Mercurial > dropbear
view libtomcrypt/src/encauth/gcm/gcm_process.c @ 1863:b550845e500b
Use venv for test_aslr
Otherwise we can't find the psutil dependency
author | Matt Johnston <matt@ucc.asn.au> |
---|---|
date | Sun, 30 Jan 2022 13:37:20 +0800 |
parents | 6dba84798cd5 |
children |
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/* 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. */ /** @file gcm_process.c GCM implementation, process message data, by Tom St Denis */ #include "tomcrypt.h" #ifdef LTC_GCM_MODE /** Process plaintext/ciphertext through GCM @param gcm The GCM state @param pt The plaintext @param ptlen The plaintext length (ciphertext length is the same) @param ct The ciphertext @param direction Encrypt or Decrypt mode (GCM_ENCRYPT or GCM_DECRYPT) @return CRYPT_OK on success */ int gcm_process(gcm_state *gcm, unsigned char *pt, unsigned long ptlen, unsigned char *ct, int direction) { unsigned long x; int y, err; unsigned char b; LTC_ARGCHK(gcm != NULL); if (ptlen > 0) { LTC_ARGCHK(pt != NULL); LTC_ARGCHK(ct != NULL); } if (gcm->buflen > 16 || gcm->buflen < 0) { return CRYPT_INVALID_ARG; } if ((err = cipher_is_valid(gcm->cipher)) != CRYPT_OK) { return err; } /* 0xFFFFFFFE0 = ((2^39)-256)/8 */ if (gcm->pttotlen / 8 + (ulong64)gcm->buflen + (ulong64)ptlen >= CONST64(0xFFFFFFFE0)) { return CRYPT_INVALID_ARG; } if (gcm->mode == LTC_GCM_MODE_IV) { /* let's process the IV */ if ((err = gcm_add_aad(gcm, NULL, 0)) != CRYPT_OK) return err; } /* in AAD mode? */ if (gcm->mode == LTC_GCM_MODE_AAD) { /* let's process the AAD */ if (gcm->buflen) { gcm->totlen += gcm->buflen * CONST64(8); gcm_mult_h(gcm, gcm->X); } /* increment counter */ for (y = 15; y >= 12; y--) { if (++gcm->Y[y] & 255) { break; } } /* encrypt the counter */ if ((err = cipher_descriptor[gcm->cipher].ecb_encrypt(gcm->Y, gcm->buf, &gcm->K)) != CRYPT_OK) { return err; } gcm->buflen = 0; gcm->mode = LTC_GCM_MODE_TEXT; } if (gcm->mode != LTC_GCM_MODE_TEXT) { return CRYPT_INVALID_ARG; } x = 0; #ifdef LTC_FAST if (gcm->buflen == 0) { if (direction == GCM_ENCRYPT) { for (x = 0; x < (ptlen & ~15); x += 16) { /* ctr encrypt */ for (y = 0; y < 16; y += sizeof(LTC_FAST_TYPE)) { *(LTC_FAST_TYPE_PTR_CAST(&ct[x + y])) = *(LTC_FAST_TYPE_PTR_CAST(&pt[x+y])) ^ *(LTC_FAST_TYPE_PTR_CAST(&gcm->buf[y])); *(LTC_FAST_TYPE_PTR_CAST(&gcm->X[y])) ^= *(LTC_FAST_TYPE_PTR_CAST(&ct[x+y])); } /* GMAC it */ gcm->pttotlen += 128; gcm_mult_h(gcm, gcm->X); /* increment counter */ for (y = 15; y >= 12; y--) { if (++gcm->Y[y] & 255) { break; } } if ((err = cipher_descriptor[gcm->cipher].ecb_encrypt(gcm->Y, gcm->buf, &gcm->K)) != CRYPT_OK) { return err; } } } else { for (x = 0; x < (ptlen & ~15); x += 16) { /* ctr encrypt */ for (y = 0; y < 16; y += sizeof(LTC_FAST_TYPE)) { *(LTC_FAST_TYPE_PTR_CAST(&gcm->X[y])) ^= *(LTC_FAST_TYPE_PTR_CAST(&ct[x+y])); *(LTC_FAST_TYPE_PTR_CAST(&pt[x + y])) = *(LTC_FAST_TYPE_PTR_CAST(&ct[x+y])) ^ *(LTC_FAST_TYPE_PTR_CAST(&gcm->buf[y])); } /* GMAC it */ gcm->pttotlen += 128; gcm_mult_h(gcm, gcm->X); /* increment counter */ for (y = 15; y >= 12; y--) { if (++gcm->Y[y] & 255) { break; } } if ((err = cipher_descriptor[gcm->cipher].ecb_encrypt(gcm->Y, gcm->buf, &gcm->K)) != CRYPT_OK) { return err; } } } } #endif /* process text */ for (; x < ptlen; x++) { if (gcm->buflen == 16) { gcm->pttotlen += 128; gcm_mult_h(gcm, gcm->X); /* increment counter */ for (y = 15; y >= 12; y--) { if (++gcm->Y[y] & 255) { break; } } if ((err = cipher_descriptor[gcm->cipher].ecb_encrypt(gcm->Y, gcm->buf, &gcm->K)) != CRYPT_OK) { return err; } gcm->buflen = 0; } if (direction == GCM_ENCRYPT) { b = ct[x] = pt[x] ^ gcm->buf[gcm->buflen]; } else { b = ct[x]; pt[x] = ct[x] ^ gcm->buf[gcm->buflen]; } gcm->X[gcm->buflen++] ^= b; } return CRYPT_OK; } #endif /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */