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:
parent
27c3afe6e1
commit
8866f405ef
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@ -1,6 +1,7 @@
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#ifndef __USBAUDIO_CARD_H
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#ifndef __USBAUDIO_CARD_H
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#define __USBAUDIO_CARD_H
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#define __USBAUDIO_CARD_H
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#define MAX_NR_RATES 1024
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#define MAX_PACKS 20
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#define MAX_PACKS 20
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#define MAX_PACKS_HS (MAX_PACKS * 8) /* in high speed mode */
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#define MAX_PACKS_HS (MAX_PACKS * 8) /* in high speed mode */
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#define MAX_URBS 8
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#define MAX_URBS 8
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@ -209,8 +209,6 @@ static int parse_audio_format_rates_v1(struct snd_usb_audio *chip, struct audiof
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return 0;
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return 0;
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}
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}
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#define MAX_UAC2_NR_RATES 1024
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/*
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/*
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* Helper function to walk the array of sample rate triplets reported by
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* Helper function to walk the array of sample rate triplets reported by
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* the device. The problem is that we need to parse whole array first to
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* the device. The problem is that we need to parse whole array first to
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@ -255,7 +253,7 @@ static int parse_uac2_sample_rate_range(struct audioformat *fp, int nr_triplets,
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fp->rates |= snd_pcm_rate_to_rate_bit(rate);
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fp->rates |= snd_pcm_rate_to_rate_bit(rate);
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nr_rates++;
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nr_rates++;
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if (nr_rates >= MAX_UAC2_NR_RATES) {
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if (nr_rates >= MAX_NR_RATES) {
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snd_printk(KERN_ERR "invalid uac2 rates\n");
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snd_printk(KERN_ERR "invalid uac2 rates\n");
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break;
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break;
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}
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}
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@ -132,10 +132,14 @@ static int create_fixed_stream_quirk(struct snd_usb_audio *chip,
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unsigned *rate_table = NULL;
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unsigned *rate_table = NULL;
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fp = kmemdup(quirk->data, sizeof(*fp), GFP_KERNEL);
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fp = kmemdup(quirk->data, sizeof(*fp), GFP_KERNEL);
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if (! fp) {
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if (!fp) {
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snd_printk(KERN_ERR "cannot memdup\n");
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snd_printk(KERN_ERR "cannot memdup\n");
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return -ENOMEM;
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return -ENOMEM;
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}
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}
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if (fp->nr_rates > MAX_NR_RATES) {
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kfree(fp);
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return -EINVAL;
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}
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if (fp->nr_rates > 0) {
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if (fp->nr_rates > 0) {
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rate_table = kmemdup(fp->rate_table,
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rate_table = kmemdup(fp->rate_table,
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sizeof(int) * fp->nr_rates, GFP_KERNEL);
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sizeof(int) * fp->nr_rates, GFP_KERNEL);
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