Merge remote-tracking branch 'origin/debian' into debian

[mech_eap.git] / libeap / src / crypto / aes-internal-dec.c

diff --git a/libeap/src/crypto/aes-internal-dec.c b/libeap/src/crypto/aes-internal-dec.c
new file mode 100644 (file)
index 0000000..720c703
--- /dev/null
+++ b/libeap/src/crypto/aes-internal-dec.c
@@ -0,0 +1,161 @@
+/*
+ * AES (Rijndael) cipher - decrypt
+ *
+ * Modifications to public domain implementation:
+ * - cleanup
+ * - use C pre-processor to make it easier to change S table access
+ * - added option (AES_SMALL_TABLES) for reducing code size by about 8 kB at
+ *   cost of reduced throughput (quite small difference on Pentium 4,
+ *   10-25% when using -O1 or -O2 optimization)
+ *
+ * Copyright (c) 2003-2012, Jouni Malinen <j@w1.fi>
+ *
+ * This software may be distributed under the terms of the BSD license.
+ * See README for more details.
+ */
+
+#include "includes.h"
+
+#include "common.h"
+#include "crypto.h"
+#include "aes_i.h"
+
+/**
+ * Expand the cipher key into the decryption key schedule.
+ *
+ * @return     the number of rounds for the given cipher key size.
+ */
+static int rijndaelKeySetupDec(u32 rk[], const u8 cipherKey[], int keyBits)
+{
+       int Nr, i, j;
+       u32 temp;
+
+       /* expand the cipher key: */
+       Nr = rijndaelKeySetupEnc(rk, cipherKey, keyBits);
+       if (Nr < 0)
+               return Nr;
+       /* invert the order of the round keys: */
+       for (i = 0, j = 4*Nr; i < j; i += 4, j -= 4) {
+               temp = rk[i    ]; rk[i    ] = rk[j    ]; rk[j    ] = temp;
+               temp = rk[i + 1]; rk[i + 1] = rk[j + 1]; rk[j + 1] = temp;
+               temp = rk[i + 2]; rk[i + 2] = rk[j + 2]; rk[j + 2] = temp;
+               temp = rk[i + 3]; rk[i + 3] = rk[j + 3]; rk[j + 3] = temp;
+       }
+       /* apply the inverse MixColumn transform to all round keys but the
+        * first and the last: */
+       for (i = 1; i < Nr; i++) {
+               rk += 4;
+               for (j = 0; j < 4; j++) {
+                       rk[j] = TD0_(TE4((rk[j] >> 24)       )) ^
+                               TD1_(TE4((rk[j] >> 16) & 0xff)) ^
+                               TD2_(TE4((rk[j] >>  8) & 0xff)) ^
+                               TD3_(TE4((rk[j]      ) & 0xff));
+               }
+       }
+
+       return Nr;
+}
+
+void * aes_decrypt_init(const u8 *key, size_t len)
+{
+       u32 *rk;
+       int res;
+       rk = os_malloc(AES_PRIV_SIZE);
+       if (rk == NULL)
+               return NULL;
+       res = rijndaelKeySetupDec(rk, key, len * 8);
+       if (res < 0) {
+               os_free(rk);
+               return NULL;
+       }
+       rk[AES_PRIV_NR_POS] = res;
+       return rk;
+}
+
+static void rijndaelDecrypt(const u32 rk[/*44*/], int Nr, const u8 ct[16],
+                           u8 pt[16])
+{
+       u32 s0, s1, s2, s3, t0, t1, t2, t3;
+#ifndef FULL_UNROLL
+       int r;
+#endif /* ?FULL_UNROLL */
+
+       /*
+        * map byte array block to cipher state
+        * and add initial round key:
+        */
+       s0 = GETU32(ct     ) ^ rk[0];
+       s1 = GETU32(ct +  4) ^ rk[1];
+       s2 = GETU32(ct +  8) ^ rk[2];
+       s3 = GETU32(ct + 12) ^ rk[3];
+
+#define ROUND(i,d,s) \
+d##0 = TD0(s##0) ^ TD1(s##3) ^ TD2(s##2) ^ TD3(s##1) ^ rk[4 * i]; \
+d##1 = TD0(s##1) ^ TD1(s##0) ^ TD2(s##3) ^ TD3(s##2) ^ rk[4 * i + 1]; \
+d##2 = TD0(s##2) ^ TD1(s##1) ^ TD2(s##0) ^ TD3(s##3) ^ rk[4 * i + 2]; \
+d##3 = TD0(s##3) ^ TD1(s##2) ^ TD2(s##1) ^ TD3(s##0) ^ rk[4 * i + 3]
+
+#ifdef FULL_UNROLL
+
+       ROUND(1,t,s);
+       ROUND(2,s,t);
+       ROUND(3,t,s);
+       ROUND(4,s,t);
+       ROUND(5,t,s);
+       ROUND(6,s,t);
+       ROUND(7,t,s);
+       ROUND(8,s,t);
+       ROUND(9,t,s);
+       if (Nr > 10) {
+               ROUND(10,s,t);
+               ROUND(11,t,s);
+               if (Nr > 12) {
+                       ROUND(12,s,t);
+                       ROUND(13,t,s);
+               }
+       }
+
+       rk += Nr << 2;
+
+#else  /* !FULL_UNROLL */
+
+       /* Nr - 1 full rounds: */
+       r = Nr >> 1;
+       for (;;) {
+               ROUND(1,t,s);
+               rk += 8;
+               if (--r == 0)
+                       break;
+               ROUND(0,s,t);
+       }
+
+#endif /* ?FULL_UNROLL */
+
+#undef ROUND
+
+       /*
+        * apply last round and
+        * map cipher state to byte array block:
+        */
+       s0 = TD41(t0) ^ TD42(t3) ^ TD43(t2) ^ TD44(t1) ^ rk[0];
+       PUTU32(pt     , s0);
+       s1 = TD41(t1) ^ TD42(t0) ^ TD43(t3) ^ TD44(t2) ^ rk[1];
+       PUTU32(pt +  4, s1);
+       s2 = TD41(t2) ^ TD42(t1) ^ TD43(t0) ^ TD44(t3) ^ rk[2];
+       PUTU32(pt +  8, s2);
+       s3 = TD41(t3) ^ TD42(t2) ^ TD43(t1) ^ TD44(t0) ^ rk[3];
+       PUTU32(pt + 12, s3);
+}
+
+void aes_decrypt(void *ctx, const u8 *crypt, u8 *plain)
+{
+       u32 *rk = ctx;
+       rijndaelDecrypt(ctx, rk[AES_PRIV_NR_POS], crypt, plain);
+}
+
+
+void aes_decrypt_deinit(void *ctx)
+{
+       os_memset(ctx, 0, AES_PRIV_SIZE);
+       os_free(ctx);
+}