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| author | Xi Wang <xi.wang@gmail.com> | 2012-02-14 05:18:48 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-06-07 12:46:48 -0700 |
| commit | 93a327fcdef0c9e089ba7b347780cf9eaa92677f (patch) | |
| tree | 79da5eb7b8f9628106eee38af666d6967203dfde | |
| parent | 44f059fb742aac78cffdab5e0d8fe0c9910c1ded (diff) | |
| download | lwn-93a327fcdef0c9e089ba7b347780cf9eaa92677f.tar.gz lwn-93a327fcdef0c9e089ba7b347780cf9eaa92677f.zip | |
ALSA: usb-audio: avoid integer overflow in create_fixed_stream_quirk()
commit 8866f405efd4171f9d9c91901d2dd02f01bacb60 upstream.
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>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | sound/usb/card.h | 1 | ||||
| -rw-r--r-- | sound/usb/format.c | 4 | ||||
| -rw-r--r-- | sound/usb/quirks.c | 6 |
3 files changed, 7 insertions, 4 deletions
diff --git a/sound/usb/card.h b/sound/usb/card.h index 19b5b5d871dd..da61252be6f8 100644 --- a/sound/usb/card.h +++ b/sound/usb/card.h @@ -1,6 +1,7 @@ #ifndef __USBAUDIO_CARD_H #define __USBAUDIO_CARD_H +#define MAX_NR_RATES 1024 #define MAX_PACKS 20 #define MAX_PACKS_HS (MAX_PACKS * 8) /* in high speed mode */ #define MAX_URBS 8 diff --git a/sound/usb/format.c b/sound/usb/format.c index be212a0a5f73..b30fcd02962b 100644 --- a/sound/usb/format.c +++ b/sound/usb/format.c @@ -209,8 +209,6 @@ static int parse_audio_format_rates_v1(struct snd_usb_audio *chip, struct audiof return 0; } -#define MAX_UAC2_NR_RATES 1024 - /* * Helper function to walk the array of sample rate triplets reported by * the device. The problem is that we need to parse whole array first to @@ -255,7 +253,7 @@ static int parse_uac2_sample_rate_range(struct audioformat *fp, int nr_triplets, fp->rates |= snd_pcm_rate_to_rate_bit(rate); nr_rates++; - if (nr_rates >= MAX_UAC2_NR_RATES) { + if (nr_rates >= MAX_NR_RATES) { snd_printk(KERN_ERR "invalid uac2 rates\n"); break; } diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c index eb2276851ad6..4a650ab1d9e1 100644 --- a/sound/usb/quirks.c +++ b/sound/usb/quirks.c @@ -131,10 +131,14 @@ 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 = kmalloc(sizeof(int) * fp->nr_rates, GFP_KERNEL); if (!rate_table) { |