Commit message: KEYS: Make the session and process keyrings per-thread

Make the session keyring per-thread rather than per-process, but still
inherited from the parent thread to solve a problem with PAM and gdm.

The problem is that join_session_keyring() will reject attempts to change the
session keyring of a multithreaded program but gdm is now multithreaded before
it gets to the point of starting PAM and running pam_keyinit to create the
session keyring.  See:

	https://bugs.freedesktop.org/show_bug.cgi?id=49211

The reason that join_session_keyring() will only change the session keyring
under a single-threaded environment is that it's hard to alter the other
thread's credentials to effect the change in a multi-threaded program.  The
problems are such as:

 (1) How to prevent two threads both running join_session_keyring() from
     racing.

 (2) Another thread's credentials may not be modified directly by this process.

 (3) The number of threads is uncertain whilst we're not holding the
     appropriate spinlock, making preallocation slightly tricky.

 (4) We could use TIF_NOTIFY_RESUME and key_replace_session_keyring() to get
     another thread to replace its keyring, but that means preallocating for
     each thread.

A reasonable way around this is to make the session keyring per-thread rather
than per-process and just document that if you want a common session keyring,
you must get it before you spawn any threads - which is the current situation
anyway.

Whilst we're at it, we can the process keyring behave in the same way.  This
means we can clean up some of the ickyness in the creds code.

Basically, after this patch, the session, process and thread keyrings are about
inheritance rules only and not about sharing changes of keyring.

Reported-by: Mantas M. <grawity@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Ray Strode <rstrode@redhat.com>
CVE: CVE-2016-0728
Vulnerability description: The join_session_keyring function in security/keys/process_keys.c in the Linux kernel before 4.4.1 mishandles object references in a certain error case, which allows local users to gain privileges or cause a denial of service (integer overflow and use-after-free) via crafted keyctl commands.

Project: linux
File: process_keys.c

static int install_process_keyring(void)
{
	struct cred *new;
	int ret;

	new = prepare_creds();
	if (!new)
		return -ENOMEM;

	ret = install_process_keyring_to_cred(new);
	if (ret < 0) {
		abort_creds(new);
		return ret != -EEXIST ? ret : 0;
	}

	return commit_creds(new);
}

Project: linux
File: keyctl.c

long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
{
	struct key_user *newowner, *zapowner = NULL;
	struct key *key;
	key_ref_t key_ref;
	long ret;

	ret = 0;
	if (uid == (uid_t) -1 && gid == (gid_t) -1)
		goto error;

	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
				  KEY_SETATTR);
	if (IS_ERR(key_ref)) {
		ret = PTR_ERR(key_ref);
		goto error;
	}

	key = key_ref_to_ptr(key_ref);

	/* make the changes with the locks held to prevent chown/chown races */
	ret = -EACCES;
	down_write(&key->sem);

	if (!capable(CAP_SYS_ADMIN)) {
		/* only the sysadmin can chown a key to some other UID */
		if (uid != (uid_t) -1 && key->uid != uid)
			goto error_put;

		/* only the sysadmin can set the key's GID to a group other
		 * than one of those that the current process subscribes to */
		if (gid != (gid_t) -1 && gid != key->gid && !in_group_p(gid))
			goto error_put;
	}

	/* change the UID */
	if (uid != (uid_t) -1 && uid != key->uid) {
		ret = -ENOMEM;
		newowner = key_user_lookup(uid, current_user_ns());
		if (!newowner)
			goto error_put;

		/* transfer the quota burden to the new user */
		if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
			unsigned maxkeys = (uid == 0) ?
				key_quota_root_maxkeys : key_quota_maxkeys;
			unsigned maxbytes = (uid == 0) ?
				key_quota_root_maxbytes : key_quota_maxbytes;

			spin_lock(&newowner->lock);
			if (newowner->qnkeys + 1 >= maxkeys ||
			    newowner->qnbytes + key->quotalen >= maxbytes ||
			    newowner->qnbytes + key->quotalen <
			    newowner->qnbytes)
				goto quota_overrun;

			newowner->qnkeys++;
			newowner->qnbytes += key->quotalen;
			spin_unlock(&newowner->lock);

			spin_lock(&key->user->lock);
			key->user->qnkeys--;
			key->user->qnbytes -= key->quotalen;
			spin_unlock(&key->user->lock);
		}

		atomic_dec(&key->user->nkeys);
		atomic_inc(&newowner->nkeys);

		if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
			atomic_dec(&key->user->nikeys);
			atomic_inc(&newowner->nikeys);
		}

		zapowner = key->user;
		key->user = newowner;
		key->uid = uid;
	}

	/* change the GID */
	if (gid != (gid_t) -1)
		key->gid = gid;

	ret = 0;

error_put:
	up_write(&key->sem);
	key_put(key);
	if (zapowner)
		key_user_put(zapowner);
error:
	return ret;

quota_overrun:
	spin_unlock(&newowner->lock);
	zapowner = newowner;
	ret = -EDQUOT;
	goto error_put;
}

Project: linux
File: keyctl.c

long keyctl_instantiate_key_iov(key_serial_t id,
				const struct iovec __user *_payload_iov,
				unsigned ioc,
				key_serial_t ringid)
{
	struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
	long ret;

	if (!_payload_iov || !ioc)
		goto no_payload;

	ret = rw_copy_check_uvector(WRITE, _payload_iov, ioc,
				    ARRAY_SIZE(iovstack), iovstack, &iov);
	if (ret < 0)
		goto err;
	if (ret == 0)
		goto no_payload_free;

	ret = keyctl_instantiate_key_common(id, iov, ioc, ret, ringid);
err:
	if (iov != iovstack)
		kfree(iov);
	return ret;

no_payload_free:
	if (iov != iovstack)
		kfree(iov);
no_payload:
	return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid);
}

Project: linux
File: process_keys.c

int install_thread_keyring_to_cred(struct cred *new)
{
	struct key *keyring;

	keyring = keyring_alloc("_tid", new->uid, new->gid, new,
				KEY_ALLOC_QUOTA_OVERRUN, NULL);
	if (IS_ERR(keyring))
		return PTR_ERR(keyring);

	new->thread_keyring = keyring;
	return 0;
}

Project: linux
File: cred.c

struct cred *prepare_kernel_cred(struct task_struct *daemon)
{
	const struct cred *old;
	struct cred *new;

	new = kmem_cache_alloc(cred_jar, GFP_KERNEL);
	if (!new)
		return NULL;

	kdebug("prepare_kernel_cred() alloc %p", new);

	if (daemon)
		old = get_task_cred(daemon);
	else
		old = get_cred(&init_cred);

	validate_creds(old);

	*new = *old;
	atomic_set(&new->usage, 1);
	set_cred_subscribers(new, 0);
	get_uid(new->user);
	get_user_ns(new->user_ns);
	get_group_info(new->group_info);

#ifdef CONFIG_KEYS
	new->session_keyring = NULL;
	new->process_keyring = NULL;
	new->thread_keyring = NULL;
	new->request_key_auth = NULL;
	new->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
#endif

#ifdef CONFIG_SECURITY
	new->security = NULL;
#endif
	if (security_prepare_creds(new, old, GFP_KERNEL) < 0)
		goto error;

	put_cred(old);
	validate_creds(new);
	return new;

error:
	put_cred(new);
	put_cred(old);
	return NULL;
}

Project: linux
File: keyctl.c

long keyctl_join_session_keyring(const char __user *_name)
{
	char *name;
	long ret;

	/* fetch the name from userspace */
	name = NULL;
	if (_name) {
		name = strndup_user(_name, PAGE_SIZE);
		if (IS_ERR(name)) {
			ret = PTR_ERR(name);
			goto error;
		}
	}

	/* join the session */
	ret = join_session_keyring(name);
	kfree(name);

error:
	return ret;
}

Project: linux
File: request_key.c

static int call_usermodehelper_keys(char *path, char **argv, char **envp,
					struct key *session_keyring, int wait)
{
	return call_usermodehelper_fns(path, argv, envp, wait,
				       umh_keys_init, umh_keys_cleanup,
				       key_get(session_keyring));
}

Project: linux
File: keyctl.c

SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
		unsigned long, arg4, unsigned long, arg5)
{
	switch (option) {
	case KEYCTL_GET_KEYRING_ID:
		return keyctl_get_keyring_ID((key_serial_t) arg2,
					     (int) arg3);

	case KEYCTL_JOIN_SESSION_KEYRING:
		return keyctl_join_session_keyring((const char __user *) arg2);

	case KEYCTL_UPDATE:
		return keyctl_update_key((key_serial_t) arg2,
					 (const void __user *) arg3,
					 (size_t) arg4);

	case KEYCTL_REVOKE:
		return keyctl_revoke_key((key_serial_t) arg2);

	case KEYCTL_DESCRIBE:
		return keyctl_describe_key((key_serial_t) arg2,
					   (char __user *) arg3,
					   (unsigned) arg4);

	case KEYCTL_CLEAR:
		return keyctl_keyring_clear((key_serial_t) arg2);

	case KEYCTL_LINK:
		return keyctl_keyring_link((key_serial_t) arg2,
					   (key_serial_t) arg3);

	case KEYCTL_UNLINK:
		return keyctl_keyring_unlink((key_serial_t) arg2,
					     (key_serial_t) arg3);

	case KEYCTL_SEARCH:
		return keyctl_keyring_search((key_serial_t) arg2,
					     (const char __user *) arg3,
					     (const char __user *) arg4,
					     (key_serial_t) arg5);

	case KEYCTL_READ:
		return keyctl_read_key((key_serial_t) arg2,
				       (char __user *) arg3,
				       (size_t) arg4);

	case KEYCTL_CHOWN:
		return keyctl_chown_key((key_serial_t) arg2,
					(uid_t) arg3,
					(gid_t) arg4);

	case KEYCTL_SETPERM:
		return keyctl_setperm_key((key_serial_t) arg2,
					  (key_perm_t) arg3);

	case KEYCTL_INSTANTIATE:
		return keyctl_instantiate_key((key_serial_t) arg2,
					      (const void __user *) arg3,
					      (size_t) arg4,
					      (key_serial_t) arg5);

	case KEYCTL_NEGATE:
		return keyctl_negate_key((key_serial_t) arg2,
					 (unsigned) arg3,
					 (key_serial_t) arg4);

	case KEYCTL_SET_REQKEY_KEYRING:
		return keyctl_set_reqkey_keyring(arg2);

	case KEYCTL_SET_TIMEOUT:
		return keyctl_set_timeout((key_serial_t) arg2,
					  (unsigned) arg3);

	case KEYCTL_ASSUME_AUTHORITY:
		return keyctl_assume_authority((key_serial_t) arg2);

	case KEYCTL_GET_SECURITY:
		return keyctl_get_security((key_serial_t) arg2,
					   (char __user *) arg3,
					   (size_t) arg4);

	case KEYCTL_SESSION_TO_PARENT:
		return keyctl_session_to_parent();

	case KEYCTL_REJECT:
		return keyctl_reject_key((key_serial_t) arg2,
					 (unsigned) arg3,
					 (unsigned) arg4,
					 (key_serial_t) arg5);

	case KEYCTL_INSTANTIATE_IOV:
		return keyctl_instantiate_key_iov(
			(key_serial_t) arg2,
			(const struct iovec __user *) arg3,
			(unsigned) arg4,
			(key_serial_t) arg5);

	case KEYCTL_INVALIDATE:
		return keyctl_invalidate_key((key_serial_t) arg2);

	default:
		return -EOPNOTSUPP;
	}
}

Project: linux
File: cred.c

static void put_cred_rcu(struct rcu_head *rcu)
{
	struct cred *cred = container_of(rcu, struct cred, rcu);

	kdebug("put_cred_rcu(%p)", cred);

#ifdef CONFIG_DEBUG_CREDENTIALS
	if (cred->magic != CRED_MAGIC_DEAD ||
	    atomic_read(&cred->usage) != 0 ||
	    read_cred_subscribers(cred) != 0)
		panic("CRED: put_cred_rcu() sees %p with"
		      " mag %x, put %p, usage %d, subscr %d\n",
		      cred, cred->magic, cred->put_addr,
		      atomic_read(&cred->usage),
		      read_cred_subscribers(cred));
#else
	if (atomic_read(&cred->usage) != 0)
		panic("CRED: put_cred_rcu() sees %p with usage %d\n",
		      cred, atomic_read(&cred->usage));
#endif

	security_cred_free(cred);
	key_put(cred->session_keyring);
	key_put(cred->process_keyring);
	key_put(cred->thread_keyring);
	key_put(cred->request_key_auth);
	if (cred->group_info)
		put_group_info(cred->group_info);
	free_uid(cred->user);
	put_user_ns(cred->user_ns);
	kmem_cache_free(cred_jar, cred);
}

Project: linux
File: keyctl.c

static long get_instantiation_keyring(key_serial_t ringid,
				      struct request_key_auth *rka,
				      struct key **_dest_keyring)
{
	key_ref_t dkref;

	*_dest_keyring = NULL;

	/* just return a NULL pointer if we weren't asked to make a link */
	if (ringid == 0)
		return 0;

	/* if a specific keyring is nominated by ID, then use that */
	if (ringid > 0) {
		dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
		if (IS_ERR(dkref))
			return PTR_ERR(dkref);
		*_dest_keyring = key_ref_to_ptr(dkref);
		return 0;
	}

	if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
		return -EINVAL;

	/* otherwise specify the destination keyring recorded in the
	 * authorisation key (any KEY_SPEC_*_KEYRING) */
	if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
		*_dest_keyring = key_get(rka->dest_keyring);
		return 0;
	}

	return -ENOKEY;
}

Project: linux
File: keyctl.c

long keyctl_instantiate_key_common(key_serial_t id,
				   const struct iovec *payload_iov,
				   unsigned ioc,
				   size_t plen,
				   key_serial_t ringid)
{
	const struct cred *cred = current_cred();
	struct request_key_auth *rka;
	struct key *instkey, *dest_keyring;
	void *payload;
	long ret;
	bool vm = false;

	kenter("%d,,%zu,%d", id, plen, ringid);

	ret = -EINVAL;
	if (plen > 1024 * 1024 - 1)
		goto error;

	/* the appropriate instantiation authorisation key must have been
	 * assumed before calling this */
	ret = -EPERM;
	instkey = cred->request_key_auth;
	if (!instkey)
		goto error;

	rka = instkey->payload.data;
	if (rka->target_key->serial != id)
		goto error;

	/* pull the payload in if one was supplied */
	payload = NULL;

	if (payload_iov) {
		ret = -ENOMEM;
		payload = kmalloc(plen, GFP_KERNEL);
		if (!payload) {
			if (plen <= PAGE_SIZE)
				goto error;
			vm = true;
			payload = vmalloc(plen);
			if (!payload)
				goto error;
		}

		ret = copy_from_user_iovec(payload, payload_iov, ioc);
		if (ret < 0)
			goto error2;
	}

	/* find the destination keyring amongst those belonging to the
	 * requesting task */
	ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
	if (ret < 0)
		goto error2;

	/* instantiate the key and link it into a keyring */
	ret = key_instantiate_and_link(rka->target_key, payload, plen,
				       dest_keyring, instkey);

	key_put(dest_keyring);

	/* discard the assumed authority if it's just been disabled by
	 * instantiation of the key */
	if (ret == 0)
		keyctl_change_reqkey_auth(NULL);

error2:
	if (!vm)
		kfree(payload);
	else
		vfree(payload);
error:
	return ret;
}

Project: linux
File: keyctl.c

long keyctl_describe_key(key_serial_t keyid,
			 char __user *buffer,
			 size_t buflen)
{
	struct key *key, *instkey;
	key_ref_t key_ref;
	char *tmpbuf;
	long ret;

	key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW);
	if (IS_ERR(key_ref)) {
		/* viewing a key under construction is permitted if we have the
		 * authorisation token handy */
		if (PTR_ERR(key_ref) == -EACCES) {
			instkey = key_get_instantiation_authkey(keyid);
			if (!IS_ERR(instkey)) {
				key_put(instkey);
				key_ref = lookup_user_key(keyid,
							  KEY_LOOKUP_PARTIAL,
							  0);
				if (!IS_ERR(key_ref))
					goto okay;
			}
		}

		ret = PTR_ERR(key_ref);
		goto error;
	}

okay:
	/* calculate how much description we're going to return */
	ret = -ENOMEM;
	tmpbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
	if (!tmpbuf)
		goto error2;

	key = key_ref_to_ptr(key_ref);

	ret = snprintf(tmpbuf, PAGE_SIZE - 1,
		       "%s;%d;%d;%08x;%s",
		       key->type->name,
		       key->uid,
		       key->gid,
		       key->perm,
		       key->description ?: "");

	/* include a NUL char at the end of the data */
	if (ret > PAGE_SIZE - 1)
		ret = PAGE_SIZE - 1;
	tmpbuf[ret] = 0;
	ret++;

	/* consider returning the data */
	if (buffer && buflen > 0) {
		if (buflen > ret)
			buflen = ret;

		if (copy_to_user(buffer, tmpbuf, buflen) != 0)
			ret = -EFAULT;
	}

	kfree(tmpbuf);
error2:
	key_ref_put(key_ref);
error:
	return ret;
}

Project: linux
File: cred.c

struct cred *prepare_creds(void)
{
	struct task_struct *task = current;
	const struct cred *old;
	struct cred *new;

	validate_process_creds();

	new = kmem_cache_alloc(cred_jar, GFP_KERNEL);
	if (!new)
		return NULL;

	kdebug("prepare_creds() alloc %p", new);

	old = task->cred;
	memcpy(new, old, sizeof(struct cred));

	atomic_set(&new->usage, 1);
	set_cred_subscribers(new, 0);
	get_group_info(new->group_info);
	get_uid(new->user);
	get_user_ns(new->user_ns);

#ifdef CONFIG_KEYS
	key_get(new->session_keyring);
	key_get(new->process_keyring);
	key_get(new->thread_keyring);
	key_get(new->request_key_auth);
#endif

#ifdef CONFIG_SECURITY
	new->security = NULL;
#endif

	if (security_prepare_creds(new, old, GFP_KERNEL) < 0)
		goto error;
	validate_creds(new);
	return new;

error:
	abort_creds(new);
	return NULL;
}

Project: linux
File: cred.c

int copy_creds(struct task_struct *p, unsigned long clone_flags)
{
	struct cred *new;
	int ret;

	if (
#ifdef CONFIG_KEYS
		!p->cred->thread_keyring &&
#endif
		clone_flags & CLONE_THREAD
	    ) {
		p->real_cred = get_cred(p->cred);
		get_cred(p->cred);
		alter_cred_subscribers(p->cred, 2);
		kdebug("share_creds(%p{%d,%d})",
		       p->cred, atomic_read(&p->cred->usage),
		       read_cred_subscribers(p->cred));
		atomic_inc(&p->cred->user->processes);
		return 0;
	}

	new = prepare_creds();
	if (!new)
		return -ENOMEM;

	if (clone_flags & CLONE_NEWUSER) {
		ret = create_user_ns(new);
		if (ret < 0)
			goto error_put;
	}

#ifdef CONFIG_KEYS
	/* new threads get their own thread keyrings if their parent already
	 * had one */
	if (new->thread_keyring) {
		key_put(new->thread_keyring);
		new->thread_keyring = NULL;
		if (clone_flags & CLONE_THREAD)
			install_thread_keyring_to_cred(new);
	}

	/* The process keyring is only shared between the threads in a process;
	 * anything outside of those threads doesn't inherit.
	 */
	if (!(clone_flags & CLONE_THREAD)) {
		key_put(new->process_keyring);
		new->process_keyring = NULL;
	}
#endif

	atomic_inc(&new->user->processes);
	p->cred = p->real_cred = get_cred(new);
	alter_cred_subscribers(new, 2);
	validate_creds(new);
	return 0;

error_put:
	put_cred(new);
	return ret;
}

Project: linux
File: keyctl.c

long keyctl_keyring_search(key_serial_t ringid,
			   const char __user *_type,
			   const char __user *_description,
			   key_serial_t destringid)
{
	struct key_type *ktype;
	key_ref_t keyring_ref, key_ref, dest_ref;
	char type[32], *description;
	long ret;

	/* pull the type and description into kernel space */
	ret = key_get_type_from_user(type, _type, sizeof(type));
	if (ret < 0)
		goto error;

	description = strndup_user(_description, PAGE_SIZE);
	if (IS_ERR(description)) {
		ret = PTR_ERR(description);
		goto error;
	}

	/* get the keyring at which to begin the search */
	keyring_ref = lookup_user_key(ringid, 0, KEY_SEARCH);
	if (IS_ERR(keyring_ref)) {
		ret = PTR_ERR(keyring_ref);
		goto error2;
	}

	/* get the destination keyring if specified */
	dest_ref = NULL;
	if (destringid) {
		dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
					   KEY_WRITE);
		if (IS_ERR(dest_ref)) {
			ret = PTR_ERR(dest_ref);
			goto error3;
		}
	}

	/* find the key type */
	ktype = key_type_lookup(type);
	if (IS_ERR(ktype)) {
		ret = PTR_ERR(ktype);
		goto error4;
	}

	/* do the search */
	key_ref = keyring_search(keyring_ref, ktype, description);
	if (IS_ERR(key_ref)) {
		ret = PTR_ERR(key_ref);

		/* treat lack or presence of a negative key the same */
		if (ret == -EAGAIN)
			ret = -ENOKEY;
		goto error5;
	}

	/* link the resulting key to the destination keyring if we can */
	if (dest_ref) {
		ret = key_permission(key_ref, KEY_LINK);
		if (ret < 0)
			goto error6;

		ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
		if (ret < 0)
			goto error6;
	}

	ret = key_ref_to_ptr(key_ref)->serial;

error6:
	key_ref_put(key_ref);
error5:
	key_type_put(ktype);
error4:
	key_ref_put(dest_ref);
error3:
	key_ref_put(keyring_ref);
error2:
	kfree(description);
error:
	return ret;
}

Project: linux
File: process_keys.c

int install_process_keyring_to_cred(struct cred *new)
{
	struct key *keyring;

	if (new->process_keyring)
		return -EEXIST;

	keyring = keyring_alloc("_pid", new->uid, new->gid,
				new, KEY_ALLOC_QUOTA_OVERRUN, NULL);
	if (IS_ERR(keyring))
		return PTR_ERR(keyring);

	new->process_keyring = keyring;
	return 0;
}

Project: linux
File: keyctl.c

long keyctl_update_key(key_serial_t id,
		       const void __user *_payload,
		       size_t plen)
{
	key_ref_t key_ref;
	void *payload;
	long ret;

	ret = -EINVAL;
	if (plen > PAGE_SIZE)
		goto error;

	/* pull the payload in if one was supplied */
	payload = NULL;
	if (_payload) {
		ret = -ENOMEM;
		payload = kmalloc(plen, GFP_KERNEL);
		if (!payload)
			goto error;

		ret = -EFAULT;
		if (copy_from_user(payload, _payload, plen) != 0)
			goto error2;
	}

	/* find the target key (which must be writable) */
	key_ref = lookup_user_key(id, 0, KEY_WRITE);
	if (IS_ERR(key_ref)) {
		ret = PTR_ERR(key_ref);
		goto error2;
	}

	/* update the key */
	ret = key_update(key_ref, payload, plen);

	key_ref_put(key_ref);
error2:
	kfree(payload);
error:
	return ret;
}

Project: linux
File: keyctl.c

long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
{
	struct key *key;
	key_ref_t key_ref;
	long ret;

	ret = -EINVAL;
	if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
		goto error;

	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
				  KEY_SETATTR);
	if (IS_ERR(key_ref)) {
		ret = PTR_ERR(key_ref);
		goto error;
	}

	key = key_ref_to_ptr(key_ref);

	/* make the changes with the locks held to prevent chown/chmod races */
	ret = -EACCES;
	down_write(&key->sem);

	/* if we're not the sysadmin, we can only change a key that we own */
	if (capable(CAP_SYS_ADMIN) || key->uid == current_fsuid()) {
		key->perm = perm;
		ret = 0;
	}

	up_write(&key->sem);
	key_put(key);
error:
	return ret;
}

Project: linux
File: keyctl.c

long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
{
	key_ref_t keyring_ref, key_ref;
	long ret;

	keyring_ref = lookup_user_key(ringid, 0, KEY_WRITE);
	if (IS_ERR(keyring_ref)) {
		ret = PTR_ERR(keyring_ref);
		goto error;
	}

	key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
	if (IS_ERR(key_ref)) {
		ret = PTR_ERR(key_ref);
		goto error2;
	}

	ret = key_unlink(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));

	key_ref_put(key_ref);
error2:
	key_ref_put(keyring_ref);
error:
	return ret;
}

Project: linux
File: process_keys.c

void key_change_session_keyring(struct callback_head *twork)
{
	const struct cred *old = current_cred();
	struct cred *new = container_of(twork, struct cred, rcu);

	if (unlikely(current->flags & PF_EXITING)) {
		put_cred(new);
		return;
	}

	new->  uid	= old->  uid;
	new-> euid	= old-> euid;
	new-> suid	= old-> suid;
	new->fsuid	= old->fsuid;
	new->  gid	= old->  gid;
	new-> egid	= old-> egid;
	new-> sgid	= old-> sgid;
	new->fsgid	= old->fsgid;
	new->user	= get_uid(old->user);
	new->user_ns	= get_user_ns(new->user_ns);
	new->group_info	= get_group_info(old->group_info);

	new->securebits	= old->securebits;
	new->cap_inheritable	= old->cap_inheritable;
	new->cap_permitted	= old->cap_permitted;
	new->cap_effective	= old->cap_effective;
	new->cap_bset		= old->cap_bset;

	new->jit_keyring	= old->jit_keyring;
	new->thread_keyring	= key_get(old->thread_keyring);
	new->process_keyring	= key_get(old->process_keyring);

	security_transfer_creds(new, old);

	commit_creds(new);
}

Project: linux
File: keyctl.c

long keyctl_set_timeout(key_serial_t id, unsigned timeout)
{
	struct key *key, *instkey;
	key_ref_t key_ref;
	long ret;

	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
				  KEY_SETATTR);
	if (IS_ERR(key_ref)) {
		/* setting the timeout on a key under construction is permitted
		 * if we have the authorisation token handy */
		if (PTR_ERR(key_ref) == -EACCES) {
			instkey = key_get_instantiation_authkey(id);
			if (!IS_ERR(instkey)) {
				key_put(instkey);
				key_ref = lookup_user_key(id,
							  KEY_LOOKUP_PARTIAL,
							  0);
				if (!IS_ERR(key_ref))
					goto okay;
			}
		}

		ret = PTR_ERR(key_ref);
		goto error;
	}

okay:
	key = key_ref_to_ptr(key_ref);
	key_set_timeout(key, timeout);
	key_put(key);

	ret = 0;
error:
	return ret;
}

Project: linux
File: keyctl.c

long keyctl_get_security(key_serial_t keyid,
			 char __user *buffer,
			 size_t buflen)
{
	struct key *key, *instkey;
	key_ref_t key_ref;
	char *context;
	long ret;

	key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW);
	if (IS_ERR(key_ref)) {
		if (PTR_ERR(key_ref) != -EACCES)
			return PTR_ERR(key_ref);

		/* viewing a key under construction is also permitted if we
		 * have the authorisation token handy */
		instkey = key_get_instantiation_authkey(keyid);
		if (IS_ERR(instkey))
			return PTR_ERR(instkey);
		key_put(instkey);

		key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
		if (IS_ERR(key_ref))
			return PTR_ERR(key_ref);
	}

	key = key_ref_to_ptr(key_ref);
	ret = security_key_getsecurity(key, &context);
	if (ret == 0) {
		/* if no information was returned, give userspace an empty
		 * string */
		ret = 1;
		if (buffer && buflen > 0 &&
		    copy_to_user(buffer, "", 1) != 0)
			ret = -EFAULT;
	} else if (ret > 0) {
		/* return as much data as there's room for */
		if (buffer && buflen > 0) {
			if (buflen > ret)
				buflen = ret;

			if (copy_to_user(buffer, context, buflen) != 0)
				ret = -EFAULT;
		}

		kfree(context);
	}

	key_ref_put(key_ref);
	return ret;
}

Project: linux
File: keyctl.c

long keyctl_revoke_key(key_serial_t id)
{
	key_ref_t key_ref;
	long ret;

	key_ref = lookup_user_key(id, 0, KEY_WRITE);
	if (IS_ERR(key_ref)) {
		ret = PTR_ERR(key_ref);
		if (ret != -EACCES)
			goto error;
		key_ref = lookup_user_key(id, 0, KEY_SETATTR);
		if (IS_ERR(key_ref)) {
			ret = PTR_ERR(key_ref);
			goto error;
		}
	}

	key_revoke(key_ref_to_ptr(key_ref));
	ret = 0;

	key_ref_put(key_ref);
error:
	return ret;
}

Project: linux
File: process_keys.c

long join_session_keyring(const char *name)
{
	const struct cred *old;
	struct cred *new;
	struct key *keyring;
	long ret, serial;

	new = prepare_creds();
	if (!new)
		return -ENOMEM;
	old = current_cred();

	/* if no name is provided, install an anonymous keyring */
	if (!name) {
		ret = install_session_keyring_to_cred(new, NULL);
		if (ret < 0)
			goto error;

		serial = new->session_keyring->serial;
		ret = commit_creds(new);
		if (ret == 0)
			ret = serial;
		goto okay;
	}

	/* allow the user to join or create a named keyring */
	mutex_lock(&key_session_mutex);

	/* look for an existing keyring of this name */
	keyring = find_keyring_by_name(name, false);
	if (PTR_ERR(keyring) == -ENOKEY) {
		/* not found - try and create a new one */
		keyring = keyring_alloc(name, old->uid, old->gid, old,
					KEY_ALLOC_IN_QUOTA, NULL);
		if (IS_ERR(keyring)) {
			ret = PTR_ERR(keyring);
			goto error2;
		}
	} else if (IS_ERR(keyring)) {
		ret = PTR_ERR(keyring);
		goto error2;
	} else if (keyring == new->session_keyring) {
		ret = 0;
		goto error2;
	}

	/* we've got a keyring - now to install it */
	ret = install_session_keyring_to_cred(new, keyring);
	if (ret < 0)
		goto error2;

	commit_creds(new);
	mutex_unlock(&key_session_mutex);

	ret = keyring->serial;
	key_put(keyring);
okay:
	return ret;

error2:
	mutex_unlock(&key_session_mutex);
error:
	abort_creds(new);
	return ret;
}

Project: linux
File: cred.c

int commit_creds(struct cred *new)
{
	struct task_struct *task = current;
	const struct cred *old = task->real_cred;

	kdebug("commit_creds(%p{%d,%d})", new,
	       atomic_read(&new->usage),
	       read_cred_subscribers(new));

	BUG_ON(task->cred != old);
#ifdef CONFIG_DEBUG_CREDENTIALS
	BUG_ON(read_cred_subscribers(old) < 2);
	validate_creds(old);
	validate_creds(new);
#endif
	BUG_ON(atomic_read(&new->usage) < 1);

	get_cred(new); /* we will require a ref for the subj creds too */

	/* dumpability changes */
	if (!uid_eq(old->euid, new->euid) ||
	    !gid_eq(old->egid, new->egid) ||
	    !uid_eq(old->fsuid, new->fsuid) ||
	    !gid_eq(old->fsgid, new->fsgid) ||
	    !cap_issubset(new->cap_permitted, old->cap_permitted)) {
		if (task->mm)
			set_dumpable(task->mm, suid_dumpable);
		task->pdeath_signal = 0;
		smp_wmb();
	}

	/* alter the thread keyring */
	if (!uid_eq(new->fsuid, old->fsuid))
		key_fsuid_changed(task);
	if (!gid_eq(new->fsgid, old->fsgid))
		key_fsgid_changed(task);

	/* do it
	 * RLIMIT_NPROC limits on user->processes have already been checked
	 * in set_user().
	 */
	alter_cred_subscribers(new, 2);
	if (new->user != old->user)
		atomic_inc(&new->user->processes);
	rcu_assign_pointer(task->real_cred, new);
	rcu_assign_pointer(task->cred, new);
	if (new->user != old->user)
		atomic_dec(&old->user->processes);
	alter_cred_subscribers(old, -2);

	/* send notifications */
	if (!uid_eq(new->uid,   old->uid)  ||
	    !uid_eq(new->euid,  old->euid) ||
	    !uid_eq(new->suid,  old->suid) ||
	    !uid_eq(new->fsuid, old->fsuid))
		proc_id_connector(task, PROC_EVENT_UID);

	if (!gid_eq(new->gid,   old->gid)  ||
	    !gid_eq(new->egid,  old->egid) ||
	    !gid_eq(new->sgid,  old->sgid) ||
	    !gid_eq(new->fsgid, old->fsgid))
		proc_id_connector(task, PROC_EVENT_GID);

	/* release the old obj and subj refs both */
	put_cred(old);
	put_cred(old);
	return 0;
}

Project: linux
File: keyctl.c

long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
{
	key_ref_t keyring_ref, key_ref;
	long ret;

	keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
	if (IS_ERR(keyring_ref)) {
		ret = PTR_ERR(keyring_ref);
		goto error;
	}

	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_LINK);
	if (IS_ERR(key_ref)) {
		ret = PTR_ERR(key_ref);
		goto error2;
	}

	ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));

	key_ref_put(key_ref);
error2:
	key_ref_put(keyring_ref);
error:
	return ret;
}

Project: linux
File: cred.c

struct cred *prepare_exec_creds(void)
{
	struct cred *new;

	new = prepare_creds();
	if (!new)
		return new;

#ifdef CONFIG_KEYS
	/* newly exec'd tasks don't get a thread keyring */
	key_put(new->thread_keyring);
	new->thread_keyring = NULL;

	/* inherit the session keyring; new process keyring */
	key_put(new->process_keyring);
	new->process_keyring = NULL;
#endif

	return new;
}

Project: linux
File: request_key.c

struct key *request_key_and_link(struct key_type *type,
				 const char *description,
				 const void *callout_info,
				 size_t callout_len,
				 void *aux,
				 struct key *dest_keyring,
				 unsigned long flags)
{
	const struct cred *cred = current_cred();
	struct key *key;
	key_ref_t key_ref;
	int ret;

	kenter("%s,%s,%p,%zu,%p,%p,%lx",
	       type->name, description, callout_info, callout_len, aux,
	       dest_keyring, flags);

	/* search all the process keyrings for a key */
	key_ref = search_process_keyrings(type, description, type->match, cred);

	if (!IS_ERR(key_ref)) {
		key = key_ref_to_ptr(key_ref);
		if (dest_keyring) {
			construct_get_dest_keyring(&dest_keyring);
			ret = key_link(dest_keyring, key);
			key_put(dest_keyring);
			if (ret < 0) {
				key_put(key);
				key = ERR_PTR(ret);
				goto error;
			}
		}
	} else if (PTR_ERR(key_ref) != -EAGAIN) {
		key = ERR_CAST(key_ref);
	} else  {
		/* the search failed, but the keyrings were searchable, so we
		 * should consult userspace if we can */
		key = ERR_PTR(-ENOKEY);
		if (!callout_info)
			goto error;

		key = construct_key_and_link(type, description, callout_info,
					     callout_len, aux, dest_keyring,
					     flags);
	}

error:
	kleave(" = %p", key);
	return key;
}

Project: linux
File: keyctl.c

long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
{
	struct key *key;
	key_ref_t key_ref;
	long ret;

	/* find the key first */
	key_ref = lookup_user_key(keyid, 0, 0);
	if (IS_ERR(key_ref)) {
		ret = -ENOKEY;
		goto error;
	}

	key = key_ref_to_ptr(key_ref);

	/* see if we can read it directly */
	ret = key_permission(key_ref, KEY_READ);
	if (ret == 0)
		goto can_read_key;
	if (ret != -EACCES)
		goto error;

	/* we can't; see if it's searchable from this process's keyrings
	 * - we automatically take account of the fact that it may be
	 *   dangling off an instantiation key
	 */
	if (!is_key_possessed(key_ref)) {
		ret = -EACCES;
		goto error2;
	}

	/* the key is probably readable - now try to read it */
can_read_key:
	ret = key_validate(key);
	if (ret == 0) {
		ret = -EOPNOTSUPP;
		if (key->type->read) {
			/* read the data with the semaphore held (since we
			 * might sleep) */
			down_read(&key->sem);
			ret = key->type->read(key, buffer, buflen);
			up_read(&key->sem);
		}
	}

error2:
	key_put(key);
error:
	return ret;
}

Project: linux
File: keyctl.c

SYSCALL_DEFINE4(request_key, const char __user *, _type,
		const char __user *, _description,
		const char __user *, _callout_info,
		key_serial_t, destringid)
{
	struct key_type *ktype;
	struct key *key;
	key_ref_t dest_ref;
	size_t callout_len;
	char type[32], *description, *callout_info;
	long ret;

	/* pull the type into kernel space */
	ret = key_get_type_from_user(type, _type, sizeof(type));
	if (ret < 0)
		goto error;

	/* pull the description into kernel space */
	description = strndup_user(_description, PAGE_SIZE);
	if (IS_ERR(description)) {
		ret = PTR_ERR(description);
		goto error;
	}

	/* pull the callout info into kernel space */
	callout_info = NULL;
	callout_len = 0;
	if (_callout_info) {
		callout_info = strndup_user(_callout_info, PAGE_SIZE);
		if (IS_ERR(callout_info)) {
			ret = PTR_ERR(callout_info);
			goto error2;
		}
		callout_len = strlen(callout_info);
	}

	/* get the destination keyring if specified */
	dest_ref = NULL;
	if (destringid) {
		dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
					   KEY_WRITE);
		if (IS_ERR(dest_ref)) {
			ret = PTR_ERR(dest_ref);
			goto error3;
		}
	}

	/* find the key type */
	ktype = key_type_lookup(type);
	if (IS_ERR(ktype)) {
		ret = PTR_ERR(ktype);
		goto error4;
	}

	/* do the search */
	key = request_key_and_link(ktype, description, callout_info,
				   callout_len, NULL, key_ref_to_ptr(dest_ref),
				   KEY_ALLOC_IN_QUOTA);
	if (IS_ERR(key)) {
		ret = PTR_ERR(key);
		goto error5;
	}

	/* wait for the key to finish being constructed */
	ret = wait_for_key_construction(key, 1);
	if (ret < 0)
		goto error6;

	ret = key->serial;

error6:
 	key_put(key);
error5:
	key_type_put(ktype);
error4:
	key_ref_put(dest_ref);
error3:
	kfree(callout_info);
error2:
	kfree(description);
error:
	return ret;
}

Project: linux
File: request_key.c

static struct key *construct_key_and_link(struct key_type *type,
					  const char *description,
					  const char *callout_info,
					  size_t callout_len,
					  void *aux,
					  struct key *dest_keyring,
					  unsigned long flags)
{
	struct key_user *user;
	struct key *key;
	int ret;

	kenter("");

	user = key_user_lookup(current_fsuid(), current_user_ns());
	if (!user)
		return ERR_PTR(-ENOMEM);

	construct_get_dest_keyring(&dest_keyring);

	ret = construct_alloc_key(type, description, dest_keyring, flags, user,
				  &key);
	key_user_put(user);

	if (ret == 0) {
		ret = construct_key(key, callout_info, callout_len, aux,
				    dest_keyring);
		if (ret < 0) {
			kdebug("cons failed");
			goto construction_failed;
		}
	} else if (ret == -EINPROGRESS) {
		ret = 0;
	} else {
		goto couldnt_alloc_key;
	}

	key_put(dest_keyring);
	kleave(" = key %d", key_serial(key));
	return key;

construction_failed:
	key_negate_and_link(key, key_negative_timeout, NULL, NULL);
	key_put(key);
couldnt_alloc_key:
	key_put(dest_keyring);
	kleave(" = %d", ret);
	return ERR_PTR(ret);
}

Project: linux
File: process_keys.c

int install_user_keyrings(void)
{
	struct user_struct *user;
	const struct cred *cred;
	struct key *uid_keyring, *session_keyring;
	char buf[20];
	int ret;

	cred = current_cred();
	user = cred->user;

	kenter("%p{%u}", user, user->uid);

	if (user->uid_keyring) {
		kleave(" = 0 [exist]");
		return 0;
	}

	mutex_lock(&key_user_keyring_mutex);
	ret = 0;

	if (!user->uid_keyring) {
		/* get the UID-specific keyring
		 * - there may be one in existence already as it may have been
		 *   pinned by a session, but the user_struct pointing to it
		 *   may have been destroyed by setuid */
		sprintf(buf, "_uid.%u", user->uid);

		uid_keyring = find_keyring_by_name(buf, true);
		if (IS_ERR(uid_keyring)) {
			uid_keyring = keyring_alloc(buf, user->uid, (gid_t) -1,
						    cred, KEY_ALLOC_IN_QUOTA,
						    NULL);
			if (IS_ERR(uid_keyring)) {
				ret = PTR_ERR(uid_keyring);
				goto error;
			}
		}

		/* get a default session keyring (which might also exist
		 * already) */
		sprintf(buf, "_uid_ses.%u", user->uid);

		session_keyring = find_keyring_by_name(buf, true);
		if (IS_ERR(session_keyring)) {
			session_keyring =
				keyring_alloc(buf, user->uid, (gid_t) -1,
					      cred, KEY_ALLOC_IN_QUOTA, NULL);
			if (IS_ERR(session_keyring)) {
				ret = PTR_ERR(session_keyring);
				goto error_release;
			}

			/* we install a link from the user session keyring to
			 * the user keyring */
			ret = key_link(session_keyring, uid_keyring);
			if (ret < 0)
				goto error_release_both;
		}

		/* install the keyrings */
		user->uid_keyring = uid_keyring;
		user->session_keyring = session_keyring;
	}

	mutex_unlock(&key_user_keyring_mutex);
	kleave(" = 0");
	return 0;

error_release_both:
	key_put(session_keyring);
error_release:
	key_put(uid_keyring);
error:
	mutex_unlock(&key_user_keyring_mutex);
	kleave(" = %d", ret);
	return ret;
}

Project: linux
File: keyctl.c

static long copy_from_user_iovec(void *buffer, const struct iovec *iov,
				 unsigned ioc)
{
	for (; ioc > 0; ioc--) {
		if (copy_from_user(buffer, iov->iov_base, iov->iov_len) != 0)
			return -EFAULT;
		buffer += iov->iov_len;
		iov++;
	}
	return 0;
}

Project: linux
File: keyctl.c

long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
		       key_serial_t ringid)
{
	const struct cred *cred = current_cred();
	struct request_key_auth *rka;
	struct key *instkey, *dest_keyring;
	long ret;

	kenter("%d,%u,%u,%d", id, timeout, error, ringid);

	/* must be a valid error code and mustn't be a kernel special */
	if (error <= 0 ||
	    error >= MAX_ERRNO ||
	    error == ERESTARTSYS ||
	    error == ERESTARTNOINTR ||
	    error == ERESTARTNOHAND ||
	    error == ERESTART_RESTARTBLOCK)
		return -EINVAL;

	/* the appropriate instantiation authorisation key must have been
	 * assumed before calling this */
	ret = -EPERM;
	instkey = cred->request_key_auth;
	if (!instkey)
		goto error;

	rka = instkey->payload.data;
	if (rka->target_key->serial != id)
		goto error;

	/* find the destination keyring if present (which must also be
	 * writable) */
	ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
	if (ret < 0)
		goto error;

	/* instantiate the key and link it into a keyring */
	ret = key_reject_and_link(rka->target_key, timeout, error,
				  dest_keyring, instkey);

	key_put(dest_keyring);

	/* discard the assumed authority if it's just been disabled by
	 * instantiation of the key */
	if (ret == 0)
		keyctl_change_reqkey_auth(NULL);

error:
	return ret;
}

Project: linux
File: keyctl.c

long keyctl_session_to_parent(void)
{
	struct task_struct *me, *parent;
	const struct cred *mycred, *pcred;
	struct callback_head *newwork, *oldwork;
	key_ref_t keyring_r;
	struct cred *cred;
	int ret;

	keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_LINK);
	if (IS_ERR(keyring_r))
		return PTR_ERR(keyring_r);

	ret = -ENOMEM;

	/* our parent is going to need a new cred struct, a new tgcred struct
	 * and new security data, so we allocate them here to prevent ENOMEM in
	 * our parent */
	cred = cred_alloc_blank();
	if (!cred)
		goto error_keyring;
	newwork = &cred->rcu;

	cred->session_keyring = key_ref_to_ptr(keyring_r);
	keyring_r = NULL;
	init_task_work(newwork, key_change_session_keyring);

	me = current;
	rcu_read_lock();
	write_lock_irq(&tasklist_lock);

	ret = -EPERM;
	oldwork = NULL;
	parent = me->real_parent;

	task_lock(parent);
	/* the parent mustn't be init and mustn't be a kernel thread */
	if (parent->pid <= 1 || !parent->mm)
		goto unlock;

	/* the parent must be single threaded */
	if (!thread_group_empty(parent))
		goto unlock;

	/* the parent and the child must have different session keyrings or
	 * there's no point */
	mycred = current_cred();
	pcred = __task_cred(parent);
	if (mycred == pcred ||
	    mycred->session_keyring == pcred->session_keyring) {
		ret = 0;
		goto unlock;
	}

	/* the parent must have the same effective ownership and mustn't be
	 * SUID/SGID */
	if (pcred->uid	!= mycred->euid	||
	    pcred->euid	!= mycred->euid	||
	    pcred->suid	!= mycred->euid	||
	    pcred->gid	!= mycred->egid	||
	    pcred->egid	!= mycred->egid	||
	    pcred->sgid	!= mycred->egid)
		goto unlock;

	/* the keyrings must have the same UID */
	if ((pcred->session_keyring &&
	     pcred->session_keyring->uid != mycred->euid) ||
	    mycred->session_keyring->uid != mycred->euid)
		goto unlock;

	/* cancel an already pending keyring replacement */
	oldwork = task_work_cancel(parent, key_change_session_keyring);

	/* the replacement session keyring is applied just prior to userspace
	 * restarting */
	ret = task_work_add(parent, newwork, true);
	if (!ret)
		newwork = NULL;
unlock:
	task_unlock(parent);
	write_unlock_irq(&tasklist_lock);
	rcu_read_unlock();
	if (oldwork)
		put_cred(container_of(oldwork, struct cred, rcu));
	if (newwork)
		put_cred(cred);
	return ret;

error_keyring:
	key_ref_put(keyring_r);
	return ret;
}

Project: linux
File: keyctl.c

long keyctl_get_keyring_ID(key_serial_t id, int create)
{
	key_ref_t key_ref;
	unsigned long lflags;
	long ret;

	lflags = create ? KEY_LOOKUP_CREATE : 0;
	key_ref = lookup_user_key(id, lflags, KEY_SEARCH);
	if (IS_ERR(key_ref)) {
		ret = PTR_ERR(key_ref);
		goto error;
	}

	ret = key_ref_to_ptr(key_ref)->serial;
	key_ref_put(key_ref);
error:
	return ret;
}

Project: linux
File: process_keys.c

static int install_thread_keyring(void)
{
	struct cred *new;
	int ret;

	new = prepare_creds();
	if (!new)
		return -ENOMEM;

	BUG_ON(new->thread_keyring);

	ret = install_thread_keyring_to_cred(new);
	if (ret < 0) {
		abort_creds(new);
		return ret;
	}

	return commit_creds(new);
}

Project: linux
File: cred.c

void abort_creds(struct cred *new)
{
	kdebug("abort_creds(%p{%d,%d})", new,
	       atomic_read(&new->usage),
	       read_cred_subscribers(new));

#ifdef CONFIG_DEBUG_CREDENTIALS
	BUG_ON(read_cred_subscribers(new) != 0);
#endif
	BUG_ON(atomic_read(&new->usage) < 1);
	put_cred(new);
}

Project: linux
File: cred.c

static inline void alter_cred_subscribers(const struct cred *_cred, int n)
{
#ifdef CONFIG_DEBUG_CREDENTIALS
	struct cred *cred = (struct cred *) _cred;

	atomic_add(n, &cred->subscribers);
#endif
}

Project: linux
File: request_key.c

static int construct_alloc_key(struct key_type *type,
			       const char *description,
			       struct key *dest_keyring,
			       unsigned long flags,
			       struct key_user *user,
			       struct key **_key)
{
	const struct cred *cred = current_cred();
	unsigned long prealloc;
	struct key *key;
	key_ref_t key_ref;
	int ret;

	kenter("%s,%s,,,", type->name, description);

	*_key = NULL;
	mutex_lock(&user->cons_lock);

	key = key_alloc(type, description, cred->fsuid, cred->fsgid, cred,
			KEY_POS_ALL, flags);
	if (IS_ERR(key))
		goto alloc_failed;

	set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);

	if (dest_keyring) {
		ret = __key_link_begin(dest_keyring, type, description,
				       &prealloc);
		if (ret < 0)
			goto link_prealloc_failed;
	}

	/* attach the key to the destination keyring under lock, but we do need
	 * to do another check just in case someone beat us to it whilst we
	 * waited for locks */
	mutex_lock(&key_construction_mutex);

	key_ref = search_process_keyrings(type, description, type->match, cred);
	if (!IS_ERR(key_ref))
		goto key_already_present;

	if (dest_keyring)
		__key_link(dest_keyring, key, &prealloc);

	mutex_unlock(&key_construction_mutex);
	if (dest_keyring)
		__key_link_end(dest_keyring, type, prealloc);
	mutex_unlock(&user->cons_lock);
	*_key = key;
	kleave(" = 0 [%d]", key_serial(key));
	return 0;

	/* the key is now present - we tell the caller that we found it by
	 * returning -EINPROGRESS  */
key_already_present:
	key_put(key);
	mutex_unlock(&key_construction_mutex);
	key = key_ref_to_ptr(key_ref);
	if (dest_keyring) {
		ret = __key_link_check_live_key(dest_keyring, key);
		if (ret == 0)
			__key_link(dest_keyring, key, &prealloc);
		__key_link_end(dest_keyring, type, prealloc);
		if (ret < 0)
			goto link_check_failed;
	}
	mutex_unlock(&user->cons_lock);
	*_key = key;
	kleave(" = -EINPROGRESS [%d]", key_serial(key));
	return -EINPROGRESS;

link_check_failed:
	mutex_unlock(&user->cons_lock);
	key_put(key);
	kleave(" = %d [linkcheck]", ret);
	return ret;

link_prealloc_failed:
	mutex_unlock(&user->cons_lock);
	kleave(" = %d [prelink]", ret);
	return ret;

alloc_failed:
	mutex_unlock(&user->cons_lock);
	kleave(" = %ld", PTR_ERR(key));
	return PTR_ERR(key);
}

Project: linux
File: keyctl.c

long keyctl_keyring_clear(key_serial_t ringid)
{
	key_ref_t keyring_ref;
	long ret;

	keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
	if (IS_ERR(keyring_ref)) {
		ret = PTR_ERR(keyring_ref);

		/* Root is permitted to invalidate certain special keyrings */
		if (capable(CAP_SYS_ADMIN)) {
			keyring_ref = lookup_user_key(ringid, 0, 0);
			if (IS_ERR(keyring_ref))
				goto error;
			if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
				     &key_ref_to_ptr(keyring_ref)->flags))
				goto clear;
			goto error_put;
		}

		goto error;
	}

clear:
	ret = keyring_clear(key_ref_to_ptr(keyring_ref));
error_put:
	key_ref_put(keyring_ref);
error:
	return ret;
}

Project: linux
File: process_keys.c

int install_session_keyring_to_cred(struct cred *cred, struct key *keyring)
{
	unsigned long flags;
	struct key *old;

	might_sleep();

	/* create an empty session keyring */
	if (!keyring) {
		flags = KEY_ALLOC_QUOTA_OVERRUN;
		if (cred->session_keyring)
			flags = KEY_ALLOC_IN_QUOTA;

		keyring = keyring_alloc("_ses", cred->uid, cred->gid,
					cred, flags, NULL);
		if (IS_ERR(keyring))
			return PTR_ERR(keyring);
	} else {
		atomic_inc(&keyring->usage);
	}

	/* install the keyring */
	old = cred->session_keyring;
	rcu_assign_pointer(cred->session_keyring, keyring);

	if (old)
		key_put(old);

	return 0;
}

Project: linux
File: keyctl.c

long keyctl_invalidate_key(key_serial_t id)
{
	key_ref_t key_ref;
	long ret;

	kenter("%d", id);

	key_ref = lookup_user_key(id, 0, KEY_SEARCH);
	if (IS_ERR(key_ref)) {
		ret = PTR_ERR(key_ref);
		goto error;
	}

	key_invalidate(key_ref_to_ptr(key_ref));
	ret = 0;

	key_ref_put(key_ref);
error:
	kleave(" = %ld", ret);
	return ret;
}

Project: linux
File: request_key.c

static int call_sbin_request_key(struct key_construction *cons,
				 const char *op,
				 void *aux)
{
	const struct cred *cred = current_cred();
	key_serial_t prkey, sskey;
	struct key *key = cons->key, *authkey = cons->authkey, *keyring,
		*session;
	char *argv[9], *envp[3], uid_str[12], gid_str[12];
	char key_str[12], keyring_str[3][12];
	char desc[20];
	int ret, i;

	kenter("{%d},{%d},%s", key->serial, authkey->serial, op);

	ret = install_user_keyrings();
	if (ret < 0)
		goto error_alloc;

	/* allocate a new session keyring */
	sprintf(desc, "_req.%u", key->serial);

	cred = get_current_cred();
	keyring = keyring_alloc(desc, cred->fsuid, cred->fsgid, cred,
				KEY_ALLOC_QUOTA_OVERRUN, NULL);
	put_cred(cred);
	if (IS_ERR(keyring)) {
		ret = PTR_ERR(keyring);
		goto error_alloc;
	}

	/* attach the auth key to the session keyring */
	ret = key_link(keyring, authkey);
	if (ret < 0)
		goto error_link;

	/* record the UID and GID */
	sprintf(uid_str, "%d", cred->fsuid);
	sprintf(gid_str, "%d", cred->fsgid);

	/* we say which key is under construction */
	sprintf(key_str, "%d", key->serial);

	/* we specify the process's default keyrings */
	sprintf(keyring_str[0], "%d",
		cred->thread_keyring ? cred->thread_keyring->serial : 0);

	prkey = 0;
	if (cred->process_keyring)
		prkey = cred->process_keyring->serial;
	sprintf(keyring_str[1], "%d", prkey);

	rcu_read_lock();
	session = rcu_dereference(cred->session_keyring);
	if (!session)
		session = cred->user->session_keyring;
	sskey = session->serial;
	rcu_read_unlock();

	sprintf(keyring_str[2], "%d", sskey);

	/* set up a minimal environment */
	i = 0;
	envp[i++] = "HOME=/";
	envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
	envp[i] = NULL;

	/* set up the argument list */
	i = 0;
	argv[i++] = "/sbin/request-key";
	argv[i++] = (char *) op;
	argv[i++] = key_str;
	argv[i++] = uid_str;
	argv[i++] = gid_str;
	argv[i++] = keyring_str[0];
	argv[i++] = keyring_str[1];
	argv[i++] = keyring_str[2];
	argv[i] = NULL;

	/* do it */
	ret = call_usermodehelper_keys(argv[0], argv, envp, keyring,
				       UMH_WAIT_PROC);
	kdebug("usermode -> 0x%x", ret);
	if (ret >= 0) {
		/* ret is the exit/wait code */
		if (test_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags) ||
		    key_validate(key) < 0)
			ret = -ENOKEY;
		else
			/* ignore any errors from userspace if the key was
			 * instantiated */
			ret = 0;
	}

error_link:
	key_put(keyring);

error_alloc:
	complete_request_key(cons, ret);
	kleave(" = %d", ret);
	return ret;
}

Project: linux
File: keyctl.c

long keyctl_instantiate_key(key_serial_t id,
			    const void __user *_payload,
			    size_t plen,
			    key_serial_t ringid)
{
	if (_payload && plen) {
		struct iovec iov[1] = {
			[0].iov_base = (void __user *)_payload,
			[0].iov_len  = plen
		};

		return keyctl_instantiate_key_common(id, iov, 1, plen, ringid);
	}

	return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid);
}

Project: linux
File: keyctl.c

SYSCALL_DEFINE5(add_key, const char __user *, _type,
		const char __user *, _description,
		const void __user *, _payload,
		size_t, plen,
		key_serial_t, ringid)
{
	key_ref_t keyring_ref, key_ref;
	char type[32], *description;
	void *payload;
	long ret;
	bool vm;

	ret = -EINVAL;
	if (plen > 1024 * 1024 - 1)
		goto error;

	/* draw all the data into kernel space */
	ret = key_get_type_from_user(type, _type, sizeof(type));
	if (ret < 0)
		goto error;

	description = strndup_user(_description, PAGE_SIZE);
	if (IS_ERR(description)) {
		ret = PTR_ERR(description);
		goto error;
	}

	/* pull the payload in if one was supplied */
	payload = NULL;

	vm = false;
	if (_payload) {
		ret = -ENOMEM;
		payload = kmalloc(plen, GFP_KERNEL | __GFP_NOWARN);
		if (!payload) {
			if (plen <= PAGE_SIZE)
				goto error2;
			vm = true;
			payload = vmalloc(plen);
			if (!payload)
				goto error2;
		}

		ret = -EFAULT;
		if (copy_from_user(payload, _payload, plen) != 0)
			goto error3;
	}

	/* find the target keyring (which must be writable) */
	keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
	if (IS_ERR(keyring_ref)) {
		ret = PTR_ERR(keyring_ref);
		goto error3;
	}

	/* create or update the requested key and add it to the target
	 * keyring */
	key_ref = key_create_or_update(keyring_ref, type, description,
				       payload, plen, KEY_PERM_UNDEF,
				       KEY_ALLOC_IN_QUOTA);
	if (!IS_ERR(key_ref)) {
		ret = key_ref_to_ptr(key_ref)->serial;
		key_ref_put(key_ref);
	}
	else {
		ret = PTR_ERR(key_ref);
	}

	key_ref_put(keyring_ref);
 error3:
	if (!vm)
		kfree(payload);
	else
		vfree(payload);
 error2:
	kfree(description);
 error:
	return ret;
}

Project: linux
File: cred.c

struct cred *cred_alloc_blank(void)
{
	struct cred *new;

	new = kmem_cache_zalloc(cred_jar, GFP_KERNEL);
	if (!new)
		return NULL;

	atomic_set(&new->usage, 1);
#ifdef CONFIG_DEBUG_CREDENTIALS
	new->magic = CRED_MAGIC;
#endif

	if (security_cred_alloc_blank(new, GFP_KERNEL) < 0)
		goto error;

	return new;

error:
	abort_creds(new);
	return NULL;
}