[CRYPTO] Handle unaligned iv from encrypt_iv/decrypt_iv

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>

1 files changed, 27 insertions, 2 deletions

diff --git a/crypto/cipher.c b/crypto/cipher.c
index d3295ce14a57..1c92c6bb138b 100644
--- a/crypto/cipher.c
+++ b/crypto/cipher.c
@@ -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,