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Commit b9fffa38 authored by David Howells's avatar David Howells Committed by James Morris
Browse files

KEYS: Add a key type op to permit the key description to be vetted 



Add a key type operation to permit the key type to vet the description of a new
key that key_alloc() is about to allocate.  The operation may reject the
description if it wishes with an error of its choosing.  If it does this, the
key will not be allocated.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Reviewed-by: default avatarMimi Zohar <zohar@us.ibm.com>
Signed-off-by: default avatarJames Morris <jmorris@namei.org>
parent 633e804e

Documentation/keys.txt

+7 −0
Original line number Diff line number Diff line
@@ -1062,6 +1062,13 @@ The structure has a number of fields, some of which are mandatory: 
     viable.





 (*) int (*vet_description)(const char *description);



     This optional method is called to vet a key description.  If the key type

     doesn't approve of the key description, it may return an error, otherwise

     it should return 0.





 (*) int (*instantiate)(struct key *key, const void *data, size_t datalen);



     This method is called to attach a payload to a key during construction.

include/linux/key-type.h

+3 −0
Original line number Diff line number Diff line
@@ -41,6 +41,9 @@ struct key_type { 
	 */

	size_t def_datalen;



	/* vet a description */

	int (*vet_description)(const char *description);



	/* instantiate a key of this type

	 * - this method should call key_payload_reserve() to determine if the

	 *   user's quota will hold the payload

net/rxrpc/ar-key.c

+19 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include <keys/user-type.h>

#include "ar-internal.h"



static int rxrpc_vet_description_s(const char *);

static int rxrpc_instantiate(struct key *, const void *, size_t);

static int rxrpc_instantiate_s(struct key *, const void *, size_t);

static void rxrpc_destroy(struct key *);
@@ -52,12 +53,30 @@ EXPORT_SYMBOL(key_type_rxrpc); 
 */

struct key_type key_type_rxrpc_s = {

	.name		= "rxrpc_s",

	.vet_description = rxrpc_vet_description_s,

	.instantiate	= rxrpc_instantiate_s,

	.match		= user_match,

	.destroy	= rxrpc_destroy_s,

	.describe	= rxrpc_describe,

};



/*

 * Vet the description for an RxRPC server key

 */

static int rxrpc_vet_description_s(const char *desc)

{

	unsigned long num;

	char *p;



	num = simple_strtoul(desc, &p, 10);

	if (*p != ':' || num > 65535)

		return -EINVAL;

	num = simple_strtoul(p + 1, &p, 10);

	if (*p || num < 1 || num > 255)

		return -EINVAL;

	return 0;

}



/*

 * parse an RxKAD type XDR format token

 * - the caller guarantees we have at least 4 words

security/keys/key.c

+8 −0
Original line number Diff line number Diff line
@@ -249,6 +249,14 @@ struct key *key_alloc(struct key_type *type, const char *desc, 
	if (!desc || !*desc)

		goto error;



	if (type->vet_description) {

		ret = type->vet_description(desc);

		if (ret < 0) {

			key = ERR_PTR(ret);

			goto error;

		}

	}



	desclen = strlen(desc) + 1;

	quotalen = desclen + type->def_datalen;