Messages in this thread Patch in this message | | | From | Ben Hutchings <> | Date | Sun, 11 Nov 2018 19:49:05 +0000 | Subject | [PATCH 3.16 305/366] netlink: Don't shift with UB on nlk->ngroups |
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3.16.61-rc1 review patch. If anyone has any objections, please let me know.
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From: Dmitry Safonov <dima@arista.com>
commit 61f4b23769f0cc72ae62c9a81cf08f0397d40da8 upstream.
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: Ben Hutchings <ben@decadent.org.uk> --- net/netlink/af_netlink.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
--- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -927,7 +927,11 @@ static int netlink_bind(struct socket *s if (err) return err; } - groups &= (1UL << nlk->ngroups) - 1; + + if (nlk->ngroups == 0) + groups = 0; + else + groups &= (1ULL << nlk->ngroups) - 1; if (nlk->portid) if (nladdr->nl_pid != nlk->portid)
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