X-Git-Url: https://git.hcoop.net/hcoop/debian/exim4.git/blobdiff_plain/188b6fee0dfdf699a1a302e16b70d17b4f325bcd..2ea97746a3f65eeffb434b8e4e18815e03b61532:/src/base64.c diff --git a/src/base64.c b/src/base64.c new file mode 100644 index 0000000..e63522e --- /dev/null +++ b/src/base64.c @@ -0,0 +1,289 @@ +/************************************************* +* Exim - an Internet mail transport agent * +*************************************************/ + +/* Copyright (c) Tom Kistner 2004, 2015 */ +/* License: GPL */ + +/* Copyright (c) University of Cambridge 1995 - 2018 */ +/* See the file NOTICE for conditions of use and distribution. */ + + +#include "exim.h" +#ifdef WITH_CONTENT_SCAN /* file-IO specific decode function */ +# include "mime.h" + +/* BASE64 decoder matrix */ +static unsigned char mime_b64[256]={ +/* 0 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, +/* 16 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, +/* 32 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 62, 128, 128, 128, 63, +/* 48 */ 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 128, 128, 128, 255, 128, 128, +/* 64 */ 128, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, +/* 80 */ 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 128, 128, 128, 128, 128, +/* 96 */ 128, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, +/* 112 */ 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 128, 128, 128, 128, 128, +/* 128 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, +/* 144 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, +/* 160 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, +/* 176 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, +/* 192 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, +/* 208 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, +/* 224 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, +/* 240 */ 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 +}; + +/* decode base64 MIME part */ +ssize_t +mime_decode_base64(FILE * in, FILE * out, uschar * boundary) +{ +uschar ibuf[MIME_MAX_LINE_LENGTH], obuf[MIME_MAX_LINE_LENGTH]; +uschar *ipos, *opos; +ssize_t len, size = 0; +int bytestate = 0; + +opos = obuf; + +while (Ufgets(ibuf, MIME_MAX_LINE_LENGTH, in) != NULL) + { + if (boundary != NULL + && Ustrncmp(ibuf, "--", 2) == 0 + && Ustrncmp((ibuf+2), boundary, Ustrlen(boundary)) == 0 + ) + break; + + for (ipos = ibuf ; *ipos != '\r' && *ipos != '\n' && *ipos != 0; ++ipos) + if (*ipos == '=') /* skip padding */ + ++bytestate; + + else if (mime_b64[*ipos] == 128) /* skip bad characters */ + mime_set_anomaly(MIME_ANOMALY_BROKEN_BASE64); + + /* simple state-machine */ + else switch((bytestate++) & 3) + { + case 0: + *opos = mime_b64[*ipos] << 2; break; + case 1: + *opos++ |= mime_b64[*ipos] >> 4; + *opos = mime_b64[*ipos] << 4; break; + case 2: + *opos++ |= mime_b64[*ipos] >> 2; + *opos = mime_b64[*ipos] << 6; break; + case 3: + *opos++ |= mime_b64[*ipos]; break; + } + + /* something to write? */ + len = opos - obuf; + if (len > 0) + { + if (fwrite(obuf, 1, len, out) != len) return -1; /* error */ + size += len; + /* copy incomplete last byte to start of obuf, where we continue */ + if ((bytestate & 3) != 0) + *obuf = *opos; + opos = obuf; + } + } /* while */ + +/* write out last byte if it was incomplete */ +if (bytestate & 3) + { + if (fwrite(obuf, 1, 1, out) != 1) return -1; + ++size; + } + +return size; +} + +#endif /*WITH_CONTENT_SCAN*/ + +/************************************************* + ************************************************* + ************************************************* + ************************************************* + ************************************************* + ************************************************* + ************************************************* + ************************************************* + ************************************************* + ************************************************* + ************************************************* + ************************************************* + ************************************************* + ************************************************* + ************************************************* + *************************************************/ + + +/************************************************* +* Decode byte-string in base 64 * +*************************************************/ + +/* This function decodes a string in base 64 format as defined in RFC 2045 +(MIME) and required by the SMTP AUTH extension (RFC 2554). The decoding +algorithm is written out in a straightforward way. Turning it into some kind of +compact loop is messy and would probably run more slowly. + +Arguments: + code points to the coded string, zero-terminated + ptr where to put the pointer to the result, which is in + allocated store, and zero-terminated + +Returns: the number of bytes in the result, + or -1 if the input was malformed + +Whitespace in the input is ignored. +A zero is added on to the end to make it easy in cases where the result is to +be interpreted as text. This is not included in the count. */ + +static uschar dec64table[] = { + 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255, /* 0-15 */ + 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255, /* 16-31 */ + 255,255,255,255,255,255,255,255,255,255,255, 62,255,255,255, 63, /* 32-47 */ + 52, 53, 54, 55, 56, 57, 58, 59, 60, 61,255,255,255,255,255,255, /* 48-63 */ + 255, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, /* 64-79 */ + 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,255,255,255,255,255, /* 80-95 */ + 255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, /* 96-111 */ + 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,255,255,255,255,255 /* 112-127*/ +}; + +int +b64decode(const uschar *code, uschar **ptr) +{ + +int x, y; +uschar *result; + +{ + int l = Ustrlen(code); + *ptr = result = store_get(1 + l/4 * 3 + l%4); +} + +/* Each cycle of the loop handles a quantum of 4 input bytes. For the last +quantum this may decode to 1, 2, or 3 output bytes. */ + +while ((x = *code++) != 0) + { + if (isspace(x)) continue; + /* debug_printf("b64d: '%c'\n", x); */ + + if (x > 127 || (x = dec64table[x]) == 255) return -1; + + while (isspace(y = *code++)) ; + /* debug_printf("b64d: '%c'\n", y); */ + if (y > 127 || (y = dec64table[y]) == 255) + return -1; + + *result++ = (x << 2) | (y >> 4); + /* debug_printf("b64d: -> %02x\n", result[-1]); */ + + while (isspace(x = *code++)) ; + /* debug_printf("b64d: '%c'\n", x); */ + if (x == '=') /* endmarker, but there should be another */ + { + while (isspace(x = *code++)) ; + /* debug_printf("b64d: '%c'\n", x); */ + if (x != '=') return -1; + while (isspace(y = *code++)) ; + if (y != 0) return -1; + /* debug_printf("b64d: DONE\n"); */ + break; + } + else + { + if (x > 127 || (x = dec64table[x]) == 255) return -1; + *result++ = (y << 4) | (x >> 2); + /* debug_printf("b64d: -> %02x\n", result[-1]); */ + + while (isspace(y = *code++)) ; + /* debug_printf("b64d: '%c'\n", y); */ + if (y == '=') + { + while (isspace(y = *code++)) ; + if (y != 0) return -1; + /* debug_printf("b64d: DONE\n"); */ + break; + } + else + { + if (y > 127 || (y = dec64table[y]) == 255) return -1; + *result++ = (x << 6) | y; + /* debug_printf("b64d: -> %02x\n", result[-1]); */ + } + } + } + +*result = 0; +return result - *ptr; +} + + +/************************************************* +* Encode byte-string in base 64 * +*************************************************/ + +/* This function encodes a string of bytes, containing any values whatsoever, +in base 64 as defined in RFC 2045 (MIME) and required by the SMTP AUTH +extension (RFC 2554). The encoding algorithm is written out in a +straightforward way. Turning it into some kind of compact loop is messy and +would probably run more slowly. + +Arguments: + clear points to the clear text bytes + len the number of bytes to encode + +Returns: a pointer to the zero-terminated base 64 string, which + is in working store +*/ + +static uschar *enc64table = + US"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; + +uschar * +b64encode(uschar *clear, int len) +{ +uschar *code = store_get(4*((len+2)/3) + 1); +uschar *p = code; + +while (len-- >0) + { + int x, y; + + x = *clear++; + *p++ = enc64table[(x >> 2) & 63]; + + if (len-- <= 0) + { + *p++ = enc64table[(x << 4) & 63]; + *p++ = '='; + *p++ = '='; + break; + } + + y = *clear++; + *p++ = enc64table[((x << 4) | ((y >> 4) & 15)) & 63]; + + if (len-- <= 0) + { + *p++ = enc64table[(y << 2) & 63]; + *p++ = '='; + break; + } + + x = *clear++; + *p++ = enc64table[((y << 2) | ((x >> 6) & 3)) & 63]; + + *p++ = enc64table[x & 63]; + } + +*p = 0; + +return code; +} + + +/* End of base64.c */ +/* vi: sw ai sw=2 +*/