crypto: s390 - Fix aes-xts parameter corruption

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).

Cc: stable@vger.kernel.org
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/arch/s390/crypto/aes_s390.c b/arch/s390/crypto/aes_s390.c
index 4363528..b3feabd 100644 (file)
--- 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;