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authorGustavo A. R. Silva <gustavo@embeddedor.com>2018-12-18 20:52:16 +0300
committerTakashi Iwai <tiwai@suse.de>2018-12-19 16:34:02 +0300
commit5ae4f61f012a097df93de2285070ec8e34716d29 (patch)
tree7e52e848a4414c037abc6ecdae46ca6ecd40a9e8
parent0b84304ef5da92add8dc75a1b07879c5374cdb05 (diff)
downloadlinux-5ae4f61f012a097df93de2285070ec8e34716d29.tar.xz
ALSA: emu10k1: Fix potential Spectre v1 vulnerabilities
ipcm->substream is indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability. This issue was detected with the help of Smatch: sound/pci/emu10k1/emufx.c:1031 snd_emu10k1_ipcm_poke() warn: potential spectre issue 'emu->fx8010.pcm' [r] (local cap) sound/pci/emu10k1/emufx.c:1075 snd_emu10k1_ipcm_peek() warn: potential spectre issue 'emu->fx8010.pcm' [r] (local cap) Fix this by sanitizing ipcm->substream before using it to index emu->fx8010.pcm Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1]. [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 Cc: stable@vger.kernel.org Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
-rw-r--r--sound/pci/emu10k1/emufx.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/sound/pci/emu10k1/emufx.c b/sound/pci/emu10k1/emufx.c
index 6ebe817801ea..1f25e6d029d8 100644
--- a/sound/pci/emu10k1/emufx.c
+++ b/sound/pci/emu10k1/emufx.c
@@ -36,6 +36,7 @@
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/moduleparam.h>
+#include <linux/nospec.h>
#include <sound/core.h>
#include <sound/tlv.h>
@@ -1026,6 +1027,8 @@ static int snd_emu10k1_ipcm_poke(struct snd_emu10k1 *emu,
if (ipcm->substream >= EMU10K1_FX8010_PCM_COUNT)
return -EINVAL;
+ ipcm->substream = array_index_nospec(ipcm->substream,
+ EMU10K1_FX8010_PCM_COUNT);
if (ipcm->channels > 32)
return -EINVAL;
pcm = &emu->fx8010.pcm[ipcm->substream];
@@ -1072,6 +1075,8 @@ static int snd_emu10k1_ipcm_peek(struct snd_emu10k1 *emu,
if (ipcm->substream >= EMU10K1_FX8010_PCM_COUNT)
return -EINVAL;
+ ipcm->substream = array_index_nospec(ipcm->substream,
+ EMU10K1_FX8010_PCM_COUNT);
pcm = &emu->fx8010.pcm[ipcm->substream];
mutex_lock(&emu->fx8010.lock);
spin_lock_irq(&emu->reg_lock);