GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / scsi / scsi_netlink.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  scsi_netlink.c  - SCSI Transport Netlink Interface
4  *
5  *  Copyright (C) 2006   James Smart, Emulex Corporation
6  */
7 #include <linux/time.h>
8 #include <linux/jiffies.h>
9 #include <linux/security.h>
10 #include <linux/delay.h>
11 #include <linux/slab.h>
12 #include <linux/export.h>
13 #include <net/sock.h>
14 #include <net/netlink.h>
15
16 #include <scsi/scsi_netlink.h>
17 #include "scsi_priv.h"
18
19 struct sock *scsi_nl_sock = NULL;
20 EXPORT_SYMBOL_GPL(scsi_nl_sock);
21
22 /**
23  * scsi_nl_rcv_msg - Receive message handler.
24  * @skb:                socket receive buffer
25  *
26  * Description: Extracts message from a receive buffer.
27  *    Validates message header and calls appropriate transport message handler
28  *
29  *
30  **/
31 static void
32 scsi_nl_rcv_msg(struct sk_buff *skb)
33 {
34         struct nlmsghdr *nlh;
35         struct scsi_nl_hdr *hdr;
36         u32 rlen;
37         int err, tport;
38
39         while (skb->len >= NLMSG_HDRLEN) {
40                 err = 0;
41
42                 nlh = nlmsg_hdr(skb);
43                 if ((nlh->nlmsg_len < (sizeof(*nlh) + sizeof(*hdr))) ||
44                     (skb->len < nlh->nlmsg_len)) {
45                         printk(KERN_WARNING "%s: discarding partial skb\n",
46                                  __func__);
47                         return;
48                 }
49
50                 rlen = NLMSG_ALIGN(nlh->nlmsg_len);
51                 if (rlen > skb->len)
52                         rlen = skb->len;
53
54                 if (nlh->nlmsg_type != SCSI_TRANSPORT_MSG) {
55                         err = -EBADMSG;
56                         goto next_msg;
57                 }
58
59                 hdr = nlmsg_data(nlh);
60                 if ((hdr->version != SCSI_NL_VERSION) ||
61                     (hdr->magic != SCSI_NL_MAGIC)) {
62                         err = -EPROTOTYPE;
63                         goto next_msg;
64                 }
65
66                 if (!netlink_capable(skb, CAP_SYS_ADMIN)) {
67                         err = -EPERM;
68                         goto next_msg;
69                 }
70
71                 if (nlh->nlmsg_len < (sizeof(*nlh) + hdr->msglen)) {
72                         printk(KERN_WARNING "%s: discarding partial message\n",
73                                  __func__);
74                         goto next_msg;
75                 }
76
77                 /*
78                  * Deliver message to the appropriate transport
79                  */
80                 tport = hdr->transport;
81                 if (tport == SCSI_NL_TRANSPORT) {
82                         switch (hdr->msgtype) {
83                         case SCSI_NL_SHOST_VENDOR:
84                                 /* Locate the driver that corresponds to the message */
85                                 err = -ESRCH;
86                                 break;
87                         default:
88                                 err = -EBADR;
89                                 break;
90                         }
91                         if (err)
92                                 printk(KERN_WARNING "%s: Msgtype %d failed - err %d\n",
93                                        __func__, hdr->msgtype, err);
94                 }
95                 else
96                         err = -ENOENT;
97
98 next_msg:
99                 if ((err) || (nlh->nlmsg_flags & NLM_F_ACK))
100                         netlink_ack(skb, nlh, err, NULL);
101
102                 skb_pull(skb, rlen);
103         }
104 }
105
106 /**
107  * scsi_netlink_init - Called by SCSI subsystem to initialize
108  *      the SCSI transport netlink interface
109  *
110  **/
111 void
112 scsi_netlink_init(void)
113 {
114         struct netlink_kernel_cfg cfg = {
115                 .input  = scsi_nl_rcv_msg,
116                 .groups = SCSI_NL_GRP_CNT,
117         };
118
119         scsi_nl_sock = netlink_kernel_create(&init_net, NETLINK_SCSITRANSPORT,
120                                              &cfg);
121         if (!scsi_nl_sock) {
122                 printk(KERN_ERR "%s: register of receive handler failed\n",
123                                 __func__);
124                 return;
125         }
126
127         return;
128 }
129
130
131 /**
132  * scsi_netlink_exit - Called by SCSI subsystem to disable the SCSI transport netlink interface
133  *
134  **/
135 void
136 scsi_netlink_exit(void)
137 {
138         if (scsi_nl_sock) {
139                 netlink_kernel_release(scsi_nl_sock);
140         }
141
142         return;
143 }
144