// SPDX-License-Identifier: GPL-2.0-or-later /* Manage a process's keyrings * * Copyright (C) 2004-2005, 2008 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) */ #include #include #include #include #include #include #include #include #include #include #include #include #include "internal.h" /* Session keyring create vs join semaphore */ static DEFINE_MUTEX(key_session_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, }; static struct key_acl user_reg_keyring_acl = { .usage = REFCOUNT_INIT(1), .possessor_viewable = true, .nr_ace = 2, .aces = { KEY_POSSESSOR_ACE(KEY_ACE_WRITE | KEY_ACE_SEARCH), KEY_OWNER_ACE(KEY_ACE_VIEW | KEY_ACE_READ), } }; static struct key_acl user_keyring_acl = { .usage = REFCOUNT_INIT(1), .possessor_viewable = true, .nr_ace = 2, .aces = { KEY_POSSESSOR_ACE(KEY_ACE_VIEW | KEY_ACE_READ | KEY_ACE_WRITE | KEY_ACE_SEARCH | KEY_ACE_LINK), KEY_OWNER_ACE(KEY_ACE__PERMS & ~(KEY_ACE_JOIN | KEY_ACE_SET_SECURITY)), } }; static struct key_acl session_keyring_acl = { .usage = REFCOUNT_INIT(1), .possessor_viewable = true, .nr_ace = 2, .aces = { KEY_POSSESSOR_ACE(KEY_ACE__PERMS & ~KEY_ACE_JOIN), KEY_OWNER_ACE(KEY_ACE_VIEW | KEY_ACE_READ), } }; static struct key_acl thread_and_process_keyring_acl = { .usage = REFCOUNT_INIT(1), .possessor_viewable = true, .nr_ace = 2, .aces = { KEY_POSSESSOR_ACE(KEY_ACE__PERMS & ~(KEY_ACE_JOIN | KEY_ACE_SET_SECURITY)), KEY_OWNER_ACE(KEY_ACE_VIEW), } }; /* * Get or create a user register keyring. */ static struct key *get_user_register(struct user_namespace *user_ns) { struct key *reg_keyring = READ_ONCE(user_ns->user_keyring_register); if (reg_keyring) return reg_keyring; down_write(&user_ns->keyring_sem); /* Make sure there's a register keyring. It gets owned by the * user_namespace's owner. */ reg_keyring = user_ns->user_keyring_register; if (!reg_keyring) { reg_keyring = keyring_alloc(".user_reg", user_ns->owner, INVALID_GID, &init_cred, &user_reg_keyring_acl, 0, NULL, NULL); if (!IS_ERR(reg_keyring)) smp_store_release(&user_ns->user_keyring_register, reg_keyring); } up_write(&user_ns->keyring_sem); /* We don't return a ref since the keyring is pinned by the user_ns */ return reg_keyring; } /* * Look up the user and user session keyrings for the current process's UID, * creating them if they don't exist. */ int look_up_user_keyrings(struct key **_user_keyring, struct key **_user_session_keyring) { const struct cred *cred = current_cred(); struct user_namespace *user_ns = current_user_ns(); struct key *reg_keyring, *uid_keyring, *session_keyring; key_ref_t uid_keyring_r, session_keyring_r; uid_t uid = from_kuid(user_ns, cred->user->uid); char buf[20]; int ret; kenter("%u", uid); reg_keyring = get_user_register(user_ns); if (IS_ERR(reg_keyring)) return PTR_ERR(reg_keyring); down_write(&user_ns->keyring_sem); ret = 0; /* Get the user keyring. Note that 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. */ snprintf(buf, sizeof(buf), "_uid.%u", uid); uid_keyring_r = keyring_search(make_key_ref(reg_keyring, true), &key_type_keyring, buf, false); kdebug("_uid %p", uid_keyring_r); if (uid_keyring_r == ERR_PTR(-EAGAIN)) { uid_keyring = keyring_alloc(buf, cred->user->uid, INVALID_GID, cred, &user_keyring_acl, KEY_ALLOC_UID_KEYRING | KEY_ALLOC_IN_QUOTA, NULL, reg_keyring); if (IS_ERR(uid_keyring)) { ret = PTR_ERR(uid_keyring); goto error; } } else if (IS_ERR(uid_keyring_r)) { ret = PTR_ERR(uid_keyring_r); goto error; } else { uid_keyring = key_ref_to_ptr(uid_keyring_r); } /* Get a default session keyring (which might also exist already) */ snprintf(buf, sizeof(buf), "_uid_ses.%u", uid); session_keyring_r = keyring_search(make_key_ref(reg_keyring, true), &key_type_keyring, buf, false); kdebug("_uid_ses %p", session_keyring_r); if (session_keyring_r == ERR_PTR(-EAGAIN)) { session_keyring = keyring_alloc(buf, cred->user->uid, INVALID_GID, cred, &user_keyring_acl, 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_session; /* And only then link the user-session keyring to the * register. */ ret = key_link(reg_keyring, session_keyring); if (ret < 0) goto error_release_session; } else if (IS_ERR(session_keyring_r)) { ret = PTR_ERR(session_keyring_r); goto error_release; } else { session_keyring = key_ref_to_ptr(session_keyring_r); } up_write(&user_ns->keyring_sem); if (_user_session_keyring) *_user_session_keyring = session_keyring; else key_put(session_keyring); if (_user_keyring) *_user_keyring = uid_keyring; else key_put(uid_keyring); kleave(" = 0"); return 0; error_release_session: key_put(session_keyring); error_release: key_put(uid_keyring); error: up_write(&user_ns->keyring_sem); kleave(" = %d", ret); return ret; } /* * Get the user session keyring if it exists, but don't create it if it * doesn't. */ struct key *get_user_session_keyring_rcu(const struct cred *cred) { struct key *reg_keyring = READ_ONCE(cred->user_ns->user_keyring_register); key_ref_t session_keyring_r; char buf[20]; struct keyring_search_context ctx = { .index_key.type = &key_type_keyring, .index_key.description = buf, .cred = cred, .match_data.cmp = key_default_cmp, .match_data.raw_data = buf, .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, .flags = KEYRING_SEARCH_DO_STATE_CHECK, }; if (!reg_keyring) return NULL; ctx.index_key.desc_len = snprintf(buf, sizeof(buf), "_uid_ses.%u", from_kuid(cred->user_ns, cred->user->uid)); session_keyring_r = keyring_search_rcu(make_key_ref(reg_keyring, true), &ctx); if (IS_ERR(session_keyring_r)) return NULL; return key_ref_to_ptr(session_keyring_r); } /* * 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, &thread_and_process_keyring_acl, 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, &thread_and_process_keyring_acl, 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. * @cred can not be in use by any task yet. * * 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, &session_keyring_acl, flags, NULL, NULL); if (IS_ERR(keyring)) return PTR_ERR(keyring); } else { __key_get(keyring); } /* install the keyring */ old = cred->session_keyring; 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 cred *new_cred) { /* update the ownership of the thread keyring */ if (new_cred->thread_keyring) { down_write(&new_cred->thread_keyring->sem); new_cred->thread_keyring->uid = new_cred->fsuid; up_write(&new_cred->thread_keyring->sem); } } /* * Handle the fsgid changing. */ void key_fsgid_changed(struct cred *new_cred) { /* update the ownership of the thread keyring */ if (new_cred->thread_keyring) { down_write(&new_cred->thread_keyring->sem); new_cred->thread_keyring->gid = new_cred->fsgid; up_write(&new_cred->thread_keyring->sem); } } /* * Search the process keyrings attached to the supplied cred for the first * matching key under RCU conditions (the caller must be holding the RCU read * lock). * * 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_cred_keyrings_rcu(struct keyring_search_context *ctx) { struct key *user_session; key_ref_t key_ref, ret, err; const struct cred *cred = ctx->cred; /* 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 (cred->thread_keyring) { key_ref = keyring_search_rcu( make_key_ref(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 (cred->process_keyring) { key_ref = keyring_search_rcu( make_key_ref(cred->process_keyring, 1), ctx); if (!IS_ERR(key_ref)) goto found; switch (PTR_ERR(key_ref)) { case -EAGAIN: /* no key */ if (ret) break; /* fall through */ case -ENOKEY: /* negative key */ ret = key_ref; break; default: err = key_ref; break; } } /* search the session keyring */ if (cred->session_keyring) { key_ref = keyring_search_rcu( make_key_ref(cred->session_keyring, 1), ctx); if (!IS_ERR(key_ref)) goto found; switch (PTR_ERR(key_ref)) { case -EAGAIN: /* no key */ if (ret) break; /* fall through */ case -ENOKEY: /* negative key */ ret = key_ref; break; default: err = key_ref; break; } } /* or search the user-session keyring */ else if ((user_session = get_user_session_keyring_rcu(cred))) { key_ref = keyring_search_rcu(make_key_ref(user_session, 1), ctx); key_put(user_session); if (!IS_ERR(key_ref)) goto found; switch (PTR_ERR(key_ref)) { case -EAGAIN: /* no key */ if (ret) break; /* fall through */ 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. * * The caller must be holding the RCU read lock. * * Return same as search_cred_keyrings_rcu(). */ key_ref_t search_process_keyrings_rcu(struct keyring_search_context *ctx) { struct request_key_auth *rka; key_ref_t key_ref, ret = ERR_PTR(-EACCES), err; key_ref = search_cred_keyrings_rcu(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; if (key_validate(cred->request_key_auth) == 0) { rka = ctx->cred->request_key_auth->payload.data[0]; //// was search_process_keyrings() [ie. recursive] ctx->cred = rka->cred; key_ref = search_cred_keyrings_rcu(ctx); ctx->cred = cred; if (!IS_ERR(key_ref)) goto found; ret = key_ref; } } /* 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, unsigned int desired_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 | KEYRING_SEARCH_RECURSE), }; struct request_key_auth *rka; struct key *key, *user_session; 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 = look_up_user_keyrings(NULL, &user_session); if (ret < 0) goto error; if (lflags & KEY_LOOKUP_CREATE) ret = join_session_keyring(NULL); else ret = install_session_keyring(user_session); key_put(user_session); if (ret < 0) goto error; goto reget_creds; } else if (test_bit(KEY_FLAG_UID_KEYRING, &ctx.cred->session_keyring->flags) && lflags & KEY_LOOKUP_CREATE) { ret = join_session_keyring(NULL); if (ret < 0) goto error; goto reget_creds; } key = ctx.cred->session_keyring; __key_get(key); key_ref = make_key_ref(key, 1); break; case KEY_SPEC_USER_KEYRING: ret = look_up_user_keyrings(&key, NULL); if (ret < 0) goto error; key_ref = make_key_ref(key, 1); break; case KEY_SPEC_USER_SESSION_KEYRING: ret = look_up_user_keyrings(NULL, &key); if (ret < 0) goto error; 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 = key->index_key; ctx.match_data.raw_data = key; kdebug("check possessed"); rcu_read_lock(); skey_ref = search_process_keyrings_rcu(&ctx); rcu_read_unlock(); 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 (desired_perm) goto invalid_key; case 0: break; } } else if (desired_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 */ if (desired_perm) { ret = key_task_permission(key_ref, ctx.cred, desired_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; } EXPORT_SYMBOL(lookup_user_key); /* * 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, &joinable_keyring_acl, KEY_ALLOC_IN_QUOTA, NULL, NULL); if (IS_ERR(keyring)) { ret = PTR_ERR(keyring); goto error2; } goto no_perm_test; } else if (IS_ERR(keyring)) { ret = PTR_ERR(keyring); goto error2; } else if (keyring == new->session_keyring) { ret = 0; goto error3; } ret = key_task_permission(make_key_ref(keyring, false), old, KEY_NEED_JOIN); if (ret < 0) goto error3; no_perm_test: /* 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 look_up_user_keyrings(NULL, NULL); } late_initcall(init_root_keyring);