From 468ed2b0c85ec4310b429e60358213b6d077289e Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 7 Oct 2005 15:07:38 +0100 Subject: [PATCH] [PATCH] Keys: Split key permissions checking into a .c file The attached patch splits key permissions checking out of key-ui.h and moves it into a .c file. It's quite large and called quite a lot, and it's about to get bigger with the addition of LSM support for keys... key_any_permission() is also discarded as it's no longer used. Signed-Off-By: David Howells Signed-off-by: Linus Torvalds --- include/linux/key-ui.h | 91 +++----------------------------------- security/keys/Makefile | 1 + security/keys/permission.c | 70 +++++++++++++++++++++++++++++ 3 files changed, 76 insertions(+), 86 deletions(-) create mode 100644 security/keys/permission.c diff --git a/include/linux/key-ui.h b/include/linux/key-ui.h index 918c34a8347e..7a2e332067c3 100644 --- a/include/linux/key-ui.h +++ b/include/linux/key-ui.h @@ -38,97 +38,16 @@ struct keyring_list { struct key *keys[0]; }; - /* * check to see whether permission is granted to use a key in the desired way */ +extern int key_task_permission(const key_ref_t key_ref, + struct task_struct *context, + key_perm_t perm); + static inline int key_permission(const key_ref_t key_ref, key_perm_t perm) { - struct key *key = key_ref_to_ptr(key_ref); - key_perm_t kperm; - - if (is_key_possessed(key_ref)) - kperm = key->perm >> 24; - else if (key->uid == current->fsuid) - kperm = key->perm >> 16; - else if (key->gid != -1 && - key->perm & KEY_GRP_ALL && - in_group_p(key->gid) - ) - kperm = key->perm >> 8; - else - kperm = key->perm; - - kperm = kperm & perm & KEY_ALL; - - return kperm == perm; -} - -/* - * check to see whether permission is granted to use a key in at least one of - * the desired ways - */ -static inline int key_any_permission(const key_ref_t key_ref, key_perm_t perm) -{ - struct key *key = key_ref_to_ptr(key_ref); - key_perm_t kperm; - - if (is_key_possessed(key_ref)) - kperm = key->perm >> 24; - else if (key->uid == current->fsuid) - kperm = key->perm >> 16; - else if (key->gid != -1 && - key->perm & KEY_GRP_ALL && - in_group_p(key->gid) - ) - kperm = key->perm >> 8; - else - kperm = key->perm; - - kperm = kperm & perm & KEY_ALL; - - return kperm != 0; -} - -static inline int key_task_groups_search(struct task_struct *tsk, gid_t gid) -{ - int ret; - - task_lock(tsk); - ret = groups_search(tsk->group_info, gid); - task_unlock(tsk); - return ret; -} - -static inline int key_task_permission(const key_ref_t key_ref, - struct task_struct *context, - key_perm_t perm) -{ - struct key *key = key_ref_to_ptr(key_ref); - key_perm_t kperm; - - if (is_key_possessed(key_ref)) { - kperm = key->perm >> 24; - } - else if (key->uid == context->fsuid) { - kperm = key->perm >> 16; - } - else if (key->gid != -1 && - key->perm & KEY_GRP_ALL && ( - key->gid == context->fsgid || - key_task_groups_search(context, key->gid) - ) - ) { - kperm = key->perm >> 8; - } - else { - kperm = key->perm; - } - - kperm = kperm & perm & KEY_ALL; - - return kperm == perm; - + return key_task_permission(key_ref, current, perm); } extern key_ref_t lookup_user_key(struct task_struct *context, diff --git a/security/keys/Makefile b/security/keys/Makefile index c392d750b208..5145adfb6a05 100644 --- a/security/keys/Makefile +++ b/security/keys/Makefile @@ -6,6 +6,7 @@ obj-y := \ key.o \ keyring.o \ keyctl.o \ + permission.o \ process_keys.o \ request_key.o \ request_key_auth.o \ diff --git a/security/keys/permission.c b/security/keys/permission.c new file mode 100644 index 000000000000..1c3651670ce9 --- /dev/null +++ b/security/keys/permission.c @@ -0,0 +1,70 @@ +/* permission.c: key permission determination + * + * 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. + */ + +#include +#include "internal.h" + +/*****************************************************************************/ +/* + * check to see whether permission is granted to use a key in the desired way, + * but permit the security modules to override + */ +int key_task_permission(const key_ref_t key_ref, + struct task_struct *context, + key_perm_t perm) +{ + struct key *key; + key_perm_t kperm; + int ret; + + key = key_ref_to_ptr(key_ref); + + /* use the top 8-bits of permissions for keys the caller possesses */ + if (is_key_possessed(key_ref)) { + kperm = key->perm >> 24; + goto use_these_perms; + } + + /* use the second 8-bits of permissions for keys the caller owns */ + if (key->uid == context->fsuid) { + kperm = key->perm >> 16; + goto use_these_perms; + } + + /* use the third 8-bits of permissions for keys the caller has a group + * membership in common with */ + if (key->gid != -1 && key->perm & KEY_GRP_ALL) { + if (key->gid == context->fsgid) { + kperm = key->perm >> 8; + goto use_these_perms; + } + + task_lock(context); + ret = groups_search(context->group_info, key->gid); + task_unlock(context); + + if (ret) { + kperm = key->perm >> 8; + goto use_these_perms; + } + } + + /* otherwise use the least-significant 8-bits */ + kperm = key->perm; + +use_these_perms: + kperm = kperm & perm & KEY_ALL; + + return kperm == perm; + +} /* end key_task_permission() */ + +EXPORT_SYMBOL(key_task_permission);