[Bug sanitizer/107698] New: ASAN misses a global-buffer-overflow

[Bug sanitizer/107698] New: ASAN misses a global-buffer-overflow

[shaohua.li at inf dot ethz.ch]

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
%

[Bug sanitizer/107698] ASAN misses a global-buffer-overflow

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107698

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |marxin at gcc dot gnu.org
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2022-11-15
             Status|UNCONFIRMED                 |ASSIGNED

--- Comment #1 from Martin Liška <marxin at gcc dot gnu.org> ---
I think it's a variation of https://github.com/google/sanitizers/issues/869,
but I will take a look deeper.

[Bug sanitizer/107698] ASAN misses a global-buffer-overflow

[shaohua.li at inf dot ethz.ch]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107698

--- Comment #2 from Li Shaohua <shaohua.li at inf dot ethz.ch> ---
I found a new test where gcc-O1 misses the global-buffer-overflow. Not sure if
these two have the same root cause:

% cat a.c
int a, c;
int *b = &a;
int main() {
  int d = *b;
  for (; c < 3; c++)
    b = b + (d == *b);
}
%
% gcc-tk -O1 -fsanitize=address a.c && ./a.out
%
% gcc-tk -O3 -fsanitize=address a.c && ./a.out
=================================================================
==3536571==ERROR: AddressSanitizer: global-buffer-overflow on address
0x000000404204 at pc 0x000000401130 bp 0x7ffe232ffd40 sp 0x7ffe232ffd38
...
%

[Bug sanitizer/107698] ASAN misses a global-buffer-overflow

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107698

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |DUPLICATE

--- Comment #3 from Martin Liška <marxin at gcc dot gnu.org> ---
Dup of PR106558, it's fixed now.

*** This bug has been marked as a duplicate of bug 106558 ***