ALSA: usb-audio: avoid integer overflow in create_fixed_stream_quirk()

A malicious USB device could feed in a large nr_rates value.  This would
cause the subsequent call to kmemdup() to allocate a smaller buffer than
expected, leading to out-of-bounds access.

This patch validates the nr_rates value and reuses the limit introduced
in commit 4fa0e81b ("ALSA: usb-audio: fix possible hang and overflow
in parse_uac2_sample_rate_range()").

Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Xi Wang
2012-02-14 05:18:48 -05:00
committed by Takashi Iwai
parent 27c3afe6e1
commit 8866f405ef
3 changed files with 7 additions and 4 deletions

View File

@@ -132,10 +132,14 @@ static int create_fixed_stream_quirk(struct snd_usb_audio *chip,
unsigned *rate_table = NULL;
fp = kmemdup(quirk->data, sizeof(*fp), GFP_KERNEL);
if (! fp) {
if (!fp) {
snd_printk(KERN_ERR "cannot memdup\n");
return -ENOMEM;
}
if (fp->nr_rates > MAX_NR_RATES) {
kfree(fp);
return -EINVAL;
}
if (fp->nr_rates > 0) {
rate_table = kmemdup(fp->rate_table,
sizeof(int) * fp->nr_rates, GFP_KERNEL);