Commit 468ed2b0 authored by David Howells's avatar David Howells Committed by Linus Torvalds
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[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: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent f1a9badc

include/linux/key-ui.h

+5 −86
Original line number Diff line number Diff line
@@ -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

 */

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,

extern 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;

			       key_perm_t perm);



static inline int key_permission(const key_ref_t key_ref, key_perm_t perm)

{

	return key_task_permission(key_ref, current, perm);

}



extern key_ref_t lookup_user_key(struct task_struct *context,

security/keys/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ obj-y := \ 
	key.o \

	keyring.o \

	keyctl.o \

	permission.o \

	process_keys.o \

	request_key.o \

	request_key_auth.o \

security/keys/permission.c

0 → 100644
+70 −0
Original line number Diff line number Diff line 
/* 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 <linux/module.h>

#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);

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