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authorGustavo A. R. Silva <gustavo@embeddedor.com>2018-12-10 12:41:24 -0600
committerDavid S. Miller <davem@davemloft.net>2018-12-10 12:10:38 -0800
commit5648451e30a0d13d11796574919a359025d52cce (patch)
tree277562e851c9842f78cd32c99d1a25fd91fcc7f6 /net
parent4a2eb0c37b4759416996fbb4c45b932500cf06d3 (diff)
ipv4: Fix potential Spectre v1 vulnerability
vr.vifi is 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: net/ipv4/ipmr.c:1616 ipmr_ioctl() warn: potential spectre issue 'mrt->vif_table' [r] (local cap) net/ipv4/ipmr.c:1690 ipmr_compat_ioctl() warn: potential spectre issue 'mrt->vif_table' [r] (local cap) Fix this by sanitizing vr.vifi before using it to index mrt->vif_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 Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/ipmr.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index a6defbec4f1b..e7a3879cedd0 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -69,6 +69,8 @@
#include <net/nexthop.h>
#include <net/switchdev.h>
+#include <linux/nospec.h>
+
struct ipmr_rule {
struct fib_rule common;
};
@@ -1612,6 +1614,7 @@ int ipmr_ioctl(struct sock *sk, int cmd, void __user *arg)
return -EFAULT;
if (vr.vifi >= mrt->maxvif)
return -EINVAL;
+ vr.vifi = array_index_nospec(vr.vifi, mrt->maxvif);
read_lock(&mrt_lock);
vif = &mrt->vif_table[vr.vifi];
if (VIF_EXISTS(mrt, vr.vifi)) {
@@ -1686,6 +1689,7 @@ int ipmr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
return -EFAULT;
if (vr.vifi >= mrt->maxvif)
return -EINVAL;
+ vr.vifi = array_index_nospec(vr.vifi, mrt->maxvif);
read_lock(&mrt_lock);
vif = &mrt->vif_table[vr.vifi];
if (VIF_EXISTS(mrt, vr.vifi)) {