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authorDmitry Safonov <dima@arista.com>2018-07-30 18:32:36 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-08-03 07:50:45 +0200
commitfffd3058eaf438e71cd301c14a0c67161a5864df (patch)
tree6b7d1d0d6f5d8db48a88de880543696fa90d4a4e
parente208cda5f10e131f149e59d7de4ceb943382f4c6 (diff)
netlink: Don't shift with UB on nlk->ngroups
[ Upstream commit 61f4b23769f0cc72ae62c9a81cf08f0397d40da8 ] On i386 nlk->ngroups might be 32 or 0. Which leads to UB, resulting in hang during boot. Check for 0 ngroups and use (unsigned long long) as a type to shift. Fixes: 7acf9d4237c4 ("netlink: Do not subscribe to non-existent groups"). Reported-by: kernel test robot <rong.a.chen@intel.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.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 143d9001e87d..b2fcbf012056 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -976,7 +976,11 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
if (err)
return err;
}
- groups &= (1UL << nlk->ngroups) - 1;
+
+ if (nlk->ngroups == 0)
+ groups = 0;
+ else
+ groups &= (1ULL << nlk->ngroups) - 1;
bound = nlk->bound;
if (bound) {