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authorDmitry Safonov <dima@arista.com>2018-08-05 01:35:53 +0100
committerDavid S. Miller <davem@davemloft.net>2018-08-04 17:52:51 -0700
commit91874ecf32e41b5d86a4cb9d60e0bee50d828058 (patch)
treea4283cc102cac38e593c53424c777eab8ab1c0fa
parent5dbfb6eca0b23751d9ab21989a07b5a22fa544fe (diff)
download96b-common-91874ecf32e41b5d86a4cb9d60e0bee50d828058.tar.gz
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>
-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 c09d16870f74..56704d95f82d 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -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) {