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
scsi_nl_rcv_msg(struct sk_buff * skb)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
scsi_netlink_init(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
scsi_netlink_exit(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 
145