| /* Request key authorisation token key definition. |
| * |
| * Copyright (C) 2005 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. |
| * |
| * See Documentation/security/keys/request-key.rst |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/sched.h> |
| #include <linux/err.h> |
| #include <linux/seq_file.h> |
| #include <linux/slab.h> |
| #include <linux/uaccess.h> |
| #include "internal.h" |
| #include <keys/request_key_auth-type.h> |
| |
| static int request_key_auth_preparse(struct key_preparsed_payload *); |
| static void request_key_auth_free_preparse(struct key_preparsed_payload *); |
| static int request_key_auth_instantiate(struct key *, |
| struct key_preparsed_payload *); |
| static void request_key_auth_describe(const struct key *, struct seq_file *); |
| static void request_key_auth_revoke(struct key *); |
| static void request_key_auth_destroy(struct key *); |
| static long request_key_auth_read(const struct key *, char __user *, size_t); |
| |
| /* |
| * The request-key authorisation key type definition. |
| */ |
| struct key_type key_type_request_key_auth = { |
| .name = ".request_key_auth", |
| .def_datalen = sizeof(struct request_key_auth), |
| .preparse = request_key_auth_preparse, |
| .free_preparse = request_key_auth_free_preparse, |
| .instantiate = request_key_auth_instantiate, |
| .describe = request_key_auth_describe, |
| .revoke = request_key_auth_revoke, |
| .destroy = request_key_auth_destroy, |
| .read = request_key_auth_read, |
| }; |
| |
| static int request_key_auth_preparse(struct key_preparsed_payload *prep) |
| { |
| return 0; |
| } |
| |
| static void request_key_auth_free_preparse(struct key_preparsed_payload *prep) |
| { |
| } |
| |
| /* |
| * Instantiate a request-key authorisation key. |
| */ |
| static int request_key_auth_instantiate(struct key *key, |
| struct key_preparsed_payload *prep) |
| { |
| key->payload.data[0] = (struct request_key_auth *)prep->data; |
| return 0; |
| } |
| |
| /* |
| * Describe an authorisation token. |
| */ |
| static void request_key_auth_describe(const struct key *key, |
| struct seq_file *m) |
| { |
| struct request_key_auth *rka = get_request_key_auth(key); |
| |
| if (!rka) |
| return; |
| |
| seq_puts(m, "key:"); |
| seq_puts(m, key->description); |
| if (key_is_positive(key)) |
| seq_printf(m, " pid:%d ci:%zu", rka->pid, rka->callout_len); |
| } |
| |
| /* |
| * Read the callout_info data (retrieves the callout information). |
| * - the key's semaphore is read-locked |
| */ |
| static long request_key_auth_read(const struct key *key, |
| char __user *buffer, size_t buflen) |
| { |
| struct request_key_auth *rka = get_request_key_auth(key); |
| size_t datalen; |
| long ret; |
| |
| if (!rka) |
| return -EKEYREVOKED; |
| |
| datalen = rka->callout_len; |
| ret = datalen; |
| |
| /* we can return the data as is */ |
| if (buffer && buflen > 0) { |
| if (buflen > datalen) |
| buflen = datalen; |
| |
| if (copy_to_user(buffer, rka->callout_info, buflen) != 0) |
| ret = -EFAULT; |
| } |
| |
| return ret; |
| } |
| |
| /* |
| * Handle revocation of an authorisation token key. |
| * |
| * Called with the key sem write-locked. |
| */ |
| static void request_key_auth_revoke(struct key *key) |
| { |
| struct request_key_auth *rka = get_request_key_auth(key); |
| |
| kenter("{%d}", key->serial); |
| |
| if (rka->cred) { |
| put_cred(rka->cred); |
| rka->cred = NULL; |
| } |
| } |
| |
| static void free_request_key_auth(struct request_key_auth *rka) |
| { |
| if (!rka) |
| return; |
| key_put(rka->target_key); |
| key_put(rka->dest_keyring); |
| if (rka->cred) |
| put_cred(rka->cred); |
| kfree(rka->callout_info); |
| kfree(rka); |
| } |
| |
| /* |
| * Destroy an instantiation authorisation token key. |
| */ |
| static void request_key_auth_destroy(struct key *key) |
| { |
| struct request_key_auth *rka = get_request_key_auth(key); |
| |
| kenter("{%d}", key->serial); |
| |
| free_request_key_auth(rka); |
| } |
| |
| /* |
| * Create an authorisation token for /sbin/request-key or whoever to gain |
| * access to the caller's security data. |
| */ |
| struct key *request_key_auth_new(struct key *target, const char *op, |
| const void *callout_info, size_t callout_len, |
| struct key *dest_keyring) |
| { |
| struct request_key_auth *rka, *irka; |
| const struct cred *cred = current->cred; |
| struct key *authkey = NULL; |
| char desc[20]; |
| int ret = -ENOMEM; |
| |
| kenter("%d,", target->serial); |
| |
| /* allocate a auth record */ |
| rka = kzalloc(sizeof(*rka), GFP_KERNEL); |
| if (!rka) |
| goto error; |
| rka->callout_info = kmemdup(callout_info, callout_len, GFP_KERNEL); |
| if (!rka->callout_info) |
| goto error_free_rka; |
| rka->callout_len = callout_len; |
| strlcpy(rka->op, op, sizeof(rka->op)); |
| |
| /* see if the calling process is already servicing the key request of |
| * another process */ |
| if (cred->request_key_auth) { |
| /* it is - use that instantiation context here too */ |
| down_read(&cred->request_key_auth->sem); |
| |
| /* if the auth key has been revoked, then the key we're |
| * servicing is already instantiated */ |
| if (test_bit(KEY_FLAG_REVOKED, |
| &cred->request_key_auth->flags)) { |
| up_read(&cred->request_key_auth->sem); |
| ret = -EKEYREVOKED; |
| goto error_free_rka; |
| } |
| |
| irka = cred->request_key_auth->payload.data[0]; |
| rka->cred = get_cred(irka->cred); |
| rka->pid = irka->pid; |
| |
| up_read(&cred->request_key_auth->sem); |
| } |
| else { |
| /* it isn't - use this process as the context */ |
| rka->cred = get_cred(cred); |
| rka->pid = current->pid; |
| } |
| |
| rka->target_key = key_get(target); |
| rka->dest_keyring = key_get(dest_keyring); |
| |
| /* allocate the auth key */ |
| sprintf(desc, "%x", target->serial); |
| |
| authkey = key_alloc(&key_type_request_key_auth, desc, |
| cred->fsuid, cred->fsgid, cred, |
| KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH | |
| KEY_USR_VIEW, KEY_ALLOC_NOT_IN_QUOTA, NULL); |
| if (IS_ERR(authkey)) { |
| ret = PTR_ERR(authkey); |
| goto error_free_rka; |
| } |
| |
| /* construct the auth key */ |
| ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL); |
| if (ret < 0) |
| goto error_put_authkey; |
| |
| kleave(" = {%d,%d}", authkey->serial, refcount_read(&authkey->usage)); |
| return authkey; |
| |
| error_put_authkey: |
| key_put(authkey); |
| error_free_rka: |
| free_request_key_auth(rka); |
| error: |
| kleave("= %d", ret); |
| return ERR_PTR(ret); |
| } |
| |
| /* |
| * Search the current process's keyrings for the authorisation key for |
| * instantiation of a key. |
| */ |
| struct key *key_get_instantiation_authkey(key_serial_t target_id) |
| { |
| char description[16]; |
| struct keyring_search_context ctx = { |
| .index_key.type = &key_type_request_key_auth, |
| .index_key.description = description, |
| .cred = current_cred(), |
| .match_data.cmp = key_default_cmp, |
| .match_data.raw_data = description, |
| .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, |
| .flags = KEYRING_SEARCH_DO_STATE_CHECK, |
| }; |
| struct key *authkey; |
| key_ref_t authkey_ref; |
| |
| ctx.index_key.desc_len = sprintf(description, "%x", target_id); |
| |
| authkey_ref = search_process_keyrings(&ctx); |
| |
| if (IS_ERR(authkey_ref)) { |
| authkey = ERR_CAST(authkey_ref); |
| if (authkey == ERR_PTR(-EAGAIN)) |
| authkey = ERR_PTR(-ENOKEY); |
| goto error; |
| } |
| |
| authkey = key_ref_to_ptr(authkey_ref); |
| if (test_bit(KEY_FLAG_REVOKED, &authkey->flags)) { |
| key_put(authkey); |
| authkey = ERR_PTR(-EKEYREVOKED); |
| } |
| |
| error: |
| return authkey; |
| } |