korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-11 21:38:32 +08:00
Code Issues Packages Projects Releases Wiki Activity

ALSA: seq: Fix function prototype mismatch in snd_seq_expand_var_event

Browse Source 
With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG),
indirect call targets are validated against the expected function
pointer prototype to make sure the call target is valid to help mitigate
ROP attacks. If they are not identical, there is a failure at run time,
which manifests as either a kernel panic or thread getting killed.

seq_copy_in_user() and seq_copy_in_kernel() did not have prototypes
matching snd_seq_dump_func_t. Adjust this and remove the casts. There
are not resulting binary output differences.

This was found as a result of Clang's new -Wcast-function-type-strict
flag, which is more sensitive than the simpler -Wcast-function-type,
which only checks for type width mismatches.

Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/lkml/202211041527.HD8TLSE1-lkp@intel.com
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: alsa-devel@alsa-project.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221118232346.never.380-kees@kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Kees Cook 2022-11-18 15:23:50 -08:00 committed by Takashi Iwai
parent 1abfd71ee8
commit 05530ef7cf
1 changed files with 7 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
sound/core/seq/seq_memory.c
View File

@ -113,15 +113,19 @@ EXPORT_SYMBOL(snd_seq_dump_var_event);
* expand the variable length event to linear buffer space.
*/
static int seq_copy_in_kernel(char **bufptr, const void *src, int size)
static int seq_copy_in_kernel(void *ptr, void *src, int size)
{
char **bufptr = ptr;
memcpy(*bufptr, src, size);
*bufptr += size;
return 0;
}
static int seq_copy_in_user(char __user **bufptr, const void *src, int size)
static int seq_copy_in_user(void *ptr, void *src, int size)
{
char __user **bufptr = ptr;
if (copy_to_user(*bufptr, src, size))
return -EFAULT;
*bufptr += size;
@ -151,8 +155,7 @@ int snd_seq_expand_var_event(const struct snd_seq_event *event, int count, char
return newlen;
}
err = snd_seq_dump_var_event(event,
in_kernel ? (snd_seq_dump_func_t)seq_copy_in_kernel :
(snd_seq_dump_func_t)seq_copy_in_user,
in_kernel ? seq_copy_in_kernel : seq_copy_in_user,
&buf);
return err < 0 ? err : newlen;
}