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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __LINUX_NET_SCM_H
3#define __LINUX_NET_SCM_H
4
5#include <linux/limits.h>
6#include <linux/net.h>
7#include <linux/cred.h>
8#include <linux/file.h>
9#include <linux/security.h>
10#include <linux/pid.h>
11#include <linux/nsproxy.h>
12#include <linux/sched/signal.h>
13#include <net/compat.h>
14
15/* Well, we should have at least one descriptor open
16 * to accept passed FDs 8)
17 */
18#define SCM_MAX_FD 253
19
20struct scm_creds {
21 u32 pid;
22 kuid_t uid;
23 kgid_t gid;
24};
25
26#ifdef CONFIG_UNIX
27struct unix_edge;
28#endif
29
30struct scm_fp_list {
31 short count;
32 short count_unix;
33 short max;
34#ifdef CONFIG_UNIX
35 bool inflight;
36 bool dead;
37 struct list_head vertices;
38 struct unix_edge *edges;
39#endif
40 struct user_struct *user;
41 struct file *fp[SCM_MAX_FD];
42};
43
44struct scm_cookie {
45 struct pid *pid; /* Skb credentials */
46 struct scm_fp_list *fp; /* Passed files */
47 struct scm_creds creds; /* Skb credentials */
48#ifdef CONFIG_SECURITY_NETWORK
49 u32 secid; /* Passed security ID */
50#endif
51};
52
53void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm);
54void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm);
55int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm);
56void __scm_destroy(struct scm_cookie *scm);
57struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl);
58
59#ifdef CONFIG_SECURITY_NETWORK
60static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
61{
62 security_socket_getpeersec_dgram(sock, NULL, &scm->secid);
63}
64#else
65static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
66{ }
67#endif /* CONFIG_SECURITY_NETWORK */
68
69static __inline__ void scm_set_cred(struct scm_cookie *scm,
70 struct pid *pid, kuid_t uid, kgid_t gid)
71{
72 scm->pid = get_pid(pid);
73 scm->creds.pid = pid_vnr(pid);
74 scm->creds.uid = uid;
75 scm->creds.gid = gid;
76}
77
78static __inline__ void scm_destroy_cred(struct scm_cookie *scm)
79{
80 put_pid(scm->pid);
81 scm->pid = NULL;
82}
83
84static __inline__ void scm_destroy(struct scm_cookie *scm)
85{
86 scm_destroy_cred(scm);
87 if (scm->fp)
88 __scm_destroy(scm);
89}
90
91static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
92 struct scm_cookie *scm, bool forcecreds)
93{
94 memset(scm, 0, sizeof(*scm));
95 scm->creds.uid = INVALID_UID;
96 scm->creds.gid = INVALID_GID;
97 if (forcecreds)
98 scm_set_cred(scm, task_tgid(current), current_uid(), current_gid());
99 unix_get_peersec_dgram(sock, scm);
100 if (msg->msg_controllen <= 0)
101 return 0;
102 return __scm_send(sock, msg, scm);
103}
104
105#ifdef CONFIG_SECURITY_NETWORK
106static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
107{
108 char *secdata;
109 u32 seclen;
110 int err;
111
112 if (test_bit(SOCK_PASSSEC, &sock->flags)) {
113 err = security_secid_to_secctx(scm->secid, &secdata, &seclen);
114
115 if (!err) {
116 put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
117 security_release_secctx(secdata, seclen);
118 }
119 }
120}
121
122static inline bool scm_has_secdata(struct socket *sock)
123{
124 return test_bit(SOCK_PASSSEC, &sock->flags);
125}
126#else
127static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
128{ }
129
130static inline bool scm_has_secdata(struct socket *sock)
131{
132 return false;
133}
134#endif /* CONFIG_SECURITY_NETWORK */
135
136static __inline__ void scm_pidfd_recv(struct msghdr *msg, struct scm_cookie *scm)
137{
138 struct file *pidfd_file = NULL;
139 int len, pidfd;
140
141 /* put_cmsg() doesn't return an error if CMSG is truncated,
142 * that's why we need to opencode these checks here.
143 */
144 if (msg->msg_flags & MSG_CMSG_COMPAT)
145 len = sizeof(struct compat_cmsghdr) + sizeof(int);
146 else
147 len = sizeof(struct cmsghdr) + sizeof(int);
148
149 if (msg->msg_controllen < len) {
150 msg->msg_flags |= MSG_CTRUNC;
151 return;
152 }
153
154 if (!scm->pid)
155 return;
156
157 pidfd = pidfd_prepare(scm->pid, 0, &pidfd_file);
158
159 if (put_cmsg(msg, SOL_SOCKET, SCM_PIDFD, sizeof(int), &pidfd)) {
160 if (pidfd_file) {
161 put_unused_fd(pidfd);
162 fput(pidfd_file);
163 }
164
165 return;
166 }
167
168 if (pidfd_file)
169 fd_install(pidfd, pidfd_file);
170}
171
172static inline bool __scm_recv_common(struct socket *sock, struct msghdr *msg,
173 struct scm_cookie *scm, int flags)
174{
175 if (!msg->msg_control) {
176 if (test_bit(SOCK_PASSCRED, &sock->flags) ||
177 test_bit(SOCK_PASSPIDFD, &sock->flags) ||
178 scm->fp || scm_has_secdata(sock))
179 msg->msg_flags |= MSG_CTRUNC;
180 scm_destroy(scm);
181 return false;
182 }
183
184 if (test_bit(SOCK_PASSCRED, &sock->flags)) {
185 struct user_namespace *current_ns = current_user_ns();
186 struct ucred ucreds = {
187 .pid = scm->creds.pid,
188 .uid = from_kuid_munged(current_ns, scm->creds.uid),
189 .gid = from_kgid_munged(current_ns, scm->creds.gid),
190 };
191 put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(ucreds), &ucreds);
192 }
193
194 scm_passec(sock, msg, scm);
195
196 if (scm->fp)
197 scm_detach_fds(msg, scm);
198
199 return true;
200}
201
202static inline void scm_recv(struct socket *sock, struct msghdr *msg,
203 struct scm_cookie *scm, int flags)
204{
205 if (!__scm_recv_common(sock, msg, scm, flags))
206 return;
207
208 scm_destroy_cred(scm);
209}
210
211static inline void scm_recv_unix(struct socket *sock, struct msghdr *msg,
212 struct scm_cookie *scm, int flags)
213{
214 if (!__scm_recv_common(sock, msg, scm, flags))
215 return;
216
217 if (test_bit(SOCK_PASSPIDFD, &sock->flags))
218 scm_pidfd_recv(msg, scm);
219
220 scm_destroy_cred(scm);
221}
222
223static inline int scm_recv_one_fd(struct file *f, int __user *ufd,
224 unsigned int flags)
225{
226 if (!ufd)
227 return -EFAULT;
228 return receive_fd(f, ufd, flags);
229}
230
231#endif /* __LINUX_NET_SCM_H */
232
1#ifndef __LINUX_NET_SCM_H
2#define __LINUX_NET_SCM_H
3
4#include <linux/limits.h>
5#include <linux/net.h>
6#include <linux/security.h>
7#include <linux/pid.h>
8#include <linux/nsproxy.h>
9
10/* Well, we should have at least one descriptor open
11 * to accept passed FDs 8)
12 */
13#define SCM_MAX_FD 253
14
15struct scm_creds {
16 u32 pid;
17 kuid_t uid;
18 kgid_t gid;
19};
20
21struct scm_fp_list {
22 short count;
23 short max;
24 struct user_struct *user;
25 struct file *fp[SCM_MAX_FD];
26};
27
28struct scm_cookie {
29 struct pid *pid; /* Skb credentials */
30 struct scm_fp_list *fp; /* Passed files */
31 struct scm_creds creds; /* Skb credentials */
32#ifdef CONFIG_SECURITY_NETWORK
33 u32 secid; /* Passed security ID */
34#endif
35};
36
37void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm);
38void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm);
39int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm);
40void __scm_destroy(struct scm_cookie *scm);
41struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl);
42
43#ifdef CONFIG_SECURITY_NETWORK
44static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
45{
46 security_socket_getpeersec_dgram(sock, NULL, &scm->secid);
47}
48#else
49static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
50{ }
51#endif /* CONFIG_SECURITY_NETWORK */
52
53static __inline__ void scm_set_cred(struct scm_cookie *scm,
54 struct pid *pid, kuid_t uid, kgid_t gid)
55{
56 scm->pid = get_pid(pid);
57 scm->creds.pid = pid_vnr(pid);
58 scm->creds.uid = uid;
59 scm->creds.gid = gid;
60}
61
62static __inline__ void scm_destroy_cred(struct scm_cookie *scm)
63{
64 put_pid(scm->pid);
65 scm->pid = NULL;
66}
67
68static __inline__ void scm_destroy(struct scm_cookie *scm)
69{
70 scm_destroy_cred(scm);
71 if (scm->fp)
72 __scm_destroy(scm);
73}
74
75static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
76 struct scm_cookie *scm, bool forcecreds)
77{
78 memset(scm, 0, sizeof(*scm));
79 scm->creds.uid = INVALID_UID;
80 scm->creds.gid = INVALID_GID;
81 if (forcecreds)
82 scm_set_cred(scm, task_tgid(current), current_uid(), current_gid());
83 unix_get_peersec_dgram(sock, scm);
84 if (msg->msg_controllen <= 0)
85 return 0;
86 return __scm_send(sock, msg, scm);
87}
88
89#ifdef CONFIG_SECURITY_NETWORK
90static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
91{
92 char *secdata;
93 u32 seclen;
94 int err;
95
96 if (test_bit(SOCK_PASSSEC, &sock->flags)) {
97 err = security_secid_to_secctx(scm->secid, &secdata, &seclen);
98
99 if (!err) {
100 put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
101 security_release_secctx(secdata, seclen);
102 }
103 }
104}
105#else
106static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
107{ }
108#endif /* CONFIG_SECURITY_NETWORK */
109
110static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg,
111 struct scm_cookie *scm, int flags)
112{
113 if (!msg->msg_control) {
114 if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp)
115 msg->msg_flags |= MSG_CTRUNC;
116 scm_destroy(scm);
117 return;
118 }
119
120 if (test_bit(SOCK_PASSCRED, &sock->flags)) {
121 struct user_namespace *current_ns = current_user_ns();
122 struct ucred ucreds = {
123 .pid = scm->creds.pid,
124 .uid = from_kuid_munged(current_ns, scm->creds.uid),
125 .gid = from_kgid_munged(current_ns, scm->creds.gid),
126 };
127 put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(ucreds), &ucreds);
128 }
129
130 scm_destroy_cred(scm);
131
132 scm_passec(sock, msg, scm);
133
134 if (!scm->fp)
135 return;
136
137 scm_detach_fds(msg, scm);
138}
139
140
141#endif /* __LINUX_NET_SCM_H */
142