[3.8.y.z extended stable] Patch "crypto: s390 - Fix aes-xts parameter corruption" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    crypto: s390 - Fix aes-xts parameter corruption

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.15.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From d1fdbda26e16fcd32631fd435d15b173e1ed1c95 Mon Sep 17 00:00:00 2001
From: Gerald Schaefer <gerald.schaefer at de.ibm.com>
Date: Tue, 19 Nov 2013 17:12:47 +0100
Subject: crypto: s390 - Fix aes-xts parameter corruption

commit 9dda2769af4f3f3093434648c409bb351120d9e8 upstream.

Some s390 crypto algorithms incorrectly use the crypto_tfm structure to
store private data. As the tfm can be shared among multiple threads, this
can result in data corruption.

This patch fixes aes-xts by moving the xts and pcc parameter blocks from
the tfm onto the stack (48 + 96 bytes).

Signed-off-by: Gerald Schaefer <gerald.schaefer at de.ibm.com>
Signed-off-by: Herbert Xu <herbert at gondor.apana.org.au>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 arch/s390/crypto/aes_s390.c | 31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/arch/s390/crypto/aes_s390.c b/arch/s390/crypto/aes_s390.c
index 2e4b5be..94e20dd 100644
--- a/arch/s390/crypto/aes_s390.c
+++ b/arch/s390/crypto/aes_s390.c
@@ -55,8 +55,7 @@ struct pcc_param {

 struct s390_xts_ctx {
 	u8 key[32];
-	u8 xts_param[16];
-	struct pcc_param pcc;
+	u8 pcc_key[32];
 	long enc;
 	long dec;
 	int key_len;
@@ -591,7 +590,7 @@ static int xts_aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
 		xts_ctx->enc = KM_XTS_128_ENCRYPT;
 		xts_ctx->dec = KM_XTS_128_DECRYPT;
 		memcpy(xts_ctx->key + 16, in_key, 16);
-		memcpy(xts_ctx->pcc.key + 16, in_key + 16, 16);
+		memcpy(xts_ctx->pcc_key + 16, in_key + 16, 16);
 		break;
 	case 48:
 		xts_ctx->enc = 0;
@@ -602,7 +601,7 @@ static int xts_aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
 		xts_ctx->enc = KM_XTS_256_ENCRYPT;
 		xts_ctx->dec = KM_XTS_256_DECRYPT;
 		memcpy(xts_ctx->key, in_key, 32);
-		memcpy(xts_ctx->pcc.key, in_key + 32, 32);
+		memcpy(xts_ctx->pcc_key, in_key + 32, 32);
 		break;
 	default:
 		*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
@@ -621,29 +620,33 @@ static int xts_aes_crypt(struct blkcipher_desc *desc, long func,
 	unsigned int nbytes = walk->nbytes;
 	unsigned int n;
 	u8 *in, *out;
-	void *param;
+	struct pcc_param pcc_param;
+	struct {
+		u8 key[32];
+		u8 init[16];
+	} xts_param;

 	if (!nbytes)
 		goto out;

-	memset(xts_ctx->pcc.block, 0, sizeof(xts_ctx->pcc.block));
-	memset(xts_ctx->pcc.bit, 0, sizeof(xts_ctx->pcc.bit));
-	memset(xts_ctx->pcc.xts, 0, sizeof(xts_ctx->pcc.xts));
-	memcpy(xts_ctx->pcc.tweak, walk->iv, sizeof(xts_ctx->pcc.tweak));
-	param = xts_ctx->pcc.key + offset;
-	ret = crypt_s390_pcc(func, param);
+	memset(pcc_param.block, 0, sizeof(pcc_param.block));
+	memset(pcc_param.bit, 0, sizeof(pcc_param.bit));
+	memset(pcc_param.xts, 0, sizeof(pcc_param.xts));
+	memcpy(pcc_param.tweak, walk->iv, sizeof(pcc_param.tweak));
+	memcpy(pcc_param.key, xts_ctx->pcc_key, 32);
+	ret = crypt_s390_pcc(func, &pcc_param.key[offset]);
 	if (ret < 0)
 		return -EIO;

-	memcpy(xts_ctx->xts_param, xts_ctx->pcc.xts, 16);
-	param = xts_ctx->key + offset;
+	memcpy(xts_param.key, xts_ctx->key, 32);
+	memcpy(xts_param.init, pcc_param.xts, 16);
 	do {
 		/* only use complete blocks */
 		n = nbytes & ~(AES_BLOCK_SIZE - 1);
 		out = walk->dst.virt.addr;
 		in = walk->src.virt.addr;

-		ret = crypt_s390_km(func, param, out, in, n);
+		ret = crypt_s390_km(func, &xts_param.key[offset], out, in, n);
 		if (ret < 0 || ret != n)
 			return -EIO;

--
1.8.3.2