[PATCH v2] crypto: caam/qi2 - fix chacha20 data size error

[PATCH v2] crypto: caam/qi2 - fix chacha20 data size error

[Horia Geantă]

HW generates a Data Size error for chacha20 requests that are not
a multiple of 64B, since algorithm state (AS) does not have
the FINAL bit set.

Since updating req->iv (for chaining) is not required,
modify skcipher descriptors to set the FINAL bit for chacha20.

[Note that for skcipher decryption we know that ctx1_iv_off is 0,
which allows for an optimization by not checking algorithm type,
since append_dec_op1() sets FINAL bit for all algorithms except AES.]

Also drop the descriptor operations that save the IV.
However, in order to keep code logic simple, things like
S/G tables generation etc. are not touched.

Cc: <stable@vger.kernel.org> # v5.3+
Fixes: 334d37c9e263 ("crypto: caam - update IV using HW support")
Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
---
 drivers/crypto/caam/caamalg_desc.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/crypto/caam/caamalg_desc.c b/drivers/crypto/caam/caamalg_desc.c
index aa9ccca67045..6171a8118b5a 100644
--- a/drivers/crypto/caam/caamalg_desc.c
+++ b/drivers/crypto/caam/caamalg_desc.c
@@ -1379,6 +1379,9 @@ void cnstr_shdsc_skcipher_encap(u32 * const desc, struct alginfo *cdata,
 				const u32 ctx1_iv_off)
 {
 	u32 *key_jump_cmd;
+	u32 options = cdata->algtype | OP_ALG_AS_INIT | OP_ALG_ENCRYPT;
+	bool is_chacha20 = ((cdata->algtype & OP_ALG_ALGSEL_MASK) ==
+			    OP_ALG_ALGSEL_CHACHA20);
 
 	init_sh_desc(desc, HDR_SHARE_SERIAL | HDR_SAVECTX);
 	/* Skip if already shared */
@@ -1417,14 +1420,15 @@ void cnstr_shdsc_skcipher_encap(u32 * const desc, struct alginfo *cdata,
 				      LDST_OFFSET_SHIFT));
 
 	/* Load operation */
-	append_operation(desc, cdata->algtype | OP_ALG_AS_INIT |
-			 OP_ALG_ENCRYPT);
+	if (is_chacha20)
+		options |= OP_ALG_AS_FINALIZE;
+	append_operation(desc, options);
 
 	/* Perform operation */
 	skcipher_append_src_dst(desc);
 
 	/* Store IV */
-	if (ivsize)
+	if (!is_chacha20 && ivsize)
 		append_seq_store(desc, ivsize, LDST_SRCDST_BYTE_CONTEXT |
 				 LDST_CLASS_1_CCB | (ctx1_iv_off <<
 				 LDST_OFFSET_SHIFT));
@@ -1451,6 +1455,8 @@ void cnstr_shdsc_skcipher_decap(u32 * const desc, struct alginfo *cdata,
 				const u32 ctx1_iv_off)
 {
 	u32 *key_jump_cmd;
+	bool is_chacha20 = ((cdata->algtype & OP_ALG_ALGSEL_MASK) ==
+			    OP_ALG_ALGSEL_CHACHA20);
 
 	init_sh_desc(desc, HDR_SHARE_SERIAL | HDR_SAVECTX);
 	/* Skip if already shared */
@@ -1499,7 +1505,7 @@ void cnstr_shdsc_skcipher_decap(u32 * const desc, struct alginfo *cdata,
 	skcipher_append_src_dst(desc);
 
 	/* Store IV */
-	if (ivsize)
+	if (!is_chacha20 && ivsize)
 		append_seq_store(desc, ivsize, LDST_SRCDST_BYTE_CONTEXT |
 				 LDST_CLASS_1_CCB | (ctx1_iv_off <<
 				 LDST_OFFSET_SHIFT));
-- 
2.17.1

RE: [PATCH v2] crypto: caam/qi2 - fix chacha20 data size error

[Valentin Ciocoi Radulescu]

> -----Original Message-----
> From: Horia Geantă <horia.geanta@nxp.com>
> Sent: Friday, February 28, 2020 08:51
> To: Herbert Xu <herbert@gondor.apana.org.au>
> Cc: David S. Miller <davem@davemloft.net>; Aymen Sghaier
> <aymen.sghaier@nxp.com>; Valentin Ciocoi Radulescu
> <valentin.ciocoi@nxp.com>; linux-crypto@vger.kernel.org; dl-linux-imx
> <linux-imx@nxp.com>
> Subject: [PATCH v2] crypto: caam/qi2 - fix chacha20 data size error
> 
> HW generates a Data Size error for chacha20 requests that are not
> a multiple of 64B, since algorithm state (AS) does not have
> the FINAL bit set.
> 
> Since updating req->iv (for chaining) is not required,
> modify skcipher descriptors to set the FINAL bit for chacha20.
> 
> [Note that for skcipher decryption we know that ctx1_iv_off is 0,
> which allows for an optimization by not checking algorithm type,
> since append_dec_op1() sets FINAL bit for all algorithms except AES.]
> 
> Also drop the descriptor operations that save the IV.
> However, in order to keep code logic simple, things like
> S/G tables generation etc. are not touched.
> 
> Cc: <stable@vger.kernel.org> # v5.3+
> Fixes: 334d37c9e263 ("crypto: caam - update IV using HW support")
> Signed-off-by: Horia Geantă <horia.geanta@nxp.com>

Tested-by: Valentin Ciocoi Radulescu <valentin.ciocoi@nxp.com>

Tested on LX2160ARDB board with cryptodev-2.6 tree:
root@TinyLinux:~# cat /proc/crypto | grep chacha20-caam -A 5
driver       : chacha20-caam-qi2
module       : kernel
priority     : 2000
refcnt       : 1
selftest     : passed
internal     : no

Re: [PATCH v2] crypto: caam/qi2 - fix chacha20 data size error

[Herbert Xu]

On Fri, Feb 28, 2020 at 08:51:23AM +0200, Horia Geantă wrote:
> HW generates a Data Size error for chacha20 requests that are not
> a multiple of 64B, since algorithm state (AS) does not have
> the FINAL bit set.
> 
> Since updating req->iv (for chaining) is not required,
> modify skcipher descriptors to set the FINAL bit for chacha20.
> 
> [Note that for skcipher decryption we know that ctx1_iv_off is 0,
> which allows for an optimization by not checking algorithm type,
> since append_dec_op1() sets FINAL bit for all algorithms except AES.]
> 
> Also drop the descriptor operations that save the IV.
> However, in order to keep code logic simple, things like
> S/G tables generation etc. are not touched.
> 
> Cc: <stable@vger.kernel.org> # v5.3+
> Fixes: 334d37c9e263 ("crypto: caam - update IV using HW support")
> Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
> ---
>  drivers/crypto/caam/caamalg_desc.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt