339 lines
9.0 KiB
C
339 lines
9.0 KiB
C
#define _FILE_OFFSET_BITS 64
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#include <assert.h>
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#include <string.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/types.h>
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#include <aio.h>
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#include <netdb.h>
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#include <openssl/bn.h>
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#include <openssl/rand.h>
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#include <openssl/pem.h>
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#include <openssl/aes.h>
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#include <openssl/sha.h>
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#include "mtproto-common.h"
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#include "interface.h"
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long long rsa_encrypted_chunks, rsa_decrypted_chunks;
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BN_CTX *BN_ctx;
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int verbosity;
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int get_random_bytes (void *buf, int n) {
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int r = 0, h = open ("/dev/random", O_RDONLY | O_NONBLOCK);
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if (h >= 0) {
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r = read (h, buf, n);
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if (r > 0) {
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if (verbosity >= 3) {
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logprintf ( "added %d bytes of real entropy to secure random numbers seed\n", r);
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}
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}
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close (h);
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}
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if (r < n) {
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h = open ("/dev/urandom", O_RDONLY);
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if (h < 0) {
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return r;
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}
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int s = read (h, buf + r, n - r);
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close (h);
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if (s < 0) {
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return r;
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}
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r += s;
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}
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if (r >= (int)sizeof (long)) {
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*(long *)buf ^= lrand48 ();
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srand48 (*(long *)buf);
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}
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return r;
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}
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void prng_seed (const char *password_filename, int password_length) {
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unsigned char *a = calloc (64 + password_length, 1);
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assert (a != NULL);
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long long r = rdtsc ();
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struct timespec T;
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assert (clock_gettime(CLOCK_REALTIME, &T) >= 0);
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memcpy (a, &T.tv_sec, 4);
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memcpy (a+4, &T.tv_nsec, 4);
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memcpy (a+8, &r, 8);
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unsigned short p = getpid ();
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memcpy (a + 16, &p, 2);
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int s = get_random_bytes (a + 18, 32) + 18;
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if (password_filename) {
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int fd = open (password_filename, O_RDONLY);
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if (fd < 0) {
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logprintf ( "Warning: fail to open password file - \"%s\", %m.\n", password_filename);
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} else {
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int l = read (fd, a + s, password_length);
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if (l < 0) {
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logprintf ( "Warning: fail to read password file - \"%s\", %m.\n", password_filename);
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} else {
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if (verbosity > 0) {
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logprintf ( "read %d bytes from password file.\n", l);
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}
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s += l;
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}
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close (fd);
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}
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}
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RAND_seed (a, s);
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BN_ctx = BN_CTX_new ();
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memset (a, 0, s);
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free (a);
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}
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int serialize_bignum (BIGNUM *b, char *buffer, int maxlen) {
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int itslen = BN_num_bytes (b);
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int reqlen;
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if (itslen < 254) {
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reqlen = itslen + 1;
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} else {
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reqlen = itslen + 4;
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}
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int newlen = (reqlen + 3) & -4;
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int pad = newlen - reqlen;
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reqlen = newlen;
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if (reqlen > maxlen) {
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return -reqlen;
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}
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if (itslen < 254) {
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*buffer++ = itslen;
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} else {
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*(int *)buffer = (itslen << 8) + 0xfe;
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buffer += 4;
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}
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int l = BN_bn2bin (b, (unsigned char *)buffer);
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assert (l == itslen);
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buffer += l;
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while (pad --> 0) {
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*buffer++ = 0;
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}
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return reqlen;
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}
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long long compute_rsa_key_fingerprint (RSA *key) {
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static char tempbuff[4096];
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static unsigned char sha[20];
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assert (key->n && key->e);
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int l1 = serialize_bignum (key->n, tempbuff, 4096);
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assert (l1 > 0);
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int l2 = serialize_bignum (key->e, tempbuff + l1, 4096 - l1);
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assert (l2 > 0 && l1 + l2 <= 4096);
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SHA1 ((unsigned char *)tempbuff, l1 + l2, sha);
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return *(long long *)(sha + 12);
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}
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void out_cstring (const char *str, long len) {
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assert (len >= 0 && len < (1 << 24));
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assert ((char *) packet_ptr + len + 8 < (char *) (packet_buffer + PACKET_BUFFER_SIZE));
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char *dest = (char *) packet_ptr;
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if (len < 254) {
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*dest++ = len;
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} else {
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*packet_ptr = (len << 8) + 0xfe;
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dest += 4;
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}
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memcpy (dest, str, len);
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dest += len;
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while ((long) dest & 3) {
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*dest++ = 0;
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}
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packet_ptr = (int *) dest;
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}
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void out_cstring_careful (const char *str, long len) {
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assert (len >= 0 && len < (1 << 24));
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assert ((char *) packet_ptr + len + 8 < (char *) (packet_buffer + PACKET_BUFFER_SIZE));
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char *dest = (char *) packet_ptr;
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if (len < 254) {
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dest++;
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if (dest != str) {
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memmove (dest, str, len);
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}
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dest[-1] = len;
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} else {
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dest += 4;
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if (dest != str) {
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memmove (dest, str, len);
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}
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*packet_ptr = (len << 8) + 0xfe;
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}
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dest += len;
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while ((long) dest & 3) {
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*dest++ = 0;
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}
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packet_ptr = (int *) dest;
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}
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void out_data (const char *data, long len) {
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assert (len >= 0 && len < (1 << 24) && !(len & 3));
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assert ((char *) packet_ptr + len + 8 < (char *) (packet_buffer + PACKET_BUFFER_SIZE));
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memcpy (packet_ptr, data, len);
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packet_ptr += len >> 2;
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}
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int *in_ptr, *in_end;
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int fetch_bignum (BIGNUM *x) {
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int l = prefetch_strlen ();
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if (l < 0) {
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return l;
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}
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char *str = fetch_str (l);
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assert (BN_bin2bn ((unsigned char *) str, l, x) == x);
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return l;
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}
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int pad_rsa_encrypt (char *from, int from_len, char *to, int size, BIGNUM *N, BIGNUM *E) {
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int pad = (255000 - from_len - 32) % 255 + 32;
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int chunks = (from_len + pad) / 255;
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int bits = BN_num_bits (N);
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assert (bits >= 2041 && bits <= 2048);
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assert (from_len > 0 && from_len <= 2550);
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assert (size >= chunks * 256);
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assert (RAND_pseudo_bytes ((unsigned char *) from + from_len, pad) >= 0);
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int i;
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BIGNUM x, y;
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BN_init (&x);
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BN_init (&y);
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rsa_encrypted_chunks += chunks;
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for (i = 0; i < chunks; i++) {
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BN_bin2bn ((unsigned char *) from, 255, &x);
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assert (BN_mod_exp (&y, &x, E, N, BN_ctx) == 1);
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unsigned l = 256 - BN_num_bytes (&y);
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assert (l <= 256);
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memset (to, 0, l);
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BN_bn2bin (&y, (unsigned char *) to + l);
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to += 256;
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}
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BN_free (&x);
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BN_free (&y);
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return chunks * 256;
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}
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int pad_rsa_decrypt (char *from, int from_len, char *to, int size, BIGNUM *N, BIGNUM *D) {
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if (from_len < 0 || from_len > 0x1000 || (from_len & 0xff)) {
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return -1;
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}
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int chunks = (from_len >> 8);
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int bits = BN_num_bits (N);
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assert (bits >= 2041 && bits <= 2048);
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assert (size >= chunks * 255);
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int i;
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BIGNUM x, y;
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BN_init (&x);
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BN_init (&y);
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for (i = 0; i < chunks; i++) {
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++rsa_decrypted_chunks;
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BN_bin2bn ((unsigned char *) from, 256, &x);
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assert (BN_mod_exp (&y, &x, D, N, BN_ctx) == 1);
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int l = BN_num_bytes (&y);
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if (l > 255) {
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BN_free (&x);
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BN_free (&y);
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return -1;
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}
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assert (l >= 0 && l <= 255);
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memset (to, 0, 255 - l);
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BN_bn2bin (&y, (unsigned char *) to + 255 - l);
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to += 255;
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}
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BN_free (&x);
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BN_free (&y);
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return chunks * 255;
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}
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unsigned char aes_key_raw[32], aes_iv[32];
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AES_KEY aes_key;
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void init_aes_unauth (const char server_nonce[16], const char hidden_client_nonce[32], int encrypt) {
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static unsigned char buffer[64], hash[20];
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memcpy (buffer, hidden_client_nonce, 32);
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memcpy (buffer + 32, server_nonce, 16);
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SHA1 (buffer, 48, aes_key_raw);
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memcpy (buffer + 32, hidden_client_nonce, 32);
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SHA1 (buffer, 64, aes_iv + 8);
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memcpy (buffer, server_nonce, 16);
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memcpy (buffer + 16, hidden_client_nonce, 32);
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SHA1 (buffer, 48, hash);
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memcpy (aes_key_raw + 20, hash, 12);
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memcpy (aes_iv, hash + 12, 8);
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memcpy (aes_iv + 28, hidden_client_nonce, 4);
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if (encrypt == AES_ENCRYPT) {
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AES_set_encrypt_key (aes_key_raw, 32*8, &aes_key);
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} else {
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AES_set_decrypt_key (aes_key_raw, 32*8, &aes_key);
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}
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}
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void init_aes_auth (char auth_key[192], char msg_key[16], int encrypt) {
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static unsigned char buffer[48], hash[20];
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// sha1_a = SHA1 (msg_key + substr (auth_key, 0, 32));
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// sha1_b = SHA1 (substr (auth_key, 32, 16) + msg_key + substr (auth_key, 48, 16));
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// sha1_с = SHA1 (substr (auth_key, 64, 32) + msg_key);
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// sha1_d = SHA1 (msg_key + substr (auth_key, 96, 32));
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// aes_key = substr (sha1_a, 0, 8) + substr (sha1_b, 8, 12) + substr (sha1_c, 4, 12);
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// aes_iv = substr (sha1_a, 8, 12) + substr (sha1_b, 0, 8) + substr (sha1_c, 16, 4) + substr (sha1_d, 0, 8);
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memcpy (buffer, msg_key, 16);
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memcpy (buffer + 16, auth_key, 32);
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SHA1 (buffer, 48, hash);
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memcpy (aes_key_raw, hash, 8);
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memcpy (aes_iv, hash + 8, 12);
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memcpy (buffer, auth_key + 32, 16);
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memcpy (buffer + 16, msg_key, 16);
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memcpy (buffer + 32, auth_key + 48, 16);
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SHA1 (buffer, 48, hash);
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memcpy (aes_key_raw + 8, hash + 8, 12);
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memcpy (aes_iv + 12, hash, 8);
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memcpy (buffer, auth_key + 64, 32);
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memcpy (buffer + 32, msg_key, 16);
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SHA1 (buffer, 48, hash);
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memcpy (aes_key_raw + 20, hash + 4, 12);
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memcpy (aes_iv + 20, hash + 16, 4);
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memcpy (buffer, msg_key, 16);
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memcpy (buffer + 16, auth_key + 96, 32);
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SHA1 (buffer, 48, hash);
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memcpy (aes_iv + 24, hash, 8);
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if (encrypt == AES_ENCRYPT) {
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AES_set_encrypt_key (aes_key_raw, 32*8, &aes_key);
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} else {
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AES_set_decrypt_key (aes_key_raw, 32*8, &aes_key);
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}
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}
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int pad_aes_encrypt (char *from, int from_len, char *to, int size) {
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int padded_size = (from_len + 15) & -16;
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assert (from_len > 0 && padded_size <= size);
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if (from_len < padded_size) {
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assert (RAND_pseudo_bytes ((unsigned char *) from + from_len, padded_size - from_len) >= 0);
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}
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AES_ige_encrypt ((unsigned char *) from, (unsigned char *) to, padded_size, &aes_key, aes_iv, AES_ENCRYPT);
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return padded_size;
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}
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int pad_aes_decrypt (char *from, int from_len, char *to, int size) {
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if (from_len <= 0 || from_len > size || (from_len & 15)) {
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return -1;
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}
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AES_ige_encrypt ((unsigned char *) from, (unsigned char *) to, from_len, &aes_key, aes_iv, AES_DECRYPT);
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return from_len;
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}
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