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authorXin Long <lucien.xin@gmail.com>2017-10-17 23:26:10 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-11-21 09:21:17 +0100
commit46bdabbca02ebabd292d0ea3f610aa54e53f0e25 (patch)
tree6da9d50bd02e9e1dc2727758681d7608a64b7a5c /net/sctp
parent11e8e55be18cd39c3d54674362aa18695b243e22 (diff)
sctp: do not peel off an assoc from one netns to another one
commit df80cd9b28b9ebaa284a41df611dbf3a2d05ca74 upstream. Now when peeling off an association to the sock in another netns, all transports in this assoc are not to be rehashed and keep use the old key in hashtable. As a transport uses sk->net as the hash key to insert into hashtable, it would miss removing these transports from hashtable due to the new netns when closing the sock and all transports are being freeed, then later an use-after-free issue could be caused when looking up an asoc and dereferencing those transports. This is a very old issue since very beginning, ChunYu found it with syzkaller fuzz testing with this series: socket$inet6_sctp() bind$inet6() sendto$inet6() unshare(0x40000000) getsockopt$inet_sctp6_SCTP_GET_ASSOC_ID_LIST() getsockopt$inet_sctp6_SCTP_SOCKOPT_PEELOFF() This patch is to block this call when peeling one assoc off from one netns to another one, so that the netns of all transport would not go out-sync with the key in hashtable. Note that this patch didn't fix it by rehashing transports, as it's difficult to handle the situation when the tuple is already in use in the new netns. Besides, no one would like to peel off one assoc to another netns, considering ipaddrs, ifaces, etc. are usually different. Reported-by: ChunYu Wang <chunwang@redhat.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/sctp')
-rw-r--r--net/sctp/socket.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 73eec73ff733..7f0f689b8d2b 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4453,6 +4453,10 @@ int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, struct socket **sockp)
struct socket *sock;
int err = 0;
+ /* Do not peel off from one netns to another one. */
+ if (!net_eq(current->nsproxy->net_ns, sock_net(sk)))
+ return -EINVAL;
+
if (!asoc)
return -EINVAL;