check buffer for possible overflow. Thanks Corydon76 Bug #788

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@1951 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index 8e963951ae205d10cef04ba77aebb577b467e7df..fc051d46645443e85083d04f76cca7fe48f1033d 100755 (executable)
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -4114,7 +4114,11 @@ static int get_msg_text(char *buf, int len, struct sip_request *req)
                y = 0;
        for (x=0;x<req->lines;x++) {
                strncat(buf, req->line[x], y);
-               strcat(buf, "\n");
+               y -= strlen(req->line[x]) + 1;
+               if (y < 0)
+                       y = 0;
+               if (y != 0)
+                       strcat(buf, "\n");
        }
        return 0;
 }