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957 lines
23 KiB
957 lines
23 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* Manage a process's keyrings |
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* |
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* Copyright (C) 2004-2005, 2008 Red Hat, Inc. All Rights Reserved. |
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* Written by David Howells ([email protected]) |
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*/ |
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|
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#include <linux/init.h> |
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#include <linux/sched.h> |
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#include <linux/sched/user.h> |
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#include <linux/keyctl.h> |
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#include <linux/fs.h> |
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#include <linux/err.h> |
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#include <linux/mutex.h> |
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#include <linux/security.h> |
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#include <linux/user_namespace.h> |
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#include <linux/uaccess.h> |
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#include <linux/init_task.h> |
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#include <keys/request_key_auth-type.h> |
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#include "internal.h" |
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|
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/* Session keyring create vs join semaphore */ |
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static DEFINE_MUTEX(key_session_mutex); |
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|
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/* The root user's tracking struct */ |
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struct key_user root_key_user = { |
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.usage = REFCOUNT_INIT(3), |
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.cons_lock = __MUTEX_INITIALIZER(root_key_user.cons_lock), |
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.lock = __SPIN_LOCK_UNLOCKED(root_key_user.lock), |
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.nkeys = ATOMIC_INIT(2), |
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.nikeys = ATOMIC_INIT(2), |
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.uid = GLOBAL_ROOT_UID, |
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}; |
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|
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/* |
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* Get or create a user register keyring. |
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*/ |
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static struct key *get_user_register(struct user_namespace *user_ns) |
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{ |
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struct key *reg_keyring = READ_ONCE(user_ns->user_keyring_register); |
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|
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if (reg_keyring) |
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return reg_keyring; |
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|
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down_write(&user_ns->keyring_sem); |
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|
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/* Make sure there's a register keyring. It gets owned by the |
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* user_namespace's owner. |
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*/ |
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reg_keyring = user_ns->user_keyring_register; |
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if (!reg_keyring) { |
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reg_keyring = keyring_alloc(".user_reg", |
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user_ns->owner, INVALID_GID, |
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&init_cred, |
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KEY_POS_WRITE | KEY_POS_SEARCH | |
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KEY_USR_VIEW | KEY_USR_READ, |
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0, |
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NULL, NULL); |
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if (!IS_ERR(reg_keyring)) |
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smp_store_release(&user_ns->user_keyring_register, |
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reg_keyring); |
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} |
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|
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up_write(&user_ns->keyring_sem); |
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|
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/* We don't return a ref since the keyring is pinned by the user_ns */ |
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return reg_keyring; |
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} |
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|
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/* |
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* Look up the user and user session keyrings for the current process's UID, |
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* creating them if they don't exist. |
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*/ |
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int look_up_user_keyrings(struct key **_user_keyring, |
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struct key **_user_session_keyring) |
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{ |
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const struct cred *cred = current_cred(); |
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struct user_namespace *user_ns = current_user_ns(); |
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struct key *reg_keyring, *uid_keyring, *session_keyring; |
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key_perm_t user_keyring_perm; |
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key_ref_t uid_keyring_r, session_keyring_r; |
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uid_t uid = from_kuid(user_ns, cred->user->uid); |
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char buf[20]; |
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int ret; |
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user_keyring_perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_ALL; |
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kenter("%u", uid); |
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reg_keyring = get_user_register(user_ns); |
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if (IS_ERR(reg_keyring)) |
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return PTR_ERR(reg_keyring); |
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|
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down_write(&user_ns->keyring_sem); |
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ret = 0; |
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|
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/* Get the user keyring. Note that there may be one in existence |
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* already as it may have been pinned by a session, but the user_struct |
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* pointing to it may have been destroyed by setuid. |
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*/ |
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snprintf(buf, sizeof(buf), "_uid.%u", uid); |
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uid_keyring_r = keyring_search(make_key_ref(reg_keyring, true), |
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&key_type_keyring, buf, false); |
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kdebug("_uid %p", uid_keyring_r); |
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if (uid_keyring_r == ERR_PTR(-EAGAIN)) { |
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uid_keyring = keyring_alloc(buf, cred->user->uid, INVALID_GID, |
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cred, user_keyring_perm, |
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KEY_ALLOC_UID_KEYRING | |
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KEY_ALLOC_IN_QUOTA, |
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NULL, reg_keyring); |
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if (IS_ERR(uid_keyring)) { |
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ret = PTR_ERR(uid_keyring); |
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goto error; |
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} |
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} else if (IS_ERR(uid_keyring_r)) { |
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ret = PTR_ERR(uid_keyring_r); |
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goto error; |
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} else { |
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uid_keyring = key_ref_to_ptr(uid_keyring_r); |
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} |
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|
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/* Get a default session keyring (which might also exist already) */ |
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snprintf(buf, sizeof(buf), "_uid_ses.%u", uid); |
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session_keyring_r = keyring_search(make_key_ref(reg_keyring, true), |
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&key_type_keyring, buf, false); |
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kdebug("_uid_ses %p", session_keyring_r); |
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if (session_keyring_r == ERR_PTR(-EAGAIN)) { |
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session_keyring = keyring_alloc(buf, cred->user->uid, INVALID_GID, |
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cred, user_keyring_perm, |
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KEY_ALLOC_UID_KEYRING | |
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KEY_ALLOC_IN_QUOTA, |
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NULL, NULL); |
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if (IS_ERR(session_keyring)) { |
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ret = PTR_ERR(session_keyring); |
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goto error_release; |
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} |
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|
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/* We install a link from the user session keyring to |
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* the user keyring. |
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*/ |
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ret = key_link(session_keyring, uid_keyring); |
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if (ret < 0) |
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goto error_release_session; |
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|
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/* And only then link the user-session keyring to the |
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* register. |
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*/ |
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ret = key_link(reg_keyring, session_keyring); |
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if (ret < 0) |
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goto error_release_session; |
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} else if (IS_ERR(session_keyring_r)) { |
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ret = PTR_ERR(session_keyring_r); |
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goto error_release; |
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} else { |
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session_keyring = key_ref_to_ptr(session_keyring_r); |
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} |
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up_write(&user_ns->keyring_sem); |
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if (_user_session_keyring) |
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*_user_session_keyring = session_keyring; |
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else |
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key_put(session_keyring); |
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if (_user_keyring) |
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*_user_keyring = uid_keyring; |
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else |
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key_put(uid_keyring); |
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kleave(" = 0"); |
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return 0; |
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error_release_session: |
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key_put(session_keyring); |
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error_release: |
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key_put(uid_keyring); |
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error: |
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up_write(&user_ns->keyring_sem); |
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kleave(" = %d", ret); |
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return ret; |
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} |
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|
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/* |
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* Get the user session keyring if it exists, but don't create it if it |
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* doesn't. |
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*/ |
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struct key *get_user_session_keyring_rcu(const struct cred *cred) |
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{ |
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struct key *reg_keyring = READ_ONCE(cred->user_ns->user_keyring_register); |
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key_ref_t session_keyring_r; |
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char buf[20]; |
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struct keyring_search_context ctx = { |
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.index_key.type = &key_type_keyring, |
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.index_key.description = buf, |
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.cred = cred, |
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.match_data.cmp = key_default_cmp, |
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.match_data.raw_data = buf, |
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.match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, |
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.flags = KEYRING_SEARCH_DO_STATE_CHECK, |
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}; |
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if (!reg_keyring) |
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return NULL; |
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ctx.index_key.desc_len = snprintf(buf, sizeof(buf), "_uid_ses.%u", |
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from_kuid(cred->user_ns, |
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cred->user->uid)); |
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session_keyring_r = keyring_search_rcu(make_key_ref(reg_keyring, true), |
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&ctx); |
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if (IS_ERR(session_keyring_r)) |
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return NULL; |
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return key_ref_to_ptr(session_keyring_r); |
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} |
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|
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/* |
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* Install a thread keyring to the given credentials struct if it didn't have |
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* one already. This is allowed to overrun the quota. |
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* |
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* Return: 0 if a thread keyring is now present; -errno on failure. |
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*/ |
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int install_thread_keyring_to_cred(struct cred *new) |
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{ |
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struct key *keyring; |
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if (new->thread_keyring) |
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return 0; |
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keyring = keyring_alloc("_tid", new->uid, new->gid, new, |
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KEY_POS_ALL | KEY_USR_VIEW, |
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KEY_ALLOC_QUOTA_OVERRUN, |
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NULL, NULL); |
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if (IS_ERR(keyring)) |
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return PTR_ERR(keyring); |
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new->thread_keyring = keyring; |
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return 0; |
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} |
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/* |
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* Install a thread keyring to the current task if it didn't have one already. |
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* |
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* Return: 0 if a thread keyring is now present; -errno on failure. |
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*/ |
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static int install_thread_keyring(void) |
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{ |
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struct cred *new; |
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int ret; |
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new = prepare_creds(); |
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if (!new) |
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return -ENOMEM; |
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ret = install_thread_keyring_to_cred(new); |
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if (ret < 0) { |
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abort_creds(new); |
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return ret; |
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} |
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return commit_creds(new); |
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} |
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/* |
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* Install a process keyring to the given credentials struct if it didn't have |
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* one already. This is allowed to overrun the quota. |
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* |
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* Return: 0 if a process keyring is now present; -errno on failure. |
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*/ |
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int install_process_keyring_to_cred(struct cred *new) |
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{ |
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struct key *keyring; |
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|
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if (new->process_keyring) |
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return 0; |
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keyring = keyring_alloc("_pid", new->uid, new->gid, new, |
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KEY_POS_ALL | KEY_USR_VIEW, |
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KEY_ALLOC_QUOTA_OVERRUN, |
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NULL, NULL); |
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if (IS_ERR(keyring)) |
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return PTR_ERR(keyring); |
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new->process_keyring = keyring; |
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return 0; |
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} |
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/* |
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* Install a process keyring to the current task if it didn't have one already. |
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* |
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* Return: 0 if a process keyring is now present; -errno on failure. |
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*/ |
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static int install_process_keyring(void) |
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{ |
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struct cred *new; |
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int ret; |
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new = prepare_creds(); |
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if (!new) |
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return -ENOMEM; |
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ret = install_process_keyring_to_cred(new); |
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if (ret < 0) { |
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abort_creds(new); |
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return ret; |
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} |
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return commit_creds(new); |
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} |
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|
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/* |
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* Install the given keyring as the session keyring of the given credentials |
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* struct, replacing the existing one if any. If the given keyring is NULL, |
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* then install a new anonymous session keyring. |
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* @cred can not be in use by any task yet. |
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* |
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* Return: 0 on success; -errno on failure. |
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*/ |
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int install_session_keyring_to_cred(struct cred *cred, struct key *keyring) |
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{ |
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unsigned long flags; |
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struct key *old; |
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|
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might_sleep(); |
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|
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/* create an empty session keyring */ |
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if (!keyring) { |
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flags = KEY_ALLOC_QUOTA_OVERRUN; |
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if (cred->session_keyring) |
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flags = KEY_ALLOC_IN_QUOTA; |
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keyring = keyring_alloc("_ses", cred->uid, cred->gid, cred, |
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KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ, |
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flags, NULL, NULL); |
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if (IS_ERR(keyring)) |
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return PTR_ERR(keyring); |
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} else { |
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__key_get(keyring); |
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} |
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/* install the keyring */ |
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old = cred->session_keyring; |
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cred->session_keyring = keyring; |
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if (old) |
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key_put(old); |
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return 0; |
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} |
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|
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/* |
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* Install the given keyring as the session keyring of the current task, |
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* replacing the existing one if any. If the given keyring is NULL, then |
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* install a new anonymous session keyring. |
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* |
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* Return: 0 on success; -errno on failure. |
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*/ |
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static int install_session_keyring(struct key *keyring) |
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{ |
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struct cred *new; |
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int ret; |
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|
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new = prepare_creds(); |
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if (!new) |
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return -ENOMEM; |
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|
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ret = install_session_keyring_to_cred(new, keyring); |
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if (ret < 0) { |
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abort_creds(new); |
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return ret; |
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} |
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|
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return commit_creds(new); |
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} |
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|
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/* |
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* Handle the fsuid changing. |
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*/ |
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void key_fsuid_changed(struct cred *new_cred) |
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{ |
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/* update the ownership of the thread keyring */ |
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if (new_cred->thread_keyring) { |
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down_write(&new_cred->thread_keyring->sem); |
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new_cred->thread_keyring->uid = new_cred->fsuid; |
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up_write(&new_cred->thread_keyring->sem); |
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} |
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} |
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|
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/* |
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* Handle the fsgid changing. |
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*/ |
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void key_fsgid_changed(struct cred *new_cred) |
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{ |
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/* update the ownership of the thread keyring */ |
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if (new_cred->thread_keyring) { |
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down_write(&new_cred->thread_keyring->sem); |
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new_cred->thread_keyring->gid = new_cred->fsgid; |
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up_write(&new_cred->thread_keyring->sem); |
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} |
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} |
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|
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/* |
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* Search the process keyrings attached to the supplied cred for the first |
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* matching key under RCU conditions (the caller must be holding the RCU read |
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* lock). |
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* |
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* The search criteria are the type and the match function. The description is |
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* given to the match function as a parameter, but doesn't otherwise influence |
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* the search. Typically the match function will compare the description |
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* parameter to the key's description. |
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* |
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* This can only search keyrings that grant Search permission to the supplied |
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* credentials. Keyrings linked to searched keyrings will also be searched if |
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* they grant Search permission too. Keys can only be found if they grant |
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* Search permission to the credentials. |
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* |
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* Returns a pointer to the key with the key usage count incremented if |
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* successful, -EAGAIN if we didn't find any matching key or -ENOKEY if we only |
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* matched negative keys. |
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* |
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* In the case of a successful return, the possession attribute is set on the |
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* returned key reference. |
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*/ |
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key_ref_t search_cred_keyrings_rcu(struct keyring_search_context *ctx) |
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{ |
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struct key *user_session; |
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key_ref_t key_ref, ret, err; |
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const struct cred *cred = ctx->cred; |
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|
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/* we want to return -EAGAIN or -ENOKEY if any of the keyrings were |
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* searchable, but we failed to find a key or we found a negative key; |
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* otherwise we want to return a sample error (probably -EACCES) if |
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* none of the keyrings were searchable |
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* |
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* in terms of priority: success > -ENOKEY > -EAGAIN > other error |
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*/ |
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key_ref = NULL; |
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ret = NULL; |
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err = ERR_PTR(-EAGAIN); |
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|
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/* search the thread keyring first */ |
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if (cred->thread_keyring) { |
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key_ref = keyring_search_rcu( |
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make_key_ref(cred->thread_keyring, 1), ctx); |
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if (!IS_ERR(key_ref)) |
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goto found; |
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|
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switch (PTR_ERR(key_ref)) { |
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case -EAGAIN: /* no key */ |
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case -ENOKEY: /* negative key */ |
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ret = key_ref; |
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break; |
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default: |
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err = key_ref; |
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break; |
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} |
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} |
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|
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/* search the process keyring second */ |
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if (cred->process_keyring) { |
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key_ref = keyring_search_rcu( |
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make_key_ref(cred->process_keyring, 1), ctx); |
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if (!IS_ERR(key_ref)) |
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goto found; |
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|
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switch (PTR_ERR(key_ref)) { |
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case -EAGAIN: /* no key */ |
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if (ret) |
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break; |
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fallthrough; |
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case -ENOKEY: /* negative key */ |
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ret = key_ref; |
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break; |
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default: |
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err = key_ref; |
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break; |
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} |
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} |
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|
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/* search the session keyring */ |
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if (cred->session_keyring) { |
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key_ref = keyring_search_rcu( |
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make_key_ref(cred->session_keyring, 1), ctx); |
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|
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if (!IS_ERR(key_ref)) |
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goto found; |
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|
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switch (PTR_ERR(key_ref)) { |
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case -EAGAIN: /* no key */ |
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if (ret) |
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break; |
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fallthrough; |
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case -ENOKEY: /* negative key */ |
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ret = key_ref; |
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break; |
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default: |
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err = key_ref; |
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break; |
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} |
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} |
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/* or search the user-session keyring */ |
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else if ((user_session = get_user_session_keyring_rcu(cred))) { |
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key_ref = keyring_search_rcu(make_key_ref(user_session, 1), |
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ctx); |
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key_put(user_session); |
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|
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if (!IS_ERR(key_ref)) |
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goto found; |
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|
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switch (PTR_ERR(key_ref)) { |
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case -EAGAIN: /* no key */ |
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if (ret) |
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break; |
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fallthrough; |
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case -ENOKEY: /* negative key */ |
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ret = key_ref; |
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break; |
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default: |
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err = key_ref; |
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break; |
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} |
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} |
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|
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/* no key - decide on the error we're going to go for */ |
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key_ref = ret ? ret : err; |
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|
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found: |
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return key_ref; |
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} |
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|
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/* |
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* Search the process keyrings attached to the supplied cred for the first |
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* matching key in the manner of search_my_process_keyrings(), but also search |
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* the keys attached to the assumed authorisation key using its credentials if |
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* one is available. |
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* |
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* The caller must be holding the RCU read lock. |
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* |
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* Return same as search_cred_keyrings_rcu(). |
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*/ |
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key_ref_t search_process_keyrings_rcu(struct keyring_search_context *ctx) |
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{ |
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struct request_key_auth *rka; |
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key_ref_t key_ref, ret = ERR_PTR(-EACCES), err; |
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|
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key_ref = search_cred_keyrings_rcu(ctx); |
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if (!IS_ERR(key_ref)) |
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goto found; |
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err = key_ref; |
|
|
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/* if this process has an instantiation authorisation key, then we also |
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* search the keyrings of the process mentioned there |
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* - we don't permit access to request_key auth keys via this method |
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*/ |
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if (ctx->cred->request_key_auth && |
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ctx->cred == current_cred() && |
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ctx->index_key.type != &key_type_request_key_auth |
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) { |
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const struct cred *cred = ctx->cred; |
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|
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if (key_validate(cred->request_key_auth) == 0) { |
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rka = ctx->cred->request_key_auth->payload.data[0]; |
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|
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//// was search_process_keyrings() [ie. recursive] |
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ctx->cred = rka->cred; |
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key_ref = search_cred_keyrings_rcu(ctx); |
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ctx->cred = cred; |
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|
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if (!IS_ERR(key_ref)) |
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goto found; |
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ret = key_ref; |
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} |
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} |
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|
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/* no key - decide on the error we're going to go for */ |
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if (err == ERR_PTR(-ENOKEY) || ret == ERR_PTR(-ENOKEY)) |
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key_ref = ERR_PTR(-ENOKEY); |
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else if (err == ERR_PTR(-EACCES)) |
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key_ref = ret; |
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else |
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key_ref = err; |
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|
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found: |
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return key_ref; |
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} |
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/* |
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* See if the key we're looking at is the target key. |
|
*/ |
|
bool lookup_user_key_possessed(const struct key *key, |
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const struct key_match_data *match_data) |
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{ |
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return key == match_data->raw_data; |
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} |
|
|
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/* |
|
* Look up a key ID given us by userspace with a given permissions mask to get |
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* the key it refers to. |
|
* |
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* 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, |
|
enum key_need_perm need_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 (need_perm != KEY_NEED_UNLINK) { |
|
if (!(lflags & KEY_LOOKUP_PARTIAL)) { |
|
ret = wait_for_key_construction(key, true); |
|
switch (ret) { |
|
case -ERESTARTSYS: |
|
goto invalid_key; |
|
default: |
|
if (need_perm != KEY_AUTHTOKEN_OVERRIDE && |
|
need_perm != KEY_DEFER_PERM_CHECK) |
|
goto invalid_key; |
|
break; |
|
case 0: |
|
break; |
|
} |
|
} else if (need_perm != KEY_DEFER_PERM_CHECK) { |
|
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, need_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, |
|
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 look_up_user_keyrings(NULL, NULL); |
|
} |
|
|
|
late_initcall(init_root_keyring);
|
|
|