Messages in this thread Patch in this message | | | Date | Tue, 16 Oct 2018 12:59:44 +0200 | From | "Gustavo A. R. Silva" <> | Subject | [PATCH] drivers/misc/sgi-gru: fix Spectre v1 vulnerability |
| |
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> --- drivers/misc/sgi-gru/grukdump.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/misc/sgi-gru/grukdump.c b/drivers/misc/sgi-gru/grukdump.c index 313da31..1540a77 100644 --- a/drivers/misc/sgi-gru/grukdump.c +++ b/drivers/misc/sgi-gru/grukdump.c @@ -27,6 +27,9 @@ #include <linux/delay.h> #include <linux/bitops.h> #include <asm/uv/uv_hub.h> + +#include <linux/nospec.h> + #include "gru.h" #include "grutables.h" #include "gruhandles.h" @@ -196,6 +199,7 @@ int gru_dump_chiplet_request(unsigned long arg) /* Currently, only dump by gid is implemented */ if (req.gid >= gru_max_gids) return -EINVAL; + req.gid = array_index_nospec(req.gid, gru_max_gids); gru = GID_TO_GRU(req.gid); ubuf = req.buf; -- 2.7.4
| |