[CRYPTO] Update IV correctly for Padlock CBC encryption

When the Padlock does CBC encryption, the memory pointed to by EAX is
not updated at all.  Instead, it updates the value of EAX by pointing
it to the last block in the output.  Therefore to maintain the correct
semantics we need to copy the IV.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/crypto/padlock-aes.c b/drivers/crypto/padlock-aes.c
index c5b58fa..71407c5 100644 (file)
--- a/drivers/crypto/padlock-aes.c
+++ b/drivers/crypto/padlock-aes.c
@@ -400,8 +400,8 @@ static inline void padlock_xcrypt_ecb(const u8 *input, u8 *output, void *key,
                      : "d"(control_word), "b"(key), "c"(count));
 }
 
-static inline void padlock_xcrypt_cbc(const u8 *input, u8 *output, void *key,
-                                     u8 *iv, void *control_word, u32 count)
+static inline u8 *padlock_xcrypt_cbc(const u8 *input, u8 *output, void *key,
+                                    u8 *iv, void *control_word, u32 count)
 {
        /* Enforce key reload. */
        asm volatile ("pushfl; popfl");
@@ -409,6 +409,7 @@ static inline void padlock_xcrypt_cbc(const u8 *input, u8 *output, void *key,
        asm volatile (".byte 0xf3,0x0f,0xa7,0xd0"
                      : "+S" (input), "+D" (output), "+a" (iv)
                      : "d" (control_word), "b" (key), "c" (count));
+       return iv;
 }
 
 static void
@@ -447,8 +448,12 @@ static unsigned int aes_encrypt_cbc(const struct cipher_desc *desc, u8 *out,
                                    const u8 *in, unsigned int nbytes)
 {
        struct aes_ctx *ctx = aes_ctx(crypto_tfm_ctx(desc->tfm));
-       padlock_xcrypt_cbc(in, out, ctx->E, desc->info, &ctx->cword.encrypt,
-                          nbytes / AES_BLOCK_SIZE);
+       u8 *iv;
+
+       iv = padlock_xcrypt_cbc(in, out, ctx->E, desc->info,
+                               &ctx->cword.encrypt, nbytes / AES_BLOCK_SIZE);
+       memcpy(desc->info, iv, AES_BLOCK_SIZE);
+
        return nbytes & ~(AES_BLOCK_SIZE - 1);
 }