netlink: Don't shift on 64 for ngroups
authorDmitry Safonov <dima@arista.com>
Sun, 5 Aug 2018 00:35:53 +0000 (01:35 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 9 Aug 2018 10:17:59 +0000 (12:17 +0200)
commitc68c772262d9b460ddd1b1d68e06ebe3254d0ead
tree57ccafa983fe00bacfaa810803a6f1df3acd34c7
parent4d502572ea7da97550891c2b0bcd36fa4eb33401
netlink: Don't shift on 64 for ngroups

commit 91874ecf32e41b5d86a4cb9d60e0bee50d828058 upstream.

It's legal to have 64 groups for netlink_sock.

As user-supplied nladdr->nl_groups is __u32, it's possible to subscribe
only to first 32 groups.

The check for correctness of .bind() userspace supplied parameter
is done by applying mask made from ngroups shift. Which broke Android
as they have 64 groups and the shift for mask resulted in an overflow.

Fixes: 61f4b23769f0 ("netlink: Don't shift with UB on nlk->ngroups")
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: netdev@vger.kernel.org
Cc: stable@vger.kernel.org
Reported-and-Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/netlink/af_netlink.c