media: ddbridge/mci: protect against out-of-bounds array access in stop()

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In stop(), an (unlikely) out-of-bounds write error can occur when setting
the demod_in_use element indexed by state->demod to zero, as state->demod
isn't checked for being in the range of the array size of demod_in_use, and
state->demod maybe carrying the magic 0xff (demod unused) value. Prevent
this by checking state->demod not exceeding the array size before setting
the element value. To make the code a bit easier to read, replace the magic
value and the number of array elements with defines, and use them at a few
more places.

Detected by CoverityScan, CID#1468550 ("Out-of-bounds write")

Thanks to Colin for reporting the problem and providing an initial patch.

Fixes: daeeb1319e ("media: ddbridge: initial support for MCI-based MaxSX8 cards")

Reported-by: Colin Ian King <colin.king@canonical.com>
Cc: Ralph Metzler <rjkm@metzlerbros.de>
Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

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Daniel Scheller 2018-05-09 16:08:00 -04:00 • committed by Mauro Carvalho Chehab

parent d7832cd2a3

commit 525cac7574

2 changed files with 15 additions and 10 deletions

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21

drivers/media/pci/ddbridge/ddbridge-mci.c

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4

drivers/media/pci/ddbridge/ddbridge-mci.h

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