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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 12:16:38 +0200
commit09901e570c9e9d6bf302716edd3a5a14417a0657 (patch)
tree4e51331dffd11768d4806992e799b86b52c61068
parent2d898915ccf4838c04531c51a598469e921a5eb5 (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>
-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 68c9d1833b95..c67abda5d639 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -981,8 +981,8 @@ 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) {