gcm128.c: API modification and readability improvements,
[openssl.git] / crypto / modes / gcm128.c
index 8b1880cf5dce6f42a6021f74d959535fe4be8dc9..6f1eb6d484c300daaa8af6d9a60f354dc8a39511 100644 (file)
@@ -47,6 +47,7 @@
  * ====================================================================
  */
 
+#include "crypto.h"
 #include "modes_lcl.h"
 #include <string.h>
 
@@ -458,8 +459,8 @@ static void gcm_ghash_4bit(u64 Xi[2],const u128 Htable[16],
     /*
      * Extra 256+16 bytes per-key plus 512 bytes shared tables
      * [should] give ~50% improvement... One could have PACK()-ed
-     * the rem_8bit even here, but priority is to minimize memory
-     * usage...
+     * the rem_8bit even here, but the priority is to minimize
+     * cache footprint...
      */ 
     u128 Hshr4[16];    /* Htable shifted right by 4 bits */
     u8   Hshl4[16];    /* Htable shifted left  by 4 bits */
@@ -496,7 +497,6 @@ static void gcm_ghash_4bit(u64 Xi[2],const u128 Htable[16],
        0xA7D0, 0xA612, 0xA454, 0xA596, 0xA0D8, 0xA11A, 0xA35C, 0xA29E,
        0xB5E0, 0xB422, 0xB664, 0xB7A6, 0xB2E8, 0xB32A, 0xB16C, 0xB0AE,
        0xBBF0, 0xBA32, 0xB874, 0xB9B6, 0xBCF8, 0xBD3A, 0xBF7C, 0xBEBE };
-
     /*
      * This pre-processing phase slows down procedure by approximately
      * same time as it makes each loop spin faster. In other words
@@ -512,24 +512,7 @@ static void gcm_ghash_4bit(u64 Xi[2],const u128 Htable[16],
     }
 
     do {
-       nlo  = ((const u8 *)Xi)[15];
-       nlo ^= inp[15];
-       nhi  = nlo>>4;
-       nlo &= 0xf;
-
-       Z.hi = Htable[nlo].hi;
-       Z.lo = Htable[nlo].lo;
-
-       rem = (size_t)Z.lo&0xff;
-
-       Z.lo = (Z.hi<<56)|(Z.lo>>8);
-       Z.hi = (Z.hi>>8);
-
-       Z.hi ^= Hshr4[nhi].hi;
-       Z.lo ^= Hshr4[nhi].lo;
-       Z.hi ^= (u64)rem_8bit[rem^Hshl4[nhi]]<<48;
-
-       for (cnt=14; cnt>0; --cnt) {
+       for (Z.lo=0, Z.hi=0, cnt=15; cnt; --cnt) {
                nlo  = ((const u8 *)Xi)[cnt];
                nlo ^= inp[cnt];
                nhi  = nlo>>4;
@@ -733,7 +716,7 @@ void CRYPTO_gcm128_init(GCM128_CONTEXT *ctx,void *key,block128_f block)
 #if    TABLE_BITS==8
        gcm_init_8bit(ctx->Htable,ctx->H.u);
 #elif  TABLE_BITS==4
-# if   defined(GHASH_ASM_IAX)
+# if   defined(GHASH_ASM_IAX)                  /* both x86 and x86_64 */
        if (OPENSSL_ia32cap_P[1]&(1<<1)) {
                gcm_init_clmul(ctx->Htable,ctx->H.u);
                ctx->gmult = gcm_gmult_clmul;
@@ -741,7 +724,7 @@ void CRYPTO_gcm128_init(GCM128_CONTEXT *ctx,void *key,block128_f block)
                return;
        }
        gcm_init_4bit(ctx->Htable,ctx->H.u);
-#  if  defined(GHASH_ASM_X86)
+#  if  defined(GHASH_ASM_X86)                  /* x86 only */
        if (OPENSSL_ia32cap_P[0]&(1<<23)) {
                ctx->gmult = gcm_gmult_4bit_mmx;
                ctx->ghash = gcm_ghash_4bit_mmx;
@@ -1109,7 +1092,8 @@ void CRYPTO_gcm128_decrypt(GCM128_CONTEXT *ctx,
        ctx->res = n;
 }
 
-void CRYPTO_gcm128_finish(GCM128_CONTEXT *ctx)
+int CRYPTO_gcm128_finish(GCM128_CONTEXT *ctx,const unsigned char *tag,
+                       size_t len)
 {
        const union { long one; char little; } is_endian = {1};
        u64 alen = ctx->len.u[0]<<3;
@@ -1139,6 +1123,29 @@ void CRYPTO_gcm128_finish(GCM128_CONTEXT *ctx)
 
        ctx->Xi.u[0] ^= ctx->EK0.u[0];
        ctx->Xi.u[1] ^= ctx->EK0.u[1];
+
+       if (tag && len<=sizeof(ctx->Xi))
+               return memcmp(ctx->Xi.c,tag,len);
+       else
+               return -1;
+}
+
+GCM128_CONTEXT *CRYPTO_gcm128_new(void *key, block128_f block)
+{
+       GCM128_CONTEXT *ret;
+
+       if ((ret = (GCM128_CONTEXT *)OPENSSL_malloc(sizeof(GCM128_CONTEXT))))
+               CRYPTO_gcm128_init(ret,key,block);
+
+       return ret;
+}
+
+void CRYPTO_gcm128_release(GCM128_CONTEXT *ctx)
+{
+       if (ctx) {
+               OPENSSL_cleanse(ctx,sizeof(*ctx));
+               OPENSSL_free(ctx);
+       }
 }
 
 #if defined(SELFTEST)
@@ -1365,15 +1372,15 @@ static const u8 IV18[]={0x93,0x13,0x22,0x5d,0xf8,0x84,0x06,0xe5,0x55,0x90,0x9c,0
        CRYPTO_gcm128_setiv(&ctx,IV##n,sizeof(IV##n));          \
        if (A##n) CRYPTO_gcm128_aad(&ctx,A##n,sizeof(A##n));    \
        if (P##n) CRYPTO_gcm128_encrypt(&ctx,P##n,out,sizeof(out));     \
-       CRYPTO_gcm128_finish(&ctx);                             \
-       if (memcmp(ctx.Xi.c,T##n,16) || (C##n && memcmp(out,C##n,sizeof(out)))) \
+       if (CRYPTO_gcm128_finish(&ctx,T##n,16) ||               \
+           (C##n && memcmp(out,C##n,sizeof(out))))             \
                ret++, printf ("encrypt test#%d failed.\n",n);\
        CRYPTO_gcm128_setiv(&ctx,IV##n,sizeof(IV##n));          \
        if (A##n) CRYPTO_gcm128_aad(&ctx,A##n,sizeof(A##n));    \
        if (C##n) CRYPTO_gcm128_decrypt(&ctx,C##n,out,sizeof(out));     \
-       CRYPTO_gcm128_finish(&ctx);                             \
-       if (memcmp(ctx.Xi.c,T##n,16) || (P##n && memcmp(out,P##n,sizeof(out)))) \
-               ret++, printf ("decrypt test#%d failed.\n",n);\
+       if (CRYPTO_gcm128_finish(&ctx,T##n,16) ||               \
+           (P##n && memcmp(out,P##n,sizeof(out))))             \
+               ret++, printf ("decrypt test#%d failed.\n",n);  \
        } while(0)
 
 int main()