[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>

1 files changed, 23 insertions, 11 deletions

diff --git a/crypto/salsa20_generic.c b/crypto/salsa20_generic.c
index b49328afcf0a..1fa4e4ddcab5 100644
--- 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;
 }