gnu/packages/patches/libssh2-CVE-2019-17498.patch

   1 https://github.com/libssh2/libssh2/commit/dedcbd106f8e52d5586b0205bc7677e4c9868f9c.patch
   2
   3 From dedcbd106f8e52d5586b0205bc7677e4c9868f9c Mon Sep 17 00:00:00 2001
   4 From: Will Cosgrove <will@panic.com>
   5 Date: Fri, 30 Aug 2019 09:57:38 -0700
   6 Subject: [PATCH] packet.c: improve message parsing (#402)
   7
   8 * packet.c: improve parsing of packets
   9
  10 file: packet.c
  11
  12 notes:
  13 Use _libssh2_get_string API in SSH_MSG_DEBUG/SSH_MSG_DISCONNECT. Additional uint32 bounds check in SSH_MSG_GLOBAL_REQUEST.
  14 ---
  15  src/packet.c | 68 ++++++++++++++++++++++------------------------------
  16  1 file changed, 29 insertions(+), 39 deletions(-)
  17
  18 diff --git a/src/packet.c b/src/packet.c
  19 index 38ab62944..2e01bfc5d 100644
  20 --- a/src/packet.c
  21 +++ b/src/packet.c
  22 @@ -419,8 +419,8 @@ _libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
  23                      size_t datalen, int macstate)
  24  {
  25      int rc = 0;
  26 -    char *message = NULL;
  27 -    char *language = NULL;
  28 +    unsigned char *message = NULL;
  29 +    unsigned char *language = NULL;
  30      size_t message_len = 0;
  31      size_t language_len = 0;
  32      LIBSSH2_CHANNEL *channelp = NULL;
  33 @@ -472,33 +472,23 @@ _libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
  34
  35          case SSH_MSG_DISCONNECT:
  36              if(datalen >= 5) {
  37 -                size_t reason = _libssh2_ntohu32(data + 1);
  38 +                uint32_t reason = 0;
  39 +                struct string_buf buf;
  40 +                buf.data = (unsigned char *)data;
  41 +                buf.dataptr = buf.data;
  42 +                buf.len = datalen;
  43 +                buf.dataptr++; /* advance past type */
  44
  45 -                if(datalen >= 9) {
  46 -                    message_len = _libssh2_ntohu32(data + 5);
  47 +                _libssh2_get_u32(&buf, &reason);
  48 +                _libssh2_get_string(&buf, &message, &message_len);
  49 +                _libssh2_get_string(&buf, &language, &language_len);
  50
  51 -                    if(message_len < datalen-13) {
  52 -                        /* 9 = packet_type(1) + reason(4) + message_len(4) */
  53 -                        message = (char *) data + 9;
  54 -
  55 -                        language_len =
  56 -                            _libssh2_ntohu32(data + 9 + message_len);
  57 -                        language = (char *) data + 9 + message_len + 4;
  58 -
  59 -                        if(language_len > (datalen-13-message_len)) {
  60 -                            /* bad input, clear info */
  61 -                            language = message = NULL;
  62 -                            language_len = message_len = 0;
  63 -                        }
  64 -                    }
  65 -                    else
  66 -                        /* bad size, clear it */
  67 -                        message_len = 0;
  68 -                }
  69                  if(session->ssh_msg_disconnect) {
  70 -                    LIBSSH2_DISCONNECT(session, reason, message,
  71 -                                       message_len, language, language_len);
  72 +                    LIBSSH2_DISCONNECT(session, reason, (const char *)message,
  73 +                                       message_len, (const char *)language,
  74 +                                       language_len);
  75                  }
  76 +
  77                  _libssh2_debug(session, LIBSSH2_TRACE_TRANS,
  78                                 "Disconnect(%d): %s(%s)", reason,
  79                                 message, language);
  80 @@ -539,24 +529,24 @@ _libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
  81                  int always_display = data[1];
  82
  83                  if(datalen >= 6) {
  84 -                    message_len = _libssh2_ntohu32(data + 2);
  85 -
  86 -                    if(message_len <= (datalen - 10)) {
  87 -                        /* 6 = packet_type(1) + display(1) + message_len(4) */
  88 -                        message = (char *) data + 6;
  89 -                        language_len = _libssh2_ntohu32(data + 6 +
  90 -                                                        message_len);
  91 -
  92 -                        if(language_len <= (datalen - 10 - message_len))
  93 -                            language = (char *) data + 10 + message_len;
  94 -                    }
  95 +                    struct string_buf buf;
  96 +                    buf.data = (unsigned char *)data;
  97 +                    buf.dataptr = buf.data;
  98 +                    buf.len = datalen;
  99 +                    buf.dataptr += 2; /* advance past type & always display */
 100 +
 101 +                    _libssh2_get_string(&buf, &message, &message_len);
 102 +                    _libssh2_get_string(&buf, &language, &language_len);
 103                  }
 104
 105                  if(session->ssh_msg_debug) {
 106 -                    LIBSSH2_DEBUG(session, always_display, message,
 107 -                                  message_len, language, language_len);
 108 +                    LIBSSH2_DEBUG(session, always_display,
 109 +                                  (const char *)message,
 110 +                                  message_len, (const char *)language,
 111 +                                  language_len);
 112                  }
 113              }
 114 +
 115              /*
 116               * _libssh2_debug will actually truncate this for us so
 117               * that it's not an inordinate about of data
 118 @@ -579,7 +569,7 @@ _libssh2_packet_add(LIBSSH2_SESSION * session, unsigned char *data,
 119                  uint32_t len = 0;
 120                  unsigned char want_reply = 0;
 121                  len = _libssh2_ntohu32(data + 1);
 122 -                if(datalen >= (6 + len)) {
 123 +                if((len <= (UINT_MAX - 6)) && (datalen >= (6 + len))) {
 124                      want_reply = data[5 + len];
 125                      _libssh2_debug(session,
 126                                     LIBSSH2_TRACE_CONN,