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57569c37f0
Fix a NULL pointer crash that occurs when we are freeing the socket at the
same time we access it via sysfs.
The problem is that:
1. iscsi_sw_tcp_conn_get_param() and iscsi_sw_tcp_host_get_param() take
the frwd_lock and do sock_hold() then drop the frwd_lock. sock_hold()
does a get on the "struct sock".
2. iscsi_sw_tcp_release_conn() does sockfd_put() which does the last put
on the "struct socket" and that does __sock_release() which sets the
sock->ops to NULL.
3. iscsi_sw_tcp_conn_get_param() and iscsi_sw_tcp_host_get_param() then
call kernel_getpeername() which accesses the NULL sock->ops.
Above we do a get on the "struct sock", but we needed a get on the "struct
socket". Originally, we just held the frwd_lock the entire time but in
commit bcf3a2953d ("scsi: iscsi: iscsi_tcp: Avoid holding spinlock while
calling getpeername()") we switched to refcount based because the network
layer changed and started taking a mutex in that path, so we could no
longer hold the frwd_lock.
Instead of trying to maintain multiple refcounts, this just has us use a
mutex for accessing the socket in the interface code paths.
Link: https://lore.kernel.org/r/20220907221700.10302-1-michael.christie@oracle.com
Fixes: bcf3a2953d ("scsi: iscsi: iscsi_tcp: Avoid holding spinlock while calling getpeername()")
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
65 lines
1.6 KiB
C
65 lines
1.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* iSCSI Initiator TCP Transport
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* Copyright (C) 2004 Dmitry Yusupov
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* Copyright (C) 2004 Alex Aizman
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* Copyright (C) 2005 - 2006 Mike Christie
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* Copyright (C) 2006 Red Hat, Inc. All rights reserved.
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* maintained by open-iscsi@googlegroups.com
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*
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* See the file COPYING included with this distribution for more details.
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*/
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#ifndef ISCSI_SW_TCP_H
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#define ISCSI_SW_TCP_H
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#include <scsi/libiscsi.h>
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#include <scsi/libiscsi_tcp.h>
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struct socket;
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struct iscsi_tcp_conn;
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/* Socket connection send helper */
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struct iscsi_sw_tcp_send {
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struct iscsi_hdr *hdr;
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struct iscsi_segment segment;
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struct iscsi_segment data_segment;
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};
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struct iscsi_sw_tcp_conn {
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struct socket *sock;
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/* Taken when accessing the sock from the netlink/sysfs interface */
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struct mutex sock_lock;
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struct work_struct recvwork;
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bool queue_recv;
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struct iscsi_sw_tcp_send out;
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/* old values for socket callbacks */
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void (*old_data_ready)(struct sock *);
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void (*old_state_change)(struct sock *);
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void (*old_write_space)(struct sock *);
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/* data and header digests */
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struct ahash_request *tx_hash; /* CRC32C (Tx) */
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struct ahash_request *rx_hash; /* CRC32C (Rx) */
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/* MIB custom statistics */
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uint32_t sendpage_failures_cnt;
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uint32_t discontiguous_hdr_cnt;
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ssize_t (*sendpage)(struct socket *, struct page *, int, size_t, int);
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};
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struct iscsi_sw_tcp_host {
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struct iscsi_session *session;
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};
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struct iscsi_sw_tcp_hdrbuf {
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struct iscsi_hdr hdrbuf;
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char hdrextbuf[ISCSI_MAX_AHS_SIZE +
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ISCSI_DIGEST_SIZE];
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};
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#endif /* ISCSI_SW_TCP_H */
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