From 29db9190634067c5a328ee5fcc2890251b836b4b Mon Sep 17 00:00:00 2001 From: David Howells Date: Sun, 30 Oct 2005 15:02:44 -0800 Subject: [PATCH] Keys: Add LSM hooks for key management [try #3] The attached patch adds LSM hooks for key management facilities. The notable changes are: (1) The key struct now supports a security pointer for the use of security modules. This will permit key labelling and restrictions on which programs may access a key. (2) Security modules get a chance to note (or abort) the allocation of a key. (3) The key permission checking can now be enhanced by the security modules; the permissions check consults LSM if all other checks bear out. (4) The key permissions checking functions now return an error code rather than a boolean value. (5) An extra permission has been added to govern the modification of attributes (UID, GID, permissions). Note that there isn't an LSM hook specifically for each keyctl() operation, but rather the permissions hook allows control of individual operations based on the permission request bits. Key management access control through LSM is enabled by automatically if both CONFIG_KEYS and CONFIG_SECURITY are enabled. This should be applied on top of the patch ensubjected: [PATCH] Keys: Possessor permissions should be additive Signed-Off-By: David Howells Signed-off-by: Chris Wright Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- security/keys/key.c | 56 ++++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 40 insertions(+), 16 deletions(-) (limited to 'security/keys/key.c') diff --git a/security/keys/key.c b/security/keys/key.c index 2182be9e930..ccde17aff61 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -1,6 +1,6 @@ /* key.c: basic authentication token and access key management * - * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved. + * 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 @@ -13,6 +13,7 @@ #include #include #include +#include #include #include #include "internal.h" @@ -253,6 +254,7 @@ struct key *key_alloc(struct key_type *type, const char *desc, struct key_user *user = NULL; struct key *key; size_t desclen, quotalen; + int ret; key = ERR_PTR(-EINVAL); if (!desc || !*desc) @@ -305,6 +307,7 @@ struct key *key_alloc(struct key_type *type, const char *desc, key->flags = 0; key->expiry = 0; key->payload.data = NULL; + key->security = NULL; if (!not_in_quota) key->flags |= 1 << KEY_FLAG_IN_QUOTA; @@ -315,16 +318,34 @@ struct key *key_alloc(struct key_type *type, const char *desc, key->magic = KEY_DEBUG_MAGIC; #endif + /* let the security module know about the key */ + ret = security_key_alloc(key); + if (ret < 0) + goto security_error; + /* publish the key by giving it a serial number */ atomic_inc(&user->nkeys); key_alloc_serial(key); - error: +error: return key; - no_memory_3: +security_error: + kfree(key->description); + kmem_cache_free(key_jar, key); + if (!not_in_quota) { + spin_lock(&user->lock); + user->qnkeys--; + user->qnbytes -= quotalen; + spin_unlock(&user->lock); + } + key_user_put(user); + key = ERR_PTR(ret); + goto error; + +no_memory_3: kmem_cache_free(key_jar, key); - no_memory_2: +no_memory_2: if (!not_in_quota) { spin_lock(&user->lock); user->qnkeys--; @@ -332,11 +353,11 @@ struct key *key_alloc(struct key_type *type, const char *desc, spin_unlock(&user->lock); } key_user_put(user); - no_memory_1: +no_memory_1: key = ERR_PTR(-ENOMEM); goto error; - no_quota: +no_quota: spin_unlock(&user->lock); key_user_put(user); key = ERR_PTR(-EDQUOT); @@ -556,6 +577,8 @@ static void key_cleanup(void *data) key_check(key); + security_key_free(key); + /* deal with the user's key tracking and quota */ if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { spin_lock(&key->user->lock); @@ -700,8 +723,8 @@ static inline key_ref_t __key_update(key_ref_t key_ref, int ret; /* need write permission on the key to update it */ - ret = -EACCES; - if (!key_permission(key_ref, KEY_WRITE)) + ret = key_permission(key_ref, KEY_WRITE); + if (ret < 0) goto error; ret = -EEXIST; @@ -711,7 +734,6 @@ static inline key_ref_t __key_update(key_ref_t key_ref, down_write(&key->sem); ret = key->type->update(key, payload, plen); - if (ret == 0) /* updating a negative key instantiates it */ clear_bit(KEY_FLAG_NEGATIVE, &key->flags); @@ -768,9 +790,11 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, /* if we're going to allocate a new key, we're going to have * to modify the keyring */ - key_ref = ERR_PTR(-EACCES); - if (!key_permission(keyring_ref, KEY_WRITE)) + ret = key_permission(keyring_ref, KEY_WRITE); + if (ret < 0) { + key_ref = ERR_PTR(ret); goto error_3; + } /* search for an existing key of the same type and description in the * destination keyring @@ -780,8 +804,8 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref, goto found_matching_key; /* decide on the permissions we want */ - perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK; - perm |= KEY_USR_VIEW | KEY_USR_SEARCH | KEY_USR_LINK; + perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR; + perm |= KEY_USR_VIEW | KEY_USR_SEARCH | KEY_USR_LINK | KEY_USR_SETATTR; if (ktype->read) perm |= KEY_POS_READ | KEY_USR_READ; @@ -840,16 +864,16 @@ int key_update(key_ref_t key_ref, const void *payload, size_t plen) key_check(key); /* the key must be writable */ - ret = -EACCES; - if (!key_permission(key_ref, KEY_WRITE)) + ret = key_permission(key_ref, KEY_WRITE); + if (ret < 0) goto error; /* attempt to update it if supported */ ret = -EOPNOTSUPP; if (key->type->update) { down_write(&key->sem); - ret = key->type->update(key, payload, plen); + ret = key->type->update(key, payload, plen); if (ret == 0) /* updating a negative key instantiates it */ clear_bit(KEY_FLAG_NEGATIVE, &key->flags); -- cgit v1.2.3