECODE; +return initial_pos; +} + + +/* -------------------------------------------------------------------------- */ + +static uschar * +pdkim_decode_qp(uschar * str) +{ +int nchar = 0; +uschar * q; +uschar * p = str; +uschar * n = store_get(Ustrlen(str)+1); + +*n = '\0'; +q = n; +while (*p) + { + if (*p == '=') + { + p = pdkim_decode_qp_char(p, &nchar); + if (nchar >= 0) + { + *q++ = nchar; + continue; + } + } + else + *q++ = *p; + p++; + } +*q = '\0'; +return n; +} + + +/* -------------------------------------------------------------------------- */ + +static void +pdkim_decode_base64(uschar *str, blob * b) +{ +int dlen; +dlen = b64decode(str, &b->data); +if (dlen < 0) b->data = NULL; +b->len = dlen; +} + +static uschar * +pdkim_encode_base64(blob * b) +{ +return b64encode(b->data, b->len); +} + + +/* -------------------------------------------------------------------------- */ +#define PDKIM_HDR_LIMBO 0 +#define PDKIM_HDR_TAG 1 +#define PDKIM_HDR_VALUE 2 + +static pdkim_signature * +pdkim_parse_sig_header(pdkim_ctx *ctx, uschar * raw_hdr) +{ +pdkim_signature *sig ; +uschar *p, *q; +uschar * cur_tag = NULL; int ts = 0, tl = 0; +uschar * cur_val = NULL; int vs = 0, vl = 0; +BOOL past_hname = FALSE; +BOOL in_b_val = FALSE; +int where = PDKIM_HDR_LIMBO; +int i; + +sig = store_get(sizeof(pdkim_signature)); +memset(sig, 0, sizeof(pdkim_signature)); +sig->bodylength = -1; + +/* Set so invalid/missing data error display is accurate */ +sig->algo = -1; +sig->version = 0; + +q = sig->rawsig_no_b_val = store_get(Ustrlen(raw_hdr)+1); + +for (p = raw_hdr; ; p++) + { + char c = *p; + + /* Ignore FWS */ + if (c == '\r' || c == '\n') + goto NEXT_CHAR; + + /* Fast-forward through header name */ + if (!past_hname) + { + if (c == ':') past_hname = TRUE; + goto NEXT_CHAR; + } + + if (where == PDKIM_HDR_LIMBO) + { + /* In limbo, just wait for a tag-char to appear */ + if (!(c >= 'a' && c <= 'z')) + goto NEXT_CHAR; + + where = PDKIM_HDR_TAG; + } + + if (where == PDKIM_HDR_TAG) + { + if (c >= 'a' && c <= 'z') + cur_tag = string_catn(cur_tag, &ts, &tl, p, 1); + + if (c == '=') + { + cur_tag[tl] = '\0'; + if (Ustrcmp(cur_tag, "b") == 0) + { + *q++ = '='; + in_b_val = TRUE; + } + where = PDKIM_HDR_VALUE; + goto NEXT_CHAR; + } + } + + if (where == PDKIM_HDR_VALUE) + { + if (c == '\r' || c == '\n' || c == ' ' || c == '\t') + goto NEXT_CHAR; + + if (c == ';' || c == '\0') + { + if (tl && vl) + { + cur_val[vl] = '\0'; + pdkim_strtrim(cur_val); + + DEBUG(D_acl) debug_printf(" %s=%s\n", cur_tag, cur_val); + + switch (*cur_tag) + { + case 'b': + pdkim_decode_base64(cur_val, + cur_tag[1] == 'h' ? &sig->bodyhash : &sig->sighash); + break; + case 'v': + /* We only support version 1, and that is currently the + only version there is. */ + sig->version = + Ustrcmp(cur_val, PDKIM_SIGNATURE_VERSION) == 0 ? 1 : -1; + break; + case 'a': + for (i = 0; pdkim_algos[i]; i++) + if (Ustrcmp(cur_val, pdkim_algos[i]) == 0) + { + sig->algo = i; + break; + } + break; + case 'c': + for (i = 0; pdkim_combined_canons[i].str; i++) + if (Ustrcmp(cur_val, pdkim_combined_canons[i].str) == 0) + { + sig->canon_headers = pdkim_combined_canons[i].canon_headers; + sig->canon_body = pdkim_combined_canons[i].canon_body; + break; + } + break; + case 'q': + for (i = 0; pdkim_querymethods[i]; i++) + if (Ustrcmp(cur_val, pdkim_querymethods[i]) == 0) + { + sig->querymethod = i; + break; + } + break; + case 's': + sig->selector = string_copy(cur_val); break; + case 'd': + sig->domain = string_copy(cur_val); break; + case 'i': + sig->identity = pdkim_decode_qp(cur_val); break; + case 't': + sig->created = strtoul(CS cur_val, NULL, 10); break; + case 'x': + sig->expires = strtoul(CS cur_val, NULL, 10); break; + case 'l': + sig->bodylength = strtol(CS cur_val, NULL, 10); break; + case 'h': + sig->headernames = string_copy(cur_val); break; + case 'z': + sig->copiedheaders = pdkim_decode_qp(cur_val); break; + default: + DEBUG(D_acl) debug_printf(" Unknown tag encountered\n"); + break; + } + } + tl = 0; + vl = 0; + in_b_val = FALSE; + where = PDKIM_HDR_LIMBO; + } + else + cur_val = string_catn(cur_val, &vs, &vl, p, 1); + } + +NEXT_CHAR: + if (c == '\0') + break; + + if (!in_b_val) + *q++ = c; + } + +*q = '\0'; +/* Chomp raw header. The final newline must not be added to the signature. */ +while (--q > sig->rawsig_no_b_val && (*q == '\r' || *q == '\n')) + *q = '\0'; + +DEBUG(D_acl) + { + debug_printf( + "PDKIM >> Raw signature w/o b= tag value >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); + pdkim_quoteprint(US sig->rawsig_no_b_val, Ustrlen(sig->rawsig_no_b_val)); + debug_printf( + "PDKIM >> Sig size: %4u bits\n", (unsigned) sig->sighash.len*8); + debug_printf( + "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); + } + +if (!exim_sha_init(&sig->body_hash_ctx, + sig->algo == PDKIM_ALGO_RSA_SHA1 ? HASH_SHA1 : HASH_SHA256)) + { + DEBUG(D_acl) debug_printf("PDKIM: hash init internal error\n"); + return NULL; + } +return sig; +} + + +/* -------------------------------------------------------------------------- */ + +static pdkim_pubkey * +pdkim_parse_pubkey_record(pdkim_ctx *ctx, const uschar *raw_record) +{ +pdkim_pubkey *pub; +const uschar *p; +uschar * cur_tag = NULL; int ts = 0, tl = 0; +uschar * cur_val = NULL; int vs = 0, vl = 0; +int where = PDKIM_HDR_LIMBO; + +pub = store_get(sizeof(pdkim_pubkey)); +memset(pub, 0, sizeof(pdkim_pubkey)); + +for (p = raw_record; ; p++) + { + uschar c = *p; + + /* Ignore FWS */ + if (c != '\r' && c != '\n') switch (where) + { + case PDKIM_HDR_LIMBO: /* In limbo, just wait for a tag-char to appear */ + if (!(c >= 'a' && c <= 'z')) + break; + where = PDKIM_HDR_TAG; + /*FALLTHROUGH*/ + + case PDKIM_HDR_TAG: + if (c >= 'a' && c <= 'z') + cur_tag = string_catn(cur_tag, &ts, &tl, p, 1); + + if (c == '=') + { + cur_tag[tl] = '\0'; + where = PDKIM_HDR_VALUE; + } + break; + + case PDKIM_HDR_VALUE: + if (c == ';' || c == '\0') + { + if (tl && vl) + { + cur_val[vl] = '\0'; + pdkim_strtrim(cur_val); + DEBUG(D_acl) debug_printf(" %s=%s\n", cur_tag, cur_val); + + switch (cur_tag[0]) + { + case 'v': + pub->version = string_copy(cur_val); break; + case 'h': + case 'k': +/* This field appears to never be used. Also, unclear why +a 'k' (key-type_ would go in this field name. There is a field +"keytype", also never used. + pub->hashes = string_copy(cur_val); +*/ + break; + case 'g': + pub->granularity = string_copy(cur_val); break; + case 'n': + pub->notes = pdkim_decode_qp(cur_val); break; + case 'p': + pdkim_decode_base64(US cur_val, &pub->key); break; + case 's': + pub->srvtype = string_copy(cur_val); break; + case 't': + if (Ustrchr(cur_val, 'y') != NULL) pub->testing = 1; + if (Ustrchr(cur_val, 's') != NULL) pub->no_subdomaining = 1; + break; + default: + DEBUG(D_acl) debug_printf(" Unknown tag encountered\n"); + break; + } + } + tl = 0; + vl = 0; + where = PDKIM_HDR_LIMBO; + } + else + cur_val = string_catn(cur_val, &vs, &vl, p, 1); + break; + } + + if (c == '\0') break; + } + +/* Set fallback defaults */ +if (!pub->version ) pub->version = string_copy(PDKIM_PUB_RECORD_VERSION); +else if (Ustrcmp(pub->version, PDKIM_PUB_RECORD_VERSION) != 0) return NULL; + +if (!pub->granularity) pub->granularity = string_copy(US"*"); +/* +if (!pub->keytype ) pub->keytype = string_copy(US"rsa"); +*/ +if (!pub->srvtype ) pub->srvtype = string_copy(US"*"); + +/* p= is required */ +if (pub->key.data) + return pub; + +return NULL; +} + + +/* -------------------------------------------------------------------------- */ + +static int +pdkim_update_bodyhash(pdkim_ctx * ctx, const char * data, int len) +{ +pdkim_signature * sig; +uschar * relaxed_data = NULL; /* Cache relaxed version of data */ +int relaxed_len = 0; + +/* Traverse all signatures, updating their hashes. */ +for (sig = ctx->sig; sig; sig = sig->next) + { + /* Defaults to simple canon (no further treatment necessary) */ + const uschar *canon_data = CUS data; + int canon_len = len; + + if (sig->canon_body == PDKIM_CANON_RELAXED) + { + /* Relax the line if not done already */ + if (!relaxed_data) + { + BOOL seen_wsp = FALSE; + const char *p; + int q = 0; + + /* We want to be able to free this else we allocate + for the entire message which could be many MB. Since + we don't know what allocations the SHA routines might + do, not safe to use store_get()/store_reset(). */ + + relaxed_data = store_malloc(len+1); + + for (p = data; *p; p++) + { + char c = *p; + if (c == '\r') + { + if (q > 0 && relaxed_data[q-1] == ' ') + q--; + } + else if (c == '\t' || c == ' ') + { + c = ' '; /* Turns WSP into SP */ + if (seen_wsp) + continue; + seen_wsp = TRUE; + } + else + seen_wsp = FALSE; + relaxed_data[q++] = c; + } + relaxed_data[q] = '\0'; + relaxed_len = q; + } + canon_data = relaxed_data; + canon_len = relaxed_len; + } + + /* Make sure we don't exceed the to-be-signed body length */ + if ( sig->bodylength >= 0 + && sig->signed_body_bytes + (unsigned long)canon_len > sig->bodylength + ) + canon_len = sig->bodylength - sig->signed_body_bytes; + + if (canon_len > 0) + { + exim_sha_update(&sig->body_hash_ctx, CUS canon_data, canon_len); + sig->signed_body_bytes += canon_len; + DEBUG(D_acl) pdkim_quoteprint(canon_data, canon_len); + } + } + +if (relaxed_data) store_free(relaxed_data); +return PDKIM_OK; +} + + +/* -------------------------------------------------------------------------- */ + +static void +pdkim_finish_bodyhash(pdkim_ctx *ctx) +{ +pdkim_signature *sig; + +/* Traverse all signatures */ +for (sig = ctx->sig; sig; sig = sig->next) + { /* Finish hashes */ + blob bh; + + exim_sha_finish(&sig->body_hash_ctx, &bh); + + DEBUG(D_acl) + { + debug_printf("PDKIM [%s] Body bytes hashed: %lu\n" + "PDKIM [%s] Body hash computed: ", + sig->domain, sig->signed_body_bytes, sig->domain); + pdkim_hexprint(CUS bh.data, bh.len); + } + + /* SIGNING -------------------------------------------------------------- */ + if (ctx->flags & PDKIM_MODE_SIGN) + { + sig->bodyhash = bh; + + /* If bodylength limit is set, and we have received less bytes + than the requested amount, effectively remove the limit tag. */ + if (sig->signed_body_bytes < sig->bodylength) + sig->bodylength = -1; + } + + else + /* VERIFICATION --------------------------------------------------------- */ + /* Be careful that the header sig included a bodyash */ + + if (sig->bodyhash.data && memcmp(bh.data, sig->bodyhash.data, bh.len) == 0) + { + DEBUG(D_acl) debug_printf("PDKIM [%s] Body hash verified OK\n", sig->domain); + } + else + { + DEBUG(D_acl) + { + debug_printf("PDKIM [%s] Body hash signature from headers: ", sig->domain); + pdkim_hexprint(sig->bodyhash.data, sig->bodyhash.len); + debug_printf("PDKIM [%s] Body hash did NOT verify\n", sig->domain); + } + sig->verify_status = PDKIM_VERIFY_FAIL; + sig->verify_ext_status = PDKIM_VERIFY_FAIL_BODY; + } + } +} + + + +static int +pdkim_body_complete(pdkim_ctx * ctx) +{ +pdkim_signature * sig = ctx->sig; /*XXX assumes only one sig */ + +/* In simple body mode, if any empty lines were buffered, +replace with one. rfc 4871 3.4.3 */ +/*XXX checking the signed-body-bytes is a gross hack; I think +it indicates that all linebreaks should be buffered, including +the one terminating a text line */ + +if ( sig && sig->canon_body == PDKIM_CANON_SIMPLE + && sig->signed_body_bytes == 0 + && ctx->num_buffered_crlf > 0 + ) + pdkim_update_bodyhash(ctx, "\r\n", 2); + +ctx->flags |= PDKIM_SEEN_EOD; +ctx->linebuf_offset = 0; +return PDKIM_OK; +} + + + +/* -------------------------------------------------------------------------- */ +/* Call from pdkim_feed below for processing complete body lines */ + +static int +pdkim_bodyline_complete(pdkim_ctx *ctx) +{ +char *p = ctx->linebuf; +int n = ctx->linebuf_offset; +pdkim_signature *sig = ctx->sig; /*XXX assumes only one sig */ + +/* Ignore extra data if we've seen the end-of-data marker */ +if (ctx->flags & PDKIM_SEEN_EOD) goto BAIL; + +/* We've always got one extra byte to stuff a zero ... */ +ctx->linebuf[ctx->linebuf_offset] = '\0'; + +/* Terminate on EOD marker */ +if (ctx->flags & PDKIM_DOT_TERM) + { + if (memcmp(p, ".\r\n", 3) == 0) + return pdkim_body_complete(ctx); + + /* Unstuff dots */ + if (memcmp(p, "..", 2) == 0) + { + p++; + n--; + } + } + +/* Empty lines need to be buffered until we find a non-empty line */ +if (memcmp(p, "\r\n", 2) == 0) + { + ctx->num_buffered_crlf++; + goto BAIL; + } + +if (sig && sig->canon_body == PDKIM_CANON_RELAXED) + { + /* Lines with just spaces need to be buffered too */ + char *check = p; + while (memcmp(check, "\r\n", 2) != 0) + { + char c = *check; + + if (c != '\t' && c != ' ') + goto PROCESS; + check++; + } + + ctx->num_buffered_crlf++; + goto BAIL; +} + +PROCESS: +/* At this point, we have a non-empty line, so release the buffered ones. */ +while (ctx->num_buffered_crlf) + { + pdkim_update_bodyhash(ctx, "\r\n", 2); + ctx->num_buffered_crlf--; + } + +pdkim_update_bodyhash(ctx, p, n); + +BAIL: +ctx->linebuf_offset = 0; +return PDKIM_OK; +} + + +/* -------------------------------------------------------------------------- */ +/* Callback from pdkim_feed below for processing complete headers */ +#define DKIM_SIGNATURE_HEADERNAME "DKIM-Signature:" + +static int +pdkim_header_complete(pdkim_ctx *ctx) +{ +/* Special case: The last header can have an extra \r appended */ +if ( (ctx->cur_header_len > 1) && + (ctx->cur_header[(ctx->cur_header_len)-1] == '\r') ) + --ctx->cur_header_len; +ctx->cur_header[ctx->cur_header_len] = '\0'; + +ctx->num_headers++; +if (ctx->num_headers > PDKIM_MAX_HEADERS) goto BAIL; + +/* SIGNING -------------------------------------------------------------- */ +if (ctx->flags & PDKIM_MODE_SIGN) + { + pdkim_signature *sig; + + for (sig = ctx->sig; sig; sig = sig->next) /* Traverse all signatures */ + + /* Add header to the signed headers list (in reverse order) */ + sig->headers = pdkim_prepend_stringlist(sig->headers, + ctx->cur_header); + } + +/* VERIFICATION ----------------------------------------------------------- */ +/* DKIM-Signature: headers are added to the verification list */ +else + { +#ifdef notdef + DEBUG(D_acl) + { + debug_printf("PDKIM >> raw hdr: "); + pdkim_quoteprint(CUS ctx->cur_header, Ustrlen(ctx->cur_header)); + } +#endif + if (strncasecmp(CCS ctx->cur_header, + DKIM_SIGNATURE_HEADERNAME, + Ustrlen(DKIM_SIGNATURE_HEADERNAME)) == 0) + { + pdkim_signature * new_sig, * last_sig; + + /* Create and chain new signature block. We could error-check for all + required tags here, but prefer to create the internal sig and expicitly + fail verification of it later. */ + + DEBUG(D_acl) debug_printf( + "PDKIM >> Found sig, trying to parse >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); + + new_sig = pdkim_parse_sig_header(ctx, ctx->cur_header); + + if (!(last_sig = ctx->sig)) + ctx->sig = new_sig; + else + { + while (last_sig->next) last_sig = last_sig->next; + last_sig->next = new_sig; + } + } + + /* all headers are stored for signature verification */ + ctx->headers = pdkim_prepend_stringlist(ctx->headers, ctx->cur_header); + } + +BAIL: +*ctx->cur_header = '\0'; +ctx->cur_header_len = 0; /* leave buffer for reuse */ +return PDKIM_OK; +} + + + +/* -------------------------------------------------------------------------- */ +#define HEADER_BUFFER_FRAG_SIZE 256 + +DLLEXPORT int +pdkim_feed(pdkim_ctx *ctx, char *data, int len) +{ +int p, rc; + +/* Alternate EOD signal, used in non-dotstuffing mode */ +if (!data) + pdkim_body_complete(ctx); + +else for (p = 0; pflags & PDKIM_PAST_HDRS) + { + if (c == '\n' && !(ctx->flags & PDKIM_SEEN_CR)) /* emulate the CR */ + { + ctx->linebuf[ctx->linebuf_offset++] = '\r'; + if (ctx->linebuf_offset == PDKIM_MAX_BODY_LINE_LEN-1) + return PDKIM_ERR_LONG_LINE; + } + + /* Processing body byte */ + ctx->linebuf[ctx->linebuf_offset++] = c; + if (c == '\r') + ctx->flags |= PDKIM_SEEN_CR; + else if (c == '\n') + { + ctx->flags &= ~PDKIM_SEEN_CR; + if ((rc = pdkim_bodyline_complete(ctx)) != PDKIM_OK) + return rc; + } + + if (ctx->linebuf_offset == PDKIM_MAX_BODY_LINE_LEN-1) + return PDKIM_ERR_LONG_LINE; + } + else + { + /* Processing header byte */ + if (c == '\r') + ctx->flags |= PDKIM_SEEN_CR; + else if (c == '\n') + { + if (!(ctx->flags & PDKIM_SEEN_CR)) /* emulate the CR */ + ctx->cur_header = string_catn(ctx->cur_header, &ctx->cur_header_size, + &ctx->cur_header_len, CUS "\r", 1); + + if (ctx->flags & PDKIM_SEEN_LF) /* Seen last header line */ + { + if ((rc = pdkim_header_complete(ctx)) != PDKIM_OK) + return rc; + + ctx->flags = (ctx->flags & ~(PDKIM_SEEN_LF|PDKIM_SEEN_CR)) | PDKIM_PAST_HDRS; + DEBUG(D_acl) debug_printf( + "PDKIM >> Body data for hash, canonicalized >>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); + continue; + } + else + ctx->flags = (ctx->flags & ~PDKIM_SEEN_CR) | PDKIM_SEEN_LF; + } + else if (ctx->flags & PDKIM_SEEN_LF) + { + if (!(c == '\t' || c == ' ')) /* End of header */ + if ((rc = pdkim_header_complete(ctx)) != PDKIM_OK) + return rc; + ctx->flags &= ~PDKIM_SEEN_LF; + } + + if (ctx->cur_header_len < PDKIM_MAX_HEADER_LEN) + ctx->cur_header = string_catn(ctx->cur_header, &ctx->cur_header_size, + &ctx->cur_header_len, CUS &data[p], 1); + } + } +return PDKIM_OK; +} + + + +/* Extend a grwong header with a continuation-linebreak */ +static uschar * +pdkim_hdr_cont(uschar * str, int * size, int * ptr, int * col) +{ +*col = 1; +return string_catn(str, size, ptr, US"\r\n\t", 3); +} + + + +/* + * RFC 5322 specifies that header line length SHOULD be no more than 78 + * lets make it so! + * pdkim_headcat + * + * returns uschar * (not nul-terminated) + * + * col: this int holds and receives column number (octets since last '\n') + * str: partial string to append to + * size: current buffer size for str + * ptr: current tail-pointer for str + * pad: padding, split line or space after before or after eg: ";" + * intro: - must join to payload eg "h=", usually the tag name + * payload: eg base64 data - long data can be split arbitrarily. + * + * this code doesn't fold the header in some of the places that RFC4871 + * allows: As per RFC5322(2.2.3) it only folds before or after tag-value + * pairs and inside long values. it also always spaces or breaks after the + * "pad" + * + * no guarantees are made for output given out-of range input. like tag + * names longer than 78, or bogus col. Input is assumed to be free of line breaks. + */ + +static uschar * +pdkim_headcat(int * col, uschar * str, int * size, int * ptr, + const uschar * pad, const uschar * intro, const uschar * payload) +{ +size_t l; + +if (pad) + { + l = Ustrlen(pad); + if (*col + l > 78) + str = pdkim_hdr_cont(str, size, ptr, col); + str = string_catn(str, size, ptr, pad, l); + *col += l; + } + +l = (pad?1:0) + (intro?Ustrlen(intro):0); + +if (*col + l > 78) + { /*can't fit intro - start a new line to make room.*/ + str = pdkim_hdr_cont(str, size, ptr, col); + l = intro?Ustrlen(intro):0; + } + +l += payload ? Ustrlen(payload):0 ; + +while (l>77) + { /* this fragment will not fit on a single line */ + if (pad) + { + str = string_catn(str, size, ptr, US" ", 1); + *col += 1; + pad = NULL; /* only want this once */ + l--; + } + + if (intro) + { + size_t sl = Ustrlen(intro); + + str = string_catn(str, size, ptr, intro, sl); + *col += sl; + l -= sl; + intro = NULL; /* only want this once */ + } + + if (payload) + { + size_t sl = Ustrlen(payload); + size_t chomp = *col+sl < 77 ? sl : 78-*col; + + str = string_catn(str, size, ptr, payload, chomp); + *col += chomp; + payload += chomp; + l -= chomp-1; + } + + /* the while precondition tells us it didn't fit. */ + str = pdkim_hdr_cont(str, size, ptr, col); + } + +if (*col + l > 78) + { + str = pdkim_hdr_cont(str, size, ptr, col); + pad = NULL; + } + +if (pad) + { + str = string_catn(str, size, ptr, US" ", 1); + *col += 1; + pad = NULL; + } + +if (intro) + { + size_t sl = Ustrlen(intro); + + str = string_catn(str, size, ptr, intro, sl); + *col += sl; + l -= sl; + intro = NULL; + } + +if (payload) + { + size_t sl = Ustrlen(payload); + + str = string_catn(str, size, ptr, payload, sl); + *col += sl; + } + +return str; +} + + +/* -------------------------------------------------------------------------- */ + +static uschar * +pdkim_create_header(pdkim_signature *sig, BOOL final) +{ +uschar * base64_bh; +uschar * base64_b; +int col = 0; +uschar * hdr; int hdr_size = 0, hdr_len = 0; +uschar * canon_all; int can_size = 0, can_len = 0; + +canon_all = string_cat (NULL, &can_size, &can_len, + pdkim_canons[sig->canon_headers]); +canon_all = string_catn(canon_all, &can_size, &can_len, US"/", 1); +canon_all = string_cat (canon_all, &can_size, &can_len, + pdkim_canons[sig->canon_body]); +canon_all[can_len] = '\0'; + +hdr = string_cat(NULL, &hdr_size, &hdr_len, + US"DKIM-Signature: v="PDKIM_SIGNATURE_VERSION); +col = hdr_len; + +/* Required and static bits */ +hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"a=", + pdkim_algos[sig->algo]); +hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"q=", + pdkim_querymethods[sig->querymethod]); +hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"c=", + canon_all); +hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"d=", + sig->domain); +hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"s=", + sig->selector); + +/* list of header names can be split between items. */ + { + uschar * n = string_copy(sig->headernames); + uschar * i = US"h="; + uschar * s = US";"; + + while (*n) + { + uschar * c = Ustrchr(n, ':'); + + if (c) *c ='\0'; + + if (!i) + hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, NULL, NULL, US":"); + + hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, s, i, n); + + if (!c) + break; + + n = c+1; + s = NULL; + i = NULL; + } + } + +base64_bh = pdkim_encode_base64(&sig->bodyhash); +hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"bh=", base64_bh); + +/* Optional bits */ +if (sig->identity) + hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"i=", sig->identity); + +if (sig->created > 0) + { + uschar minibuf[20]; + + snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->created); + hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"t=", minibuf); +} + +if (sig->expires > 0) + { + uschar minibuf[20]; + + snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->expires); + hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"x=", minibuf); + } + +if (sig->bodylength >= 0) + { + uschar minibuf[20]; + + snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->bodylength); + hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"l=", minibuf); + } + +/* Preliminary or final version? */ +base64_b = final ? pdkim_encode_base64(&sig->sighash) : US""; +hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"b=", base64_b); + +/* add trailing semicolon: I'm not sure if this is actually needed */ +hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, NULL, US";", US""); + +hdr[hdr_len] = '\0'; +return hdr; +} + + +/* -------------------------------------------------------------------------- */ + +static pdkim_pubkey * +pdkim_key_from_dns(pdkim_ctx * ctx, pdkim_signature * sig, ev_ctx * vctx) +{ +uschar * dns_txt_name, * dns_txt_reply; +pdkim_pubkey * p; +const uschar * errstr; + +/* Fetch public key for signing domain, from DNS */ + +dns_txt_name = string_sprintf("%s._domainkey.%s.", sig->selector, sig->domain); + +dns_txt_reply = store_get(PDKIM_DNS_TXT_MAX_RECLEN); +memset(dns_txt_reply, 0, PDKIM_DNS_TXT_MAX_RECLEN); + +if ( ctx->dns_txt_callback(CS dns_txt_name, CS dns_txt_reply) != PDKIM_OK + || dns_txt_reply[0] == '\0' + ) + { + sig->verify_status = PDKIM_VERIFY_INVALID; + sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE; + return NULL; + } + +DEBUG(D_acl) + { + debug_printf( + "PDKIM >> Parsing public key record >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n" + " Raw record: "); + pdkim_quoteprint(CUS dns_txt_reply, Ustrlen(dns_txt_reply)); + } + +if ( !(p = pdkim_parse_pubkey_record(ctx, CUS dns_txt_reply)) + || (Ustrcmp(p->srvtype, "*") != 0 && Ustrcmp(p->srvtype, "email") != 0) + ) + { + sig->verify_status = PDKIM_VERIFY_INVALID; + sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD; + + DEBUG(D_acl) + { + if (p) + debug_printf(" Invalid public key service type '%s'\n", p->srvtype); + else + debug_printf(" Error while parsing public key record\n"); + debug_printf( + "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); + } + return NULL; + } + +DEBUG(D_acl) debug_printf( + "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); + +/* Import public key */ +if ((errstr = exim_rsa_verify_init(&p->key, vctx))) + { + DEBUG(D_acl) debug_printf("verify_init: %s\n", errstr); + sig->verify_status = PDKIM_VERIFY_INVALID; + sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_IMPORT; + return NULL; + } + +return p; +} + + +/* -------------------------------------------------------------------------- */ + +DLLEXPORT int +pdkim_feed_finish(pdkim_ctx *ctx, pdkim_signature **return_signatures) +{ +pdkim_signature *sig = ctx->sig; + +/* Check if we must still flush a (partial) header. If that is the + case, the message has no body, and we must compute a body hash + out of '' */ +if (ctx->cur_header && ctx->cur_header_len) + { + int rc = pdkim_header_complete(ctx); + if (rc != PDKIM_OK) return rc; + pdkim_update_bodyhash(ctx, "\r\n", 2); + } +else + DEBUG(D_acl) debug_printf( + "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); + +/* Build (and/or evaluate) body hash */ +pdkim_finish_bodyhash(ctx); + +while (sig) + { + BOOL is_sha1 = sig->algo == PDKIM_ALGO_RSA_SHA1; + hctx hhash_ctx; + uschar * sig_hdr = US""; + blob hhash; + blob hdata; + int hdata_alloc = 0; + + hdata.data = NULL; + hdata.len = 0; + + if (!exim_sha_init(&hhash_ctx, is_sha1 ? HASH_SHA1 : HASH_SHA256)) + { + DEBUG(D_acl) debug_printf("PDKIM: hask setup internal error\n"); + break; + } + + DEBUG(D_acl) debug_printf( + "PDKIM >> Header data for hash, canonicalized, in sequence >>>>>>>>>>>>>>\n"); + + /* SIGNING ---------------------------------------------------------------- */ + /* When signing, walk through our header list and add them to the hash. As we + go, construct a list of the header's names to use for the h= parameter. + Then append to that list any remaining header names for which there was no + header to sign. */ + + if (ctx->flags & PDKIM_MODE_SIGN) + { + uschar * headernames = NULL; /* Collected signed header names */ + int hs = 0, hl = 0; + pdkim_stringlist *p; + const uschar * l; + uschar * s; + int sep = 0; + + for (p = sig->headers; p; p = p->next) + if (header_name_match(p->value, sig->sign_headers) == PDKIM_OK) + { + uschar * rh; + /* Collect header names (Note: colon presence is guaranteed here) */ + uschar * q = Ustrchr(p->value, ':'); + + headernames = string_catn(headernames, &hs, &hl, + p->value, (q - US p->value) + (p->next ? 1 : 0)); + + rh = sig->canon_headers == PDKIM_CANON_RELAXED + ? pdkim_relax_header(p->value, 1) /* cook header for relaxed canon */ + : string_copy(CUS p->value); /* just copy it for simple canon */ + + /* Feed header to the hash algorithm */ + exim_sha_update(&hhash_ctx, CUS rh, Ustrlen(rh)); + + /* Remember headers block for signing (when the library cannot do incremental) */ + (void) exim_rsa_data_append(&hdata, &hdata_alloc, rh); + + DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh)); + } + + l = sig->sign_headers; + while((s = string_nextinlist(&l, &sep, NULL, 0))) + if (*s != '_') + { /*SSS string_append_listele() */ + if (hl > 0 && headernames[hl-1] != ':') + headernames = string_catn(headernames, &hs, &hl, US":", 1); + + headernames = string_cat(headernames, &hs, &hl, s); + } + headernames[hl] = '\0'; + + /* Copy headernames to signature struct */ + sig->headernames = headernames; + + /* Create signature header with b= omitted */ + sig_hdr = pdkim_create_header(sig, FALSE); + } + + /* VERIFICATION ----------------------------------------------------------- */ + /* When verifying, walk through the header name list in the h= parameter and + add the headers to the hash in that order. */ + else + { + uschar * p = sig->headernames; + uschar * q; + pdkim_stringlist * hdrs; + + if (p) + { + /* clear tags */ + for (hdrs = ctx->headers; hdrs; hdrs = hdrs->next) + hdrs->tag = 0; + + p = string_copy(p); + while(1) + { + if ((q = Ustrchr(p, ':'))) + *q = '\0'; + + /*XXX walk the list of headers in same order as received. */ + for (hdrs = ctx->headers; hdrs; hdrs = hdrs->next) + if ( hdrs->tag == 0 + && strncasecmp(CCS hdrs->value, CCS p, Ustrlen(p)) == 0 + && (hdrs->value)[Ustrlen(p)] == ':' + ) + { + /* cook header for relaxed canon, or just copy it for simple */ + + uschar * rh = sig->canon_headers == PDKIM_CANON_RELAXED + ? pdkim_relax_header(hdrs->value, 1) + : string_copy(CUS hdrs->value); + + /* Feed header to the hash algorithm */ + exim_sha_update(&hhash_ctx, CUS rh, Ustrlen(rh)); + + DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh)); + hdrs->tag = 1; + break; + } + + if (!q) break; + p = q+1; + } + + sig_hdr = string_copy(sig->rawsig_no_b_val); + } + } + + DEBUG(D_acl) debug_printf( + "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); + + /* Relax header if necessary */ + if (sig->canon_headers == PDKIM_CANON_RELAXED) + sig_hdr = pdkim_relax_header(sig_hdr, 0); + + DEBUG(D_acl) + { + debug_printf( + "PDKIM >> Signed DKIM-Signature header, canonicalized >>>>>>>>>>>>>>>>>\n"); + pdkim_quoteprint(CUS sig_hdr, Ustrlen(sig_hdr)); + debug_printf( + "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); + } + + /* Finalize header hash */ + exim_sha_update(&hhash_ctx, CUS sig_hdr, Ustrlen(sig_hdr)); + exim_sha_finish(&hhash_ctx, &hhash); + + DEBUG(D_acl) + { + debug_printf("PDKIM [%s] Header hash computed: ", sig->domain); + pdkim_hexprint(hhash.data, hhash.len); + } + + /* Remember headers block for signing (when the library cannot do incremental) */ + if (ctx->flags & PDKIM_MODE_SIGN) + (void) exim_rsa_data_append(&hdata, &hdata_alloc, US sig_hdr); + + /* SIGNING ---------------------------------------------------------------- */ + if (ctx->flags & PDKIM_MODE_SIGN) + { + es_ctx sctx; + const uschar * errstr; + + /* Import private key */ + if ((errstr = exim_rsa_signing_init(US sig->rsa_privkey, &sctx))) + { + DEBUG(D_acl) debug_printf("signing_init: %s\n", errstr); + return PDKIM_ERR_RSA_PRIVKEY; + } + + /* Do signing. With OpenSSL we are signing the hash of headers just + calculated, with GnuTLS we have to sign an entire block of headers + (due to available interfaces) and it recalculates the hash internally. */ + +#if defined(RSA_OPENSSL) || defined(RSA_GCRYPT) + hdata = hhash; +#endif + + if ((errstr = exim_rsa_sign(&sctx, is_sha1, &hdata, &sig->sighash))) + { + DEBUG(D_acl) debug_printf("signing: %s\n", errstr); + return PDKIM_ERR_RSA_SIGNING; + } + + DEBUG(D_acl) + { + debug_printf( "PDKIM [%s] b computed: ", sig->domain); + pdkim_hexprint(sig->sighash.data, sig->sighash.len); + } + + sig->signature_header = pdkim_create_header(sig, TRUE); + } + + /* VERIFICATION ----------------------------------------------------------- */ + else + { + ev_ctx vctx; + const uschar * errstr; + pdkim_pubkey * p; + + /* Make sure we have all required signature tags */ + if (!( sig->domain && *sig->domain + && sig->selector && *sig->selector + && sig->headernames && *sig->headernames + && sig->bodyhash.data + && sig->sighash.data + && sig->algo > -1 + && sig->version + ) ) + { + sig->verify_status = PDKIM_VERIFY_INVALID; + sig->verify_ext_status = PDKIM_VERIFY_INVALID_SIGNATURE_ERROR; + + DEBUG(D_acl) debug_printf( + " Error in DKIM-Signature header: tags missing or invalid\n" + "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); + goto NEXT_VERIFY; + } + + /* Make sure sig uses supported DKIM version (only v1) */ + if (sig->version != 1) + { + sig->verify_status = PDKIM_VERIFY_INVALID; + sig->verify_ext_status = PDKIM_VERIFY_INVALID_DKIM_VERSION; + + DEBUG(D_acl) debug_printf( + " Error in DKIM-Signature header: unsupported DKIM version\n" + "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); + goto NEXT_VERIFY; + } + + if (!(sig->pubkey = pdkim_key_from_dns(ctx, sig, &vctx))) + goto NEXT_VERIFY; + + /* Check the signature */ + if ((errstr = exim_rsa_verify(&vctx, is_sha1, &hhash, &sig->sighash))) + { + DEBUG(D_acl) debug_printf("headers verify: %s\n", errstr); + sig->verify_status = PDKIM_VERIFY_FAIL; + sig->verify_ext_status = PDKIM_VERIFY_FAIL_MESSAGE; + goto NEXT_VERIFY; + } + + + /* We have a winner! (if bodyhash was correct earlier) */ + if (sig->verify_status == PDKIM_VERIFY_NONE) + sig->verify_status = PDKIM_VERIFY_PASS; + +NEXT_VERIFY: + + DEBUG(D_acl) + { + debug_printf("PDKIM [%s] signature status: %s", + sig->domain, pdkim_verify_status_str(sig->verify_status)); + if (sig->verify_ext_status > 0) + debug_printf(" (%s)\n", + pdkim_verify_ext_status_str(sig->verify_ext_status)); + else + debug_printf("\n"); + } + } + + sig = sig->next; + } + +/* If requested, set return pointer to signature(s) */ +if (return_signatures) + *return_signatures = ctx->sig; + +return PDKIM_OK; +} + + +/* -------------------------------------------------------------------------- */ + +DLLEXPORT pdkim_ctx * +pdkim_init_verify(int(*dns_txt_callback)(char *, char *), BOOL dot_stuffing) +{ +pdkim_ctx * ctx; + +ctx = store_get(sizeof(pdkim_ctx)); +memset(ctx, 0, sizeof(pdkim_ctx)); + +if (dot_stuffing) ctx->flags = PDKIM_DOT_TERM; +ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN); +ctx->dns_txt_callback = dns_txt_callback; + +return ctx; +} + + +/* -------------------------------------------------------------------------- */ + +DLLEXPORT pdkim_ctx * +pdkim_init_sign(char * domain, char * selector, char * rsa_privkey, int algo, + BOOL dot_stuffed, int(*dns_txt_callback)(char *, char *)) +{ +pdkim_ctx * ctx; +pdkim_signature * sig; + +if (!domain || !selector || !rsa_privkey) + return NULL; + +ctx = store_get(sizeof(pdkim_ctx) + PDKIM_MAX_BODY_LINE_LEN + sizeof(pdkim_signature)); +memset(ctx, 0, sizeof(pdkim_ctx)); + +ctx->flags = dot_stuffed ? PDKIM_MODE_SIGN | PDKIM_DOT_TERM : PDKIM_MODE_SIGN; +ctx->linebuf = CS (ctx+1); + +DEBUG(D_acl) ctx->dns_txt_callback = dns_txt_callback; + +sig = (pdkim_signature *)(ctx->linebuf + PDKIM_MAX_BODY_LINE_LEN); +memset(sig, 0, sizeof(pdkim_signature)); + +sig->bodylength = -1; +ctx->sig = sig; + +sig->domain = string_copy(US domain); +sig->selector = string_copy(US selector); +sig->rsa_privkey = string_copy(US rsa_privkey); +sig->algo = algo; + +if (!exim_sha_init(&sig->body_hash_ctx, + algo == PDKIM_ALGO_RSA_SHA1 ? HASH_SHA1 : HASH_SHA256)) + { + DEBUG(D_acl) debug_printf("PDKIM: hash setup internal error\n"); + return NULL; + } + +DEBUG(D_acl) + { + pdkim_signature s = *sig; + ev_ctx vctx; + + debug_printf("PDKIM (checking verify key)<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); + if (!pdkim_key_from_dns(ctx, &s, &vctx)) + debug_printf("WARNING: bad dkim key in dns\n"); + debug_printf("PDKIM (finished checking verify key)<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); + } +return ctx; +} + + +/* -------------------------------------------------------------------------- */ + +DLLEXPORT int +pdkim_set_optional(pdkim_ctx *ctx, + char *sign_headers, + char *identity, + int canon_headers, + int canon_body, + long bodylength, + unsigned long created, + unsigned long expires) +{ +pdkim_signature * sig = ctx->sig; + +if (identity) + sig->identity = string_copy(US identity); + +sig->sign_headers = string_copy(sign_headers + ? US sign_headers : US PDKIM_DEFAULT_SIGN_HEADERS); + +sig->canon_headers = canon_headers; +sig->canon_body = canon_body; +sig->bodylength = bodylength; +sig->created = created; +sig->expires = expires; + +return PDKIM_OK; +} + + +void +pdkim_init(void) +{ +exim_rsa_init(); +} + + + +#endif /*DISABLE_DKIM*/