On 7/30/20 03:41, Takashi Iwai wrote:
On Thu, 30 Jul 2020 00:18:29 +0200, Gustavo A. R. Silva wrote:
Make use of the flex_array_size() helper to calculate the size of a flexible array member within an enclosing structure.
This helper offers defense-in-depth against potential integer overflows and makes it explicitly clear that we are dealing with a flexible array member.
Signed-off-by: Gustavo A. R. Silva gustavoars@kernel.org
sound/core/vmaster.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/sound/core/vmaster.c b/sound/core/vmaster.c index ab36f9898711..21ce4082cb5f 100644 --- a/sound/core/vmaster.c +++ b/sound/core/vmaster.c @@ -262,7 +262,8 @@ int _snd_ctl_add_follower(struct snd_kcontrol *master, return -ENOMEM; srec->kctl = follower; srec->follower = *follower;
- memcpy(srec->follower.vd, follower->vd, follower->count * sizeof(*follower->vd));
- memcpy(srec->follower.vd, follower->vd, flex_array_size(srec, follower.vd,
srec->follower.count));Changing from follower->count to srec->follower.count isn't obvious, so it should have been mentioned in the log; other than that, the code change looks good.
Yeah; you're right. I'll include that in the changelog text.
But since the API isn't in Linus tree yet, I'll postpone the merge until the API reaches to upstream. Maybe I can merge this during RC1 merge window, as those are trivial.
The API is already in mainline, see: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/incl...
BTW, looking at those patterns, I wonder whether it'd make sense to make the whole memset() call as a macro like
safe_copy_array(srec->follower.vd, follower->vd, follower->count);
?
Yep; I was actually thinking about that, yesterday. I might implement it for the next development cycle. :)
Thanks for the feedback. -- Gustavo