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netlink: Fix spectre v1 gadget in netlink_create()
authorJeremy Cline <jcline@redhat.com>
Tue, 31 Jul 2018 21:13:16 +0000 (21:13 +0000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Mon, 6 Aug 2018 14:24:41 +0000 (16:24 +0200)
commit8cac0ce0a8853cae7dc01256f88bc9b7e53ad3ce
tree8ee89223f1c53f66775a35945bce2a098ccb0012
parentb5fef54e3212e2ec1449a4445becb25208c9410c
netlink: Fix spectre v1 gadget in netlink_create()

[ Upstream commit bc5b6c0b62b932626a135f516a41838c510c6eba ]

'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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/netlink/af_netlink.c