From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- security/keys/request_key.c | 359 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 359 insertions(+) create mode 100644 security/keys/request_key.c (limited to 'security/keys/request_key.c') diff --git a/security/keys/request_key.c b/security/keys/request_key.c new file mode 100644 index 000000000000..9705b1aeba5d --- /dev/null +++ b/security/keys/request_key.c @@ -0,0 +1,359 @@ +/* request_key.c: request a key from userspace + * + * Copyright (C) 2004 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 +#include +#include +#include +#include "internal.h" + +struct key_construction { + struct list_head link; /* link in construction queue */ + struct key *key; /* key being constructed */ +}; + +/* when waiting for someone else's keys, you get added to this */ +DECLARE_WAIT_QUEUE_HEAD(request_key_conswq); + +/*****************************************************************************/ +/* + * request userspace finish the construction of a key + * - execute "/sbin/request-key " + * - if callout_info is an empty string, it'll be rendered as a "-" instead + */ +static int call_request_key(struct key *key, + const char *op, + const char *callout_info) +{ + struct task_struct *tsk = current; + unsigned long flags; + key_serial_t prkey, sskey; + char *argv[10], *envp[3], uid_str[12], gid_str[12]; + char key_str[12], keyring_str[3][12]; + int i; + + /* record the UID and GID */ + sprintf(uid_str, "%d", current->fsuid); + sprintf(gid_str, "%d", current->fsgid); + + /* we say which key is under construction */ + sprintf(key_str, "%d", key->serial); + + /* we specify the process's default keyrings */ + sprintf(keyring_str[0], "%d", + tsk->thread_keyring ? tsk->thread_keyring->serial : 0); + + prkey = 0; + if (tsk->signal->process_keyring) + prkey = tsk->signal->process_keyring->serial; + + sskey = 0; + spin_lock_irqsave(&tsk->sighand->siglock, flags); + if (tsk->signal->session_keyring) + sskey = tsk->signal->session_keyring->serial; + spin_unlock_irqrestore(&tsk->sighand->siglock, flags); + + + if (!sskey) + sskey = tsk->user->session_keyring->serial; + + sprintf(keyring_str[1], "%d", prkey); + sprintf(keyring_str[2], "%d", sskey); + + /* set up a minimal environment */ + i = 0; + envp[i++] = "HOME=/"; + envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; + envp[i] = NULL; + + /* set up the argument list */ + i = 0; + argv[i++] = "/sbin/request-key"; + argv[i++] = (char *) op; + argv[i++] = key_str; + argv[i++] = uid_str; + argv[i++] = gid_str; + argv[i++] = keyring_str[0]; + argv[i++] = keyring_str[1]; + argv[i++] = keyring_str[2]; + argv[i++] = callout_info[0] ? (char *) callout_info : "-"; + argv[i] = NULL; + + /* do it */ + return call_usermodehelper(argv[0], argv, envp, 1); + +} /* end call_request_key() */ + +/*****************************************************************************/ +/* + * call out to userspace for the key + * - called with the construction sem held, but the sem is dropped here + * - we ignore program failure and go on key status instead + */ +static struct key *__request_key_construction(struct key_type *type, + const char *description, + const char *callout_info) +{ + struct key_construction cons; + struct timespec now; + struct key *key; + int ret, negative; + + /* create a key and add it to the queue */ + key = key_alloc(type, description, + current->fsuid, current->fsgid, KEY_USR_ALL, 0); + if (IS_ERR(key)) + goto alloc_failed; + + write_lock(&key->lock); + key->flags |= KEY_FLAG_USER_CONSTRUCT; + write_unlock(&key->lock); + + cons.key = key; + list_add_tail(&cons.link, &key->user->consq); + + /* we drop the construction sem here on behalf of the caller */ + up_write(&key_construction_sem); + + /* make the call */ + ret = call_request_key(key, "create", callout_info); + if (ret < 0) + goto request_failed; + + /* if the key wasn't instantiated, then we want to give an error */ + ret = -ENOKEY; + if (!(key->flags & KEY_FLAG_INSTANTIATED)) + goto request_failed; + + down_write(&key_construction_sem); + list_del(&cons.link); + up_write(&key_construction_sem); + + /* also give an error if the key was negatively instantiated */ + check_not_negative: + if (key->flags & KEY_FLAG_NEGATIVE) { + key_put(key); + key = ERR_PTR(-ENOKEY); + } + + out: + return key; + + request_failed: + /* it wasn't instantiated + * - remove from construction queue + * - mark the key as dead + */ + negative = 0; + down_write(&key_construction_sem); + + list_del(&cons.link); + + write_lock(&key->lock); + key->flags &= ~KEY_FLAG_USER_CONSTRUCT; + + /* check it didn't get instantiated between the check and the down */ + if (!(key->flags & KEY_FLAG_INSTANTIATED)) { + key->flags |= KEY_FLAG_INSTANTIATED | KEY_FLAG_NEGATIVE; + negative = 1; + } + + write_unlock(&key->lock); + up_write(&key_construction_sem); + + if (!negative) + goto check_not_negative; /* surprisingly, the key got + * instantiated */ + + /* set the timeout and store in the session keyring if we can */ + now = current_kernel_time(); + key->expiry = now.tv_sec + key_negative_timeout; + + if (current->signal->session_keyring) { + unsigned long flags; + struct key *keyring; + + spin_lock_irqsave(¤t->sighand->siglock, flags); + keyring = current->signal->session_keyring; + atomic_inc(&keyring->usage); + spin_unlock_irqrestore(¤t->sighand->siglock, flags); + + key_link(keyring, key); + key_put(keyring); + } + + key_put(key); + + /* notify anyone who was waiting */ + wake_up_all(&request_key_conswq); + + key = ERR_PTR(ret); + goto out; + + alloc_failed: + up_write(&key_construction_sem); + goto out; + +} /* end __request_key_construction() */ + +/*****************************************************************************/ +/* + * call out to userspace to request the key + * - we check the construction queue first to see if an appropriate key is + * already being constructed by userspace + */ +static struct key *request_key_construction(struct key_type *type, + const char *description, + struct key_user *user, + const char *callout_info) +{ + struct key_construction *pcons; + struct key *key, *ckey; + + DECLARE_WAITQUEUE(myself, current); + + /* see if there's such a key under construction already */ + down_write(&key_construction_sem); + + list_for_each_entry(pcons, &user->consq, link) { + ckey = pcons->key; + + if (ckey->type != type) + continue; + + if (type->match(ckey, description)) + goto found_key_under_construction; + } + + /* see about getting userspace to construct the key */ + key = __request_key_construction(type, description, callout_info); + error: + return key; + + /* someone else has the same key under construction + * - we want to keep an eye on their key + */ + found_key_under_construction: + atomic_inc(&ckey->usage); + up_write(&key_construction_sem); + + /* wait for the key to be completed one way or another */ + add_wait_queue(&request_key_conswq, &myself); + + for (;;) { + set_current_state(TASK_UNINTERRUPTIBLE); + if (!(ckey->flags & KEY_FLAG_USER_CONSTRUCT)) + break; + schedule(); + } + + set_current_state(TASK_RUNNING); + remove_wait_queue(&request_key_conswq, &myself); + + /* we'll need to search this process's keyrings to see if the key is + * now there since we can't automatically assume it's also available + * there */ + key_put(ckey); + ckey = NULL; + + key = NULL; /* request a retry */ + goto error; + +} /* end request_key_construction() */ + +/*****************************************************************************/ +/* + * request a key + * - search the process's keyrings + * - check the list of keys being created or updated + * - call out to userspace for a key if requested (supplementary info can be + * passed) + */ +struct key *request_key(struct key_type *type, + const char *description, + const char *callout_info) +{ + struct key_user *user; + struct key *key; + + /* search all the process keyrings for a key */ + key = search_process_keyrings_aux(type, description, type->match); + + if (PTR_ERR(key) == -EAGAIN) { + /* the search failed, but the keyrings were searchable, so we + * should consult userspace if we can */ + key = ERR_PTR(-ENOKEY); + if (!callout_info) + goto error; + + /* - get hold of the user's construction queue */ + user = key_user_lookup(current->fsuid); + if (!user) { + key = ERR_PTR(-ENOMEM); + goto error; + } + + for (;;) { + /* ask userspace (returns NULL if it waited on a key + * being constructed) */ + key = request_key_construction(type, description, + user, callout_info); + if (key) + break; + + /* someone else made the key we want, so we need to + * search again as it might now be available to us */ + key = search_process_keyrings_aux(type, description, + type->match); + if (PTR_ERR(key) != -EAGAIN) + break; + } + + key_user_put(user); + } + + error: + return key; + +} /* end request_key() */ + +EXPORT_SYMBOL(request_key); + +/*****************************************************************************/ +/* + * validate a key + */ +int key_validate(struct key *key) +{ + struct timespec now; + int ret = 0; + + if (key) { + /* check it's still accessible */ + ret = -EKEYREVOKED; + if (key->flags & (KEY_FLAG_REVOKED | KEY_FLAG_DEAD)) + goto error; + + /* check it hasn't expired */ + ret = 0; + if (key->expiry) { + now = current_kernel_time(); + if (now.tv_sec >= key->expiry) + ret = -EKEYEXPIRED; + } + } + + error: + return ret; + +} /* end key_validate() */ + +EXPORT_SYMBOL(key_validate); -- cgit v1.2.1