[PATCH 3.2 106/185] crypto: s390 - Fix aes-xts parameter corruption

Ben Hutchings
2013-12-29T02:08:44Z

From: Gerald Schaefer <gerald.schaefer@de.ibm.com>

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@de.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
arch/s390/crypto/aes_s390.c | 31 +++++++++++++++++--------------
1 file changed, 17 insertions(+), 14 deletions(-)

--- 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;
@@ -592,7 +591,7 @@ static int xts_aes_set_key(struct crypto
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;
@@ -603,7 +602,7 @@ static int xts_aes_set_key(struct crypto
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;
@@ -622,28 +621,32 @@ static int xts_aes_crypt(struct blkciphe
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]);
BUG_ON(ret < 0);

- 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);
BUG_ON(ret < 0 || ret != n);

nbytes &= AES_BLOCK_SIZE - 1;