[CRYPTO] salsa20_generic: Fix multi-page processing

This patch fixes the multi-page processing bug that affects large test
vectors (the same bug that previously affected ctr.c).

There is an optimization for the case walk.nbytes == nbytes. Also we
now use crypto_xor() instead of adhoc XOR routines.

Signed-off-by: Tan Swee Heng <thesweeheng@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/salsa20_generic.c b/crypto/salsa20_generic.c
index b49328a..1fa4e4d 100644 (file)
--- a/crypto/salsa20_generic.c
+++ b/crypto/salsa20_generic.c
@@ -143,7 +143,6 @@ static void salsa20_encrypt_bytes(struct salsa20_ctx *ctx, u8 *dst,
                                  const u8 *src, unsigned int bytes)
 {
        u8 buf[64];
-       int i;
 
        if (dst != src)
                memcpy(dst, src, bytes);
@@ -156,15 +155,11 @@ static void salsa20_encrypt_bytes(struct salsa20_ctx *ctx, u8 *dst,
                        ctx->input[9] = PLUSONE(ctx->input[9]);
 
                if (bytes <= 64) {
-                       for (i = 0; i < bytes/4; ++i)
-                               ((u32*)dst)[i] ^= ((u32*)buf)[i];
-                       for (i = bytes - bytes % 4; i < bytes; ++i)
-                               dst[i] ^= buf[i];
+                       crypto_xor(dst, buf, bytes);
                        return;
                }
 
-               for (i = 0; i < 64/4; ++i)
-                       ((u32*)dst)[i] ^= ((u32*)buf)[i];
+               crypto_xor(dst, buf, 64);
                bytes -= 64;
                dst += 64;
        }
@@ -192,13 +187,30 @@ static int encrypt(struct blkcipher_desc *desc,
        int err;
 
        blkcipher_walk_init(&walk, dst, src, nbytes);
-       err = blkcipher_walk_virt(desc, &walk);
+       err = blkcipher_walk_virt_block(desc, &walk, 64);
 
        salsa20_ivsetup(ctx, walk.iv);
-       salsa20_encrypt_bytes(ctx, walk.dst.virt.addr,
-                             walk.src.virt.addr, nbytes);
 
-       err = blkcipher_walk_done(desc, &walk, 0);
+       if (likely(walk.nbytes == nbytes))
+       {
+               salsa20_encrypt_bytes(ctx, walk.dst.virt.addr,
+                                     walk.src.virt.addr, nbytes);
+               return blkcipher_walk_done(desc, &walk, 0);
+       }
+
+       while (walk.nbytes >= 64) {
+               salsa20_encrypt_bytes(ctx, walk.dst.virt.addr,
+                                     walk.src.virt.addr,
+                                     walk.nbytes - (walk.nbytes % 64));
+               err = blkcipher_walk_done(desc, &walk, walk.nbytes % 64);
+       }
+
+       if (walk.nbytes) {
+               salsa20_encrypt_bytes(ctx, walk.dst.virt.addr,
+                                     walk.src.virt.addr, walk.nbytes);
+               err = blkcipher_walk_done(desc, &walk, 0);
+       }
+
        return err;
 }