Mercurial > dropbear
view libtomcrypt/src/ciphers/aes/aes.c @ 1790:42745af83b7d
Introduce extra delay before closing unauthenticated sessions
To make it harder for attackers, introduce a delay to keep an
unauthenticated session open a bit longer, thus blocking a connection
slot until after the delay.
Without this, while there is a limit on the amount of attempts an attacker
can make at the same time (MAX_UNAUTH_PER_IP), the time taken by dropbear to
handle one attempt is still short and thus for each of the allowed parallel
attempts many attempts can be chained one after the other. The attempt rate
is then:
"MAX_UNAUTH_PER_IP / <process time of one attempt>".
With the delay, this rate becomes:
"MAX_UNAUTH_PER_IP / UNAUTH_CLOSE_DELAY".
author | Thomas De Schampheleire <thomas.de_schampheleire@nokia.com> |
---|---|
date | Wed, 15 Feb 2017 13:53:04 +0100 |
parents | 1ff2a1034c52 |
children |
line wrap: on
line source
/* LibTomCrypt, modular cryptographic library -- Tom St Denis * * LibTomCrypt is a library that provides various cryptographic * algorithms in a highly modular and flexible manner. * * The library is free for all purposes without any express * guarantee it works. */ /* AES implementation by Tom St Denis * * Derived from the Public Domain source code by --- * rijndael-alg-fst.c * * @version 3.0 (December 2000) * * Optimised ANSI C code for the Rijndael cipher (now AES) * * @author Vincent Rijmen <[email protected]> * @author Antoon Bosselaers <[email protected]> * @author Paulo Barreto <[email protected]> --- */ /** @file aes.c Implementation of AES */ #include "tomcrypt.h" #ifdef LTC_RIJNDAEL #ifndef ENCRYPT_ONLY #define SETUP rijndael_setup #define ECB_ENC rijndael_ecb_encrypt #define ECB_DEC rijndael_ecb_decrypt #define ECB_DONE rijndael_done #define ECB_TEST rijndael_test #define ECB_KS rijndael_keysize #if 0 const struct ltc_cipher_descriptor rijndael_desc = { "rijndael", 6, 16, 32, 16, 10, SETUP, ECB_ENC, ECB_DEC, ECB_TEST, ECB_DONE, ECB_KS, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL }; #endif const struct ltc_cipher_descriptor aes_desc = { "aes", 6, 16, 32, 16, 10, SETUP, ECB_ENC, ECB_DEC, ECB_TEST, ECB_DONE, ECB_KS, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL }; #else #define SETUP rijndael_enc_setup #define ECB_ENC rijndael_enc_ecb_encrypt #define ECB_KS rijndael_enc_keysize #define ECB_DONE rijndael_enc_done const struct ltc_cipher_descriptor rijndael_enc_desc = { "rijndael", 6, 16, 32, 16, 10, SETUP, ECB_ENC, NULL, NULL, ECB_DONE, ECB_KS, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL }; const struct ltc_cipher_descriptor aes_enc_desc = { "aes", 6, 16, 32, 16, 10, SETUP, ECB_ENC, NULL, NULL, ECB_DONE, ECB_KS, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL }; #endif #define __LTC_AES_TAB_C__ #include "aes_tab.c" static ulong32 setup_mix(ulong32 temp) { return (Te4_3[byte(temp, 2)]) ^ (Te4_2[byte(temp, 1)]) ^ (Te4_1[byte(temp, 0)]) ^ (Te4_0[byte(temp, 3)]); } #ifndef ENCRYPT_ONLY #ifdef LTC_SMALL_CODE static ulong32 setup_mix2(ulong32 temp) { return Td0(255 & Te4[byte(temp, 3)]) ^ Td1(255 & Te4[byte(temp, 2)]) ^ Td2(255 & Te4[byte(temp, 1)]) ^ Td3(255 & Te4[byte(temp, 0)]); } #endif #endif /** Initialize the AES (Rijndael) block cipher @param key The symmetric key you wish to pass @param keylen The key length in bytes @param num_rounds The number of rounds desired (0 for default) @param skey The key in as scheduled by this function. @return CRYPT_OK if successful */ int SETUP(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey) { int i; ulong32 temp, *rk; #ifndef ENCRYPT_ONLY ulong32 *rrk; #endif LTC_ARGCHK(key != NULL); LTC_ARGCHK(skey != NULL); if (keylen != 16 && keylen != 24 && keylen != 32) { return CRYPT_INVALID_KEYSIZE; } if (num_rounds != 0 && num_rounds != (10 + ((keylen/8)-2)*2)) { return CRYPT_INVALID_ROUNDS; } skey->rijndael.Nr = 10 + ((keylen/8)-2)*2; /* setup the forward key */ i = 0; rk = skey->rijndael.eK; LOAD32H(rk[0], key ); LOAD32H(rk[1], key + 4); LOAD32H(rk[2], key + 8); LOAD32H(rk[3], key + 12); if (keylen == 16) { for (;;) { temp = rk[3]; rk[4] = rk[0] ^ setup_mix(temp) ^ rcon[i]; rk[5] = rk[1] ^ rk[4]; rk[6] = rk[2] ^ rk[5]; rk[7] = rk[3] ^ rk[6]; if (++i == 10) { break; } rk += 4; } } else if (keylen == 24) { LOAD32H(rk[4], key + 16); LOAD32H(rk[5], key + 20); for (;;) { #ifdef _MSC_VER temp = skey->rijndael.eK[rk - skey->rijndael.eK + 5]; #else temp = rk[5]; #endif rk[ 6] = rk[ 0] ^ setup_mix(temp) ^ rcon[i]; rk[ 7] = rk[ 1] ^ rk[ 6]; rk[ 8] = rk[ 2] ^ rk[ 7]; rk[ 9] = rk[ 3] ^ rk[ 8]; if (++i == 8) { break; } rk[10] = rk[ 4] ^ rk[ 9]; rk[11] = rk[ 5] ^ rk[10]; rk += 6; } } else if (keylen == 32) { LOAD32H(rk[4], key + 16); LOAD32H(rk[5], key + 20); LOAD32H(rk[6], key + 24); LOAD32H(rk[7], key + 28); for (;;) { #ifdef _MSC_VER temp = skey->rijndael.eK[rk - skey->rijndael.eK + 7]; #else temp = rk[7]; #endif rk[ 8] = rk[ 0] ^ setup_mix(temp) ^ rcon[i]; rk[ 9] = rk[ 1] ^ rk[ 8]; rk[10] = rk[ 2] ^ rk[ 9]; rk[11] = rk[ 3] ^ rk[10]; if (++i == 7) { break; } temp = rk[11]; rk[12] = rk[ 4] ^ setup_mix(RORc(temp, 8)); rk[13] = rk[ 5] ^ rk[12]; rk[14] = rk[ 6] ^ rk[13]; rk[15] = rk[ 7] ^ rk[14]; rk += 8; } } else { /* this can't happen */ /* coverity[dead_error_line] */ return CRYPT_ERROR; } #ifndef ENCRYPT_ONLY /* setup the inverse key now */ rk = skey->rijndael.dK; rrk = skey->rijndael.eK + (28 + keylen) - 4; /* apply the inverse MixColumn transform to all round keys but the first and the last: */ /* copy first */ *rk++ = *rrk++; *rk++ = *rrk++; *rk++ = *rrk++; *rk = *rrk; rk -= 3; rrk -= 3; for (i = 1; i < skey->rijndael.Nr; i++) { rrk -= 4; rk += 4; #ifdef LTC_SMALL_CODE temp = rrk[0]; rk[0] = setup_mix2(temp); temp = rrk[1]; rk[1] = setup_mix2(temp); temp = rrk[2]; rk[2] = setup_mix2(temp); temp = rrk[3]; rk[3] = setup_mix2(temp); #else temp = rrk[0]; rk[0] = Tks0[byte(temp, 3)] ^ Tks1[byte(temp, 2)] ^ Tks2[byte(temp, 1)] ^ Tks3[byte(temp, 0)]; temp = rrk[1]; rk[1] = Tks0[byte(temp, 3)] ^ Tks1[byte(temp, 2)] ^ Tks2[byte(temp, 1)] ^ Tks3[byte(temp, 0)]; temp = rrk[2]; rk[2] = Tks0[byte(temp, 3)] ^ Tks1[byte(temp, 2)] ^ Tks2[byte(temp, 1)] ^ Tks3[byte(temp, 0)]; temp = rrk[3]; rk[3] = Tks0[byte(temp, 3)] ^ Tks1[byte(temp, 2)] ^ Tks2[byte(temp, 1)] ^ Tks3[byte(temp, 0)]; #endif } /* copy last */ rrk -= 4; rk += 4; *rk++ = *rrk++; *rk++ = *rrk++; *rk++ = *rrk++; *rk = *rrk; #endif /* ENCRYPT_ONLY */ return CRYPT_OK; } /** Encrypts a block of text with AES @param pt The input plaintext (16 bytes) @param ct The output ciphertext (16 bytes) @param skey The key as scheduled @return CRYPT_OK if successful */ #ifdef LTC_CLEAN_STACK static int _rijndael_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey) #else int ECB_ENC(const unsigned char *pt, unsigned char *ct, symmetric_key *skey) #endif { ulong32 s0, s1, s2, s3, t0, t1, t2, t3, *rk; int Nr, r; LTC_ARGCHK(pt != NULL); LTC_ARGCHK(ct != NULL); LTC_ARGCHK(skey != NULL); Nr = skey->rijndael.Nr; rk = skey->rijndael.eK; /* * map byte array block to cipher state * and add initial round key: */ LOAD32H(s0, pt ); s0 ^= rk[0]; LOAD32H(s1, pt + 4); s1 ^= rk[1]; LOAD32H(s2, pt + 8); s2 ^= rk[2]; LOAD32H(s3, pt + 12); s3 ^= rk[3]; #ifdef LTC_SMALL_CODE for (r = 0; ; r++) { rk += 4; t0 = Te0(byte(s0, 3)) ^ Te1(byte(s1, 2)) ^ Te2(byte(s2, 1)) ^ Te3(byte(s3, 0)) ^ rk[0]; t1 = Te0(byte(s1, 3)) ^ Te1(byte(s2, 2)) ^ Te2(byte(s3, 1)) ^ Te3(byte(s0, 0)) ^ rk[1]; t2 = Te0(byte(s2, 3)) ^ Te1(byte(s3, 2)) ^ Te2(byte(s0, 1)) ^ Te3(byte(s1, 0)) ^ rk[2]; t3 = Te0(byte(s3, 3)) ^ Te1(byte(s0, 2)) ^ Te2(byte(s1, 1)) ^ Te3(byte(s2, 0)) ^ rk[3]; if (r == Nr-2) { break; } s0 = t0; s1 = t1; s2 = t2; s3 = t3; } rk += 4; #else /* * Nr - 1 full rounds: */ r = Nr >> 1; for (;;) { t0 = Te0(byte(s0, 3)) ^ Te1(byte(s1, 2)) ^ Te2(byte(s2, 1)) ^ Te3(byte(s3, 0)) ^ rk[4]; t1 = Te0(byte(s1, 3)) ^ Te1(byte(s2, 2)) ^ Te2(byte(s3, 1)) ^ Te3(byte(s0, 0)) ^ rk[5]; t2 = Te0(byte(s2, 3)) ^ Te1(byte(s3, 2)) ^ Te2(byte(s0, 1)) ^ Te3(byte(s1, 0)) ^ rk[6]; t3 = Te0(byte(s3, 3)) ^ Te1(byte(s0, 2)) ^ Te2(byte(s1, 1)) ^ Te3(byte(s2, 0)) ^ rk[7]; rk += 8; if (--r == 0) { break; } s0 = Te0(byte(t0, 3)) ^ Te1(byte(t1, 2)) ^ Te2(byte(t2, 1)) ^ Te3(byte(t3, 0)) ^ rk[0]; s1 = Te0(byte(t1, 3)) ^ Te1(byte(t2, 2)) ^ Te2(byte(t3, 1)) ^ Te3(byte(t0, 0)) ^ rk[1]; s2 = Te0(byte(t2, 3)) ^ Te1(byte(t3, 2)) ^ Te2(byte(t0, 1)) ^ Te3(byte(t1, 0)) ^ rk[2]; s3 = Te0(byte(t3, 3)) ^ Te1(byte(t0, 2)) ^ Te2(byte(t1, 1)) ^ Te3(byte(t2, 0)) ^ rk[3]; } #endif /* * apply last round and * map cipher state to byte array block: */ s0 = (Te4_3[byte(t0, 3)]) ^ (Te4_2[byte(t1, 2)]) ^ (Te4_1[byte(t2, 1)]) ^ (Te4_0[byte(t3, 0)]) ^ rk[0]; STORE32H(s0, ct); s1 = (Te4_3[byte(t1, 3)]) ^ (Te4_2[byte(t2, 2)]) ^ (Te4_1[byte(t3, 1)]) ^ (Te4_0[byte(t0, 0)]) ^ rk[1]; STORE32H(s1, ct+4); s2 = (Te4_3[byte(t2, 3)]) ^ (Te4_2[byte(t3, 2)]) ^ (Te4_1[byte(t0, 1)]) ^ (Te4_0[byte(t1, 0)]) ^ rk[2]; STORE32H(s2, ct+8); s3 = (Te4_3[byte(t3, 3)]) ^ (Te4_2[byte(t0, 2)]) ^ (Te4_1[byte(t1, 1)]) ^ (Te4_0[byte(t2, 0)]) ^ rk[3]; STORE32H(s3, ct+12); return CRYPT_OK; } #ifdef LTC_CLEAN_STACK int ECB_ENC(const unsigned char *pt, unsigned char *ct, symmetric_key *skey) { int err = _rijndael_ecb_encrypt(pt, ct, skey); burn_stack(sizeof(unsigned long)*8 + sizeof(unsigned long*) + sizeof(int)*2); return err; } #endif #ifndef ENCRYPT_ONLY /** Decrypts a block of text with AES @param ct The input ciphertext (16 bytes) @param pt The output plaintext (16 bytes) @param skey The key as scheduled @return CRYPT_OK if successful */ #ifdef LTC_CLEAN_STACK static int _rijndael_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey) #else int ECB_DEC(const unsigned char *ct, unsigned char *pt, symmetric_key *skey) #endif { ulong32 s0, s1, s2, s3, t0, t1, t2, t3, *rk; int Nr, r; LTC_ARGCHK(pt != NULL); LTC_ARGCHK(ct != NULL); LTC_ARGCHK(skey != NULL); Nr = skey->rijndael.Nr; rk = skey->rijndael.dK; /* * map byte array block to cipher state * and add initial round key: */ LOAD32H(s0, ct ); s0 ^= rk[0]; LOAD32H(s1, ct + 4); s1 ^= rk[1]; LOAD32H(s2, ct + 8); s2 ^= rk[2]; LOAD32H(s3, ct + 12); s3 ^= rk[3]; #ifdef LTC_SMALL_CODE for (r = 0; ; r++) { rk += 4; t0 = Td0(byte(s0, 3)) ^ Td1(byte(s3, 2)) ^ Td2(byte(s2, 1)) ^ Td3(byte(s1, 0)) ^ rk[0]; t1 = Td0(byte(s1, 3)) ^ Td1(byte(s0, 2)) ^ Td2(byte(s3, 1)) ^ Td3(byte(s2, 0)) ^ rk[1]; t2 = Td0(byte(s2, 3)) ^ Td1(byte(s1, 2)) ^ Td2(byte(s0, 1)) ^ Td3(byte(s3, 0)) ^ rk[2]; t3 = Td0(byte(s3, 3)) ^ Td1(byte(s2, 2)) ^ Td2(byte(s1, 1)) ^ Td3(byte(s0, 0)) ^ rk[3]; if (r == Nr-2) { break; } s0 = t0; s1 = t1; s2 = t2; s3 = t3; } rk += 4; #else /* * Nr - 1 full rounds: */ r = Nr >> 1; for (;;) { t0 = Td0(byte(s0, 3)) ^ Td1(byte(s3, 2)) ^ Td2(byte(s2, 1)) ^ Td3(byte(s1, 0)) ^ rk[4]; t1 = Td0(byte(s1, 3)) ^ Td1(byte(s0, 2)) ^ Td2(byte(s3, 1)) ^ Td3(byte(s2, 0)) ^ rk[5]; t2 = Td0(byte(s2, 3)) ^ Td1(byte(s1, 2)) ^ Td2(byte(s0, 1)) ^ Td3(byte(s3, 0)) ^ rk[6]; t3 = Td0(byte(s3, 3)) ^ Td1(byte(s2, 2)) ^ Td2(byte(s1, 1)) ^ Td3(byte(s0, 0)) ^ rk[7]; rk += 8; if (--r == 0) { break; } s0 = Td0(byte(t0, 3)) ^ Td1(byte(t3, 2)) ^ Td2(byte(t2, 1)) ^ Td3(byte(t1, 0)) ^ rk[0]; s1 = Td0(byte(t1, 3)) ^ Td1(byte(t0, 2)) ^ Td2(byte(t3, 1)) ^ Td3(byte(t2, 0)) ^ rk[1]; s2 = Td0(byte(t2, 3)) ^ Td1(byte(t1, 2)) ^ Td2(byte(t0, 1)) ^ Td3(byte(t3, 0)) ^ rk[2]; s3 = Td0(byte(t3, 3)) ^ Td1(byte(t2, 2)) ^ Td2(byte(t1, 1)) ^ Td3(byte(t0, 0)) ^ rk[3]; } #endif /* * apply last round and * map cipher state to byte array block: */ s0 = (Td4[byte(t0, 3)] & 0xff000000) ^ (Td4[byte(t3, 2)] & 0x00ff0000) ^ (Td4[byte(t2, 1)] & 0x0000ff00) ^ (Td4[byte(t1, 0)] & 0x000000ff) ^ rk[0]; STORE32H(s0, pt); s1 = (Td4[byte(t1, 3)] & 0xff000000) ^ (Td4[byte(t0, 2)] & 0x00ff0000) ^ (Td4[byte(t3, 1)] & 0x0000ff00) ^ (Td4[byte(t2, 0)] & 0x000000ff) ^ rk[1]; STORE32H(s1, pt+4); s2 = (Td4[byte(t2, 3)] & 0xff000000) ^ (Td4[byte(t1, 2)] & 0x00ff0000) ^ (Td4[byte(t0, 1)] & 0x0000ff00) ^ (Td4[byte(t3, 0)] & 0x000000ff) ^ rk[2]; STORE32H(s2, pt+8); s3 = (Td4[byte(t3, 3)] & 0xff000000) ^ (Td4[byte(t2, 2)] & 0x00ff0000) ^ (Td4[byte(t1, 1)] & 0x0000ff00) ^ (Td4[byte(t0, 0)] & 0x000000ff) ^ rk[3]; STORE32H(s3, pt+12); return CRYPT_OK; } #ifdef LTC_CLEAN_STACK int ECB_DEC(const unsigned char *ct, unsigned char *pt, symmetric_key *skey) { int err = _rijndael_ecb_decrypt(ct, pt, skey); burn_stack(sizeof(unsigned long)*8 + sizeof(unsigned long*) + sizeof(int)*2); return err; } #endif /** Performs a self-test of the AES block cipher @return CRYPT_OK if functional, CRYPT_NOP if self-test has been disabled */ int ECB_TEST(void) { #ifndef LTC_TEST return CRYPT_NOP; #else int err; static const struct { int keylen; unsigned char key[32], pt[16], ct[16]; } tests[] = { { 16, { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f }, { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff }, { 0x69, 0xc4, 0xe0, 0xd8, 0x6a, 0x7b, 0x04, 0x30, 0xd8, 0xcd, 0xb7, 0x80, 0x70, 0xb4, 0xc5, 0x5a } }, { 24, { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17 }, { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff }, { 0xdd, 0xa9, 0x7c, 0xa4, 0x86, 0x4c, 0xdf, 0xe0, 0x6e, 0xaf, 0x70, 0xa0, 0xec, 0x0d, 0x71, 0x91 } }, { 32, { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f }, { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff }, { 0x8e, 0xa2, 0xb7, 0xca, 0x51, 0x67, 0x45, 0xbf, 0xea, 0xfc, 0x49, 0x90, 0x4b, 0x49, 0x60, 0x89 } } }; symmetric_key key; unsigned char tmp[2][16]; int i, y; for (i = 0; i < (int)(sizeof(tests)/sizeof(tests[0])); i++) { zeromem(&key, sizeof(key)); if ((err = rijndael_setup(tests[i].key, tests[i].keylen, 0, &key)) != CRYPT_OK) { return err; } rijndael_ecb_encrypt(tests[i].pt, tmp[0], &key); rijndael_ecb_decrypt(tmp[0], tmp[1], &key); if (compare_testvector(tmp[0], 16, tests[i].ct, 16, "AES Encrypt", i) || compare_testvector(tmp[1], 16, tests[i].pt, 16, "AES Decrypt", i)) { return CRYPT_FAIL_TESTVECTOR; } /* now see if we can encrypt all zero bytes 1000 times, decrypt and come back where we started */ for (y = 0; y < 16; y++) tmp[0][y] = 0; for (y = 0; y < 1000; y++) rijndael_ecb_encrypt(tmp[0], tmp[0], &key); for (y = 0; y < 1000; y++) rijndael_ecb_decrypt(tmp[0], tmp[0], &key); for (y = 0; y < 16; y++) if (tmp[0][y] != 0) return CRYPT_FAIL_TESTVECTOR; } return CRYPT_OK; #endif } #endif /* ENCRYPT_ONLY */ /** Terminate the context @param skey The scheduled key */ void ECB_DONE(symmetric_key *skey) { LTC_UNUSED_PARAM(skey); } /** Gets suitable key size @param keysize [in/out] The length of the recommended key (in bytes). This function will store the suitable size back in this variable. @return CRYPT_OK if the input key size is acceptable. */ int ECB_KS(int *keysize) { LTC_ARGCHK(keysize != NULL); if (*keysize < 16) return CRYPT_INVALID_KEYSIZE; if (*keysize < 24) { *keysize = 16; return CRYPT_OK; } else if (*keysize < 32) { *keysize = 24; return CRYPT_OK; } else { *keysize = 32; return CRYPT_OK; } } #endif /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */