request_key_auth.rar__auth.requestToken

/* Request key authorisation token key definition. * * * * * 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.txt */ #include <linux/module.h> #include <linux/sched.h> #include <linux/err.h> #include <linux/seq_file.h> #include <linux/slab.h> #include <asm/uaccess.h> #include "internal.h" static int request_key_auth_instantiate(struct key *, const void *, size_t); 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), .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, }; /* * Instantiate a request-key authorisation key. */ static int request_key_auth_instantiate(struct key *key, const void *data, size_t datalen) { key->payload.data = (struct request_key_auth *) 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 = key->payload.data; seq_puts(m, "key:"); seq_puts(m, key->description); if (key_is_instantiated(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 = key->payload.data; size_t datalen; long ret; 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 = key->payload.data; kenter("{%d}", key->serial); if (rka->cred) { put_cred(rka->cred); rka->cred = NULL; } } /* * Destroy an instantiation authorisation token key. */ static void request_key_auth_destroy(struct key *key) { struct request_key_auth *rka = key->payload.data; kenter("{%d}", key->serial); if (rka->cred) { put_cred(rka->cred); rka->cred = NULL; } key_put(rka->target_key); key_put(rka->dest_keyring); kfree(rka->callout_info); kfree(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 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; kenter("%d,", target->serial); /* allocate a auth record */ rka = kmalloc(sizeof(*rka), GFP_KERNEL); if (!rka) { kleave(" = -ENOMEM"); return ERR_PTR(-ENOMEM); } rka->callout_info = kmalloc(callout_len, GFP_KERNEL); if (!rka->callout_info) { kleave(" = -ENOMEM"); kfree(rka); return ERR_PTR(-ENOMEM); } /* 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)) goto auth_key_revoked; irka = cred->request_key_auth->payload.data; 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); memcpy(rka->callout_info, callout_info, callout_len); rka->callout_len = callout_len; /* 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); if (IS_ERR(authkey)) { ret = PTR_ERR(authkey); goto error_alloc; } /* construct the auth key */ ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL); if (ret < 0) goto error_inst; kleave(" = {%d,%d}", authkey->serial, atomic_read(&authkey->usage)); return authkey; auth_key_revoked: up_read(&cred->request_key_auth->sem); kfree(rka->callout_info); kfree(rka); kleave("= -EKEYREVOKED"); return ERR_PTR(-EKEYREVOKED); error_inst: key_revoke(authkey); key_put(authkey); error_alloc: key_put(rka->target_key); key_put(rka->dest_keyring); kfree(rka->callout_info); kfree(rka); kleave("= %d", ret); return ERR_PTR(ret); } /* * See if an authorisation key is associated with a particular key. */ static int key_get_instantiation_authkey_match(const struct key *key, const void *_id) { struct request_key_auth *rka = key->payload.data; key_serial_t id = (key_serial_t)(unsigned long) _id; return rka->target_key->serial == id; } /* * 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) { const struct cred *cred = current_cred(); struct key *authkey; key_ref_t authkey_ref; authkey_ref = search_process_keyrings( &key_type_request_key_auth, (void *) (unsigned long) target_id, key_get_instantiation_authkey_match, cred); if (IS_ERR(authkey_ref)) { authkey = ERR_CAST(authkey_ref); 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; }