mpls, nospec: Sanitize array index in mpls_label_ok()
commit 3968523f85
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>
eirik/updates-from-linux-fsl
parent
d77763dc70
commit
93f3aff1d9
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@ -7,6 +7,7 @@
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#include <linux/if_arp.h>
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#include <linux/if_arp.h>
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#include <linux/ipv6.h>
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#include <linux/ipv6.h>
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#include <linux/mpls.h>
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#include <linux/mpls.h>
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#include <linux/nospec.h>
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#include <linux/vmalloc.h>
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#include <linux/vmalloc.h>
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#include <net/ip.h>
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#include <net/ip.h>
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#include <net/dst.h>
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#include <net/dst.h>
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@ -756,17 +757,20 @@ errout:
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return err;
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return err;
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}
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}
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static bool mpls_label_ok(struct net *net, unsigned int index)
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static bool mpls_label_ok(struct net *net, unsigned int *index)
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{
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{
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bool is_ok = true;
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/* Reserved labels may not be set */
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/* Reserved labels may not be set */
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if (index < MPLS_LABEL_FIRST_UNRESERVED)
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if (*index < MPLS_LABEL_FIRST_UNRESERVED)
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return false;
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is_ok = false;
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/* The full 20 bit range may not be supported. */
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/* The full 20 bit range may not be supported. */
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if (index >= net->mpls.platform_labels)
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if (is_ok && *index >= net->mpls.platform_labels)
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return false;
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is_ok = false;
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return true;
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*index = array_index_nospec(*index, net->mpls.platform_labels);
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return is_ok;
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}
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}
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static int mpls_route_add(struct mpls_route_config *cfg)
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static int mpls_route_add(struct mpls_route_config *cfg)
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@ -787,7 +791,7 @@ static int mpls_route_add(struct mpls_route_config *cfg)
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index = find_free_label(net);
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index = find_free_label(net);
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}
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}
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if (!mpls_label_ok(net, index))
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if (!mpls_label_ok(net, &index))
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goto errout;
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goto errout;
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/* Append makes no sense with mpls */
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/* Append makes no sense with mpls */
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@ -848,7 +852,7 @@ static int mpls_route_del(struct mpls_route_config *cfg)
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index = cfg->rc_label;
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index = cfg->rc_label;
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if (!mpls_label_ok(net, index))
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if (!mpls_label_ok(net, &index))
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goto errout;
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goto errout;
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mpls_route_update(net, index, NULL, &cfg->rc_nlinfo);
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mpls_route_update(net, index, NULL, &cfg->rc_nlinfo);
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@ -1283,7 +1287,7 @@ static int rtm_to_route_config(struct sk_buff *skb, struct nlmsghdr *nlh,
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goto errout;
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goto errout;
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if (!mpls_label_ok(cfg->rc_nlinfo.nl_net,
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if (!mpls_label_ok(cfg->rc_nlinfo.nl_net,
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cfg->rc_label))
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&cfg->rc_label))
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goto errout;
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goto errout;
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break;
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break;
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}
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}
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