add flag for normalizing pgno in HMAC check

sjlombardo · sjlombardo · commit 70ef31ff5dcc · 2012-07-17T16:45:02.000-04:00
diff --git a/src/crypto.h b/src/crypto.h
@@ -57,10 +57,11 @@
 #endif
 
 /* possible flags for cipher_ctx->flags */
-#define CIPHER_FLAG_HMAC 0x01
+#define CIPHER_FLAG_HMAC          0x01
+#define CIPHER_FLAG_LE_PGNO       0x02
 
 #ifndef DEFAULT_CIPHER_FLAGS
-#define DEFAULT_CIPHER_FLAGS CIPHER_FLAG_HMAC
+#define DEFAULT_CIPHER_FLAGS CIPHER_FLAG_HMAC | CIPHER_FLAG_LE_PGNO
 #endif
 
 
diff --git a/src/crypto_impl.c b/src/crypto_impl.c
@@ -512,7 +512,11 @@ int sqlcipher_page_hmac(cipher_ctx *ctx, Pgno pgno, unsigned char *in, int in_sz
      valid pages out of order in a database */ 
   HMAC_Update(&ctx->hctx, in, in_sz);
   
-  HMAC_Update(&ctx->hctx, (const unsigned char*) pgno_le, sizeof(pgno_le));
+  if(ctx->flags & CIPHER_FLAG_LE_PGNO) /* default compute hmac using little endian */
+    HMAC_Update(&ctx->hctx, (const unsigned char*) pgno_le, sizeof(pgno_le)); 
+  else /* legacy setting - compute using native byte ordering */
+    HMAC_Update(&ctx->hctx, (const unsigned char*) &pgno, sizeof(pgno)); 
+  
   HMAC_Final(&ctx->hctx, out, NULL);
   HMAC_CTX_cleanup(&ctx->hctx);
   return SQLITE_OK; 
