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authorGustavo A. R. Silva <gustavo@embeddedor.com>2018-12-11 14:10:08 -0600
committerDavid S. Miller <davem@davemloft.net>2018-12-14 15:34:28 -0800
commit69d2c86766da2ded2b70281f1bf242cb0d58a778 (patch)
tree2dff5a7d1cb78ea10ed065a738fa4ba991ec3eac /net/ipv6/ip6mr.c
parent51367e423c6501a26e67d91a655d2bc892303462 (diff)
ip6mr: Fix potential Spectre v1 vulnerability
vr.mifi 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/ipv6/ip6mr.c:1845 ip6mr_ioctl() warn: potential spectre issue 'mrt->vif_table' [r] (local cap) net/ipv6/ip6mr.c:1919 ip6mr_compat_ioctl() warn: potential spectre issue 'mrt->vif_table' [r] (local cap) Fix this by sanitizing vr.mifi 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/ipv6/ip6mr.c')
-rw-r--r--net/ipv6/ip6mr.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index e2ea691e42c6..377a2ee5d9ad 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -52,6 +52,8 @@
#include <net/ip6_checksum.h>
#include <linux/netconf.h>
+#include <linux/nospec.h>
+
struct ip6mr_rule {
struct fib_rule common;
};
@@ -1841,6 +1843,7 @@ int ip6mr_ioctl(struct sock *sk, int cmd, void __user *arg)
return -EFAULT;
if (vr.mifi >= mrt->maxvif)
return -EINVAL;
+ vr.mifi = array_index_nospec(vr.mifi, mrt->maxvif);
read_lock(&mrt_lock);
vif = &mrt->vif_table[vr.mifi];
if (VIF_EXISTS(mrt, vr.mifi)) {
@@ -1915,6 +1918,7 @@ int ip6mr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
return -EFAULT;
if (vr.mifi >= mrt->maxvif)
return -EINVAL;
+ vr.mifi = array_index_nospec(vr.mifi, mrt->maxvif);
read_lock(&mrt_lock);
vif = &mrt->vif_table[vr.mifi];
if (VIF_EXISTS(mrt, vr.mifi)) {