/* keyctl.c: userspace keyctl operations * * Copyright (C) 2004-5 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/slab.h> #include <linux/syscalls.h> #include <linux/keyctl.h> #include <linux/fs.h> #include <linux/capability.h> #include <linux/string.h> #include <linux/err.h> #include <linux/vmalloc.h> #include <linux/security.h> #include <asm/uaccess.h> #include "internal.h" static int key_get_type_from_user(char *type, const char __user *_type, unsigned len) { int ret; ret = strncpy_from_user(type, _type, len); if (ret < 0) return -EFAULT; if (ret == 0 || ret >= len) return -EINVAL; if (type[0] == '.') return -EPERM; type[len - 1] = '\0'; return 0; } /*****************************************************************************/ /* * extract the description of a new key from userspace and either add it as a * new key to the specified keyring or update a matching key in that keyring * - the keyring must be writable * - returns the new key's serial number * - implements add_key() */ asmlinkage long sys_add_key(const char __user *_type, const char __user *_description, const void __user *_payload, size_t plen, key_serial_t ringid) { key_ref_t keyring_ref, key_ref; char type[32], *description; void *payload; long ret; bool vm; ret = -EINVAL; if (plen > 1024 * 1024 - 1) goto error; /* draw all the data into kernel space */ ret = key_get_type_from_user(type, _type, sizeof(type)); if (ret < 0) goto error; description = strndup_user(_description, PAGE_SIZE); if (IS_ERR(description)) { ret = PTR_ERR(description); goto error; } /* pull the payload in if one was supplied */ payload = NULL; vm = false; if (_payload) { ret = -ENOMEM; payload = kmalloc(plen, GFP_KERNEL); if (!payload) { if (plen <= PAGE_SIZE) goto error2; vm = true; payload = vmalloc(plen); if (!payload) goto error2; } ret = -EFAULT; if (copy_from_user(payload, _payload, plen) != 0) goto error3; } /* find the target keyring (which must be writable) */ keyring_ref = lookup_user_key(NULL, ringid, 1, 0, KEY_WRITE); if (IS_ERR(keyring_ref)) { ret = PTR_ERR(keyring_ref); goto error3; } /* create or update the requested key and add it to the target * keyring */ key_ref = key_create_or_update(keyring_ref, type, description, payload, plen, KEY_PERM_UNDEF, KEY_ALLOC_IN_QUOTA); if (!IS_ERR(key_ref)) { ret = key_ref_to_ptr(key_ref)->serial; key_ref_put(key_ref); } else { ret = PTR_ERR(key_ref); } key_ref_put(keyring_ref); error3: if (!vm) kfree(payload); else vfree(payload); error2: kfree(description); error: return ret; } /* end sys_add_key() */ /*****************************************************************************/ /* * search the process keyrings for a matching key * - nested keyrings may also be searched if they have Search permission * - if a key is found, it will be attached to the destination keyring if * there's one specified * - /sbin/request-key will be invoked if _callout_info is non-NULL * - the _callout_info string will be passed to /sbin/request-key * - if the _callout_info string is empty, it will be rendered as "-" * - implements request_key() */ asmlinkage long sys_request_key(const char __user *_type, const char __user *_description, const char __user *_callout_info, key_serial_t destringid) { struct key_type *ktype; struct key *key; key_ref_t dest_ref; size_t callout_len; char type[32], *description, *callout_info; long ret; /* pull the type into kernel space */ ret = key_get_type_from_user(type, _type, sizeof(type)); if (ret < 0) goto error; /* pull the description into kernel space */ description = strndup_user(_description, PAGE_SIZE); if (IS_ERR(description)) { ret = PTR_ERR(description); goto error; } /* pull the callout info into kernel space */ callout_info = NULL; callout_len = 0; if (_callout_info) { callout_info = strndup_user(_callout_info, PAGE_SIZE); if (IS_ERR(callout_info)) { ret = PTR_ERR(callout_info); goto error2; } callout_len = strlen(callout_info); } /* get the destination keyring if specified */ dest_ref = NULL; if (destringid) { dest_ref = lookup_user_key(NULL, destringid, 1, 0, KEY_WRITE); if (IS_ERR(dest_ref)) { ret = PTR_ERR(dest_ref); goto error3; } } /* find the key type */ ktype = key_type_lookup(type); if (IS_ERR(ktype)) { ret = PTR_ERR(ktype); goto error4; } /* do the search */ key = request_key_and_link(ktype, description, callout_info, callout_len, NULL, key_ref_to_ptr(dest_ref), KEY_ALLOC_IN_QUOTA); if (IS_ERR(key)) { ret = PTR_ERR(key); goto error5; } ret = key->serial; key_put(key); error5: key_type_put(ktype); error4: key_ref_put(dest_ref); error3: kfree(callout_info); error2: kfree(description); error: return ret; } /* end sys_request_key() */ /*****************************************************************************/ /* * get the ID of the specified process keyring * - the keyring must have search permission to be found * - implements keyctl(KEYCTL_GET_KEYRING_ID) */ long keyctl_get_keyring_ID(key_serial_t id, int create) { key_ref_t key_ref; long ret; key_ref = lookup_user_key(NULL, id, create, 0, KEY_SEARCH); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); goto error; } ret = key_ref_to_ptr(key_ref)->serial; key_ref_put(key_ref); error: return ret; } /* end keyctl_get_keyring_ID() */ /*****************************************************************************/ /* * join the session keyring * - implements keyctl(KEYCTL_JOIN_SESSION_KEYRING) */ long keyctl_join_session_keyring(const char __user *_name) { char *name; long ret; /* fetch the name from userspace */ name = NULL; if (_name) { name = strndup_user(_name, PAGE_SIZE); if (IS_ERR(name)) { ret = PTR_ERR(name); goto error; } } /* join the session */ ret = join_session_keyring(name); error: return ret; } /* end keyctl_join_session_keyring() */ /*****************************************************************************/ /* * update a key's data payload * - the key must be writable * - implements keyctl(KEYCTL_UPDATE) */ long keyctl_update_key(key_serial_t id, const void __user *_payload, size_t plen) { key_ref_t key_ref; void *payload; long ret; ret = -EINVAL; if (plen > PAGE_SIZE) goto error; /* pull the payload in if one was supplied */ payload = NULL; if (_payload) { ret = -ENOMEM; payload = kmalloc(plen, GFP_KERNEL); if (!payload) goto error; ret = -EFAULT; if (copy_from_user(payload, _payload, plen) != 0) goto error2; } /* find the target key (which must be writable) */ key_ref = lookup_user_key(NULL, id, 0, 0, KEY_WRITE); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); goto error2; } /* update the key */ ret = key_update(key_ref, payload, plen); key_ref_put(key_ref); error2: kfree(payload); error: return ret; } /* end keyctl_update_key() */ /*****************************************************************************/ /* * revoke a key * - the key must be writable * - implements keyctl(KEYCTL_REVOKE) */ long keyctl_revoke_key(key_serial_t id) { key_ref_t key_ref; long ret; key_ref = lookup_user_key(NULL, id, 0, 0, KEY_WRITE); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); goto error; } key_revoke(key_ref_to_ptr(key_ref)); ret = 0; key_ref_put(key_ref); error: return ret; } /* end keyctl_revoke_key() */ /*****************************************************************************/ /* * clear the specified process keyring * - the keyring must be writable * - implements keyctl(KEYCTL_CLEAR) */ long keyctl_keyring_clear(key_serial_t ringid) { key_ref_t keyring_ref; long ret; keyring_ref = lookup_user_key(NULL, ringid, 1, 0, KEY_WRITE); if (IS_ERR(keyring_ref)) { ret = PTR_ERR(keyring_ref); goto error; } ret = keyring_clear(key_ref_to_ptr(keyring_ref)); key_ref_put(keyring_ref); error: return ret; } /* end keyctl_keyring_clear() */ /*****************************************************************************/ /* * link a key into a keyring * - the keyring must be writable * - the key must be linkable * - implements keyctl(KEYCTL_LINK) */ long keyctl_keyring_link(key_serial_t id, key_serial_t ringid) { key_ref_t keyring_ref, key_ref; long ret; keyring_ref = lookup_user_key(NULL, ringid, 1, 0, KEY_WRITE); if (IS_ERR(keyring_ref)) { ret = PTR_ERR(keyring_ref); goto error; } key_ref = lookup_user_key(NULL, id, 1, 0, KEY_LINK); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); goto error2; } ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref)); key_ref_put(key_ref); error2: key_ref_put(keyring_ref); error: return ret; } /* end keyctl_keyring_link() */ /*****************************************************************************/ /* * unlink the first attachment of a key from a keyring * - the keyring must be writable * - we don't need any permissions on the key * - implements keyctl(KEYCTL_UNLINK) */ long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid) { key_ref_t keyring_ref, key_ref; long ret; keyring_ref = lookup_user_key(NULL, ringid, 0, 0, KEY_WRITE); if (IS_ERR(keyring_ref)) { ret = PTR_ERR(keyring_ref); goto error; } key_ref = lookup_user_key(NULL, id, 0, 0, 0); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); goto error2; } ret = key_unlink(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref)); key_ref_put(key_ref); error2: key_ref_put(keyring_ref); error: return ret; } /* end keyctl_keyring_unlink() */ /*****************************************************************************/ /* * describe a user key * - the key must have view permission * - if there's a buffer, we place up to buflen bytes of data into it * - unless there's an error, we return the amount of description available, * irrespective of how much we may have copied * - the description is formatted thus: * type;uid;gid;perm;description<NUL> * - implements keyctl(KEYCTL_DESCRIBE) */ long keyctl_describe_key(key_serial_t keyid, char __user *buffer, size_t buflen) { struct key *key, *instkey; key_ref_t key_ref; char *tmpbuf; long ret; key_ref = lookup_user_key(NULL, keyid, 0, 1, KEY_VIEW); if (IS_ERR(key_ref)) { /* viewing a key under construction is permitted if we have the * authorisation token handy */ if (PTR_ERR(key_ref) == -EACCES) { instkey = key_get_instantiation_authkey(keyid); if (!IS_ERR(instkey)) { key_put(instkey); key_ref = lookup_user_key(NULL, keyid, 0, 1, 0); if (!IS_ERR(key_ref)) goto okay; } } ret = PTR_ERR(key_ref); goto error; } okay: /* calculate how much description we're going to return */ ret = -ENOMEM; tmpbuf = kmalloc(PAGE_SIZE, GFP_KERNEL); if (!tmpbuf) goto error2; key = key_ref_to_ptr(key_ref); ret = snprintf(tmpbuf, PAGE_SIZE - 1, "%s;%d;%d;%08x;%s", key_ref_to_ptr(key_ref)->type->name, key_ref_to_ptr(key_ref)->uid, key_ref_to_ptr(key_ref)->gid, key_ref_to_ptr(key_ref)->perm, key_ref_to_ptr(key_ref)->description ? key_ref_to_ptr(key_ref)->description : "" ); /* include a NUL char at the end of the data */ if (ret > PAGE_SIZE - 1) ret = PAGE_SIZE - 1; tmpbuf[ret] = 0; ret++; /* consider returning the data */ if (buffer && buflen > 0) { if (buflen > ret) buflen = ret; if (copy_to_user(buffer, tmpbuf, buflen) != 0) ret = -EFAULT; } kfree(tmpbuf); error2: key_ref_put(key_ref); error: return ret; } /* end keyctl_describe_key() */ /*****************************************************************************/ /* * search the specified keyring for a matching key * - the start keyring must be searchable * - nested keyrings may also be searched if they are searchable * - only keys with search permission may be found * - if a key is found, it will be attached to the destination keyring if * there's one specified * - implements keyctl(KEYCTL_SEARCH) */ long keyctl_keyring_search(key_serial_t ringid, const char __user *_type, const char __user *_description, key_serial_t destringid) { struct key_type *ktype; key_ref_t keyring_ref, key_ref, dest_ref; char type[32], *description; long ret; /* pull the type and description into kernel space */ ret = key_get_type_from_user(type, _type, sizeof(type)); if (ret < 0) goto error; description = strndup_user(_description, PAGE_SIZE); if (IS_ERR(description)) { ret = PTR_ERR(description); goto error; } /* get the keyring at which to begin the search */ keyring_ref = lookup_user_key(NULL, ringid, 0, 0, KEY_SEARCH); if (IS_ERR(keyring_ref)) { ret = PTR_ERR(keyring_ref); goto error2; } /* get the destination keyring if specified */ dest_ref = NULL; if (destringid) { dest_ref = lookup_user_key(NULL, destringid, 1, 0, KEY_WRITE); if (IS_ERR(dest_ref)) { ret = PTR_ERR(dest_ref); goto error3; } } /* find the key type */ ktype = key_type_lookup(type); if (IS_ERR(ktype)) { ret = PTR_ERR(ktype); goto error4; } /* do the search */ key_ref = keyring_search(keyring_ref, ktype, description); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); /* treat lack or presence of a negative key the same */ if (ret == -EAGAIN) ret = -ENOKEY; goto error5; } /* link the resulting key to the destination keyring if we can */ if (dest_ref) { ret = key_permission(key_ref, KEY_LINK); if (ret < 0) goto error6; ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref)); if (ret < 0) goto error6; } ret = key_ref_to_ptr(key_ref)->serial; error6: key_ref_put(key_ref); error5: key_type_put(ktype); error4: key_ref_put(dest_ref); error3: key_ref_put(keyring_ref); error2: kfree(description); error: return ret; } /* end keyctl_keyring_search() */ /*****************************************************************************/ /* * read a user key's payload * - the keyring must be readable or the key must be searchable from the * process's keyrings * - if there's a buffer, we place up to buflen bytes of data into it * - unless there's an error, we return the amount of data in the key, * irrespective of how much we may have copied * - implements keyctl(KEYCTL_READ) */ long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen) { struct key *key; key_ref_t key_ref; long ret; /* find the key first */ key_ref = lookup_user_key(NULL, keyid, 0, 0, 0); if (IS_ERR(key_ref)) { ret = -ENOKEY; goto error; } key = key_ref_to_ptr(key_ref); /* see if we can read it directly */ ret = key_permission(key_ref, KEY_READ); if (ret == 0) goto can_read_key; if (ret != -EACCES) goto error; /* we can't; see if it's searchable from this process's keyrings * - we automatically take account of the fact that it may be * dangling off an instantiation key */ if (!is_key_possessed(key_ref)) { ret = -EACCES; goto error2; } /* the key is probably readable - now try to read it */ can_read_key: ret = key_validate(key); if (ret == 0) { ret = -EOPNOTSUPP; if (key->type->read) { /* read the data with the semaphore held (since we * might sleep) */ down_read(&key->sem); ret = key->type->read(key, buffer, buflen); up_read(&key->sem); } } error2: key_put(key); error: return ret; } /* end keyctl_read_key() */ /*****************************************************************************/ /* * change the ownership of a key * - the keyring owned by the changer * - if the uid or gid is -1, then that parameter is not changed * - implements keyctl(KEYCTL_CHOWN) */ long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid) { struct key_user *newowner, *zapowner = NULL; struct key *key; key_ref_t key_ref; long ret; ret = 0; if (uid == (uid_t) -1 && gid == (gid_t) -1) goto error; key_ref = lookup_user_key(NULL, id, 1, 1, KEY_SETATTR); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); goto error; } key = key_ref_to_ptr(key_ref); /* make the changes with the locks held to prevent chown/chown races */ ret = -EACCES; down_write(&key->sem); if (!capable(CAP_SYS_ADMIN)) { /* only the sysadmin can chown a key to some other UID */ if (uid != (uid_t) -1 && key->uid != uid) goto error_put; /* only the sysadmin can set the key's GID to a group other * than one of those that the current process subscribes to */ if (gid != (gid_t) -1 && gid != key->gid && !in_group_p(gid)) goto error_put; } /* change the UID */ if (uid != (uid_t) -1 && uid != key->uid) { ret = -ENOMEM; newowner = key_user_lookup(uid); if (!newowner) goto error_put; /* transfer the quota burden to the new user */ if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { unsigned maxkeys = (uid == 0) ? key_quota_root_maxkeys : key_quota_maxkeys; unsigned maxbytes = (uid == 0) ? key_quota_root_maxbytes : key_quota_maxbytes; spin_lock(&newowner->lock); if (newowner->qnkeys + 1 >= maxkeys || newowner->qnbytes + key->quotalen >= maxbytes || newowner->qnbytes + key->quotalen < newowner->qnbytes) goto quota_overrun; newowner->qnkeys++; newowner->qnbytes += key->quotalen; spin_unlock(&newowner->lock); spin_lock(&key->user->lock); key->user->qnkeys--; key->user->qnbytes -= key->quotalen; spin_unlock(&key->user->lock); } atomic_dec(&key->user->nkeys); atomic_inc(&newowner->nkeys); if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { atomic_dec(&key->user->nikeys); atomic_inc(&newowner->nikeys); } zapowner = key->user; key->user = newowner; key->uid = uid; } /* change the GID */ if (gid != (gid_t) -1) key->gid = gid; ret = 0; error_put: up_write(&key->sem); key_put(key); if (zapowner) key_user_put(zapowner); error: return ret; quota_overrun: spin_unlock(&newowner->lock); zapowner = newowner; ret = -EDQUOT; goto error_put; } /* end keyctl_chown_key() */ /*****************************************************************************/ /* * change the permission mask on a key * - the keyring owned by the changer * - implements keyctl(KEYCTL_SETPERM) */ long keyctl_setperm_key(key_serial_t id, key_perm_t perm) { struct key *key; key_ref_t key_ref; long ret; ret = -EINVAL; if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL)) goto error; key_ref = lookup_user_key(NULL, id, 1, 1, KEY_SETATTR); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); goto error; } key = key_ref_to_ptr(key_ref); /* make the changes with the locks held to prevent chown/chmod races */ ret = -EACCES; down_write(&key->sem); /* if we're not the sysadmin, we can only change a key that we own */ if (capable(CAP_SYS_ADMIN) || key->uid == current->fsuid) { key->perm = perm; ret = 0; } up_write(&key->sem); key_put(key); error: return ret; } /* end keyctl_setperm_key() */ /*****************************************************************************/ /* * instantiate the key with the specified payload, and, if one is given, link * the key into the keyring */ long keyctl_instantiate_key(key_serial_t id, const void __user *_payload, size_t plen, key_serial_t ringid) { struct request_key_auth *rka; struct key *instkey; key_ref_t keyring_ref; void *payload; long ret; bool vm = false; ret = -EINVAL; if (plen > 1024 * 1024 - 1) goto error; /* the appropriate instantiation authorisation key must have been * assumed before calling this */ ret = -EPERM; instkey = current->request_key_auth; if (!instkey) goto error; rka = instkey->payload.data; if (rka->target_key->serial != id) goto error; /* pull the payload in if one was supplied */ payload = NULL; if (_payload) { ret = -ENOMEM; payload = kmalloc(plen, GFP_KERNEL); if (!payload) { if (plen <= PAGE_SIZE) goto error; vm = true; payload = vmalloc(plen); if (!payload) goto error; } ret = -EFAULT; if (copy_from_user(payload, _payload, plen) != 0) goto error2; } /* find the destination keyring amongst those belonging to the * requesting task */ keyring_ref = NULL; if (ringid) { keyring_ref = lookup_user_key(rka->context, ringid, 1, 0, KEY_WRITE); if (IS_ERR(keyring_ref)) { ret = PTR_ERR(keyring_ref); goto error2; } } /* instantiate the key and link it into a keyring */ ret = key_instantiate_and_link(rka->target_key, payload, plen, key_ref_to_ptr(keyring_ref), instkey); key_ref_put(keyring_ref); /* discard the assumed authority if it's just been disabled by * instantiation of the key */ if (ret == 0) { key_put(current->request_key_auth); current->request_key_auth = NULL; } error2: if (!vm) kfree(payload); else vfree(payload); error: return ret; } /* end keyctl_instantiate_key() */ /*****************************************************************************/ /* * negatively instantiate the key with the given timeout (in seconds), and, if * one is given, link the key into the keyring */ long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid) { struct request_key_auth *rka; struct key *instkey; key_ref_t keyring_ref; long ret; /* the appropriate instantiation authorisation key must have been * assumed before calling this */ ret = -EPERM; instkey = current->request_key_auth; if (!instkey) goto error; rka = instkey->payload.data; if (rka->target_key->serial != id) goto error; /* find the destination keyring if present (which must also be * writable) */ keyring_ref = NULL; if (ringid) { keyring_ref = lookup_user_key(NULL, ringid, 1, 0, KEY_WRITE); if (IS_ERR(keyring_ref)) { ret = PTR_ERR(keyring_ref); goto error; } } /* instantiate the key and link it into a keyring */ ret = key_negate_and_link(rka->target_key, timeout, key_ref_to_ptr(keyring_ref), instkey); key_ref_put(keyring_ref); /* discard the assumed authority if it's just been disabled by * instantiation of the key */ if (ret == 0) { key_put(current->request_key_auth); current->request_key_auth = NULL; } error: return ret; } /* end keyctl_negate_key() */ /*****************************************************************************/ /* * set the default keyring in which request_key() will cache keys * - return the old setting */ long keyctl_set_reqkey_keyring(int reqkey_defl) { int ret; switch (reqkey_defl) { case KEY_REQKEY_DEFL_THREAD_KEYRING: ret = install_thread_keyring(current); if (ret < 0) return ret; goto set; case KEY_REQKEY_DEFL_PROCESS_KEYRING: ret = install_process_keyring(current); if (ret < 0) return ret; case KEY_REQKEY_DEFL_DEFAULT: case KEY_REQKEY_DEFL_SESSION_KEYRING: case KEY_REQKEY_DEFL_USER_KEYRING: case KEY_REQKEY_DEFL_USER_SESSION_KEYRING: set: current->jit_keyring = reqkey_defl; case KEY_REQKEY_DEFL_NO_CHANGE: return current->jit_keyring; case KEY_REQKEY_DEFL_GROUP_KEYRING: default: return -EINVAL; } } /* end keyctl_set_reqkey_keyring() */ /*****************************************************************************/ /* * set or clear the timeout for a key */ long keyctl_set_timeout(key_serial_t id, unsigned timeout) { struct timespec now; struct key *key; key_ref_t key_ref; time_t expiry; long ret; key_ref = lookup_user_key(NULL, id, 1, 1, KEY_SETATTR); if (IS_ERR(key_ref)) { ret = PTR_ERR(key_ref); goto error; } key = key_ref_to_ptr(key_ref); /* make the changes with the locks held to prevent races */ down_write(&key->sem); expiry = 0; if (timeout > 0) { now = current_kernel_time(); expiry = now.tv_sec + timeout; } key->expiry = expiry; up_write(&key->sem); key_put(key); ret = 0; error: return ret; } /* end keyctl_set_timeout() */ /*****************************************************************************/ /* * assume the authority to instantiate the specified key */ long keyctl_assume_authority(key_serial_t id) { struct key *authkey; long ret; /* special key IDs aren't permitted */ ret = -EINVAL; if (id < 0) goto error; /* we divest ourselves of authority if given an ID of 0 */ if (id == 0) { key_put(current->request_key_auth); current->request_key_auth = NULL; ret = 0; goto error; } /* attempt to assume the authority temporarily granted to us whilst we * instantiate the specified key * - the authorisation key must be in the current task's keyrings * somewhere */ authkey = key_get_instantiation_authkey(id); if (IS_ERR(authkey)) { ret = PTR_ERR(authkey); goto error; } key_put(current->request_key_auth); current->request_key_auth = authkey; ret = authkey->serial; error: return ret; } /* end keyctl_assume_authority() */ /* * get the security label of a key * - the key must grant us view permission * - if there's a buffer, we place up to buflen bytes of data into it * - unless there's an error, we return the amount of information available, * irrespective of how much we may have copied (including the terminal NUL) * - implements keyctl(KEYCTL_GET_SECURITY) */ long keyctl_get_security(key_serial_t keyid, char __user *buffer, size_t buflen) { struct key *key, *instkey; key_ref_t key_ref; char *context; long ret; key_ref = lookup_user_key(NULL, keyid, 0, 1, KEY_VIEW); if (IS_ERR(key_ref)) { if (PTR_ERR(key_ref) != -EACCES) return PTR_ERR(key_ref); /* viewing a key under construction is also permitted if we * have the authorisation token handy */ instkey = key_get_instantiation_authkey(keyid); if (IS_ERR(instkey)) return PTR_ERR(key_ref); key_put(instkey); key_ref = lookup_user_key(NULL, keyid, 0, 1, 0); if (IS_ERR(key_ref)) return PTR_ERR(key_ref); } key = key_ref_to_ptr(key_ref); ret = security_key_getsecurity(key, &context); if (ret == 0) { /* if no information was returned, give userspace an empty * string */ ret = 1; if (buffer && buflen > 0 && copy_to_user(buffer, "", 1) != 0) ret = -EFAULT; } else if (ret > 0) { /* return as much data as there's room for */ if (buffer && buflen > 0) { if (buflen > ret) buflen = ret; if (copy_to_user(buffer, context, buflen) != 0) ret = -EFAULT; } kfree(context); } key_ref_put(key_ref); return ret; } /*****************************************************************************/ /* * the key control system call */ asmlinkage long sys_keyctl(int option, unsigned long arg2, unsigned long arg3, unsigned long arg4, unsigned long arg5) { switch (option) { case KEYCTL_GET_KEYRING_ID: return keyctl_get_keyring_ID((key_serial_t) arg2, (int) arg3); case KEYCTL_JOIN_SESSION_KEYRING: return keyctl_join_session_keyring((const char __user *) arg2); case KEYCTL_UPDATE: return keyctl_update_key((key_serial_t) arg2, (const void __user *) arg3, (size_t) arg4); case KEYCTL_REVOKE: return keyctl_revoke_key((key_serial_t) arg2); case KEYCTL_DESCRIBE: return keyctl_describe_key((key_serial_t) arg2, (char __user *) arg3, (unsigned) arg4); case KEYCTL_CLEAR: return keyctl_keyring_clear((key_serial_t) arg2); case KEYCTL_LINK: return keyctl_keyring_link((key_serial_t) arg2, (key_serial_t) arg3); case KEYCTL_UNLINK: return keyctl_keyring_unlink((key_serial_t) arg2, (key_serial_t) arg3); case KEYCTL_SEARCH: return keyctl_keyring_search((key_serial_t) arg2, (const char __user *) arg3, (const char __user *) arg4, (key_serial_t) arg5); case KEYCTL_READ: return keyctl_read_key((key_serial_t) arg2, (char __user *) arg3, (size_t) arg4); case KEYCTL_CHOWN: return keyctl_chown_key((key_serial_t) arg2, (uid_t) arg3, (gid_t) arg4); case KEYCTL_SETPERM: return keyctl_setperm_key((key_serial_t) arg2, (key_perm_t) arg3); case KEYCTL_INSTANTIATE: return keyctl_instantiate_key((key_serial_t) arg2, (const void __user *) arg3, (size_t) arg4, (key_serial_t) arg5); case KEYCTL_NEGATE: return keyctl_negate_key((key_serial_t) arg2, (unsigned) arg3, (key_serial_t) arg4); case KEYCTL_SET_REQKEY_KEYRING: return keyctl_set_reqkey_keyring(arg2); case KEYCTL_SET_TIMEOUT: return keyctl_set_timeout((key_serial_t) arg2, (unsigned) arg3); case KEYCTL_ASSUME_AUTHORITY: return keyctl_assume_authority((key_serial_t) arg2); case KEYCTL_GET_SECURITY: return keyctl_get_security((key_serial_t) arg2, (char *) arg3, (size_t) arg4); default: return -EOPNOTSUPP; } } /* end sys_keyctl() */