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Commit 06deeec7 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Steve French
Browse files

cifs: Fix smbencrypt() to stop pointing a scatterlist at the stack 



smbencrypt() points a scatterlist to the stack, which is breaks if
CONFIG_VMAP_STACK=y.

Fix it by switching to crypto_cipher_encrypt_one().  The new code
should be considerably faster as an added benefit.

This code is nearly identical to some code that Eric Biggers
suggested.

Cc: stable@vger.kernel.org # 4.9 only
Reported-by: default avatarEric Biggers <ebiggers3@gmail.com>
Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Acked-by: default avatarJeff Layton <jlayton@redhat.com>
Signed-off-by: default avatarSteve French <smfrench@gmail.com>
parent 96a988ff

fs/cifs/smbencrypt.c

+8 −32
Original line number Diff line number Diff line
@@ -23,7 +23,7 @@ 
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/



#include <crypto/skcipher.h>

#include <linux/crypto.h>

#include <linux/module.h>

#include <linux/slab.h>

#include <linux/fs.h>
@@ -69,46 +69,22 @@ str_to_key(unsigned char *str, unsigned char *key) 
static int

smbhash(unsigned char *out, const unsigned char *in, unsigned char *key)

{

	int rc;

	unsigned char key2[8];

	struct crypto_skcipher *tfm_des;

	struct scatterlist sgin, sgout;

	struct skcipher_request *req;

	struct crypto_cipher *tfm_des;



	str_to_key(key, key2);



	tfm_des = crypto_alloc_skcipher("ecb(des)", 0, CRYPTO_ALG_ASYNC);

	tfm_des = crypto_alloc_cipher("des", 0, 0);

	if (IS_ERR(tfm_des)) {

		rc = PTR_ERR(tfm_des);

		cifs_dbg(VFS, "could not allocate des crypto API\n");

		goto smbhash_err;

	}



	req = skcipher_request_alloc(tfm_des, GFP_KERNEL);

	if (!req) {

		rc = -ENOMEM;

		cifs_dbg(VFS, "could not allocate des crypto API\n");

		goto smbhash_free_skcipher;

		return PTR_ERR(tfm_des);

	}



	crypto_skcipher_setkey(tfm_des, key2, 8);



	sg_init_one(&sgin, in, 8);

	sg_init_one(&sgout, out, 8);

	crypto_cipher_setkey(tfm_des, key2, 8);

	crypto_cipher_encrypt_one(tfm_des, out, in);

	crypto_free_cipher(tfm_des);



	skcipher_request_set_callback(req, 0, NULL, NULL);

	skcipher_request_set_crypt(req, &sgin, &sgout, 8, NULL);



	rc = crypto_skcipher_encrypt(req);

	if (rc)

		cifs_dbg(VFS, "could not encrypt crypt key rc: %d\n", rc);



	skcipher_request_free(req);



smbhash_free_skcipher:

	crypto_free_skcipher(tfm_des);

smbhash_err:

	return rc;

	return 0;

}



static int