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authorGustavo A. R. Silva <gustavo@embeddedor.com>2018-05-03 21:45:58 +0300
committerDavid S. Miller <davem@davemloft.net>2018-05-04 19:52:47 +0300
commitacf784bd0ce257fe43da7ca266f7a10b837479d2 (patch)
tree8dd84537bf4b37809868b378a7a819437db625ae /net/atm/lec.c
parent2be147f7459db5bbf292e0a6f135037b55e20b39 (diff)
downloadlinux-acf784bd0ce257fe43da7ca266f7a10b837479d2.tar.xz
net: atm: Fix potential Spectre v1
ioc_data.dev_num can be 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: net/atm/lec.c:702 lec_vcc_attach() warn: potential spectre issue 'dev_lec' Fix this by sanitizing ioc_data.dev_num before using it to index dev_lec. Also, notice that there is another instance in which array dev_lec is being indexed using ioc_data.dev_num at line 705: lec_vcc_added(netdev_priv(dev_lec[ioc_data.dev_num]), 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: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/atm/lec.c')
-rw-r--r--net/atm/lec.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/net/atm/lec.c b/net/atm/lec.c
index 01d5d20a6eb1..3138a869b5c0 100644
--- a/net/atm/lec.c
+++ b/net/atm/lec.c
@@ -41,6 +41,9 @@ static unsigned char bridge_ula_lec[] = { 0x01, 0x80, 0xc2, 0x00, 0x00 };
#include <linux/module.h>
#include <linux/init.h>
+/* Hardening for Spectre-v1 */
+#include <linux/nospec.h>
+
#include "lec.h"
#include "lec_arpc.h"
#include "resources.h"
@@ -687,8 +690,10 @@ static int lec_vcc_attach(struct atm_vcc *vcc, void __user *arg)
bytes_left = copy_from_user(&ioc_data, arg, sizeof(struct atmlec_ioc));
if (bytes_left != 0)
pr_info("copy from user failed for %d bytes\n", bytes_left);
- if (ioc_data.dev_num < 0 || ioc_data.dev_num >= MAX_LEC_ITF ||
- !dev_lec[ioc_data.dev_num])
+ if (ioc_data.dev_num < 0 || ioc_data.dev_num >= MAX_LEC_ITF)
+ return -EINVAL;
+ ioc_data.dev_num = array_index_nospec(ioc_data.dev_num, MAX_LEC_ITF);
+ if (!dev_lec[ioc_data.dev_num])
return -EINVAL;
vpriv = kmalloc(sizeof(struct lec_vcc_priv), GFP_KERNEL);
if (!vpriv)