* [PATCH v3 7/7] fs: cifs: switch to RC4 library interface
[not found] <20190611134750.2974-1-ard.biesheuvel@linaro.org>
@ 2019-06-11 13:47 ` Ard Biesheuvel
2019-06-11 18:17 ` Eric Biggers
0 siblings, 1 reply; 2+ messages in thread
From: Ard Biesheuvel @ 2019-06-11 13:47 UTC (permalink / raw)
To: linux-crypto
Cc: Ard Biesheuvel, Herbert Xu, David S. Miller, Eric Biggers,
Johannes Berg, linux-cifs, Steve French
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@vger.kernel.org
Cc: Steve French <sfrench@samba.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
fs/cifs/Kconfig | 2 +-
fs/cifs/cifsencrypt.c | 53 ++++++--------------
2 files changed, 16 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..3b7b5e83493d 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -33,7 +33,8 @@
#include <linux/ctype.h>
#include <linux/random.h>
#include <linux/highmem.h>
-#include <crypto/skcipher.h>
+#include <linux/fips.h>
+#include <crypto/arc4.h>
#include <crypto/aead.h>
int __cifs_calc_signature(struct smb_rqst *rqst,
@@ -772,11 +773,12 @@ 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 arc4_ctx *ctx_arc4;
unsigned char *sec_key;
+ int rc = 0;
+
+ if (fips_enabled)
+ return -ENODEV;
sec_key = kmalloc(CIFS_SESS_KEY_SIZE, GFP_KERNEL);
if (sec_key == NULL)
@@ -784,49 +786,24 @@ 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;
- }
+ arc4_setkey(ctx_arc4, ses->auth_key.response, CIFS_SESS_KEY_SIZE);
+ 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
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v3 7/7] fs: cifs: switch to RC4 library interface
2019-06-11 13:47 ` [PATCH v3 7/7] fs: cifs: switch to RC4 library interface Ard Biesheuvel
@ 2019-06-11 18:17 ` Eric Biggers
0 siblings, 0 replies; 2+ messages in thread
From: Eric Biggers @ 2019-06-11 18:17 UTC (permalink / raw)
To: Ard Biesheuvel
Cc: linux-crypto, Herbert Xu, David S. Miller, Johannes Berg,
linux-cifs, Steve French
On Tue, Jun 11, 2019 at 03:47:50PM +0200, Ard Biesheuvel wrote:
> 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@vger.kernel.org
> Cc: Steve French <sfrench@samba.org>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
> fs/cifs/Kconfig | 2 +-
> fs/cifs/cifsencrypt.c | 53 ++++++--------------
> 2 files changed, 16 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
Since the "arc4" module is no longer needed, the
MODULE_SOFTDEP("pre: arc4");
in fs/cifs/cifsfs.c should be removed too.
(Note that it doesn't need a soft dependency on libarc4 instead, since the cifs
module will link directly to it.)
> diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
> index d2a05e46d6f5..3b7b5e83493d 100644
> --- a/fs/cifs/cifsencrypt.c
> +++ b/fs/cifs/cifsencrypt.c
> @@ -33,7 +33,8 @@
> #include <linux/ctype.h>
> #include <linux/random.h>
> #include <linux/highmem.h>
> -#include <crypto/skcipher.h>
> +#include <linux/fips.h>
> +#include <crypto/arc4.h>
> #include <crypto/aead.h>
>
> int __cifs_calc_signature(struct smb_rqst *rqst,
> @@ -772,11 +773,12 @@ 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 arc4_ctx *ctx_arc4;
> unsigned char *sec_key;
> + int rc = 0;
> +
> + if (fips_enabled)
> + return -ENODEV;
>
> sec_key = kmalloc(CIFS_SESS_KEY_SIZE, GFP_KERNEL);
> if (sec_key == NULL)
sec_key should be moved back to the stack now, basically reverting this commit:
commit 5f4b55699aaff1028468e3f53853d781cdafedd6
Author: Sachin Prabhu <sprabhu@redhat.com>
Date: Mon Oct 17 16:40:22 2016 -0400
CIFS: Fix BUG() in calc_seckey()
It was only moved to the heap because it had to go in a scatterlist.
> + arc4_setkey(ctx_arc4, ses->auth_key.response, CIFS_SESS_KEY_SIZE);
> + 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);
Should be kzfree().
- Eric
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2019-06-11 18:17 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
[not found] <20190611134750.2974-1-ard.biesheuvel@linaro.org>
2019-06-11 13:47 ` [PATCH v3 7/7] fs: cifs: switch to RC4 library interface Ard Biesheuvel
2019-06-11 18:17 ` Eric Biggers
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).