From: Gustavo A. R. Silva Date: Tue, 11 Dec 2018 20:10:08 +0000 (-0600) Subject: ip6mr: Fix potential Spectre v1 vulnerability X-Git-Tag: v4.9.149~65 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=5d9a7965b157f61040047e7006b987ac4a58278b;p=platform%2Fkernel%2Flinux-amlogic.git ip6mr: Fix potential Spectre v1 vulnerability [ Upstream commit 69d2c86766da2ded2b70281f1bf242cb0d58a778 ] 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 Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c index 4b93ad4fe6d8..ad597b4b22a0 100644 --- a/net/ipv6/ip6mr.c +++ b/net/ipv6/ip6mr.c @@ -72,6 +72,8 @@ struct mr6_table { #endif }; +#include + struct ip6mr_rule { struct fib_rule common; }; @@ -1873,6 +1875,7 @@ 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->vif6_table[vr.mifi]; if (MIF_EXISTS(mrt, vr.mifi)) { @@ -1947,6 +1950,7 @@ 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->vif6_table[vr.mifi]; if (MIF_EXISTS(mrt, vr.mifi)) {