Re: [PATCH] ALSA: hda: Annotate struct hda_conn_list with __counted_by

From: Gustavo A. R. Silva
Date: Sat Sep 23 2023 - 08:23:07 EST




On 9/22/23 11:50, Kees Cook wrote:
Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct hda_conn_list.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: Jaroslav Kysela <perex@xxxxxxxx>
Cc: Takashi Iwai <tiwai@xxxxxxxx>
Cc: Cezary Rojewski <cezary.rojewski@xxxxxxxxx>
Cc: alsa-devel@xxxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>

Reviewed-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>

Thanks
--
Gustavo

---
sound/pci/hda/hda_codec.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index 33af707a65ab..01718b1fc9a7 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -88,7 +88,7 @@ struct hda_conn_list {
struct list_head list;
int len;
hda_nid_t nid;
- hda_nid_t conns[];
+ hda_nid_t conns[] __counted_by(len);
};
/* look up the cached results */