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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        =?UTF-8?q?Horia=20Geant=C4=83?= <horia.geanta@nxp.com>,
        Valentin Ciocoi Radulescu <valentin.ciocoi@nxp.com>,
        Herbert Xu <herbert@gondor.apana.org.au>
Subject: [PATCH 5.4 168/232] crypto: caam/qi2 - fix chacha20 data size error
Date:   Thu, 16 Apr 2020 15:24:22 +0200
Message-Id: <20200416131336.009875806@linuxfoundation.org>
In-Reply-To: <20200416131316.640996080@linuxfoundation.org>
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From: Horia Geantă <horia.geanta@nxp.com>

commit 3a5a9e1ef37b030b836d92df8264f840988f4a38 upstream.

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>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/crypto/caam/caamalg_desc.c |   14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

--- a/drivers/crypto/caam/caamalg_desc.c
+++ b/drivers/crypto/caam/caamalg_desc.c
@@ -1379,6 +1379,9 @@ void cnstr_shdsc_skcipher_encap(u32 * co
 				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 * co
 				      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 * co
 				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 * co
 	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));