/* 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_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_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:Lines 1–500 of 888. 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/* 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_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_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: