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From: | Zhuo Zhang |
Subject: | [Tinycc-devel] AddressSanitizer: heap-buffer-overflow |
Date: | Thu, 11 Feb 2021 12:25:28 +0000 |
A heap-buffer overflow occurs in commit fbef90a7039b994907db34fde50f6fa5e46ab535 (ASAN on). System info: ubuntu 18.04, x86-64
$ cat poc.c
a() {
int b;
asm("" : : ""(b == 0), ""(b));
}
$ ./tcc poc.c
=================================================================
==33065==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x625000000098 at pc 0x00000061a8bd bp 0x7ffdac9d2490 sp 0x7ffdac9d2488
READ of size 2 at 0x625000000098 thread T0
#0 0x61a8bc (/root/git/tinycc/tcc+0x61a8bc)
#1 0x5e4588 (/root/git/tinycc/tcc+0x5e4588)
#2 0x589d3a (/root/git/tinycc/tcc+0x589d3a)
#3 0x588c25 (/root/git/tinycc/tcc+0x588c25)
#4 0x5afa26 (/root/git/tinycc/tcc+0x5afa26)
#5 0x5abf86 (/root/git/tinycc/tcc+0x5abf86)
#6 0x554412 (/root/git/tinycc/tcc+0x554412)
#7 0x51b550 (/root/git/tinycc/tcc+0x51b550)
#8 0x51d252 (/root/git/tinycc/tcc+0x51d252)
#9 0x51697a (/root/git/tinycc/tcc+0x51697a)
#10 0x7f2b7dfd7b96 in __libc_start_main /build/glibc-2ORdQG/glibc-2.27/csu/../csu/libc-start.c:310
#11 0x41a5d9 in pthread_getattr_np (/root/git/tinycc/tcc+0x41a5d9)
0x625000000098 is located 104 bytes to the left of 9296-byte region [0x625000000100,0x625000002550)
allocated by thread T0 here:
#0 0x4da490 in malloc (/root/git/tinycc/tcc+0x4da490)
#1 0x51879b (/root/git/tinycc/tcc+0x51879b)
#2 0x51b073 (/root/git/tinycc/tcc+0x51b073)
#3 0x51d252 (/root/git/tinycc/tcc+0x51d252)
#4 0x51697a (/root/git/tinycc/tcc+0x51697a)
#5 0x7f2b7dfd7b96 in __libc_start_main /build/glibc-2ORdQG/glibc-2.27/csu/../csu/libc-start.c:310
SUMMARY: AddressSanitizer: heap-buffer-overflow (/root/git/tinycc/tcc+0x61a8bc)
Shadow bytes around the buggy address:
0x0c4a7fff7fc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c4a7fff7fd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c4a7fff7fe0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c4a7fff7ff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c4a7fff8000: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
=>0x0c4a7fff8010: fa fa fa[fa]fa fa fa fa fa fa fa fa fa fa fa fa
0x0c4a7fff8020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c4a7fff8030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c4a7fff8040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c4a7fff8050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c4a7fff8060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
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
==33065==ABORTING
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