From d0495f4139f36079b2d3d6745f94f45646d2d36a Mon Sep 17 00:00:00 2001 From: Scott Griepentrog Date: Fri, 14 Nov 2014 15:46:30 +0000 Subject: [PATCH] stun: correct attribute string padding to match rfc When sending the USERNAME attribute in an RTP STUN response, the implementation in append_attr_string passed the actual length, instead of padding it up to a multiple of four bytes as required by the RFC 3489. This change adds separate variables for the string and padded attributed lengths, and performs padding correctly. Reported by: Thomas Arimont Review: https://reviewboard.asterisk.org/r/4139/ git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/11@427874 65c4cc65-6c06-0410-ace0-fbb531ad65f3 --- main/stun.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/main/stun.c b/main/stun.c index 268bbe4dec..e0a25594f6 100644 --- a/main/stun.c +++ b/main/stun.c @@ -201,12 +201,15 @@ static int stun_process_attr(struct stun_state *state, struct stun_attr *attr) /*! \brief append a string to an STUN message */ static void append_attr_string(struct stun_attr **attr, int attrval, const char *s, int *len, int *left) { - int size = sizeof(**attr) + strlen(s); + int str_length = strlen(s); + int attr_length = str_length + ((~(str_length - 1)) & 0x3); + int size = sizeof(**attr) + attr_length; if (*left > size) { (*attr)->attr = htons(attrval); - (*attr)->len = htons(strlen(s)); - memcpy((*attr)->value, s, strlen(s)); - (*attr) = (struct stun_attr *)((*attr)->value + strlen(s)); + (*attr)->len = htons(attr_length); + memcpy((*attr)->value, s, str_length); + memset((*attr)->value + str_length, 0, attr_length - str_length); + (*attr) = (struct stun_attr *)((*attr)->value + attr_length); *len += size; *left -= size; }