diff options
| author | Dan Williams <dan.j.williams@intel.com> | 2018-03-08 18:39:24 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-03-11 16:21:34 +0100 |
| commit | 93f3aff1d910c5363a42c2c18dec9939cb0d58c2 (patch) | |
| tree | 23ad162a5b5474d79e675955d9ea4132d9ab2568 /net | |
| parent | d77763dc70c4afa451b33f80013910d502bf3bb7 (diff) | |
mpls, nospec: Sanitize array index in mpls_label_ok()
commit 3968523f855050b8195134da951b87c20bd66130 upstream.
mpls_label_ok() validates that the 'platform_label' array index from a
userspace netlink message payload is valid. Under speculation the
mpls_label_ok() result may not resolve in the CPU pipeline until after
the index is used to access an array element. Sanitize the index to zero
to prevent userspace-controlled arbitrary out-of-bounds speculation, a
precursor for a speculative execution side channel vulnerability.
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 4.4:
- mpls_label_ok() doesn't take an extack parameter
- Drop change in mpls_getroute()]
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/mpls/af_mpls.c | 22 |
1 files changed, 13 insertions, 9 deletions
diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c index 3e8d1f6ac907..ffab94d61e1d 100644 --- a/net/mpls/af_mpls.c +++ b/net/mpls/af_mpls.c @@ -7,6 +7,7 @@ #include <linux/if_arp.h> #include <linux/ipv6.h> #include <linux/mpls.h> +#include <linux/nospec.h> #include <linux/vmalloc.h> #include <net/ip.h> #include <net/dst.h> @@ -756,17 +757,20 @@ errout: return err; } -static bool mpls_label_ok(struct net *net, unsigned int index) +static bool mpls_label_ok(struct net *net, unsigned int *index) { + bool is_ok = true; + /* Reserved labels may not be set */ - if (index < MPLS_LABEL_FIRST_UNRESERVED) - return false; + if (*index < MPLS_LABEL_FIRST_UNRESERVED) + is_ok = false; /* The full 20 bit range may not be supported. */ - if (index >= net->mpls.platform_labels) - return false; + if (is_ok && *index >= net->mpls.platform_labels) + is_ok = false; - return true; + *index = array_index_nospec(*index, net->mpls.platform_labels); + return is_ok; } static int mpls_route_add(struct mpls_route_config *cfg) @@ -787,7 +791,7 @@ static int mpls_route_add(struct mpls_route_config *cfg) index = find_free_label(net); } - if (!mpls_label_ok(net, index)) + if (!mpls_label_ok(net, &index)) goto errout; /* Append makes no sense with mpls */ @@ -848,7 +852,7 @@ static int mpls_route_del(struct mpls_route_config *cfg) index = cfg->rc_label; - if (!mpls_label_ok(net, index)) + if (!mpls_label_ok(net, &index)) goto errout; mpls_route_update(net, index, NULL, &cfg->rc_nlinfo); @@ -1283,7 +1287,7 @@ static int rtm_to_route_config(struct sk_buff *skb, struct nlmsghdr *nlh, goto errout; if (!mpls_label_ok(cfg->rc_nlinfo.nl_net, - cfg->rc_label)) + &cfg->rc_label)) goto errout; break; } |