4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx> 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 Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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 @@ -50,6 +50,7 @@ #include <linux/stringify.h> #include <linux/sched.h> #include <linux/slab.h> +#include <linux/nospec.h> #include <asm/uaccess.h> #include "common.h" @@ -2259,6 +2260,7 @@ 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;
