ALSA: seq: oss: Fix Spectre v1 vulnerability

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commit c709f14f06 upstream.

dev 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/core/seq/oss/seq_oss_synth.c:626 snd_seq_oss_synth_make_info() warn: potential spectre issue 'dp->synths' [w] (local cap)

Fix this by sanitizing dev before using it to index dp->synths.

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://lore.kernel.org/lkml/20180423164740.GY17484@dhcp22.suse.cz/

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

...

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Gustavo A. R. Silva 2019-03-20 18:42:01 -05:00 • committed by Ben Hutchings

parent 748cfcf4db

commit 09e3abfd0c

1 changed files with 4 additions and 3 deletions

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sound/core/seq/oss/seq_oss_synth.c

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