iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

netlink: Don't shift on 64 for ngroups

Browse Source 
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>
This commit is contained in:
Dmitry Safonov 2018-08-05 01:35:53 +01:00 committed by David S. Miller
parent 5dbfb6eca0
commit 91874ecf32
1 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
net/netlink/af_netlink.c
View File

@ -1013,8 +1013,8 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
if (nlk->ngroups == 0)
groups = 0;
else
groups &= (1ULL << nlk->ngroups) - 1;
else if (nlk->ngroups < 8*sizeof(groups))
groups &= (1UL << nlk->ngroups) - 1;
bound = nlk->bound;
if (bound) {