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authorDmitry Safonov <dima@arista.com>2018-08-05 01:35:53 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-08-09 12:17:59 +0200
commitc68c772262d9b460ddd1b1d68e06ebe3254d0ead (patch)
tree57ccafa983fe00bacfaa810803a6f1df3acd34c7 /net
parent4d502572ea7da97550891c2b0bcd36fa4eb33401 (diff)
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>
Diffstat (limited to 'net')
-rw-r--r--net/netlink/af_netlink.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 26ff1c7bbcfa..025487436438 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -988,8 +988,8 @@ 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) {