https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107696
Bug ID: 107696
Summary: GCC trunk misses a stack-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 -O0 -fsanitize=address` misses the
stack-buffer-overflow, while `gcc-trunk -Ox -fsanitize=address` (x=1,2,3, or s)
can detect it.
clang can detect it at all optimization levels.
gcc-8 can detect it at all optimization levels.
Compiler explorer: https://godbolt.org/z/z18Kzhxq5
% cat a.c
int main() {
int i;
int a[1];
for (; i < 1;){
i = 2;
a[i] = 1;
}
__builtin_printf("%d\n", a[i]);
}
%
% gcc-tk -O0 -fsanitize=address a.c &&./a.out
0
% gcc-tk -O3 -fsanitize=address a.c &&./a.out
=================================================================
==1940238==ERROR: AddressSanitizer: stack-buffer-overflow on address
0x7f9590400028 at pc 0x000000401147 bp 0x7fff56ba4240 sp 0x7fff56ba4238
READ of size 4 at 0x7f9590400028 thread T0
#0 0x401146 in main
/zdata/shaoli/sanitizertesting/mutate/synthesizer/bugs/gcc_work1_0/a.c:8
#1 0x7f9592de7082 in __libc_start_main
(/lib/x86_64-linux-gnu/libc.so.6+0x24082) (BuildId:
1878e6b475720c7c51969e69ab2d276fae6d1dee)
#2 0x4011dd in _start
(/zdata/shaoli/sanitizertesting/mutate/synthesizer/bugs/gcc_work1_0/a.out+0x4011dd)
Address 0x7f9590400028 is located in stack of thread T0 at offset 40 in frame
#0 0x4010bf in main
/zdata/shaoli/sanitizertesting/mutate/synthesizer/bugs/gcc_work1_0/a.c:1
This frame has 1 object(s):
[32, 36) 'a' (line 3) <== Memory access at offset 40 overflows this
variable
HINT: this may be a false positive if your program uses some custom stack
unwind mechanism, swapcontext or vfork
(longjmp and C++ exceptions *are* supported)
SUMMARY: AddressSanitizer: stack-buffer-overflow
/zdata/shaoli/sanitizertesting/mutate/synthesizer/bugs/gcc_work1_0/a.c:8 in
main
Shadow bytes around the buggy address:
0x0ff332077fb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0ff332077fc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0ff332077fd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0ff332077fe0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0ff332077ff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0ff332078000: f1 f1 f1 f1 04[f3]f3 f3 00 00 00 00 00 00 00 00
0x0ff332078010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0ff332078020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0ff332078030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0ff332078040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0ff332078050: 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
==1940238==ABORTING
%
% gcc-tk -v
Using built-in specs.
COLLECT_GCC=gcc-tk
COLLECT_LTO_WRAPPER=/zdata/shaoli/compilers/ccbuilder-compilers/gcc-7ca912b46e0eb45ebefeb0eda4c28afe1513d272/libexec/gcc/x86_64-pc-linux-gnu/13.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../configure --disable-multilib --disable-bootstrap
--enable-languages=c,c++
--prefix=/zdata/shaoli/compilers/ccbuilder-compilers/gcc-7ca912b46e0eb45ebefeb0eda4c28afe1513d272
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 13.0.0 20221108 (experimental) (GCC)
%
