From 6dd87a82a733184df3a6f09e020f6a3c2b365ca2 Mon Sep 17 00:00:00 2001 From: Jeremy Allison Date: Wed, 20 Sep 2017 11:04:50 -0700 Subject: [PATCH] s3: smbd: Chain code can return uninitialized memory when talloc buffer is grown. Ensure we zero out unused grown area. CVE-2017-15275 BUG: https://bugzilla.samba.org/show_bug.cgi?id=13077 Signed-off-by: Jeremy Allison --- source3/smbd/srvstr.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/source3/smbd/srvstr.c b/source3/smbd/srvstr.c index 56dceba8c6c..c2d70b32c32 100644 --- a/source3/smbd/srvstr.c +++ b/source3/smbd/srvstr.c @@ -110,6 +110,20 @@ ssize_t message_push_string(uint8_t **outbuf, const char *str, int flags) DEBUG(0, ("srvstr_push failed\n")); return -1; } + + /* + * Ensure we clear out the extra data we have + * grown the buffer by, but not written to. + */ + if (buf_size + result < buf_size) { + return -1; + } + if (grow_size < result) { + return -1; + } + + memset(tmp + buf_size + result, '\0', grow_size - result); + set_message_bcc((char *)tmp, smb_buflen(tmp) + result); *outbuf = tmp; -- 2.14.2.920.gcf0c67979c-goog