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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2018-12-11 14:10:08 -0600 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-01-13 10:05:27 +0100 |
| commit | 6dc50507697ce02fc8118e794b9ffdb20e6ed4ea (patch) | |
| tree | 6526ee3d5c1863f0f800a65e8a275b419e5a7daf /net | |
| parent | a2a840d6dcae960c2dfdf3fcb1b759e1b7d90663 (diff) | |
| download | linux-artik7-6dc50507697ce02fc8118e794b9ffdb20e6ed4ea.tar.gz linux-artik7-6dc50507697ce02fc8118e794b9ffdb20e6ed4ea.tar.bz2 linux-artik7-6dc50507697ce02fc8118e794b9ffdb20e6ed4ea.zip | |
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 <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv6/ip6mr.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c index 9b92960f024d..74b3e9718e84 100644 --- a/net/ipv6/ip6mr.c +++ b/net/ipv6/ip6mr.c @@ -72,6 +72,8 @@ struct mr6_table { #endif }; +#include <linux/nospec.h> + struct ip6mr_rule { struct fib_rule common; }; @@ -1871,6 +1873,7 @@ 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)) { @@ -1945,6 +1948,7 @@ 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)) { |