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| author | Takashi Iwai <tiwai@suse.de> | 2018-11-23 15:44:00 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-12-13 09:22:28 +0100 |
| commit | 310c205b0c8f5b68e0a99d62408d22b5fd69d17c (patch) | |
| tree | 544116a47b71e0cd8ffd1022f91f1bac6fc3dddb /sound/pci | |
| parent | 88f27f2ba875e7488696480e28ddfcb5f78252b9 (diff) | |
| download | linux-stable-310c205b0c8f5b68e0a99d62408d22b5fd69d17c.tar.gz linux-stable-310c205b0c8f5b68e0a99d62408d22b5fd69d17c.tar.bz2 linux-stable-310c205b0c8f5b68e0a99d62408d22b5fd69d17c.zip | |
ALSA: ac97: Fix incorrect bit shift at AC97-SPSA control write
commit 7194eda1ba0872d917faf3b322540b4f57f11ba5 upstream.
The function snd_ac97_put_spsa() gets the bit shift value from the
associated private_value, but it extracts too much; the current code
extracts 8 bit values in bits 8-15, but this is a combination of two
nibbles (bits 8-11 and bits 12-15) for left and right shifts.
Due to the incorrect bits extraction, the actual shift may go beyond
the 32bit value, as spotted recently by UBSAN check:
UBSAN: Undefined behaviour in sound/pci/ac97/ac97_codec.c:836:7
shift exponent 68 is too large for 32-bit type 'int'
This patch fixes the shift value extraction by masking the properly
with 0x0f instead of 0xff.
Reported-and-tested-by: Meelis Roos <mroos@linux.ee>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'sound/pci')
| -rw-r--r-- | sound/pci/ac97/ac97_codec.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/sound/pci/ac97/ac97_codec.c b/sound/pci/ac97/ac97_codec.c index 14ad54b7928c..416c46bf2a12 100644 --- a/sound/pci/ac97/ac97_codec.c +++ b/sound/pci/ac97/ac97_codec.c @@ -829,7 +829,7 @@ static int snd_ac97_put_spsa(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_ { struct snd_ac97 *ac97 = snd_kcontrol_chip(kcontrol); int reg = kcontrol->private_value & 0xff; - int shift = (kcontrol->private_value >> 8) & 0xff; + int shift = (kcontrol->private_value >> 8) & 0x0f; int mask = (kcontrol->private_value >> 16) & 0xff; // int invert = (kcontrol->private_value >> 24) & 0xff; unsigned short value, old, new; |