lkml.org 
[lkml]   [2018]   [Nov]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.9 162/171] IB/ucm: Fix Spectre v1 vulnerability
Date
4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Gustavo A. R. Silva <gustavo@embeddedor.com>

commit 0295e39595e1146522f2722715dba7f7fba42217 upstream.

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/ucm.c:1127 ib_ucm_write() warn: potential
spectre issue 'ucm_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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/infiniband/core/ucm.c | 3 +++
1 file changed, 3 insertions(+)

--- a/drivers/infiniband/core/ucm.c
+++ b/drivers/infiniband/core/ucm.c
@@ -46,6 +46,8 @@
#include <linux/mutex.h>
#include <linux/slab.h>

+#include <linux/nospec.h>
+
#include <asm/uaccess.h>

#include <rdma/ib.h>
@@ -1115,6 +1117,7 @@ static ssize_t ib_ucm_write(struct file

if (hdr.cmd >= ARRAY_SIZE(ucm_cmd_table))
return -EINVAL;
+ hdr.cmd = array_index_nospec(hdr.cmd, ARRAY_SIZE(ucm_cmd_table));

if (hdr.in + sizeof(hdr) > len)
return -EINVAL;

\
 
 \ /
  Last update: 2018-11-08 23:17    [W:0.380 / U:0.564 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site