[asterisk-bugs] [JIRA] (ASTERISK-21198) a potential problem in chan_sip
Rusty Newton (JIRA)
noreply at issues.asterisk.org
Fri Mar 1 09:58:18 CST 2013
Rusty Newton created ASTERISK-21198:
---------------------------------------
Summary: a potential problem in chan_sip
Key: ASTERISK-21198
URL: https://issues.asterisk.org/jira/browse/ASTERISK-21198
Project: Asterisk
Issue Type: Bug
Security Level: None
Components: Channels/chan_mgcp
Affects Versions: 11.2.1
Environment: FC 18
Reporter: adomjan
Severity: Critical
I've got from a bugy MTA a chunked message:
{noformat}
200 61838464 OK
I: 11B72
v=0
o=- 61838464 72562 IN IP4 10.252.5.203
s=-
c=IN IP4 10.252.5.203
b=AS:82
t=0 0
m=audio 53
{noformat}
asterisk crashed, when parsed the m line
{noformat}
#0 0x0000003f85478d50 in strlen () from /lib64/libc.so.6
No symbol table info available.
#1 0x00002aaab9a82e12 in process_sdp (sub=0x2aaaac4a3c10, req=0x40cf9010)
at chan_mgcp.c:2477
__old = 0x40cfbf61 ""
__len = <value optimized out>
__new = <value optimized out>
m = 0x40cf94b7 "audio 53"
c = <value optimized out>
a = <value optimized out>
host = "10.252.5.203", '\0' <repeats 245 times>
len = 10922
portno = 53
peercapability = <value optimized out>
peerNonCodecCapability = <value optimized out>
sin = {sin_family = 2, sin_port = 13568, sin_addr = {
{noformat}
it occured:
{noformat}
if (sscanf(m, "audio %30d RTP/AVP %n", &portno, &len) != 1) {
{noformat}
the len is unitialized no, the %30d initialized, return value will be 1, but the sscanf() never reach the %n position
fix:
{noformat}
len = 0;
if (sscanf(m, "audio %30d RTP/AVP %n", &portno, &len) != 1 || !len) {
ast_log(LOG_WARNING, "Unable to determine port number or codecs for RTP in '%s'\n", m);
return -1;
}
{noformat}
in another usege not needed:
{noformat}
if (sscanf(codecs, "%30d%n", &codec, &len) != 1) {
{noformat}
if return 1 here, the sscanf always will reach the %n positions
The sip channel driver is effected too many places
in chan_sip.c:
{noformat}
if ((media == SDP_AUDIO && ((sscanf(m, "audio %30u/%30u RTP/AVP %n", &x, &numberofports, &len) == 2 && len > 0)
{noformat}
the len value is checked, but missing the len = 0; before sscanf()
all asterisk versions are affected
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