Bug#862556: heap-buffer-overflow vulnerability in the SIZECHCK
Package: libytnef
Version: 1.5-6+deb8u1
Severity: normal
Tags: security
Hi,
We found a heap-buffer-overflow vulnerability in the libytnef.
This affects both 1.5-6+deb8u1 and 1.9.1 .
The cause is an incorrect boundary checking in SIZECHCK macro in lib/ytnef.c:39
-- #define SIZECHECK(x) { if ((((char *)d - (char *)data) + x) >
size) { printf("Corrupted file detected at %s : %i\n", __FILE__,
__LINE__); return(-1); } }
++ #define SIZECHECK(x) { if ((((char *)d - (char *)data) + x) >=
size) { printf("Corrupted file detected at %s : %i\n", __FILE__,
__LINE__); return(-1); } }
To verify this, use the testcase from:
https://github.com/bingosxs/fuzzdata/blob/master/ytnef-1.9/TNEFFreeMapiProps-Invalid-read.tnef?raw=true
run the sample with command:
ytnef/.libs/ytnef -v @@
The tracelog is:
=================================================================
==15221==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60200000ef90 at pc 0x7f7f8986e69f bp 0x7ffe3fc1b820 sp 0x7ffe3fc1b818
READ of size 4 at 0x60200000ef90 thread T0
#0 0x7f7f8986e69e in SwapDWord /home/canicula/afl/test/libytnef0/libytnef-1.5.x/ytnef.c:136:12
#1 0x7f7f8986e69e in TNEFPriority /home/canicula/afl/test/libytnef0/libytnef-1.5.x/ytnef.c:670
#2 0x7f7f8987ac87 in TNEFParse /home/canicula/afl/test/libytnef0/libytnef-1.5.x/ytnef.c:1076:29
#3 0x7f7f8987997f in TNEFParseFile /home/canicula/afl/test/libytnef0/libytnef-1.5.x/ytnef.c:936:12
#4 0x4ea71b in main /home/canicula/afl/test/ytnef.0/ytnef/main.c:125:9
#5 0x7f7f8897782f in __libc_start_main /build/glibc-9tT8Do/glibc-2.23/csu/../csu/libc-start.c:291
#6 0x418bd8 in _start (/data/canicula/afl/test/ytnef.0/ytnef/.libs/ytnef+0x418bd8)
0x60200000ef92 is located 0 bytes to the right of 2-byte region [0x60200000ef90,0x60200000ef92)
allocated by thread T0 here:
#0 0x4b8e90 in calloc (/data/canicula/afl/test/ytnef.0/ytnef/.libs/ytnef+0x4b8e90)
#1 0x7f7f8987a29d in TNEFParse /home/canicula/afl/test/libytnef0/libytnef-1.5.x/ytnef.c:1046:20
#2 0x7f7f8987997f in TNEFParseFile /home/canicula/afl/test/libytnef0/libytnef-1.5.x/ytnef.c:936:12
#3 0x4ea71b in main /home/canicula/afl/test/ytnef.0/ytnef/main.c:125:9
#4 0x7f7f8897782f in __libc_start_main /build/glibc-9tT8Do/glibc-2.23/csu/../csu/libc-start.c:291
SUMMARY: AddressSanitizer: heap-buffer-overflow /home/canicula/afl/test/libytnef0/libytnef-1.5.x/ytnef.c:136:12 in SwapDWord
Shadow bytes around the buggy address:
0x0c047fff9da0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9db0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9dc0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9dd0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9de0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
=>0x0c047fff9df0: fa fa[02]fa fa fa 00 fa fa fa fd fa fa fa fd fa
0x0c047fff9e00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9e10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9e20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9e30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9e40: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Heap right redzone: fb
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack partial redzone: f4
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
==15221==ABORTING
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