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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2018-12-11 23:10:08 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-01-09 19:14:43 +0300 |
| commit | 18e260fd2a4c7433e2daa861678f2dd58501904b (patch) | |
| tree | aaae791a0e80a1666d11a111dc5a2db66810bdce /net/ipv6 | |
| parent | 26a697a9a56ccba99f5ed900dcb0973ff828e75f (diff) | |
| download | linux-18e260fd2a4c7433e2daa861678f2dd58501904b.tar.xz | |
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/ipv6')
| -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 8015e74fd7d9..b2fdb3fdd217 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; }; @@ -1883,6 +1885,7 @@ 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)) { @@ -1957,6 +1960,7 @@ 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)) { |