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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: Eric Biggers <ebiggers3@gmail.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
This commit is contained in:
Andy Lutomirski 2016-12-12 12:54:37 -08:00 committed by Steve French
parent 96a988ffeb
commit 06deeec77a
1 changed files with 8 additions and 32 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

40
fs/cifs/smbencrypt.c
View File

@ -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;
return PTR_ERR(tfm_des);
}
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;
}
crypto_cipher_setkey(tfm_des, key2, 8);
crypto_cipher_encrypt_one(tfm_des, out, in);
crypto_free_cipher(tfm_des);
crypto_skcipher_setkey(tfm_des, key2, 8);
sg_init_one(&sgin, in, 8);
sg_init_one(&sgout, out, 8);
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