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authorIlya Dryomov <idryomov@gmail.com>2018-04-24 19:10:55 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-05-01 15:13:09 -0700
commit30c85553d822c2d882ed5fe1652be5acdf405509 (patch)
tree3ced39ac04023644e55882fccfc5e1cd5cec3d2b /net
parent6044c69297adb224e4a2ec1bc8680b2e51428cc9 (diff)
libceph: validate con->state at the top of try_write()
commit 9c55ad1c214d9f8c4594ac2c3fa392c1c32431a7 upstream. ceph_con_workfn() validates con->state before calling try_read() and then try_write(). However, try_read() temporarily releases con->mutex, notably in process_message() and ceph_con_in_msg_alloc(), opening the window for ceph_con_close() to sneak in, close the connection and release con->sock. When try_write() is called on the assumption that con->state is still valid (i.e. not STANDBY or CLOSED), a NULL sock gets passed to the networking stack: BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 IP: selinux_socket_sendmsg+0x5/0x20 Make sure con->state is valid at the top of try_write() and add an explicit BUG_ON for this, similar to try_read(). Cc: stable@vger.kernel.org Link: https://tracker.ceph.com/issues/23706 Signed-off-by: Ilya Dryomov <idryomov@gmail.com> Reviewed-by: Jason Dillaman <dillaman@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
-rw-r--r--net/ceph/messenger.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 25a30be862e9..98ea28dc03f9 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -2512,6 +2512,11 @@ static int try_write(struct ceph_connection *con)
int ret = 1;
dout("try_write start %p state %lu\n", con, con->state);
+ if (con->state != CON_STATE_PREOPEN &&
+ con->state != CON_STATE_CONNECTING &&
+ con->state != CON_STATE_NEGOTIATING &&
+ con->state != CON_STATE_OPEN)
+ return 0;
more:
dout("try_write out_kvec_bytes %d\n", con->out_kvec_bytes);
@@ -2537,6 +2542,8 @@ more:
}
more_kvec:
+ BUG_ON(!con->sock);
+
/* kvec data queued? */
if (con->out_kvec_left) {
ret = write_partial_kvec(con);