path: root/sound
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authorGustavo A. R. Silva <gustavo@embeddedor.com>2018-12-18 11:18:34 -0600
committerTakashi Iwai <tiwai@suse.de>2018-12-19 14:32:41 +0100
commit0b84304ef5da92add8dc75a1b07879c5374cdb05 (patch)
treea3f09b35b3ca14e353c8d247abb2bbb40ca38a28 /sound
parented49e839199e73966b9ff5946c3e87759827b40e (diff)
ALSA: rme9652: Fix potential Spectre v1 vulnerability
info->channel 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/rme9652/hdsp.c:4100 snd_hdsp_channel_info() warn: potential spectre issue 'hdsp->channel_map' [r] (local cap) Fix this by sanitizing info->channel before using it to index hdsp->channel_map 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]. Also, notice that I refactored the code a bit in order to get rid of the following checkpatch warning: ERROR: do not use assignment in if condition FILE: sound/pci/rme9652/hdsp.c:4103: if ((mapped_channel = hdsp->channel_map[info->channel]) < 0) [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>
Diffstat (limited to 'sound')
1 files changed, 6 insertions, 4 deletions
diff --git a/sound/pci/rme9652/hdsp.c b/sound/pci/rme9652/hdsp.c
index 1bff4b1b39cd..ba99ff0e93e0 100644
--- a/sound/pci/rme9652/hdsp.c
+++ b/sound/pci/rme9652/hdsp.c
@@ -30,6 +30,7 @@
#include <linux/math64.h>
#include <linux/vmalloc.h>
#include <linux/io.h>
+#include <linux/nospec.h>
#include <sound/core.h>
#include <sound/control.h>
@@ -4092,15 +4093,16 @@ static int snd_hdsp_channel_info(struct snd_pcm_substream *substream,
struct snd_pcm_channel_info *info)
struct hdsp *hdsp = snd_pcm_substream_chip(substream);
- int mapped_channel;
+ unsigned int channel = info->channel;
- if (snd_BUG_ON(info->channel >= hdsp->max_channels))
+ if (snd_BUG_ON(channel >= hdsp->max_channels))
return -EINVAL;
+ channel = array_index_nospec(channel, hdsp->max_channels);
- if ((mapped_channel = hdsp->channel_map[info->channel]) < 0)
+ if (hdsp->channel_map[channel] < 0)
return -EINVAL;
- info->offset = mapped_channel * HDSP_CHANNEL_BUFFER_BYTES;
+ info->offset = hdsp->channel_map[channel] * HDSP_CHANNEL_BUFFER_BYTES;
info->first = 0;
info->step = 32;
return 0;