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