v4.19.13 snapshot.
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
new file mode 100644
index 0000000..d5b25e5
--- /dev/null
+++ b/security/keys/process_keys.c
@@ -0,0 +1,890 @@
+/* Manage a process's keyrings
+ *
+ * Copyright (C) 2004-2005, 2008 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/sched/user.h>
+#include <linux/keyctl.h>
+#include <linux/fs.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+#include <linux/security.h>
+#include <linux/user_namespace.h>
+#include <linux/uaccess.h>
+#include "internal.h"
+
+/* Session keyring create vs join semaphore */
+static DEFINE_MUTEX(key_session_mutex);
+
+/* User keyring creation semaphore */
+static DEFINE_MUTEX(key_user_keyring_mutex);
+
+/* The root user's tracking struct */
+struct key_user root_key_user = {
+ .usage = REFCOUNT_INIT(3),
+ .cons_lock = __MUTEX_INITIALIZER(root_key_user.cons_lock),
+ .lock = __SPIN_LOCK_UNLOCKED(root_key_user.lock),
+ .nkeys = ATOMIC_INIT(2),
+ .nikeys = ATOMIC_INIT(2),
+ .uid = GLOBAL_ROOT_UID,
+};
+
+/*
+ * Install the user and user session keyrings for the current process's UID.
+ */
+int install_user_keyrings(void)
+{
+ struct user_struct *user;
+ const struct cred *cred;
+ struct key *uid_keyring, *session_keyring;
+ key_perm_t user_keyring_perm;
+ char buf[20];
+ int ret;
+ uid_t uid;
+
+ user_keyring_perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_ALL;
+ cred = current_cred();
+ user = cred->user;
+ uid = from_kuid(cred->user_ns, user->uid);
+
+ kenter("%p{%u}", user, uid);
+
+ if (user->uid_keyring && user->session_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", uid);
+
+ uid_keyring = find_keyring_by_name(buf, true);
+ if (IS_ERR(uid_keyring)) {
+ uid_keyring = keyring_alloc(buf, user->uid, INVALID_GID,
+ cred, user_keyring_perm,
+ KEY_ALLOC_UID_KEYRING |
+ KEY_ALLOC_IN_QUOTA,
+ NULL, 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", uid);
+
+ session_keyring = find_keyring_by_name(buf, true);
+ if (IS_ERR(session_keyring)) {
+ session_keyring =
+ keyring_alloc(buf, user->uid, INVALID_GID,
+ cred, user_keyring_perm,
+ KEY_ALLOC_UID_KEYRING |
+ KEY_ALLOC_IN_QUOTA,
+ NULL, 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;
+}
+
+/*
+ * Install a thread keyring to the given credentials struct if it didn't have
+ * one already. This is allowed to overrun the quota.
+ *
+ * Return: 0 if a thread keyring is now present; -errno on failure.
+ */
+int install_thread_keyring_to_cred(struct cred *new)
+{
+ struct key *keyring;
+
+ if (new->thread_keyring)
+ return 0;
+
+ keyring = keyring_alloc("_tid", new->uid, new->gid, new,
+ KEY_POS_ALL | KEY_USR_VIEW,
+ KEY_ALLOC_QUOTA_OVERRUN,
+ NULL, NULL);
+ if (IS_ERR(keyring))
+ return PTR_ERR(keyring);
+
+ new->thread_keyring = keyring;
+ return 0;
+}
+
+/*
+ * Install a thread keyring to the current task if it didn't have one already.
+ *
+ * Return: 0 if a thread keyring is now present; -errno on failure.
+ */
+static int install_thread_keyring(void)
+{
+ struct cred *new;
+ int ret;
+
+ new = prepare_creds();
+ if (!new)
+ return -ENOMEM;
+
+ ret = install_thread_keyring_to_cred(new);
+ if (ret < 0) {
+ abort_creds(new);
+ return ret;
+ }
+
+ return commit_creds(new);
+}
+
+/*
+ * Install a process keyring to the given credentials struct if it didn't have
+ * one already. This is allowed to overrun the quota.
+ *
+ * Return: 0 if a process keyring is now present; -errno on failure.
+ */
+int install_process_keyring_to_cred(struct cred *new)
+{
+ struct key *keyring;
+
+ if (new->process_keyring)
+ return 0;
+
+ keyring = keyring_alloc("_pid", new->uid, new->gid, new,
+ KEY_POS_ALL | KEY_USR_VIEW,
+ KEY_ALLOC_QUOTA_OVERRUN,
+ NULL, NULL);
+ if (IS_ERR(keyring))
+ return PTR_ERR(keyring);
+
+ new->process_keyring = keyring;
+ return 0;
+}
+
+/*
+ * Install a process keyring to the current task if it didn't have one already.
+ *
+ * Return: 0 if a process keyring is now present; -errno on failure.
+ */
+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;
+ }
+
+ return commit_creds(new);
+}
+
+/*
+ * Install the given keyring as the session keyring of the given credentials
+ * struct, replacing the existing one if any. If the given keyring is NULL,
+ * then install a new anonymous session keyring.
+ *
+ * Return: 0 on success; -errno on failure.
+ */
+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,
+ KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ,
+ flags, NULL, NULL);
+ if (IS_ERR(keyring))
+ return PTR_ERR(keyring);
+ } else {
+ __key_get(keyring);
+ }
+
+ /* install the keyring */
+ old = cred->session_keyring;
+ rcu_assign_pointer(cred->session_keyring, keyring);
+
+ if (old)
+ key_put(old);
+
+ return 0;
+}
+
+/*
+ * Install the given keyring as the session keyring of the current task,
+ * replacing the existing one if any. If the given keyring is NULL, then
+ * install a new anonymous session keyring.
+ *
+ * Return: 0 on success; -errno on failure.
+ */
+static int install_session_keyring(struct key *keyring)
+{
+ struct cred *new;
+ int ret;
+
+ new = prepare_creds();
+ if (!new)
+ return -ENOMEM;
+
+ ret = install_session_keyring_to_cred(new, keyring);
+ if (ret < 0) {
+ abort_creds(new);
+ return ret;
+ }
+
+ return commit_creds(new);
+}
+
+/*
+ * Handle the fsuid changing.
+ */
+void key_fsuid_changed(struct task_struct *tsk)
+{
+ /* update the ownership of the thread keyring */
+ BUG_ON(!tsk->cred);
+ if (tsk->cred->thread_keyring) {
+ down_write(&tsk->cred->thread_keyring->sem);
+ tsk->cred->thread_keyring->uid = tsk->cred->fsuid;
+ up_write(&tsk->cred->thread_keyring->sem);
+ }
+}
+
+/*
+ * Handle the fsgid changing.
+ */
+void key_fsgid_changed(struct task_struct *tsk)
+{
+ /* update the ownership of the thread keyring */
+ BUG_ON(!tsk->cred);
+ if (tsk->cred->thread_keyring) {
+ down_write(&tsk->cred->thread_keyring->sem);
+ tsk->cred->thread_keyring->gid = tsk->cred->fsgid;
+ up_write(&tsk->cred->thread_keyring->sem);
+ }
+}
+
+/*
+ * Search the process keyrings attached to the supplied cred for the first
+ * matching key.
+ *
+ * The search criteria are the type and the match function. The description is
+ * given to the match function as a parameter, but doesn't otherwise influence
+ * the search. Typically the match function will compare the description
+ * parameter to the key's description.
+ *
+ * This can only search keyrings that grant Search permission to the supplied
+ * credentials. Keyrings linked to searched keyrings will also be searched if
+ * they grant Search permission too. Keys can only be found if they grant
+ * Search permission to the credentials.
+ *
+ * Returns a pointer to the key with the key usage count incremented if
+ * successful, -EAGAIN if we didn't find any matching key or -ENOKEY if we only
+ * matched negative keys.
+ *
+ * In the case of a successful return, the possession attribute is set on the
+ * returned key reference.
+ */
+key_ref_t search_my_process_keyrings(struct keyring_search_context *ctx)
+{
+ key_ref_t key_ref, ret, err;
+
+ /* we want to return -EAGAIN or -ENOKEY if any of the keyrings were
+ * searchable, but we failed to find a key or we found a negative key;
+ * otherwise we want to return a sample error (probably -EACCES) if
+ * none of the keyrings were searchable
+ *
+ * in terms of priority: success > -ENOKEY > -EAGAIN > other error
+ */
+ key_ref = NULL;
+ ret = NULL;
+ err = ERR_PTR(-EAGAIN);
+
+ /* search the thread keyring first */
+ if (ctx->cred->thread_keyring) {
+ key_ref = keyring_search_aux(
+ make_key_ref(ctx->cred->thread_keyring, 1), ctx);
+ if (!IS_ERR(key_ref))
+ goto found;
+
+ switch (PTR_ERR(key_ref)) {
+ case -EAGAIN: /* no key */
+ case -ENOKEY: /* negative key */
+ ret = key_ref;
+ break;
+ default:
+ err = key_ref;
+ break;
+ }
+ }
+
+ /* search the process keyring second */
+ if (ctx->cred->process_keyring) {
+ key_ref = keyring_search_aux(
+ make_key_ref(ctx->cred->process_keyring, 1), ctx);
+ if (!IS_ERR(key_ref))
+ goto found;
+
+ switch (PTR_ERR(key_ref)) {
+ case -EAGAIN: /* no key */
+ if (ret)
+ break;
+ case -ENOKEY: /* negative key */
+ ret = key_ref;
+ break;
+ default:
+ err = key_ref;
+ break;
+ }
+ }
+
+ /* search the session keyring */
+ if (ctx->cred->session_keyring) {
+ rcu_read_lock();
+ key_ref = keyring_search_aux(
+ make_key_ref(rcu_dereference(ctx->cred->session_keyring), 1),
+ ctx);
+ rcu_read_unlock();
+
+ if (!IS_ERR(key_ref))
+ goto found;
+
+ switch (PTR_ERR(key_ref)) {
+ case -EAGAIN: /* no key */
+ if (ret)
+ break;
+ case -ENOKEY: /* negative key */
+ ret = key_ref;
+ break;
+ default:
+ err = key_ref;
+ break;
+ }
+ }
+ /* or search the user-session keyring */
+ else if (ctx->cred->user->session_keyring) {
+ key_ref = keyring_search_aux(
+ make_key_ref(ctx->cred->user->session_keyring, 1),
+ ctx);
+ if (!IS_ERR(key_ref))
+ goto found;
+
+ switch (PTR_ERR(key_ref)) {
+ case -EAGAIN: /* no key */
+ if (ret)
+ break;
+ case -ENOKEY: /* negative key */
+ ret = key_ref;
+ break;
+ default:
+ err = key_ref;
+ break;
+ }
+ }
+
+ /* no key - decide on the error we're going to go for */
+ key_ref = ret ? ret : err;
+
+found:
+ return key_ref;
+}
+
+/*
+ * Search the process keyrings attached to the supplied cred for the first
+ * matching key in the manner of search_my_process_keyrings(), but also search
+ * the keys attached to the assumed authorisation key using its credentials if
+ * one is available.
+ *
+ * Return same as search_my_process_keyrings().
+ */
+key_ref_t search_process_keyrings(struct keyring_search_context *ctx)
+{
+ struct request_key_auth *rka;
+ key_ref_t key_ref, ret = ERR_PTR(-EACCES), err;
+
+ might_sleep();
+
+ key_ref = search_my_process_keyrings(ctx);
+ if (!IS_ERR(key_ref))
+ goto found;
+ err = key_ref;
+
+ /* if this process has an instantiation authorisation key, then we also
+ * search the keyrings of the process mentioned there
+ * - we don't permit access to request_key auth keys via this method
+ */
+ if (ctx->cred->request_key_auth &&
+ ctx->cred == current_cred() &&
+ ctx->index_key.type != &key_type_request_key_auth
+ ) {
+ const struct cred *cred = ctx->cred;
+
+ /* defend against the auth key being revoked */
+ down_read(&cred->request_key_auth->sem);
+
+ if (key_validate(ctx->cred->request_key_auth) == 0) {
+ rka = ctx->cred->request_key_auth->payload.data[0];
+
+ ctx->cred = rka->cred;
+ key_ref = search_process_keyrings(ctx);
+ ctx->cred = cred;
+
+ up_read(&cred->request_key_auth->sem);
+
+ if (!IS_ERR(key_ref))
+ goto found;
+
+ ret = key_ref;
+ } else {
+ up_read(&cred->request_key_auth->sem);
+ }
+ }
+
+ /* no key - decide on the error we're going to go for */
+ if (err == ERR_PTR(-ENOKEY) || ret == ERR_PTR(-ENOKEY))
+ key_ref = ERR_PTR(-ENOKEY);
+ else if (err == ERR_PTR(-EACCES))
+ key_ref = ret;
+ else
+ key_ref = err;
+
+found:
+ return key_ref;
+}
+
+/*
+ * See if the key we're looking at is the target key.
+ */
+bool lookup_user_key_possessed(const struct key *key,
+ const struct key_match_data *match_data)
+{
+ return key == match_data->raw_data;
+}
+
+/*
+ * Look up a key ID given us by userspace with a given permissions mask to get
+ * the key it refers to.
+ *
+ * Flags can be passed to request that special keyrings be created if referred
+ * to directly, to permit partially constructed keys to be found and to skip
+ * validity and permission checks on the found key.
+ *
+ * Returns a pointer to the key with an incremented usage count if successful;
+ * -EINVAL if the key ID is invalid; -ENOKEY if the key ID does not correspond
+ * to a key or the best found key was a negative key; -EKEYREVOKED or
+ * -EKEYEXPIRED if the best found key was revoked or expired; -EACCES if the
+ * found key doesn't grant the requested permit or the LSM denied access to it;
+ * or -ENOMEM if a special keyring couldn't be created.
+ *
+ * In the case of a successful return, the possession attribute is set on the
+ * returned key reference.
+ */
+key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags,
+ key_perm_t perm)
+{
+ struct keyring_search_context ctx = {
+ .match_data.cmp = lookup_user_key_possessed,
+ .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
+ .flags = KEYRING_SEARCH_NO_STATE_CHECK,
+ };
+ struct request_key_auth *rka;
+ struct key *key;
+ key_ref_t key_ref, skey_ref;
+ int ret;
+
+try_again:
+ ctx.cred = get_current_cred();
+ key_ref = ERR_PTR(-ENOKEY);
+
+ switch (id) {
+ case KEY_SPEC_THREAD_KEYRING:
+ if (!ctx.cred->thread_keyring) {
+ if (!(lflags & KEY_LOOKUP_CREATE))
+ goto error;
+
+ ret = install_thread_keyring();
+ if (ret < 0) {
+ key_ref = ERR_PTR(ret);
+ goto error;
+ }
+ goto reget_creds;
+ }
+
+ key = ctx.cred->thread_keyring;
+ __key_get(key);
+ key_ref = make_key_ref(key, 1);
+ break;
+
+ case KEY_SPEC_PROCESS_KEYRING:
+ if (!ctx.cred->process_keyring) {
+ if (!(lflags & KEY_LOOKUP_CREATE))
+ goto error;
+
+ ret = install_process_keyring();
+ if (ret < 0) {
+ key_ref = ERR_PTR(ret);
+ goto error;
+ }
+ goto reget_creds;
+ }
+
+ key = ctx.cred->process_keyring;
+ __key_get(key);
+ key_ref = make_key_ref(key, 1);
+ break;
+
+ case KEY_SPEC_SESSION_KEYRING:
+ if (!ctx.cred->session_keyring) {
+ /* always install a session keyring upon access if one
+ * doesn't exist yet */
+ ret = install_user_keyrings();
+ if (ret < 0)
+ goto error;
+ if (lflags & KEY_LOOKUP_CREATE)
+ ret = join_session_keyring(NULL);
+ else
+ ret = install_session_keyring(
+ ctx.cred->user->session_keyring);
+
+ if (ret < 0)
+ goto error;
+ goto reget_creds;
+ } else if (ctx.cred->session_keyring ==
+ ctx.cred->user->session_keyring &&
+ lflags & KEY_LOOKUP_CREATE) {
+ ret = join_session_keyring(NULL);
+ if (ret < 0)
+ goto error;
+ goto reget_creds;
+ }
+
+ rcu_read_lock();
+ key = rcu_dereference(ctx.cred->session_keyring);
+ __key_get(key);
+ rcu_read_unlock();
+ key_ref = make_key_ref(key, 1);
+ break;
+
+ case KEY_SPEC_USER_KEYRING:
+ if (!ctx.cred->user->uid_keyring) {
+ ret = install_user_keyrings();
+ if (ret < 0)
+ goto error;
+ }
+
+ key = ctx.cred->user->uid_keyring;
+ __key_get(key);
+ key_ref = make_key_ref(key, 1);
+ break;
+
+ case KEY_SPEC_USER_SESSION_KEYRING:
+ if (!ctx.cred->user->session_keyring) {
+ ret = install_user_keyrings();
+ if (ret < 0)
+ goto error;
+ }
+
+ key = ctx.cred->user->session_keyring;
+ __key_get(key);
+ key_ref = make_key_ref(key, 1);
+ break;
+
+ case KEY_SPEC_GROUP_KEYRING:
+ /* group keyrings are not yet supported */
+ key_ref = ERR_PTR(-EINVAL);
+ goto error;
+
+ case KEY_SPEC_REQKEY_AUTH_KEY:
+ key = ctx.cred->request_key_auth;
+ if (!key)
+ goto error;
+
+ __key_get(key);
+ key_ref = make_key_ref(key, 1);
+ break;
+
+ case KEY_SPEC_REQUESTOR_KEYRING:
+ if (!ctx.cred->request_key_auth)
+ goto error;
+
+ down_read(&ctx.cred->request_key_auth->sem);
+ if (test_bit(KEY_FLAG_REVOKED,
+ &ctx.cred->request_key_auth->flags)) {
+ key_ref = ERR_PTR(-EKEYREVOKED);
+ key = NULL;
+ } else {
+ rka = ctx.cred->request_key_auth->payload.data[0];
+ key = rka->dest_keyring;
+ __key_get(key);
+ }
+ up_read(&ctx.cred->request_key_auth->sem);
+ if (!key)
+ goto error;
+ key_ref = make_key_ref(key, 1);
+ break;
+
+ default:
+ key_ref = ERR_PTR(-EINVAL);
+ if (id < 1)
+ goto error;
+
+ key = key_lookup(id);
+ if (IS_ERR(key)) {
+ key_ref = ERR_CAST(key);
+ goto error;
+ }
+
+ key_ref = make_key_ref(key, 0);
+
+ /* check to see if we possess the key */
+ ctx.index_key.type = key->type;
+ ctx.index_key.description = key->description;
+ ctx.index_key.desc_len = strlen(key->description);
+ ctx.match_data.raw_data = key;
+ kdebug("check possessed");
+ skey_ref = search_process_keyrings(&ctx);
+ kdebug("possessed=%p", skey_ref);
+
+ if (!IS_ERR(skey_ref)) {
+ key_put(key);
+ key_ref = skey_ref;
+ }
+
+ break;
+ }
+
+ /* unlink does not use the nominated key in any way, so can skip all
+ * the permission checks as it is only concerned with the keyring */
+ if (lflags & KEY_LOOKUP_FOR_UNLINK) {
+ ret = 0;
+ goto error;
+ }
+
+ if (!(lflags & KEY_LOOKUP_PARTIAL)) {
+ ret = wait_for_key_construction(key, true);
+ switch (ret) {
+ case -ERESTARTSYS:
+ goto invalid_key;
+ default:
+ if (perm)
+ goto invalid_key;
+ case 0:
+ break;
+ }
+ } else if (perm) {
+ ret = key_validate(key);
+ if (ret < 0)
+ goto invalid_key;
+ }
+
+ ret = -EIO;
+ if (!(lflags & KEY_LOOKUP_PARTIAL) &&
+ key_read_state(key) == KEY_IS_UNINSTANTIATED)
+ goto invalid_key;
+
+ /* check the permissions */
+ ret = key_task_permission(key_ref, ctx.cred, perm);
+ if (ret < 0)
+ goto invalid_key;
+
+ key->last_used_at = ktime_get_real_seconds();
+
+error:
+ put_cred(ctx.cred);
+ return key_ref;
+
+invalid_key:
+ key_ref_put(key_ref);
+ key_ref = ERR_PTR(ret);
+ goto error;
+
+ /* if we attempted to install a keyring, then it may have caused new
+ * creds to be installed */
+reget_creds:
+ put_cred(ctx.cred);
+ goto try_again;
+}
+
+/*
+ * Join the named keyring as the session keyring if possible else attempt to
+ * create a new one of that name and join that.
+ *
+ * If the name is NULL, an empty anonymous keyring will be installed as the
+ * session keyring.
+ *
+ * Named session keyrings are joined with a semaphore held to prevent the
+ * keyrings from going away whilst the attempt is made to going them and also
+ * to prevent a race in creating compatible session keyrings.
+ */
+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_POS_ALL | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_LINK,
+ KEY_ALLOC_IN_QUOTA, NULL, 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 error3;
+ }
+
+ /* we've got a keyring - now to install it */
+ ret = install_session_keyring_to_cred(new, keyring);
+ if (ret < 0)
+ goto error3;
+
+ commit_creds(new);
+ mutex_unlock(&key_session_mutex);
+
+ ret = keyring->serial;
+ key_put(keyring);
+okay:
+ return ret;
+
+error3:
+ key_put(keyring);
+error2:
+ mutex_unlock(&key_session_mutex);
+error:
+ abort_creds(new);
+ return ret;
+}
+
+/*
+ * Replace a process's session keyring on behalf of one of its children when
+ * the target process is about to resume userspace execution.
+ */
+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(old->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_ambient = old->cap_ambient;
+ 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);
+}
+
+/*
+ * Make sure that root's user and user-session keyrings exist.
+ */
+static int __init init_root_keyring(void)
+{
+ return install_user_keyrings();
+}
+
+late_initcall(init_root_keyring);