diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2018-12-11 14:10:08 -0600 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-12-14 15:34:28 -0800 |
| commit | 69d2c86766da2ded2b70281f1bf242cb0d58a778 (patch) | |
| tree | 2dff5a7d1cb78ea10ed065a738fa4ba991ec3eac /net/ipv6/ip6mr.c | |
| parent | 51367e423c6501a26e67d91a655d2bc892303462 (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.c | 4 |
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)) { |