* [ammarfaizi2-block:rostedt/linux-trace/ftrace/core 12/13] include/linux/fortify-string.h:47:30: error: '__builtin_strncat' output truncated before terminating nul copying as many bytes from a string as its length
@ 2022-02-13 22:42 kernel test robot
2022-02-14 16:57 ` Steven Rostedt
0 siblings, 1 reply; 2+ messages in thread
From: kernel test robot @ 2022-02-13 22:42 UTC (permalink / raw)
To: Tom Zanussi
Cc: kbuild-all, GNU/Weeb Mailing List, linux-kernel, Steven Rostedt (Google)
tree: https://github.com/ammarfaizi2/linux-block rostedt/linux-trace/ftrace/core
head: f125ef075cd648a7794aa0cc61a188b1c40c8f94
commit: a76d8704e28d6591e72ab79fd2807254bd79327e [12/13] tracing: Remove size restriction on hist trigger cmd error logging
config: i386-allyesconfig (https://download.01.org/0day-ci/archive/20220214/[email protected]/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
# https://github.com/ammarfaizi2/linux-block/commit/a76d8704e28d6591e72ab79fd2807254bd79327e
git remote add ammarfaizi2-block https://github.com/ammarfaizi2/linux-block
git fetch --no-tags ammarfaizi2-block rostedt/linux-trace/ftrace/core
git checkout a76d8704e28d6591e72ab79fd2807254bd79327e
# save the config file to linux build tree
mkdir build_dir
make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All errors (new ones prefixed by >>):
In file included from include/linux/string.h:253,
from arch/x86/include/asm/page_32.h:22,
from arch/x86/include/asm/page.h:14,
from arch/x86/include/asm/processor.h:19,
from arch/x86/include/asm/timex.h:5,
from include/linux/timex.h:65,
from include/linux/time32.h:13,
from include/linux/time.h:60,
from include/linux/stat.h:19,
from include/linux/module.h:13,
from kernel/trace/trace_events_hist.c:8:
In function 'strncat',
inlined from 'last_cmd_set' at kernel/trace/trace_events_hist.c:759:2:
>> include/linux/fortify-string.h:47:30: error: '__builtin_strncat' output truncated before terminating nul copying as many bytes from a string as its length [-Werror=stringop-truncation]
47 | #define __underlying_strncat __builtin_strncat
| ^
include/linux/fortify-string.h:191:10: note: in expansion of macro '__underlying_strncat'
191 | return __underlying_strncat(p, q, count);
| ^~~~~~~~~~~~~~~~~~~~
kernel/trace/trace_events_hist.c: In function 'last_cmd_set':
include/linux/fortify-string.h:46:29: note: length computed here
46 | #define __underlying_strlen __builtin_strlen
| ^
include/linux/fortify-string.h:102:10: note: in expansion of macro '__underlying_strlen'
102 | return __underlying_strlen(p);
| ^~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
vim +/__builtin_strncat +47 include/linux/fortify-string.h
3009f891bb9f32 Kees Cook 2021-08-02 26
a28a6e860c6cf2 Francis Laniel 2021-02-25 27 #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
a28a6e860c6cf2 Francis Laniel 2021-02-25 28 extern void *__underlying_memchr(const void *p, int c, __kernel_size_t size) __RENAME(memchr);
a28a6e860c6cf2 Francis Laniel 2021-02-25 29 extern int __underlying_memcmp(const void *p, const void *q, __kernel_size_t size) __RENAME(memcmp);
a28a6e860c6cf2 Francis Laniel 2021-02-25 30 extern void *__underlying_memcpy(void *p, const void *q, __kernel_size_t size) __RENAME(memcpy);
a28a6e860c6cf2 Francis Laniel 2021-02-25 31 extern void *__underlying_memmove(void *p, const void *q, __kernel_size_t size) __RENAME(memmove);
a28a6e860c6cf2 Francis Laniel 2021-02-25 32 extern void *__underlying_memset(void *p, int c, __kernel_size_t size) __RENAME(memset);
a28a6e860c6cf2 Francis Laniel 2021-02-25 33 extern char *__underlying_strcat(char *p, const char *q) __RENAME(strcat);
a28a6e860c6cf2 Francis Laniel 2021-02-25 34 extern char *__underlying_strcpy(char *p, const char *q) __RENAME(strcpy);
a28a6e860c6cf2 Francis Laniel 2021-02-25 35 extern __kernel_size_t __underlying_strlen(const char *p) __RENAME(strlen);
a28a6e860c6cf2 Francis Laniel 2021-02-25 36 extern char *__underlying_strncat(char *p, const char *q, __kernel_size_t count) __RENAME(strncat);
a28a6e860c6cf2 Francis Laniel 2021-02-25 37 extern char *__underlying_strncpy(char *p, const char *q, __kernel_size_t size) __RENAME(strncpy);
a28a6e860c6cf2 Francis Laniel 2021-02-25 38 #else
a28a6e860c6cf2 Francis Laniel 2021-02-25 39 #define __underlying_memchr __builtin_memchr
a28a6e860c6cf2 Francis Laniel 2021-02-25 40 #define __underlying_memcmp __builtin_memcmp
a28a6e860c6cf2 Francis Laniel 2021-02-25 41 #define __underlying_memcpy __builtin_memcpy
a28a6e860c6cf2 Francis Laniel 2021-02-25 42 #define __underlying_memmove __builtin_memmove
a28a6e860c6cf2 Francis Laniel 2021-02-25 43 #define __underlying_memset __builtin_memset
a28a6e860c6cf2 Francis Laniel 2021-02-25 44 #define __underlying_strcat __builtin_strcat
a28a6e860c6cf2 Francis Laniel 2021-02-25 45 #define __underlying_strcpy __builtin_strcpy
a28a6e860c6cf2 Francis Laniel 2021-02-25 46 #define __underlying_strlen __builtin_strlen
a28a6e860c6cf2 Francis Laniel 2021-02-25 @47 #define __underlying_strncat __builtin_strncat
a28a6e860c6cf2 Francis Laniel 2021-02-25 48 #define __underlying_strncpy __builtin_strncpy
a28a6e860c6cf2 Francis Laniel 2021-02-25 49 #endif
a28a6e860c6cf2 Francis Laniel 2021-02-25 50
:::::: The code at line 47 was first introduced by commit
:::::: a28a6e860c6cf231cf3c5171c75c342adcd00406 string.h: move fortified functions definitions in a dedicated header.
:::::: TO: Francis Laniel <[email protected]>
:::::: CC: Linus Torvalds <[email protected]>
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [ammarfaizi2-block:rostedt/linux-trace/ftrace/core 12/13] include/linux/fortify-string.h:47:30: error: '__builtin_strncat' output truncated before terminating nul copying as many bytes from a string as its length
2022-02-13 22:42 [ammarfaizi2-block:rostedt/linux-trace/ftrace/core 12/13] include/linux/fortify-string.h:47:30: error: '__builtin_strncat' output truncated before terminating nul copying as many bytes from a string as its length kernel test robot
@ 2022-02-14 16:57 ` Steven Rostedt
0 siblings, 0 replies; 2+ messages in thread
From: Steven Rostedt @ 2022-02-14 16:57 UTC (permalink / raw)
To: kernel test robot
Cc: Tom Zanussi, kbuild-all, GNU/Weeb Mailing List, linux-kernel
On Mon, 14 Feb 2022 06:42:59 +0800
kernel test robot <[email protected]> wrote:
> All errors (new ones prefixed by >>):
>
> In file included from include/linux/string.h:253,
> from arch/x86/include/asm/page_32.h:22,
> from arch/x86/include/asm/page.h:14,
> from arch/x86/include/asm/processor.h:19,
> from arch/x86/include/asm/timex.h:5,
> from include/linux/timex.h:65,
> from include/linux/time32.h:13,
> from include/linux/time.h:60,
> from include/linux/stat.h:19,
> from include/linux/module.h:13,
> from kernel/trace/trace_events_hist.c:8:
> In function 'strncat',
> inlined from 'last_cmd_set' at
> kernel/trace/trace_events_hist.c:759:2:
> >> include/linux/fortify-string.h:47:30: error: '__builtin_strncat'
> >> output truncated before terminating nul copying as many bytes from a
> >> string as its length [-Werror=stringop-truncation]
> 47 | #define __underlying_strncat __builtin_strncat
> | ^
> include/linux/fortify-string.h:191:10: note: in expansion of macro
> '__underlying_strncat' 191 | return __underlying_strncat(p, q, count);
> | ^~~~~~~~~~~~~~~~~~~~
> kernel/trace/trace_events_hist.c: In function 'last_cmd_set':
> include/linux/fortify-string.h:46:29: note: length computed here
> 46 | #define __underlying_strlen __builtin_strlen
> | ^
> include/linux/fortify-string.h:102:10: note: in expansion of macro
> '__underlying_strlen' 102 | return __underlying_strlen(p);
> | ^~~~~~~~~~~~~~~~~~~
> cc1: all warnings being treated as errors
I have no idea what the above riddle is saying. But looking at the code, I
can figure out a few issues with it.
> static void last_cmd_set(struct trace_event_file *file, char *str)
> {
> const char *system = NULL, *name = NULL;
> struct trace_event_call *call;
> int len = 0;
>
> if (!str)
> return;
>
> len += sizeof(HIST_PREFIX) + strlen(str) + 1;
Nit, I have no idea why len has += and is initialized to zero. Looks like
it could have just been:
len = sizeof(HIST_PREFIX) + strlen(str) + 1;
> kfree(last_cmd);
> last_cmd = kzalloc(len, GFP_KERNEL);
> if (!last_cmd)
> return;
>
> strcpy(last_cmd, HIST_PREFIX);
> strncat(last_cmd, str, len - sizeof(HIST_PREFIX));
OK, I think the issue here is that "len" contains the "+1" for the nul
byte. According to the man page for strncat(), it states that "dest" needs
to be at least strlen(dest)+n+1. And since len has + 1 in it already, it
can't have it in the strncat().
Perhaps we need to change this to:
len -= sizeof(HIST_PREFIX) + 1;
strncat(last_cmd, str, len);
-- Steve
>
> if (file) {
> call = file->event_call;
> system = call->class->system;
> if (system) {
> name = trace_event_name(call);
> if (!name)
> system = NULL;
> }
> }
>
> if (system)
> snprintf(last_cmd_loc, MAX_FILTER_STR_VAL, HIST_PREFIX "%s:%s", system, name); }
^ permalink raw reply [flat|nested] 2+ messages in thread
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2022-02-13 22:42 [ammarfaizi2-block:rostedt/linux-trace/ftrace/core 12/13] include/linux/fortify-string.h:47:30: error: '__builtin_strncat' output truncated before terminating nul copying as many bytes from a string as its length kernel test robot
2022-02-14 16:57 ` Steven Rostedt
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