ALSA: usb-audio - Fix possible access over audio_feature_info[] array

The audio_feature_info[] array should contain all entries for UAC2_FU_*,
but currently a few last entries are missing.  Even though, the driver
tries to probe these entries in parse_audio_feature_unit() and may
access the range over the array.  This patch fixes the bug by limiting
the loop size properly using ARRAY_SIZE() instead of a hard-coded
magic number.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index b13b7ac..60f65ac 100644 (file)
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -1259,7 +1259,7 @@ static int parse_audio_feature_unit(struct mixer_build *state, int unitid, void
                                build_feature_ctl(state, _ftr, 0, i, &iterm, unitid, 0);
                }
        } else { /* UAC_VERSION_2 */
-               for (i = 0; i < 30/2; i++) {
+               for (i = 0; i < ARRAY_SIZE(audio_feature_info); i++) {
                        unsigned int ch_bits = 0;
                        unsigned int ch_read_only = 0;