From: Paolo Abeni pabeni@redhat.com
[ Upstream commit 86581852d7710990d8af9dadfe9a661f0abf2114 ]
Unrolling mcast state at msk dismantel time is bug prone, as syzkaller reported:
====================================================== WARNING: possible circular locking dependency detected 5.11.0-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor905/8822 is trying to acquire lock: ffffffff8d678fe8 (rtnl_mutex){+.+.}-{3:3}, at: ipv6_sock_mc_close+0xd7/0x110 net/ipv6/mcast.c:323
but task is already holding lock: ffff888024390120 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1600 [inline] ffff888024390120 (sk_lock-AF_INET6){+.+.}-{0:0}, at: mptcp6_release+0x57/0x130 net/mptcp/protocol.c:3507
which lock already depends on the new lock.
Instead we can simply forbit any mcast-related setsockopt
Fixes: 717e79c867ca5 ("mptcp: Add setsockopt()/getsockopt() socket operations") Signed-off-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Mat Martineau mathew.j.martineau@linux.intel.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/mptcp/protocol.c | 45 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index f56b2e331bb6..27f6672589ce 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2245,6 +2245,48 @@ static int mptcp_setsockopt_v6(struct mptcp_sock *msk, int optname, return ret; }
+static bool mptcp_unsupported(int level, int optname) +{ + if (level == SOL_IP) { + switch (optname) { + case IP_ADD_MEMBERSHIP: + case IP_ADD_SOURCE_MEMBERSHIP: + case IP_DROP_MEMBERSHIP: + case IP_DROP_SOURCE_MEMBERSHIP: + case IP_BLOCK_SOURCE: + case IP_UNBLOCK_SOURCE: + case MCAST_JOIN_GROUP: + case MCAST_LEAVE_GROUP: + case MCAST_JOIN_SOURCE_GROUP: + case MCAST_LEAVE_SOURCE_GROUP: + case MCAST_BLOCK_SOURCE: + case MCAST_UNBLOCK_SOURCE: + case MCAST_MSFILTER: + return true; + } + return false; + } + if (level == SOL_IPV6) { + switch (optname) { + case IPV6_ADDRFORM: + case IPV6_ADD_MEMBERSHIP: + case IPV6_DROP_MEMBERSHIP: + case IPV6_JOIN_ANYCAST: + case IPV6_LEAVE_ANYCAST: + case MCAST_JOIN_GROUP: + case MCAST_LEAVE_GROUP: + case MCAST_JOIN_SOURCE_GROUP: + case MCAST_LEAVE_SOURCE_GROUP: + case MCAST_BLOCK_SOURCE: + case MCAST_UNBLOCK_SOURCE: + case MCAST_MSFILTER: + return true; + } + return false; + } + return false; +} + static int mptcp_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval, unsigned int optlen) { @@ -2253,6 +2295,9 @@ static int mptcp_setsockopt(struct sock *sk, int level, int optname,
pr_debug("msk=%p", msk);
+ if (mptcp_unsupported(level, optname)) + return -ENOPROTOOPT; + if (level == SOL_SOCKET) return mptcp_setsockopt_sol_socket(msk, optname, optval, optlen);