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> --- 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; -- 2.34.1
