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netlink: Don't shift on 64 for ngroups
authorDmitry Safonov <dima@arista.com>
Sun, 5 Aug 2018 00:35:53 +0000 (01:35 +0100)
committerDavid S. Miller <davem@davemloft.net>
Sun, 5 Aug 2018 00:52:51 +0000 (17:52 -0700)
commit91874ecf32e41b5d86a4cb9d60e0bee50d828058
treea4283cc102cac38e593c53424c777eab8ab1c0fa
parent5dbfb6eca0b23751d9ab21989a07b5a22fa544fe
netlink: Don't shift on 64 for ngroups

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>
net/netlink/af_netlink.c