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authorGustavo A. R. Silva <gustavo@embeddedor.com>2018-10-16 16:59:01 +0200
committerDoug Ledford <dledford@redhat.com>2018-10-16 12:47:40 -0400
commita3671a4f973ee9d9621d60166cc3b037c397d604 (patch)
treeef3c0975d7284a25fd265d63793c5edcee2d322f /drivers/infiniband/core/ucma.c
parent0295e39595e1146522f2722715dba7f7fba42217 (diff)
RDMA/ucma: Fix Spectre v1 vulnerability
hdr.cmd 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/infiniband/core/ucma.c:1686 ucma_write() warn: potential spectre issue 'ucma_cmd_table' [r] (local cap) Fix this by sanitizing hdr.cmd before using it to index ucm_cmd_table. 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: Doug Ledford <dledford@redhat.com>
Diffstat (limited to 'drivers/infiniband/core/ucma.c')
-rw-r--r--drivers/infiniband/core/ucma.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
index 21863ddde63e..01d68ed46c1b 100644
--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -44,6 +44,8 @@
#include <linux/module.h>
#include <linux/nsproxy.h>
+#include <linux/nospec.h>
+
#include <rdma/rdma_user_cm.h>
#include <rdma/ib_marshall.h>
#include <rdma/rdma_cm.h>
@@ -1676,6 +1678,7 @@ static ssize_t ucma_write(struct file *filp, const char __user *buf,
if (hdr.cmd >= ARRAY_SIZE(ucma_cmd_table))
return -EINVAL;
+ hdr.cmd = array_index_nospec(hdr.cmd, ARRAY_SIZE(ucma_cmd_table));
if (hdr.in + sizeof(hdr) > len)
return -EINVAL;