diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2018-12-10 12:41:24 -0600 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-12-10 12:10:38 -0800 |
| commit | 5648451e30a0d13d11796574919a359025d52cce (patch) | |
| tree | 277562e851c9842f78cd32c99d1a25fd91fcc7f6 /net | |
| parent | 4a2eb0c37b4759416996fbb4c45b932500cf06d3 (diff) | |
ipv4: Fix potential Spectre v1 vulnerability
vr.vifi 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/ipv4/ipmr.c:1616 ipmr_ioctl() warn: potential spectre issue 'mrt->vif_table' [r] (local cap)
net/ipv4/ipmr.c:1690 ipmr_compat_ioctl() warn: potential spectre issue 'mrt->vif_table' [r] (local cap)
Fix this by sanitizing vr.vifi 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')
| -rw-r--r-- | net/ipv4/ipmr.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c index a6defbec4f1b..e7a3879cedd0 100644 --- a/net/ipv4/ipmr.c +++ b/net/ipv4/ipmr.c @@ -69,6 +69,8 @@ #include <net/nexthop.h> #include <net/switchdev.h> +#include <linux/nospec.h> + struct ipmr_rule { struct fib_rule common; }; @@ -1612,6 +1614,7 @@ int ipmr_ioctl(struct sock *sk, int cmd, void __user *arg) return -EFAULT; if (vr.vifi >= mrt->maxvif) return -EINVAL; + vr.vifi = array_index_nospec(vr.vifi, mrt->maxvif); read_lock(&mrt_lock); vif = &mrt->vif_table[vr.vifi]; if (VIF_EXISTS(mrt, vr.vifi)) { @@ -1686,6 +1689,7 @@ int ipmr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg) return -EFAULT; if (vr.vifi >= mrt->maxvif) return -EINVAL; + vr.vifi = array_index_nospec(vr.vifi, mrt->maxvif); read_lock(&mrt_lock); vif = &mrt->vif_table[vr.vifi]; if (VIF_EXISTS(mrt, vr.vifi)) { |