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authorJeremy Cline <jcline@redhat.com>2018-07-31 21:13:16 +0000
committerDavid S. Miller <davem@davemloft.net>2018-08-01 09:50:58 -0700
commitbc5b6c0b62b932626a135f516a41838c510c6eba (patch)
tree60b67dc5c86603034ca42c875e73f7922489a553 /net
parente02ee9819a03c5d6439636c8fc152b4cc1b48304 (diff)
downloadlinux-bc5b6c0b62b932626a135f516a41838c510c6eba.tar.gz
netlink: Fix spectre v1 gadget in netlink_create()
'protocol' is a user-controlled value, so sanitize it after the bounds
check to avoid using it for speculative out-of-bounds access to arrays
indexed by it.

This addresses the following accesses detected with the help of smatch:

* net/netlink/af_netlink.c:654 __netlink_create() warn: potential
  spectre issue 'nlk_cb_mutex_keys' [w]

* net/netlink/af_netlink.c:654 __netlink_create() warn: potential
  spectre issue 'nlk_cb_mutex_key_strings' [w]

* net/netlink/af_netlink.c:685 netlink_create() warn: potential spectre
  issue 'nl_table' [w] (local cap)

Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jeremy Cline <jcline@redhat.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/netlink/af_netlink.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 7d860a22e5fb..c09d16870f74 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -63,6 +63,7 @@
 #include <linux/hash.h>
 #include <linux/genetlink.h>
 #include <linux/net_namespace.h>
+#include <linux/nospec.h>
 
 #include <net/net_namespace.h>
 #include <net/netns/generic.h>
@@ -679,6 +680,7 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol,
 
 	if (protocol < 0 || protocol >= MAX_LINKS)
 		return -EPROTONOSUPPORT;
+	protocol = array_index_nospec(protocol, MAX_LINKS);
 
 	netlink_lock_table();
 #ifdef CONFIG_MODULES