The CIFS code uses the sync skcipher API to invoke the ecb(arc4) skcipher,
of which only a single generic C code implementation exists. This means
that going through all the trouble of using scatterlists etc buys us
very little, and we're better off just invoking the arc4 library directly.
Cc: linux-cifs@xxxxxxxxxxxxxxx
Cc: Steve French <sfrench@xxxxxxxxx>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
fs/cifs/Kconfig | 2 +-
fs/cifs/cifsencrypt.c | 50 +++++---------------
2 files changed, 13 insertions(+), 39 deletions(-)
diff --git a/fs/cifs/Kconfig b/fs/cifs/Kconfig
index aae2b8b2adf5..523e9ea78a28 100644
--- a/fs/cifs/Kconfig
+++ b/fs/cifs/Kconfig
@@ -10,7 +10,7 @@ config CIFS
select CRYPTO_SHA512
select CRYPTO_CMAC
select CRYPTO_HMAC
- select CRYPTO_ARC4
+ select CRYPTO_LIB_ARC4
select CRYPTO_AEAD2
select CRYPTO_CCM
select CRYPTO_ECB
diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index d2a05e46d6f5..d0ab5a38e5d2 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -33,7 +33,7 @@
#include <linux/ctype.h>
#include <linux/random.h>
#include <linux/highmem.h>
-#include <crypto/skcipher.h>
+#include <crypto/arc4.h>
#include <crypto/aead.h>
int __cifs_calc_signature(struct smb_rqst *rqst,
@@ -772,11 +772,9 @@ setup_ntlmv2_rsp(struct cifs_ses *ses, const struct nls_table *nls_cp)
int
calc_seckey(struct cifs_ses *ses)
{
- int rc;
- struct crypto_skcipher *tfm_arc4;
- struct scatterlist sgin, sgout;
- struct skcipher_request *req;
+ struct crypto_arc4_ctx *ctx_arc4;
unsigned char *sec_key;
+ int rc = 0;
sec_key = kmalloc(CIFS_SESS_KEY_SIZE, GFP_KERNEL);
if (sec_key == NULL)
@@ -784,49 +782,25 @@ calc_seckey(struct cifs_ses *ses)
get_random_bytes(sec_key, CIFS_SESS_KEY_SIZE);
- tfm_arc4 = crypto_alloc_skcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
- if (IS_ERR(tfm_arc4)) {
- rc = PTR_ERR(tfm_arc4);
- cifs_dbg(VFS, "could not allocate crypto API arc4\n");
- goto out;
- }
-
- rc = crypto_skcipher_setkey(tfm_arc4, ses->auth_key.response,
- CIFS_SESS_KEY_SIZE);
- if (rc) {
- cifs_dbg(VFS, "%s: Could not set response as a key\n",
- __func__);
- goto out_free_cipher;
- }
-
- req = skcipher_request_alloc(tfm_arc4, GFP_KERNEL);
- if (!req) {
+ ctx_arc4 = kmalloc(sizeof(*ctx_arc4), GFP_KERNEL);
+ if (!ctx_arc4) {
rc = -ENOMEM;
- cifs_dbg(VFS, "could not allocate crypto API arc4 request\n");
- goto out_free_cipher;
+ cifs_dbg(VFS, "could not allocate arc4 context\n");
+ goto out;
}
- sg_init_one(&sgin, sec_key, CIFS_SESS_KEY_SIZE);
- sg_init_one(&sgout, ses->ntlmssp->ciphertext, CIFS_CPHTXT_SIZE);
-
- skcipher_request_set_callback(req, 0, NULL, NULL);
- skcipher_request_set_crypt(req, &sgin, &sgout, CIFS_CPHTXT_SIZE, NULL);
-
- rc = crypto_skcipher_encrypt(req);
- skcipher_request_free(req);
- if (rc) {
- cifs_dbg(VFS, "could not encrypt session key rc: %d\n", rc);
- goto out_free_cipher;
- }
+ crypto_arc4_set_key(ctx_arc4, ses->auth_key.response,
+ CIFS_SESS_KEY_SIZE);
+ crypto_arc4_crypt(ctx_arc4, ses->ntlmssp->ciphertext, sec_key,
+ CIFS_CPHTXT_SIZE);
/* make secondary_key/nonce as session key */
memcpy(ses->auth_key.response, sec_key, CIFS_SESS_KEY_SIZE);
/* and make len as that of session key only */
ses->auth_key.len = CIFS_SESS_KEY_SIZE;
-out_free_cipher:
- crypto_free_skcipher(tfm_arc4);
out:
+ kfree(ctx_arc4);
kfree(sec_key);
return rc;
}
--
2.20.1
