https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107698
Bug ID: 107698
Summary: ASAN misses a global-buffer-overflow
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: sanitizer
Assignee: unassigned at gcc dot gnu.org
Reporter: shaohua.li at inf dot ethz.ch
CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
jakub at gcc dot gnu.org, kcc at gcc dot gnu.org, marxin at
gcc dot gnu.org
Target Milestone: ---
For the following code, `gcc-trunk -O1 -fsanitize=address` misses the
global-buffer-overflow, while `gcc-trunk -Ox -fsanitize=address` (x=0,2,3, or
s) can detect it.
clang can detect it at all optimization levels.
Compiler explorer: https://godbolt.org/z/5Tcjrc4zf
% cat a.c
int a=0, d=1;
int *b = &a, *c = &a;
int main() {
*b = 0;
b = b + 1;
*c = 1;
*b = d;
}
%
% gcc-tk -O1 -fsanitize=address a.c && ./a.out
%
% gcc-tk -O3 -fsanitize=address a.c && ./a.out
=================================================================
==851733==ERROR: AddressSanitizer: global-buffer-overflow on address
0x000000404284 at pc 0x000000401130 bp 0x7ffd4cb2a6a0 sp 0x7ffd4cb2a698
WRITE of size 4 at 0x000000404284 thread T0
#0 0x40112f in main
/zdata/shaoli/sanitizertesting/mutate/synthesizer/bugs/work119_1/a.c:7
#1 0x7fb79dc33082 in __libc_start_main
(/lib/x86_64-linux-gnu/libc.so.6+0x24082) (BuildId:
1878e6b475720c7c51969e69ab2d276fae6d1dee)
#2 0x40119d in _start
(/zdata/shaoli/sanitizertesting/mutate/synthesizer/bugs/work119_1/a.out+0x40119d)
0x000000404284 is located 0 bytes to the right of global variable 'a' defined
in 'a.c:1:5' (0x404280) of size 4
SUMMARY: AddressSanitizer: global-buffer-overflow
/zdata/shaoli/sanitizertesting/mutate/synthesizer/bugs/work119_1/a.c:7 in main
Shadow bytes around the buggy address:
0x000080078800: 00 00 00 00 00 00 00 00 00 00 00 00 00 f9 f9 f9
0x000080078810: f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9 04 f9 f9 f9
0x000080078820: f9 f9 f9 f9 00 00 00 00 00 00 00 00 f9 f9 f9 f9
0x000080078830: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9
0x000080078840: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 00 00 00 00
=>0x000080078850:[04]f9 f9 f9 f9 f9 f9 f9 00 00 00 00 00 00 00 00
0x000080078860: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x000080078870: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x000080078880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x000080078890: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0000800788a0: 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
==851733==ABORTING
%
