[CRYPTO] Handle unaligned iv from encrypt_iv/decrypt_iv
Herbert Xu [Wed, 6 Jul 2005 20:53:47 +0000 (13:53 -0700)]
Even though cit_iv is now always aligned, the user can still supply an
unaligned iv through crypto_cipher_encrypt_iv/crypto_cipher_decrypt_iv.
This patch will check the alignment of the user-supplied iv and copy
it if necessary.

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

crypto/cipher.c

index d3295ce..1c92c6b 100644 (file)
@@ -154,6 +154,31 @@ static int crypt(const struct cipher_desc *desc,
        return 0;
 }
 
+static int crypt_iv_unaligned(struct cipher_desc *desc,
+                             struct scatterlist *dst,
+                             struct scatterlist *src,
+                             unsigned int nbytes)
+{
+       struct crypto_tfm *tfm = desc->tfm;
+       unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
+       u8 *iv = desc->info;
+
+       if (unlikely(((unsigned long)iv & alignmask))) {
+               unsigned int ivsize = tfm->crt_cipher.cit_ivsize;
+               u8 buffer[ivsize + alignmask];
+               u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
+               int err;
+
+               desc->info = memcpy(tmp, iv, ivsize);
+               err = crypt(desc, dst, src, nbytes);
+               memcpy(iv, tmp, ivsize);
+
+               return err;
+       }
+
+       return crypt(desc, dst, src, nbytes);
+}
+
 static unsigned int cbc_process_encrypt(const struct cipher_desc *desc,
                                        u8 *dst, const u8 *src,
                                        unsigned int nbytes)
@@ -298,7 +323,7 @@ static int cbc_encrypt_iv(struct crypto_tfm *tfm,
        desc.prfn = cipher->cia_encrypt_cbc ?: cbc_process_encrypt;
        desc.info = iv;
 
-       return crypt(&desc, dst, src, nbytes);
+       return crypt_iv_unaligned(&desc, dst, src, nbytes);
 }
 
 static int cbc_decrypt(struct crypto_tfm *tfm,
@@ -330,7 +355,7 @@ static int cbc_decrypt_iv(struct crypto_tfm *tfm,
        desc.prfn = cipher->cia_decrypt_cbc ?: cbc_process_decrypt;
        desc.info = iv;
 
-       return crypt(&desc, dst, src, nbytes);
+       return crypt_iv_unaligned(&desc, dst, src, nbytes);
 }
 
 static int nocrypt(struct crypto_tfm *tfm,