1 /* Kernel module to match various things tied to sockets associated with
2 locally generated outgoing packets.
3
4 Copyright (C) 2000,2001 Marc Boucher
5 */
6 #include <linux/module.h>
7 #include <linux/skbuff.h>
8 #include <linux/file.h>
9 #include <net/sock.h>
10
11 #include <linux/netfilter_ipv6/ip6t_owner.h>
12 #include <linux/netfilter_ipv6/ip6_tables.h>
13
14 MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>");
15 MODULE_DESCRIPTION("IP6 tables owner matching module");
16 MODULE_LICENSE("GPL");
17
18 static int
match_pid(const struct sk_buff * skb,pid_t pid)19 match_pid(const struct sk_buff *skb, pid_t pid)
20 {
21 struct task_struct *p;
22 struct files_struct *files;
23 int i;
24
25 read_lock(&tasklist_lock);
26 p = find_task_by_pid(pid);
27 if (!p)
28 goto out;
29 task_lock(p);
30 files = p->files;
31 if(files) {
32 read_lock(&files->file_lock);
33 for (i=0; i < files->max_fds; i++) {
34 if (fcheck_files(files, i) == skb->sk->socket->file) {
35 read_unlock(&files->file_lock);
36 task_unlock(p);
37 read_unlock(&tasklist_lock);
38 return 1;
39 }
40 }
41 read_unlock(&files->file_lock);
42 }
43 task_unlock(p);
44 out:
45 read_unlock(&tasklist_lock);
46 return 0;
47 }
48
49 static int
match_sid(const struct sk_buff * skb,pid_t sid)50 match_sid(const struct sk_buff *skb, pid_t sid)
51 {
52 struct task_struct *p;
53 struct file *file = skb->sk->socket->file;
54 int i, found=0;
55
56 read_lock(&tasklist_lock);
57 for_each_task(p) {
58 struct files_struct *files;
59 if (p->session != sid)
60 continue;
61
62 task_lock(p);
63 files = p->files;
64 if (files) {
65 read_lock(&files->file_lock);
66 for (i=0; i < files->max_fds; i++) {
67 if (fcheck_files(files, i) == file) {
68 found = 1;
69 break;
70 }
71 }
72 read_unlock(&files->file_lock);
73 }
74 task_unlock(p);
75 if(found)
76 break;
77 }
78 read_unlock(&tasklist_lock);
79
80 return found;
81 }
82
83 static int
match(const struct sk_buff * skb,const struct net_device * in,const struct net_device * out,const void * matchinfo,int offset,const void * hdr,u_int16_t datalen,int * hotdrop)84 match(const struct sk_buff *skb,
85 const struct net_device *in,
86 const struct net_device *out,
87 const void *matchinfo,
88 int offset,
89 const void *hdr,
90 u_int16_t datalen,
91 int *hotdrop)
92 {
93 const struct ip6t_owner_info *info = matchinfo;
94
95 if (!skb->sk || !skb->sk->socket || !skb->sk->socket->file)
96 return 0;
97
98 if(info->match & IP6T_OWNER_UID) {
99 if((skb->sk->socket->file->f_uid != info->uid) ^
100 !!(info->invert & IP6T_OWNER_UID))
101 return 0;
102 }
103
104 if(info->match & IP6T_OWNER_GID) {
105 if((skb->sk->socket->file->f_gid != info->gid) ^
106 !!(info->invert & IP6T_OWNER_GID))
107 return 0;
108 }
109
110 if(info->match & IP6T_OWNER_PID) {
111 if (!match_pid(skb, info->pid) ^
112 !!(info->invert & IP6T_OWNER_PID))
113 return 0;
114 }
115
116 if(info->match & IP6T_OWNER_SID) {
117 if (!match_sid(skb, info->sid) ^
118 !!(info->invert & IP6T_OWNER_SID))
119 return 0;
120 }
121
122 return 1;
123 }
124
125 static int
checkentry(const char * tablename,const struct ip6t_ip6 * ip,void * matchinfo,unsigned int matchsize,unsigned int hook_mask)126 checkentry(const char *tablename,
127 const struct ip6t_ip6 *ip,
128 void *matchinfo,
129 unsigned int matchsize,
130 unsigned int hook_mask)
131 {
132 if (hook_mask
133 & ~((1 << NF_IP6_LOCAL_OUT) | (1 << NF_IP6_POST_ROUTING))) {
134 printk("ip6t_owner: only valid for LOCAL_OUT or POST_ROUTING.\n");
135 return 0;
136 }
137
138 if (matchsize != IP6T_ALIGN(sizeof(struct ip6t_owner_info)))
139 return 0;
140 #ifdef CONFIG_SMP
141 /* files->file_lock can not be used in a BH */
142 if (((struct ip6t_owner_info *)matchinfo)->match
143 & (IP6T_OWNER_PID|IP6T_OWNER_SID)) {
144 printk("ip6t_owner: pid and sid matching is broken on SMP.\n");
145 return 0;
146 }
147 #endif
148 return 1;
149 }
150
151 static struct ip6t_match owner_match
152 = { { NULL, NULL }, "owner", &match, &checkentry, NULL, THIS_MODULE };
153
init(void)154 static int __init init(void)
155 {
156 return ip6t_register_match(&owner_match);
157 }
158
fini(void)159 static void __exit fini(void)
160 {
161 ip6t_unregister_match(&owner_match);
162 }
163
164 module_init(init);
165 module_exit(fini);
166