| From: "Gustavo A. R. Silva" <gustavo@embeddedor.com> |
| Date: Mon, 16 Jul 2018 20:59:58 -0500 |
| Subject: net: cxgb3_main: fix potential Spectre v1 |
| |
| commit 676bcfece19f83621e905aa55b5ed2d45cc4f2d3 upstream. |
| |
| t.qset_idx 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: |
| |
| drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c:2286 cxgb_extension_ioctl() |
| warn: potential spectre issue 'adapter->msix_info' |
| |
| Fix this by sanitizing t.qset_idx before using it to index |
| adapter->msix_info |
| |
| 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> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| [bwh: Backported to 3.16: adjust context] |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c | 2 ++ |
| 1 file changed, 2 insertions(+) |
| |
| --- a/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c |
| +++ b/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c |
| @@ -51,6 +51,7 @@ |
| #include <linux/sched.h> |
| #include <linux/slab.h> |
| #include <asm/uaccess.h> |
| +#include <linux/nospec.h> |
| |
| #include "common.h" |
| #include "cxgb3_ioctl.h" |
| @@ -2256,6 +2257,7 @@ static int cxgb_extension_ioctl(struct n |
| |
| if (t.qset_idx >= nqsets) |
| return -EINVAL; |
| + t.qset_idx = array_index_nospec(t.qset_idx, nqsets); |
| |
| q = &adapter->params.sge.qset[q1 + t.qset_idx]; |
| t.rspq_size = q->rspq_size; |
