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