pidgin/pidgin

Fix a possible MSN remote crash
release-2.x.y
2012-05-07, Mark Doliner
4d6bcb4f4ea4
Parents 5f9d676cefdb
Children 1d00b9e4aa6a
Fix a possible MSN remote crash

Incoming messages with certain characters or character encodings
can cause clients to crash. The fix is for the contents of all
incoming plaintext messages are converted to UTF-8 and validated
before used.

This was reported to us by Fabian Yamaguchi and this patch was written
by Elliott Sales de Andrade (maybe with small, insignificant changes by me)
1 files changed, 41 insertions(+), 7 deletions(-)
  • +41 -7
    libpurple/protocols/msn/msg.c
    • --- a/libpurple/protocols/msn/msg.c Mon May 07 03:16:31 2012 +0000
    +++ b/libpurple/protocols/msn/msg.c Mon May 07 03:18:08 2012 +0000
    @@ -257,13 +257,47 @@
    msg->body[msg->body_len] = '\0';
    }
    - if ((!content_type || !strcmp(content_type, "text/plain"))
    - && msg->charset == NULL) {
    - char *body = g_convert(msg->body, msg->body_len, "UTF-8",
    - "ISO-8859-1", NULL, &msg->body_len, NULL);
    - g_free(msg->body);
    - msg->body = body;
    - msg->charset = g_strdup("UTF-8");
    + if (msg->body && content_type && purple_str_has_prefix(content_type, "text/")) {
    + char *body = NULL;
    +
    + if (msg->charset == NULL || g_str_equal(msg->charset, "UTF-8")) {
    + /* Charset is UTF-8 */
    + if (!g_utf8_validate(msg->body, msg->body_len, NULL)) {
    + purple_debug_warning("msn", "Message contains invalid "
    + "UTF-8. Attempting to salvage.\n");
    + body = purple_utf8_salvage(msg->body);
    + payload_len = strlen(body);
    + }
    + } else {
    + /* Charset is something other than UTF-8 */
    + GError *err = NULL;
    + body = g_convert(msg->body, msg->body_len, "UTF-8",
    + msg->charset, NULL, &payload_len, &err);
    + if (!body || err) {
    + purple_debug_warning("msn", "Unable to convert message from "
    + "%s to UTF-8: %s\n", msg->charset,
    + err ? err->message : "Unknown error");
    + if (err)
    + g_error_free(err);
    +
    + /* Fallback to ISO-8859-1 */
    + g_free(body);
    + body = g_convert(msg->body, msg->body_len, "UTF-8",
    + "ISO-8859-1", NULL, &payload_len, NULL);
    + if (!body) {
    + g_free(msg->body);
    + msg->body = NULL;
    + msg->body_len = 0;
    + }
    + }
    + }
    +
    + if (body) {
    + g_free(msg->body);
    + msg->body = body;
    + msg->body_len = payload_len;
    + msn_message_set_charset(msg, "UTF-8");
    + }
    }
    g_free(tmp_base);