include/linux/fortify-string.h:57:33: warning: '__builtin_memcpy' offset -32 is out of the bounds of object 'boot_command_line' with type 'char[]'

From: kernel test robot
Date: Tue Sep 19 2023 - 14:50:10 EST


tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 2cf0f715623872823a72e451243bbf555d10d032
commit: 55c84a5cf2c72a821719823ef2ebef01b119025b fortify: strcat: Move definition to use fortified strlcat()
date: 4 months ago
config: s390-randconfig-r016-20211009 (https://download.01.org/0day-ci/archive/20230920/202309200205.bFzhzjRt-lkp@xxxxxxxxx/config)
compiler: s390-linux-gcc (GCC) 11.3.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20230920/202309200205.bFzhzjRt-lkp@xxxxxxxxx/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202309200205.bFzhzjRt-lkp@xxxxxxxxx/

All warnings (new ones prefixed by >>):

In file included from include/linux/string.h:254,
from include/linux/bitmap.h:11,
from include/linux/cpumask.h:12,
from include/linux/smp.h:13,
from include/linux/lockdep.h:14,
from include/linux/rcupdate.h:29,
from include/linux/rculist.h:11,
from include/linux/pid.h:5,
from include/linux/sched.h:14,
from arch/s390/kernel/setup.c:21:
In function 'strlcat',
inlined from 'strcat' at include/linux/fortify-string.h:432:6,
inlined from 'setup_zfcpdump' at arch/s390/kernel/setup.c:308:2,
inlined from 'setup_arch' at arch/s390/kernel/setup.c:1008:2:
include/linux/fortify-string.h:406:19: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]
406 | p[actual] = '\0';
| ~~~~~~~~~~^~~~~~
In file included from include/linux/printk.h:6,
from include/asm-generic/bug.h:22,
from arch/s390/include/asm/bug.h:69,
from include/linux/bug.h:5,
from include/linux/mmdebug.h:5,
from arch/s390/include/asm/cmpxchg.h:11,
from arch/s390/include/asm/atomic.h:16,
from include/linux/atomic.h:7,
from include/linux/rcupdate.h:25,
from include/linux/rculist.h:11,
from include/linux/pid.h:5,
from include/linux/sched.h:14,
from arch/s390/kernel/setup.c:21:
arch/s390/kernel/setup.c: In function 'setup_arch':
include/linux/init.h:146:24: note: at offset -2 into destination object 'boot_command_line' of size [0, 9223372036854775807]
146 | extern char __initdata boot_command_line[];
| ^~~~~~~~~~~~~~~~~
In file included from include/linux/string.h:254,
from include/linux/bitmap.h:11,
from include/linux/cpumask.h:12,
from include/linux/smp.h:13,
from include/linux/lockdep.h:14,
from include/linux/rcupdate.h:29,
from include/linux/rculist.h:11,
from include/linux/pid.h:5,
from include/linux/sched.h:14,
from arch/s390/kernel/setup.c:21:
In function 'strlcat',
inlined from 'strcat' at include/linux/fortify-string.h:432:6,
inlined from 'setup_zfcpdump' at arch/s390/kernel/setup.c:308:2,
inlined from 'setup_arch' at arch/s390/kernel/setup.c:1008:2:
>> include/linux/fortify-string.h:57:33: warning: '__builtin_memcpy' offset -32 is out of the bounds of object 'boot_command_line' with type 'char[]' [-Warray-bounds]
57 | #define __underlying_memcpy __builtin_memcpy
| ^
include/linux/fortify-string.h:405:9: note: in expansion of macro '__underlying_memcpy'
405 | __underlying_memcpy(p + p_len, q, copy_len);
| ^~~~~~~~~~~~~~~~~~~
In file included from include/linux/printk.h:6,
from include/asm-generic/bug.h:22,
from arch/s390/include/asm/bug.h:69,
from include/linux/bug.h:5,
from include/linux/mmdebug.h:5,
from arch/s390/include/asm/cmpxchg.h:11,
from arch/s390/include/asm/atomic.h:16,
from include/linux/atomic.h:7,
from include/linux/rcupdate.h:25,
from include/linux/rculist.h:11,
from include/linux/pid.h:5,
from include/linux/sched.h:14,
from arch/s390/kernel/setup.c:21:
arch/s390/kernel/setup.c: In function 'setup_arch':
include/linux/init.h:146:24: note: 'boot_command_line' declared here
146 | extern char __initdata boot_command_line[];
| ^~~~~~~~~~~~~~~~~


vim +57 include/linux/fortify-string.h

78a498c3a227f2 Alexander Potapenko 2022-10-24 46
78a498c3a227f2 Alexander Potapenko 2022-10-24 47 #if defined(__SANITIZE_MEMORY__)
78a498c3a227f2 Alexander Potapenko 2022-10-24 48 /*
78a498c3a227f2 Alexander Potapenko 2022-10-24 49 * For KMSAN builds all memcpy/memset/memmove calls should be replaced by the
78a498c3a227f2 Alexander Potapenko 2022-10-24 50 * corresponding __msan_XXX functions.
78a498c3a227f2 Alexander Potapenko 2022-10-24 51 */
78a498c3a227f2 Alexander Potapenko 2022-10-24 52 #include <linux/kmsan_string.h>
78a498c3a227f2 Alexander Potapenko 2022-10-24 53 #define __underlying_memcpy __msan_memcpy
78a498c3a227f2 Alexander Potapenko 2022-10-24 54 #define __underlying_memmove __msan_memmove
78a498c3a227f2 Alexander Potapenko 2022-10-24 55 #define __underlying_memset __msan_memset
78a498c3a227f2 Alexander Potapenko 2022-10-24 56 #else
a28a6e860c6cf2 Francis Laniel 2021-02-25 @57 #define __underlying_memcpy __builtin_memcpy
a28a6e860c6cf2 Francis Laniel 2021-02-25 58 #define __underlying_memmove __builtin_memmove
a28a6e860c6cf2 Francis Laniel 2021-02-25 59 #define __underlying_memset __builtin_memset
78a498c3a227f2 Alexander Potapenko 2022-10-24 60 #endif
78a498c3a227f2 Alexander Potapenko 2022-10-24 61

:::::: The code at line 57 was first introduced by commit
:::::: a28a6e860c6cf231cf3c5171c75c342adcd00406 string.h: move fortified functions definitions in a dedicated header.

:::::: TO: Francis Laniel <laniel_francis@xxxxxxxxxxxxxxxxxxx>
:::::: CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>

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