libceph: validate con->state at the top of try_write()
commit 9c55ad1c21
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>
pull/10/head
parent
c2bc3eb559
commit
7563d6f2be
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@ -2530,6 +2530,11 @@ static int try_write(struct ceph_connection *con)
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int ret = 1;
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dout("try_write start %p state %lu\n", con, con->state);
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if (con->state != CON_STATE_PREOPEN &&
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con->state != CON_STATE_CONNECTING &&
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con->state != CON_STATE_NEGOTIATING &&
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con->state != CON_STATE_OPEN)
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return 0;
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more:
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dout("try_write out_kvec_bytes %d\n", con->out_kvec_bytes);
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@ -2555,6 +2560,8 @@ more:
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}
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more_kvec:
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BUG_ON(!con->sock);
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/* kvec data queued? */
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if (con->out_kvec_left) {
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ret = write_partial_kvec(con);
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