Add a separate buffer for SRTCP packets

The function ast_srtp_protect used a common buffer for both SRTP and SRTCP
packets. Since this function can be called from multiple threads for the same
SRTP session (scheduler for SRTCP and channel for SRTP) it was possible for the
packets to become corrupted as the buffer was used by both threads
simultaneously.

This patch adds a separate buffer for SRTCP packets to avoid the problem.

(closes issue ASTERISK-18889, Reported/patch by Daniel Collins)

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@347995 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/res/res_srtp.c b/res/res_srtp.c
index fe1ee73ced4a506a62925672e950e76257be2655..a232314fae8a2d468492424964099f373fe943e9 100644 (file)
--- a/res/res_srtp.c
+++ b/res/res_srtp.c
@@ -56,6 +56,7 @@ struct ast_srtp {
        void *data;
        int warned;
        unsigned char buf[8192 + AST_FRIENDLY_OFFSET];
+       unsigned char rtcpbuf[8192 + AST_FRIENDLY_OFFSET];
 };
 
 struct ast_srtp_policy {
@@ -401,19 +402,22 @@ static int ast_srtp_unprotect(struct ast_srtp *srtp, void *buf, int *len, int rt
 static int ast_srtp_protect(struct ast_srtp *srtp, void **buf, int *len, int rtcp)
 {
        int res;
+       unsigned char *localbuf;
 
        if ((*len + SRTP_MAX_TRAILER_LEN) > sizeof(srtp->buf)) {
                return -1;
        }
+       
+       localbuf = rtcp ? srtp->rtcpbuf : srtp->buf;
 
-       memcpy(srtp->buf, *buf, *len);
+       memcpy(localbuf, *buf, *len);
 
-       if ((res = rtcp ? srtp_protect_rtcp(srtp->session, srtp->buf, len) : srtp_protect(srtp->session, srtp->buf, len)) != err_status_ok && res != err_status_replay_fail) {
+       if ((res = rtcp ? srtp_protect_rtcp(srtp->session, localbuf, len) : srtp_protect(srtp->session, localbuf, len)) != err_status_ok && res != err_status_replay_fail) {
                ast_log(LOG_WARNING, "SRTP protect: %s\n", srtp_errstr(res));
                return -1;
        }
 
-       *buf = srtp->buf;
+       *buf = localbuf;
        return *len;
 }