drivers/misc/sgi-gru: fix Spectre v1 vulnerability
commit fee05f455ceb5c670cbe48e2f9454ebc4a388554 upstream.
req.gid can be 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:
vers/misc/sgi-gru/grukdump.c:200 gru_dump_chiplet_request() warn:
potential spectre issue 'gru_base' [w]
Fix this by sanitizing req.gid before calling macro GID_TO_GRU, which
uses it to index gru_base.
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 file changed