On 10/4/23 01:28, 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 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 snd_soc_dapm_widget_list.
Additionally, since the element count member must be set before accessing
the annotated flexible array member, move its initialization earlier.
Cc: Liam Girdwood <lgirdwood@xxxxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxx>
Cc: Jaroslav Kysela <perex@xxxxxxxx>
Cc: Takashi Iwai <tiwai@xxxxxxxx>
Cc: "Gustavo A. R. Silva" <gustavoars@xxxxxxxxxx>
Cc: alsa-devel@xxxxxxxxxxxxxxxx
Cc: linux-hardening@xxxxxxxxxxxxxxx
Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Reviewed-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
Thanks
--
Gustavo
---
include/sound/soc-dapm.h | 2 +-
sound/soc/soc-dapm.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/sound/soc-dapm.h b/include/sound/soc-dapm.h
index d2faec9a323e..51516c93916e 100644
--- a/include/sound/soc-dapm.h
+++ b/include/sound/soc-dapm.h
@@ -717,7 +717,7 @@ struct snd_soc_dapm_context {
/* A list of widgets associated with an object, typically a snd_kcontrol */
struct snd_soc_dapm_widget_list {
int num_widgets;
- struct snd_soc_dapm_widget *widgets[];
+ struct snd_soc_dapm_widget *widgets[] __counted_by(num_widgets);
};
#define for_each_dapm_widgets(list, i, widget) \
diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c
index 2512aadf95f7..2e3df47c9cf3 100644
--- a/sound/soc/soc-dapm.c
+++ b/sound/soc/soc-dapm.c
@@ -497,8 +497,8 @@ static int dapm_kcontrol_add_widget(struct snd_kcontrol *kcontrol,
if (!new_wlist)
return -ENOMEM;
- new_wlist->widgets[n - 1] = widget;
new_wlist->num_widgets = n;
+ new_wlist->widgets[n - 1] = widget;
data->wlist = new_wlist;
