[linux-block.git] / net / core / scm.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* scm.c - Socket level control messages processing.
 *
 * Author:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 *              Alignment and value checking mods by Craig Metz
 */

#include <linux/module.h>
#include <linux/signal.h>
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/sched/user.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/stat.h>
#include <linux/socket.h>
#include <linux/file.h>
#include <linux/fcntl.h>
#include <linux/net.h>
#include <linux/interrupt.h>
#include <linux/netdevice.h>
#include <linux/security.h>
#include <linux/pid_namespace.h>
#include <linux/pid.h>
#include <linux/nsproxy.h>
#include <linux/slab.h>
#include <linux/errqueue.h>
#include <linux/io_uring.h>

#include <linux/uaccess.h>

#include <net/protocol.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/compat.h>
#include <net/scm.h>
#include <net/cls_cgroup.h>
#include <net/af_unix.h>


/*
 *	Only allow a user to send credentials, that they could set with
 *	setu(g)id.
 */

static __inline__ int scm_check_creds(struct ucred *creds)
{
	const struct cred *cred = current_cred();
	kuid_t uid = make_kuid(cred->user_ns, creds->uid);
	kgid_t gid = make_kgid(cred->user_ns, creds->gid);

	if (!uid_valid(uid) || !gid_valid(gid))
		return -EINVAL;

	if ((creds->pid == task_tgid_vnr(current) ||
	     ns_capable(task_active_pid_ns(current)->user_ns, CAP_SYS_ADMIN)) &&
	    ((uid_eq(uid, cred->uid)   || uid_eq(uid, cred->euid) ||
	      uid_eq(uid, cred->suid)) || ns_capable(cred->user_ns, CAP_SETUID)) &&
	    ((gid_eq(gid, cred->gid)   || gid_eq(gid, cred->egid) ||
	      gid_eq(gid, cred->sgid)) || ns_capable(cred->user_ns, CAP_SETGID))) {
	       return 0;
	}
	return -EPERM;
}

static int scm_fp_copy(struct cmsghdr *cmsg, struct scm_fp_list **fplp)
{
	int *fdp = (int*)CMSG_DATA(cmsg);
	struct scm_fp_list *fpl = *fplp;
	struct file **fpp;
	int i, num;

	num = (cmsg->cmsg_len - sizeof(struct cmsghdr))/sizeof(int);

	if (num <= 0)
		return 0;

	if (num > SCM_MAX_FD)
		return -EINVAL;

	if (!fpl)
	{
		fpl = kmalloc(sizeof(struct scm_fp_list), GFP_KERNEL_ACCOUNT);
		if (!fpl)
			return -ENOMEM;
		*fplp = fpl;
		fpl->count = 0;
		fpl->count_unix = 0;
		fpl->max = SCM_MAX_FD;
		fpl->user = NULL;
#if IS_ENABLED(CONFIG_UNIX)
		fpl->inflight = false;
		fpl->dead = false;
		fpl->edges = NULL;
		INIT_LIST_HEAD(&fpl->vertices);
#endif
	}
	fpp = &fpl->fp[fpl->count];

	if (fpl->count + num > fpl->max)
		return -EINVAL;

	/*
	 *	Verify the descriptors and increment the usage count.
	 */

	for (i=0; i< num; i++)
	{
		int fd = fdp[i];
		struct file *file;

		if (fd < 0 || !(file = fget_raw(fd)))
			return -EBADF;
		/* don't allow io_uring files */
		if (io_is_uring_fops(file)) {
			fput(file);
			return -EINVAL;
		}
		if (unix_get_socket(file))
			fpl->count_unix++;

		*fpp++ = file;
		fpl->count++;
	}

	if (!fpl->user)
		fpl->user = get_uid(current_user());

	return num;
}

void __scm_destroy(struct scm_cookie *scm)
{
	struct scm_fp_list *fpl = scm->fp;
	int i;

	if (fpl) {
		scm->fp = NULL;
		for (i=fpl->count-1; i>=0; i--)
			fput(fpl->fp[i]);
		free_uid(fpl->user);
		kfree(fpl);
	}
}
EXPORT_SYMBOL(__scm_destroy);

int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *p)
{
	const struct proto_ops *ops = READ_ONCE(sock->ops);
	struct cmsghdr *cmsg;
	int err;

	for_each_cmsghdr(cmsg, msg) {
		err = -EINVAL;

		/* Verify that cmsg_len is at least sizeof(struct cmsghdr) */
		/* The first check was omitted in <= 2.2.5. The reasoning was
		   that parser checks cmsg_len in any case, so that
		   additional check would be work duplication.
		   But if cmsg_level is not SOL_SOCKET, we do not check
		   for too short ancillary data object at all! Oops.
		   OK, let's add it...
		 */
		if (!CMSG_OK(msg, cmsg))
			goto error;

		if (cmsg->cmsg_level != SOL_SOCKET)
			continue;

		switch (cmsg->cmsg_type)
		{
		case SCM_RIGHTS:
			if (!ops || ops->family != PF_UNIX)
				goto error;
			err=scm_fp_copy(cmsg, &p->fp);
			if (err<0)
				goto error;
			break;
		case SCM_CREDENTIALS:
		{
			struct ucred creds;
			kuid_t uid;
			kgid_t gid;
			if (cmsg->cmsg_len != CMSG_LEN(sizeof(struct ucred)))
				goto error;
			memcpy(&creds, CMSG_DATA(cmsg), sizeof(struct ucred));
			err = scm_check_creds(&creds);
			if (err)
				goto error;

			p->creds.pid = creds.pid;
			if (!p->pid || pid_vnr(p->pid) != creds.pid) {
				struct pid *pid;
				err = -ESRCH;
				pid = find_get_pid(creds.pid);
				if (!pid)
					goto error;
				put_pid(p->pid);
				p->pid = pid;
			}

			err = -EINVAL;
			uid = make_kuid(current_user_ns(), creds.uid);
			gid = make_kgid(current_user_ns(), creds.gid);
			if (!uid_valid(uid) || !gid_valid(gid))
				goto error;

			p->creds.uid = uid;
			p->creds.gid = gid;
			break;
		}
		default:
			goto error;
		}
	}

	if (p->fp && !p->fp->count)
	{
		kfree(p->fp);
		p->fp = NULL;
	}
	return 0;

error:
	scm_destroy(p);
	return err;
}
EXPORT_SYMBOL(__scm_send);

int put_cmsg(struct msghdr * msg, int level, int type, int len, void *data)
{
	int cmlen = CMSG_LEN(len);

	if (msg->msg_flags & MSG_CMSG_COMPAT)
		return put_cmsg_compat(msg, level, type, len, data);

	if (!msg->msg_control || msg->msg_controllen < sizeof(struct cmsghdr)) {
		msg->msg_flags |= MSG_CTRUNC;
		return 0; /* XXX: return error? check spec. */
	}
	if (msg->msg_controllen < cmlen) {
		msg->msg_flags |= MSG_CTRUNC;
		cmlen = msg->msg_controllen;
	}

	if (msg->msg_control_is_user) {
		struct cmsghdr __user *cm = msg->msg_control_user;

		check_object_size(data, cmlen - sizeof(*cm), true);

		if (!user_write_access_begin(cm, cmlen))
			goto efault;

		unsafe_put_user(cmlen, &cm->cmsg_len, efault_end);
		unsafe_put_user(level, &cm->cmsg_level, efault_end);
		unsafe_put_user(type, &cm->cmsg_type, efault_end);
		unsafe_copy_to_user(CMSG_USER_DATA(cm), data,
				    cmlen - sizeof(*cm), efault_end);
		user_write_access_end();
	} else {
		struct cmsghdr *cm = msg->msg_control;

		cm->cmsg_level = level;
		cm->cmsg_type = type;
		cm->cmsg_len = cmlen;
		memcpy(CMSG_DATA(cm), data, cmlen - sizeof(*cm));
	}

	cmlen = min(CMSG_SPACE(len), msg->msg_controllen);
	if (msg->msg_control_is_user)
		msg->msg_control_user += cmlen;
	else
		msg->msg_control += cmlen;
	msg->msg_controllen -= cmlen;
	return 0;

efault_end:
	user_write_access_end();
efault:
	return -EFAULT;
}
EXPORT_SYMBOL(put_cmsg);

void put_cmsg_scm_timestamping64(struct msghdr *msg, struct scm_timestamping_internal *tss_internal)
{
	struct scm_timestamping64 tss;
	int i;

	for (i = 0; i < ARRAY_SIZE(tss.ts); i++) {
		tss.ts[i].tv_sec = tss_internal->ts[i].tv_sec;
		tss.ts[i].tv_nsec = tss_internal->ts[i].tv_nsec;
	}

	put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMPING_NEW, sizeof(tss), &tss);
}
EXPORT_SYMBOL(put_cmsg_scm_timestamping64);

void put_cmsg_scm_timestamping(struct msghdr *msg, struct scm_timestamping_internal *tss_internal)
{
	struct scm_timestamping tss;
	int i;

	for (i = 0; i < ARRAY_SIZE(tss.ts); i++) {
		tss.ts[i].tv_sec = tss_internal->ts[i].tv_sec;
		tss.ts[i].tv_nsec = tss_internal->ts[i].tv_nsec;
	}

	put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMPING_OLD, sizeof(tss), &tss);
}
EXPORT_SYMBOL(put_cmsg_scm_timestamping);

static int scm_max_fds(struct msghdr *msg)
{
	if (msg->msg_controllen <= sizeof(struct cmsghdr))
		return 0;
	return (msg->msg_controllen - sizeof(struct cmsghdr)) / sizeof(int);
}

void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm)
{
	struct cmsghdr __user *cm =
		(__force struct cmsghdr __user *)msg->msg_control_user;
	unsigned int o_flags = (msg->msg_flags & MSG_CMSG_CLOEXEC) ? O_CLOEXEC : 0;
	int fdmax = min_t(int, scm_max_fds(msg), scm->fp->count);
	int __user *cmsg_data = CMSG_USER_DATA(cm);
	int err = 0, i;

	/* no use for FD passing from kernel space callers */
	if (WARN_ON_ONCE(!msg->msg_control_is_user))
		return;

	if (msg->msg_flags & MSG_CMSG_COMPAT) {
		scm_detach_fds_compat(msg, scm);
		return;
	}

	for (i = 0; i < fdmax; i++) {
		err = scm_recv_one_fd(scm->fp->fp[i], cmsg_data + i, o_flags);
		if (err < 0)
			break;
	}

	if (i > 0) {
		int cmlen = CMSG_LEN(i * sizeof(int));

		err = put_user(SOL_SOCKET, &cm->cmsg_level);
		if (!err)
			err = put_user(SCM_RIGHTS, &cm->cmsg_type);
		if (!err)
			err = put_user(cmlen, &cm->cmsg_len);
		if (!err) {
			cmlen = CMSG_SPACE(i * sizeof(int));
			if (msg->msg_controllen < cmlen)
				cmlen = msg->msg_controllen;
			msg->msg_control_user += cmlen;
			msg->msg_controllen -= cmlen;
		}
	}

	if (i < scm->fp->count || (scm->fp->count && fdmax <= 0))
		msg->msg_flags |= MSG_CTRUNC;

	/*
	 * All of the files that fit in the message have had their usage counts
	 * incremented, so we just free the list.
	 */
	__scm_destroy(scm);
}
EXPORT_SYMBOL(scm_detach_fds);

struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl)
{
	struct scm_fp_list *new_fpl;
	int i;

	if (!fpl)
		return NULL;

	new_fpl = kmemdup(fpl, offsetof(struct scm_fp_list, fp[fpl->count]),
			  GFP_KERNEL_ACCOUNT);
	if (new_fpl) {
		for (i = 0; i < fpl->count; i++)
			get_file(fpl->fp[i]);

		new_fpl->max = new_fpl->count;
		new_fpl->user = get_uid(fpl->user);
#if IS_ENABLED(CONFIG_UNIX)
		new_fpl->inflight = false;
		new_fpl->edges = NULL;
		INIT_LIST_HEAD(&new_fpl->vertices);
#endif
	}
	return new_fpl;
}
EXPORT_SYMBOL(scm_fp_dup);
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4 LT	2	/* scm.c - Socket level control messages processing.
	3	*
	4	* Author: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
	5	* Alignment and value checking mods by Craig Metz
1da177e4 LT	6	*/
	7
	8	#include <linux/module.h>
	9	#include <linux/signal.h>
4fc268d2	10	#include <linux/capability.h>
1da177e4 LT	11	#include <linux/errno.h>
1da177e4 LT	12	#include <linux/sched.h>
8703e8a4	13	#include <linux/sched/user.h>
1da177e4 LT	14	#include <linux/mm.h>
1da177e4 LT	15	#include <linux/kernel.h>
1da177e4 LT	16	#include <linux/stat.h>
	17	#include <linux/socket.h>
	18	#include <linux/file.h>
	19	#include <linux/fcntl.h>
	20	#include <linux/net.h>
	21	#include <linux/interrupt.h>
	22	#include <linux/netdevice.h>
	23	#include <linux/security.h>
92f28d97	24	#include <linux/pid_namespace.h>
b488893a PE	25	#include <linux/pid.h>
b488893a PE	26	#include <linux/nsproxy.h>
5a0e3ad6	27	#include <linux/slab.h>
9718475e	28	#include <linux/errqueue.h>
705318a9	29	#include <linux/io_uring.h>
1da177e4	30
7c0f6ba6	31	#include <linux/uaccess.h>
1da177e4 LT	32
	33	#include <net/protocol.h>
	34	#include <linux/skbuff.h>
	35	#include <net/sock.h>
	36	#include <net/compat.h>
	37	#include <net/scm.h>
d8429506	38	#include <net/cls_cgroup.h>
d9f21b36	39	#include <net/af_unix.h>
1da177e4 LT	40
	41
	42	/*
4ec93edb	43	* Only allow a user to send credentials, that they could set with
1da177e4 LT	44	* setu(g)id.
	45	*/
	46
	47	static __inline__ int scm_check_creds(struct ucred *creds)
	48	{
86a264ab	49	const struct cred *cred = current_cred();
b2e4f544 EB	50	kuid_t uid = make_kuid(cred->user_ns, creds->uid);
	51	kgid_t gid = make_kgid(cred->user_ns, creds->gid);
	52
	53	if (!uid_valid(uid) \|\| !gid_valid(gid))
	54	return -EINVAL;
b6dff3ec	55
92f28d97	56	if ((creds->pid == task_tgid_vnr(current) \|\|
d661684c	57	ns_capable(task_active_pid_ns(current)->user_ns, CAP_SYS_ADMIN)) &&
b2e4f544	58	((uid_eq(uid, cred->uid) \|\| uid_eq(uid, cred->euid) \|\|
c7b96acf	59	uid_eq(uid, cred->suid)) \|\| ns_capable(cred->user_ns, CAP_SETUID)) &&
b2e4f544	60	((gid_eq(gid, cred->gid) \|\| gid_eq(gid, cred->egid) \|\|
c7b96acf	61	gid_eq(gid, cred->sgid)) \|\| ns_capable(cred->user_ns, CAP_SETGID))) {
1da177e4 LT	62	return 0;
	63	}
	64	return -EPERM;
	65	}
	66
	67	static int scm_fp_copy(struct cmsghdr cmsg, struct scm_fp_list *fplp)
	68	{
	69	int fdp = (int)CMSG_DATA(cmsg);
	70	struct scm_fp_list fpl = fplp;
	71	struct file **fpp;
	72	int i, num;
	73
1ff8cebf	74	num = (cmsg->cmsg_len - sizeof(struct cmsghdr))/sizeof(int);
1da177e4 LT	75
	76	if (num <= 0)
	77	return 0;
	78
	79	if (num > SCM_MAX_FD)
	80	return -EINVAL;
	81
	82	if (!fpl)
	83	{
2c6ad20b	84	fpl = kmalloc(sizeof(struct scm_fp_list), GFP_KERNEL_ACCOUNT);
1da177e4 LT	85	if (!fpl)
	86	return -ENOMEM;
	87	*fplp = fpl;
	88	fpl->count = 0;
d9f21b36	89	fpl->count_unix = 0;
bba14de9	90	fpl->max = SCM_MAX_FD;
415e3d3e	91	fpl->user = NULL;
1fbfdfaa	92	#if IS_ENABLED(CONFIG_UNIX)
42f298c0	93	fpl->inflight = false;
7172dc93	94	fpl->dead = false;
29b64e35	95	fpl->edges = NULL;
1fbfdfaa KI	96	INIT_LIST_HEAD(&fpl->vertices);
1fbfdfaa KI	97	#endif
1da177e4 LT	98	}
	99	fpp = &fpl->fp[fpl->count];
	100
bba14de9	101	if (fpl->count + num > fpl->max)
1da177e4	102	return -EINVAL;
4ec93edb	103
1da177e4 LT	104	/*
	105	* Verify the descriptors and increment the usage count.
	106	*/
4ec93edb	107
1da177e4 LT	108	for (i=0; i< num; i++)
	109	{
	110	int fd = fdp[i];
	111	struct file *file;
	112
326be7b4	113	if (fd < 0 \|\| !(file = fget_raw(fd)))
1da177e4	114	return -EBADF;
705318a9	115	/* don't allow io_uring files */
a4104821	116	if (io_is_uring_fops(file)) {
705318a9 PB	117	fput(file);
	118	return -EINVAL;
	119	}
d9f21b36 KI	120	if (unix_get_socket(file))
	121	fpl->count_unix++;
	122
1da177e4 LT	123	*fpp++ = file;
	124	fpl->count++;
	125	}
415e3d3e HFS	126
	127	if (!fpl->user)
	128	fpl->user = get_uid(current_user());
	129
1da177e4 LT	130	return num;
	131	}
	132
	133	void __scm_destroy(struct scm_cookie *scm)
	134	{
	135	struct scm_fp_list *fpl = scm->fp;
	136	int i;
	137
	138	if (fpl) {
	139	scm->fp = NULL;
6120d3db AV	140	for (i=fpl->count-1; i>=0; i--)
6120d3db AV	141	fput(fpl->fp[i]);
415e3d3e	142	free_uid(fpl->user);
6120d3db	143	kfree(fpl);
1da177e4 LT	144	}
1da177e4 LT	145	}
9e34a5b5	146	EXPORT_SYMBOL(__scm_destroy);
1da177e4 LT	147
	148	int __scm_send(struct socket sock, struct msghdr msg, struct scm_cookie *p)
	149	{
1ded5e5a	150	const struct proto_ops *ops = READ_ONCE(sock->ops);
1da177e4 LT	151	struct cmsghdr *cmsg;
	152	int err;
	153
f95b414e	154	for_each_cmsghdr(cmsg, msg) {
1da177e4 LT	155	err = -EINVAL;
	156
	157	/* Verify that cmsg_len is at least sizeof(struct cmsghdr) */
	158	/* The first check was omitted in <= 2.2.5. The reasoning was
	159	that parser checks cmsg_len in any case, so that
	160	additional check would be work duplication.
4ec93edb	161	But if cmsg_level is not SOL_SOCKET, we do not check
1da177e4 LT	162	for too short ancillary data object at all! Oops.
	163	OK, let's add it...
	164	*/
	165	if (!CMSG_OK(msg, cmsg))
	166	goto error;
	167
	168	if (cmsg->cmsg_level != SOL_SOCKET)
	169	continue;
	170
	171	switch (cmsg->cmsg_type)
	172	{
	173	case SCM_RIGHTS:
1ded5e5a	174	if (!ops \|\| ops->family != PF_UNIX)
76dadd76	175	goto error;
1da177e4 LT	176	err=scm_fp_copy(cmsg, &p->fp);
	177	if (err<0)
	178	goto error;
	179	break;
	180	case SCM_CREDENTIALS:
b2e4f544	181	{
dbe9a417	182	struct ucred creds;
b2e4f544 EB	183	kuid_t uid;
b2e4f544 EB	184	kgid_t gid;
1da177e4 LT	185	if (cmsg->cmsg_len != CMSG_LEN(sizeof(struct ucred)))
1da177e4 LT	186	goto error;
dbe9a417 EB	187	memcpy(&creds, CMSG_DATA(cmsg), sizeof(struct ucred));
dbe9a417 EB	188	err = scm_check_creds(&creds);
1da177e4 LT	189	if (err)
1da177e4 LT	190	goto error;
257b5358	191
dbe9a417 EB	192	p->creds.pid = creds.pid;
dbe9a417 EB	193	if (!p->pid \|\| pid_vnr(p->pid) != creds.pid) {
257b5358 EB	194	struct pid *pid;
257b5358 EB	195	err = -ESRCH;
dbe9a417	196	pid = find_get_pid(creds.pid);
257b5358 EB	197	if (!pid)
	198	goto error;
	199	put_pid(p->pid);
	200	p->pid = pid;
	201	}
	202
b2e4f544	203	err = -EINVAL;
dbe9a417 EB	204	uid = make_kuid(current_user_ns(), creds.uid);
dbe9a417 EB	205	gid = make_kgid(current_user_ns(), creds.gid);
b2e4f544 EB	206	if (!uid_valid(uid) \|\| !gid_valid(gid))
	207	goto error;
	208
dbe9a417 EB	209	p->creds.uid = uid;
dbe9a417 EB	210	p->creds.gid = gid;
1da177e4	211	break;
b2e4f544	212	}
1da177e4 LT	213	default:
	214	goto error;
	215	}
	216	}
	217
	218	if (p->fp && !p->fp->count)
	219	{
	220	kfree(p->fp);
	221	p->fp = NULL;
	222	}
	223	return 0;
4ec93edb	224
1da177e4 LT	225	error:
	226	scm_destroy(p);
	227	return err;
	228	}
9e34a5b5	229	EXPORT_SYMBOL(__scm_send);
1da177e4 LT	230
	231	int put_cmsg(struct msghdr * msg, int level, int type, int len, void *data)
	232	{
1da177e4	233	int cmlen = CMSG_LEN(len);
1da177e4	234
1f466e1f	235	if (msg->msg_flags & MSG_CMSG_COMPAT)
1da177e4 LT	236	return put_cmsg_compat(msg, level, type, len, data);
1da177e4 LT	237
1f466e1f	238	if (!msg->msg_control \|\| msg->msg_controllen < sizeof(struct cmsghdr)) {
1da177e4 LT	239	msg->msg_flags \|= MSG_CTRUNC;
	240	return 0; /* XXX: return error? check spec. */
	241	}
	242	if (msg->msg_controllen < cmlen) {
	243	msg->msg_flags \|= MSG_CTRUNC;
	244	cmlen = msg->msg_controllen;
	245	}
1f466e1f CH	246
	247	if (msg->msg_control_is_user) {
	248	struct cmsghdr __user *cm = msg->msg_control_user;
38ebcf50	249
5f1eb1ff ED	250	check_object_size(data, cmlen - sizeof(*cm), true);
5f1eb1ff ED	251
38ebcf50 ED	252	if (!user_write_access_begin(cm, cmlen))
	253	goto efault;
	254
e7ad33fa	255	unsafe_put_user(cmlen, &cm->cmsg_len, efault_end);
38ebcf50 ED	256	unsafe_put_user(level, &cm->cmsg_level, efault_end);
	257	unsafe_put_user(type, &cm->cmsg_type, efault_end);
	258	unsafe_copy_to_user(CMSG_USER_DATA(cm), data,
	259	cmlen - sizeof(*cm), efault_end);
	260	user_write_access_end();
1f466e1f CH	261	} else {
	262	struct cmsghdr *cm = msg->msg_control;
	263
	264	cm->cmsg_level = level;
	265	cm->cmsg_type = type;
	266	cm->cmsg_len = cmlen;
	267	memcpy(CMSG_DATA(cm), data, cmlen - sizeof(*cm));
	268	}
	269
	270	cmlen = min(CMSG_SPACE(len), msg->msg_controllen);
c39ef213 KB	271	if (msg->msg_control_is_user)
	272	msg->msg_control_user += cmlen;
	273	else
	274	msg->msg_control += cmlen;
1da177e4	275	msg->msg_controllen -= cmlen;
1f466e1f	276	return 0;
38ebcf50 ED	277
	278	efault_end:
	279	user_write_access_end();
	280	efault:
	281	return -EFAULT;
1da177e4	282	}
9e34a5b5	283	EXPORT_SYMBOL(put_cmsg);
1da177e4	284
9718475e DD	285	void put_cmsg_scm_timestamping64(struct msghdr msg, struct scm_timestamping_internal tss_internal)
	286	{
	287	struct scm_timestamping64 tss;
	288	int i;
	289
	290	for (i = 0; i < ARRAY_SIZE(tss.ts); i++) {
	291	tss.ts[i].tv_sec = tss_internal->ts[i].tv_sec;
	292	tss.ts[i].tv_nsec = tss_internal->ts[i].tv_nsec;
	293	}
	294
	295	put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMPING_NEW, sizeof(tss), &tss);
	296	}
	297	EXPORT_SYMBOL(put_cmsg_scm_timestamping64);
	298
	299	void put_cmsg_scm_timestamping(struct msghdr msg, struct scm_timestamping_internal tss_internal)
	300	{
	301	struct scm_timestamping tss;
	302	int i;
	303
0309f98f AB	304	for (i = 0; i < ARRAY_SIZE(tss.ts); i++) {
	305	tss.ts[i].tv_sec = tss_internal->ts[i].tv_sec;
	306	tss.ts[i].tv_nsec = tss_internal->ts[i].tv_nsec;
	307	}
9718475e DD	308
	309	put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMPING_OLD, sizeof(tss), &tss);
	310	}
	311	EXPORT_SYMBOL(put_cmsg_scm_timestamping);
	312
2618d530 CH	313	static int scm_max_fds(struct msghdr *msg)
	314	{
	315	if (msg->msg_controllen <= sizeof(struct cmsghdr))
	316	return 0;
	317	return (msg->msg_controllen - sizeof(struct cmsghdr)) / sizeof(int);
	318	}
	319
1da177e4 LT	320	void scm_detach_fds(struct msghdr msg, struct scm_cookie scm)
1da177e4 LT	321	{
c0029de5	322	struct cmsghdr __user *cm =
c39ef213	323	(__force struct cmsghdr __user *)msg->msg_control_user;
c0029de5	324	unsigned int o_flags = (msg->msg_flags & MSG_CMSG_CLOEXEC) ? O_CLOEXEC : 0;
2618d530 CH	325	int fdmax = min_t(int, scm_max_fds(msg), scm->fp->count);
2618d530 CH	326	int __user *cmsg_data = CMSG_USER_DATA(cm);
1da177e4 LT	327	int err = 0, i;
1da177e4 LT	328
c0029de5 KC	329	/* no use for FD passing from kernel space callers */
	330	if (WARN_ON_ONCE(!msg->msg_control_is_user))
	331	return;
	332
2618d530	333	if (msg->msg_flags & MSG_CMSG_COMPAT) {
1da177e4 LT	334	scm_detach_fds_compat(msg, scm);
	335	return;
	336	}
	337
2618d530	338	for (i = 0; i < fdmax; i++) {
eac9189c	339	err = scm_recv_one_fd(scm->fp->fp[i], cmsg_data + i, o_flags);
deefa7f3	340	if (err < 0)
1da177e4	341	break;
1da177e4 LT	342	}
1da177e4 LT	343
c0029de5	344	if (i > 0) {
2618d530 CH	345	int cmlen = CMSG_LEN(i * sizeof(int));
2618d530 CH	346
effee6a0	347	err = put_user(SOL_SOCKET, &cm->cmsg_level);
1da177e4 LT	348	if (!err)
	349	err = put_user(SCM_RIGHTS, &cm->cmsg_type);
	350	if (!err)
	351	err = put_user(cmlen, &cm->cmsg_len);
	352	if (!err) {
2618d530	353	cmlen = CMSG_SPACE(i * sizeof(int));
6900317f DB	354	if (msg->msg_controllen < cmlen)
6900317f DB	355	cmlen = msg->msg_controllen;
c39ef213	356	msg->msg_control_user += cmlen;
1da177e4 LT	357	msg->msg_controllen -= cmlen;
	358	}
	359	}
2618d530 CH	360
2618d530 CH	361	if (i < scm->fp->count \|\| (scm->fp->count && fdmax <= 0))
1da177e4 LT	362	msg->msg_flags \|= MSG_CTRUNC;
	363
	364	/*
2618d530 CH	365	* All of the files that fit in the message have had their usage counts
2618d530 CH	366	* incremented, so we just free the list.
1da177e4 LT	367	*/
	368	__scm_destroy(scm);
	369	}
9e34a5b5	370	EXPORT_SYMBOL(scm_detach_fds);
1da177e4 LT	371
	372	struct scm_fp_list scm_fp_dup(struct scm_fp_list fpl)
	373	{
	374	struct scm_fp_list *new_fpl;
	375	int i;
	376
	377	if (!fpl)
	378	return NULL;
	379
bba14de9	380	new_fpl = kmemdup(fpl, offsetof(struct scm_fp_list, fp[fpl->count]),
2c6ad20b	381	GFP_KERNEL_ACCOUNT);
1da177e4	382	if (new_fpl) {
bba14de9	383	for (i = 0; i < fpl->count; i++)
1da177e4	384	get_file(fpl->fp[i]);
1fbfdfaa	385
bba14de9	386	new_fpl->max = new_fpl->count;
415e3d3e	387	new_fpl->user = get_uid(fpl->user);
1fbfdfaa	388	#if IS_ENABLED(CONFIG_UNIX)
42f298c0	389	new_fpl->inflight = false;
29b64e35	390	new_fpl->edges = NULL;
1fbfdfaa KI	391	INIT_LIST_HEAD(&new_fpl->vertices);
1fbfdfaa KI	392	#endif
1da177e4 LT	393	}
	394	return new_fpl;
	395	}
1da177e4	396	EXPORT_SYMBOL(scm_fp_dup);