modes/gcm128.c: harmonize GCM_MUL macro with GHASH.

Reviewed-by: Rich Salz <rsalz@openssl.org>

1 files changed, 56 insertions, 45 deletions

diff --git a/crypto/modes/gcm128.c b/crypto/modes/gcm128.c
index c3a9259451..4c8ae910ed 100644
--- a/crypto/modes/gcm128.c
+++ b/crypto/modes/gcm128.c
@@ -209,7 +209,7 @@ static void gcm_gmult_8bit(u64 Xi[2], const u128 Htable[256])
     }
 }
 
-# define GCM_MUL(ctx,Xi)   gcm_gmult_8bit(ctx->Xi.u,ctx->Htable)
+# define GCM_MUL(ctx)      gcm_gmult_8bit(ctx->Xi.u,ctx->Htable)
 
 #elif   TABLE_BITS==4
 
@@ -550,7 +550,7 @@ void gcm_ghash_4bit(u64 Xi[2], const u128 Htable[16], const u8 *inp,
                     size_t len);
 # endif
 
-# define GCM_MUL(ctx,Xi)   gcm_gmult_4bit(ctx->Xi.u,ctx->Htable)
+# define GCM_MUL(ctx)      gcm_gmult_4bit(ctx->Xi.u,ctx->Htable)
 # if defined(GHASH_ASM) || !defined(OPENSSL_SMALL_FOOTPRINT)
 #  define GHASH(ctx,in,len) gcm_ghash_4bit((ctx)->Xi.u,(ctx)->Htable,in,len)
 /*
@@ -624,7 +624,7 @@ static void gcm_gmult_1bit(u64 Xi[2], const u64 H[2])
     }
 }
 
-# define GCM_MUL(ctx,Xi)   gcm_gmult_1bit(ctx->Xi.u,ctx->H.u)
+# define GCM_MUL(ctx)      gcm_gmult_1bit(ctx->Xi.u,ctx->H.u)
 
 #endif
 
@@ -703,7 +703,7 @@ void gcm_ghash_p8(u64 Xi[2], const u128 Htable[16], const u8 *inp,
 
 #ifdef GCM_FUNCREF_4BIT
 # undef  GCM_MUL
-# define GCM_MUL(ctx,Xi)        (*gcm_gmult_p)(ctx->Xi.u,ctx->Htable)
+# define GCM_MUL(ctx)           (*gcm_gmult_p)(ctx->Xi.u,ctx->Htable)
 # ifdef GHASH
 #  undef  GHASH
 #  define GHASH(ctx,in,len)     (*gcm_ghash_p)(ctx->Xi.u,ctx->Htable,in,len)
@@ -836,10 +836,6 @@ void CRYPTO_gcm128_setiv(GCM128_CONTEXT *ctx, const unsigned char *iv,
     void (*gcm_gmult_p) (u64 Xi[2], const u128 Htable[16]) = ctx->gmult;
 #endif
 
-    ctx->Yi.u[0] = 0;
-    ctx->Yi.u[1] = 0;
-    ctx->Xi.u[0] = 0;
-    ctx->Xi.u[1] = 0;
     ctx->len.u[0] = 0;          /* AAD length */
     ctx->len.u[1] = 0;          /* message length */
     ctx->ares = 0;
@@ -847,53 +843,68 @@ void CRYPTO_gcm128_setiv(GCM128_CONTEXT *ctx, const unsigned char *iv,
 
     if (len == 12) {
         memcpy(ctx->Yi.c, iv, 12);
+        ctx->Yi.c[12] = 0;
+        ctx->Yi.c[13] = 0;
+        ctx->Yi.c[14] = 0;
         ctx->Yi.c[15] = 1;
         ctr = 1;
     } else {
         size_t i;
         u64 len0 = len;
 
+        /* Borrow ctx->Xi to calculate initial Yi */
+        ctx->Xi.u[0] = 0;
+        ctx->Xi.u[1] = 0;
+
         while (len >= 16) {
             for (i = 0; i < 16; ++i)
-                ctx->Yi.c[i] ^= iv[i];
-            GCM_MUL(ctx, Yi);
+                ctx->Xi.c[i] ^= iv[i];
+            GCM_MUL(ctx);
             iv += 16;
             len -= 16;
         }
         if (len) {
             for (i = 0; i < len; ++i)
-                ctx->Yi.c[i] ^= iv[i];
-            GCM_MUL(ctx, Yi);
+                ctx->Xi.c[i] ^= iv[i];
+            GCM_MUL(ctx);
         }
         len0 <<= 3;
         if (is_endian.little) {
 #ifdef BSWAP8
-            ctx->Yi.u[1] ^= BSWAP8(len0);
+            ctx->Xi.u[1] ^= BSWAP8(len0);
 #else
-            ctx->Yi.c[8] ^= (u8)(len0 >> 56);
-            ctx->Yi.c[9] ^= (u8)(len0 >> 48);
-            ctx->Yi.c[10] ^= (u8)(len0 >> 40);
-            ctx->Yi.c[11] ^= (u8)(len0 >> 32);
-            ctx->Yi.c[12] ^= (u8)(len0 >> 24);
-            ctx->Yi.c[13] ^= (u8)(len0 >> 16);
-            ctx->Yi.c[14] ^= (u8)(len0 >> 8);
-            ctx->Yi.c[15] ^= (u8)(len0);
+            ctx->Xi.c[8] ^= (u8)(len0 >> 56);
+            ctx->Xi.c[9] ^= (u8)(len0 >> 48);
+            ctx->Xi.c[10] ^= (u8)(len0 >> 40);
+            ctx->Xi.c[11] ^= (u8)(len0 >> 32);
+            ctx->Xi.c[12] ^= (u8)(len0 >> 24);
+            ctx->Xi.c[13] ^= (u8)(len0 >> 16);
+            ctx->Xi.c[14] ^= (u8)(len0 >> 8);
+            ctx->Xi.c[15] ^= (u8)(len0);
 #endif
-        } else
-            ctx->Yi.u[1] ^= len0;
+        } else {
+            ctx->Xi.u[1] ^= len0;
+        }
 
-        GCM_MUL(ctx, Yi);
+        GCM_MUL(ctx);
 
         if (is_endian.little)
 #ifdef BSWAP4
-            ctr = BSWAP4(ctx->Yi.d[3]);
+            ctr = BSWAP4(ctx->Xi.d[3]);
 #else
-            ctr = GETU32(ctx->Yi.c + 12);
+            ctr = GETU32(ctx->Xi.c + 12);
 #endif
         else
-            ctr = ctx->Yi.d[3];
+            ctr = ctx->Xi.d[3];
+
+        /* Copy borrowed Xi to Yi */
+        ctx->Yi.u[0] = ctx->Xi.u[0];
+        ctx->Yi.u[1] = ctx->Xi.u[1];
     }
 
+    ctx->Xi.u[0] = 0;
+    ctx->Xi.u[1] = 0;
+
     (*ctx->block) (ctx->Yi.c, ctx->EK0.c, ctx->key);
     ++ctr;
     if (is_endian.little)
@@ -936,7 +947,7 @@ int CRYPTO_gcm128_aad(GCM128_CONTEXT *ctx, const unsigned char *aad,
             n = (n + 1) % 16;
         }
         if (n == 0)
-            GCM_MUL(ctx, Xi);
+            GCM_MUL(ctx);
         else {
             ctx->ares = n;
             return 0;
@@ -952,7 +963,7 @@ int CRYPTO_gcm128_aad(GCM128_CONTEXT *ctx, const unsigned char *aad,
     while (len >= 16) {
         for (i = 0; i < 16; ++i)
             ctx->Xi.c[i] ^= aad[i];
-        GCM_MUL(ctx, Xi);
+        GCM_MUL(ctx);
         aad += 16;
         len -= 16;
     }
@@ -995,7 +1006,7 @@ int CRYPTO_gcm128_encrypt(GCM128_CONTEXT *ctx,
 
     if (ctx->ares) {
         /* First call to encrypt finalizes GHASH(AAD) */
-        GCM_MUL(ctx, Xi);
+        GCM_MUL(ctx);
         ctx->ares = 0;
     }
 
@@ -1019,7 +1030,7 @@ int CRYPTO_gcm128_encrypt(GCM128_CONTEXT *ctx,
                     n = (n + 1) % 16;
                 }
                 if (n == 0)
-                    GCM_MUL(ctx, Xi);
+                    GCM_MUL(ctx);
                 else {
                     ctx->mres = n;
                     return 0;
@@ -1100,7 +1111,7 @@ int CRYPTO_gcm128_encrypt(GCM128_CONTEXT *ctx,
                     ctx->Yi.d[3] = ctr;
                 for (i = 0; i < 16 / sizeof(size_t); ++i)
                     ctx->Xi.t[i] ^= out_t[i] = in_t[i] ^ ctx->EKi.t[i];
-                GCM_MUL(ctx, Xi);
+                GCM_MUL(ctx);
                 out += 16;
                 in += 16;
                 len -= 16;
@@ -1144,7 +1155,7 @@ int CRYPTO_gcm128_encrypt(GCM128_CONTEXT *ctx,
         ctx->Xi.c[n] ^= out[i] = in[i] ^ ctx->EKi.c[n];
         n = (n + 1) % 16;
         if (n == 0)
-            GCM_MUL(ctx, Xi);
+            GCM_MUL(ctx);
     }
 
     ctx->mres = n;
@@ -1179,7 +1190,7 @@ int CRYPTO_gcm128_decrypt(GCM128_CONTEXT *ctx,
 
     if (ctx->ares) {
         /* First call to decrypt finalizes GHASH(AAD) */
-        GCM_MUL(ctx, Xi);
+        GCM_MUL(ctx);
         ctx->ares = 0;
     }
 
@@ -1205,7 +1216,7 @@ int CRYPTO_gcm128_decrypt(GCM128_CONTEXT *ctx,
                     n = (n + 1) % 16;
                 }
                 if (n == 0)
-                    GCM_MUL(ctx, Xi);
+                    GCM_MUL(ctx);
                 else {
                     ctx->mres = n;
                     return 0;
@@ -1287,7 +1298,7 @@ int CRYPTO_gcm128_decrypt(GCM128_CONTEXT *ctx,
                     out[i] = c ^ ctx->EKi.t[i];
                     ctx->Xi.t[i] ^= c;
                 }
-                GCM_MUL(ctx, Xi);
+                GCM_MUL(ctx);
                 out += 16;
                 in += 16;
                 len -= 16;
@@ -1336,7 +1347,7 @@ int CRYPTO_gcm128_decrypt(GCM128_CONTEXT *ctx,
         ctx->Xi.c[n] ^= c;
         n = (n + 1) % 16;
         if (n == 0)
-            GCM_MUL(ctx, Xi);
+            GCM_MUL(ctx);
     }
 
     ctx->mres = n;
@@ -1373,7 +1384,7 @@ int CRYPTO_gcm128_encrypt_ctr32(GCM128_CONTEXT *ctx,
 
     if (ctx->ares) {
         /* First call to encrypt finalizes GHASH(AAD) */
-        GCM_MUL(ctx, Xi);
+        GCM_MUL(ctx);
         ctx->ares = 0;
     }
 
@@ -1394,7 +1405,7 @@ int CRYPTO_gcm128_encrypt_ctr32(GCM128_CONTEXT *ctx,
             n = (n + 1) % 16;
         }
         if (n == 0)
-            GCM_MUL(ctx, Xi);
+            GCM_MUL(ctx);
         else {
             ctx->mres = n;
             return 0;
@@ -1440,7 +1451,7 @@ int CRYPTO_gcm128_encrypt_ctr32(GCM128_CONTEXT *ctx,
         while (j--) {
             for (i = 0; i < 16; ++i)
                 ctx->Xi.c[i] ^= out[i];
-            GCM_MUL(ctx, Xi);
+            GCM_MUL(ctx);
             out += 16;
         }
 # endif
@@ -1497,7 +1508,7 @@ int CRYPTO_gcm128_decrypt_ctr32(GCM128_CONTEXT *ctx,
 
     if (ctx->ares) {
         /* First call to decrypt finalizes GHASH(AAD) */
-        GCM_MUL(ctx, Xi);
+        GCM_MUL(ctx);
         ctx->ares = 0;
     }
 
@@ -1520,7 +1531,7 @@ int CRYPTO_gcm128_decrypt_ctr32(GCM128_CONTEXT *ctx,
             n = (n + 1) % 16;
         }
         if (n == 0)
-            GCM_MUL(ctx, Xi);
+            GCM_MUL(ctx);
         else {
             ctx->mres = n;
             return 0;
@@ -1554,7 +1565,7 @@ int CRYPTO_gcm128_decrypt_ctr32(GCM128_CONTEXT *ctx,
             size_t k;
             for (k = 0; k < 16; ++k)
                 ctx->Xi.c[k] ^= in[k];
-            GCM_MUL(ctx, Xi);
+            GCM_MUL(ctx);
             in += 16;
         }
         j = i / 16;
@@ -1612,7 +1623,7 @@ int CRYPTO_gcm128_finish(GCM128_CONTEXT *ctx, const unsigned char *tag,
 #endif
 
     if (ctx->mres || ctx->ares)
-        GCM_MUL(ctx, Xi);
+        GCM_MUL(ctx);
 
     if (is_endian.little) {
 #ifdef BSWAP8
@@ -1631,7 +1642,7 @@ int CRYPTO_gcm128_finish(GCM128_CONTEXT *ctx, const unsigned char *tag,
 
     ctx->Xi.u[0] ^= alen;
     ctx->Xi.u[1] ^= clen;
-    GCM_MUL(ctx, Xi);
+    GCM_MUL(ctx);
 
     ctx->Xi.u[0] ^= ctx->EK0.u[0];
     ctx->Xi.u[1] ^= ctx->EK0.u[1];