Dear gobbles (at) hushmail (dot) com [email concealed],

Beside all the noise: it's trivial stack overflow due to invalid maximum
frame size calculation in mpg123. Maximum frame size is defined to be
1792 (mpglib/mpg123.h) and 1920 (common.c where overflow probably
actually occures). Gobblez construct frame (160 * 144000)/8000 + 1 - 4 =
2877 bytes. Maximum frame may be constructed is probably (384 *
144000)/16000 + 1 - 4 = 3453 bytes. Redefining MAX_INPUT_FRAMESIZE to
4096 should probably fix the problem. mpg123.h (not one from mpglib, but
one from mpg123 itself) already has MAXFRAMESIZE defined as 4096. It
also could be nice to add fr->framesize check. Fix below. I'm too lazy
to test it.

If there are any programs using same mpglib they are vulnerable too.

--- common.old 2003-01-15 20:18:14.000000000 +0300
+++ common.c 2003-01-15 20:25:26.000000000 +0300
@@ -140,7 +140,7 @@
* -1: giving up
* 1: synched
*/
-#define MAX_INPUT_FRAMESIZE 1920
+#define MAX_INPUT_FRAMESIZE 4096
#define SYNC_HEAD_MASK 0xffff0000
#define SYNC_HEAD_MASK_FF 0x0000f000
#define LOOK_AHEAD_NUM 3
@@ -237,6 +237,8 @@
}
}
else {
+ if(frameInfo.framesize > MAX_INPUT_FRAMESIZE) return 0;
+
if(!rds->read_frame_body(rds,dummybuf,frameInfo.framesize))
return 0;

--Monday, January 13, 2003, 9:23:18 PM, you wrote to bugtraq (at) securityfocus (dot) com [email concealed]:

ghc> Affected Software: mpg123 (pre0.59s) http://www.mpg123.de

--
~/ZARAZA
You know my name - look up my number (Beatles)

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