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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2018-12-12 20:20:49 +0300 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2018-12-13 11:13:04 +0300 |
| commit | 4aea96f4237cea0c51a8bc87c0db31f0f932f1f0 (patch) | |
| tree | c10f89ad1d9ca4155a16fe6cb11296a9f0f23f34 /sound | |
| parent | c7072f5f2aa1124d57042d1d7f17521532657dc6 (diff) | |
| download | linux-4aea96f4237cea0c51a8bc87c0db31f0f932f1f0.tar.xz | |
ALSA: emux: Fix potential Spectre v1 vulnerabilities
info.mode and info.port are indirectly controlled by user-space,
hence leading to a potential exploitation of the Spectre variant 1
vulnerability.
These issues were detected with the help of Smatch:
sound/synth/emux/emux_hwdep.c:72 snd_emux_hwdep_misc_mode() warn: potential spectre issue 'emu->portptrs[i]->ctrls' [w] (local cap)
sound/synth/emux/emux_hwdep.c:75 snd_emux_hwdep_misc_mode() warn: potential spectre issue 'emu->portptrs' [w] (local cap)
sound/synth/emux/emux_hwdep.c:75 snd_emux_hwdep_misc_mode() warn: potential spectre issue 'emu->portptrs[info.port]->ctrls' [w] (local cap)
Fix this by sanitizing both info.mode and info.port before using them
to index emu->portptrs[i]->ctrls, emu->portptrs[info.port]->ctrls and
emu->portptrs.
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
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Cc: stable@vger.kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound')
| -rw-r--r-- | sound/synth/emux/emux_hwdep.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/sound/synth/emux/emux_hwdep.c b/sound/synth/emux/emux_hwdep.c index e557946718a9..d9fcae071b47 100644 --- a/sound/synth/emux/emux_hwdep.c +++ b/sound/synth/emux/emux_hwdep.c @@ -22,9 +22,9 @@ #include <sound/core.h> #include <sound/hwdep.h> #include <linux/uaccess.h> +#include <linux/nospec.h> #include "emux_voice.h" - #define TMP_CLIENT_ID 0x1001 /* @@ -66,13 +66,16 @@ snd_emux_hwdep_misc_mode(struct snd_emux *emu, void __user *arg) return -EFAULT; if (info.mode < 0 || info.mode >= EMUX_MD_END) return -EINVAL; + info.mode = array_index_nospec(info.mode, EMUX_MD_END); if (info.port < 0) { for (i = 0; i < emu->num_ports; i++) emu->portptrs[i]->ctrls[info.mode] = info.value; } else { - if (info.port < emu->num_ports) + if (info.port < emu->num_ports) { + info.port = array_index_nospec(info.port, emu->num_ports); emu->portptrs[info.port]->ctrls[info.mode] = info.value; + } } return 0; } |