| /* |
| * |
| * bufaux.c |
| * |
| * Author: Tatu Ylonen <ylo@cs.hut.fi> |
| * |
| * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| * All rights reserved |
| * |
| * Created: Wed Mar 29 02:24:47 1995 ylo |
| * |
| * Auxiliary functions for storing and retrieving various data types to/from |
| * Buffers. |
| * |
| * SSH2 packet format added by Markus Friedl |
| * |
| */ |
| |
| #include "includes.h" |
| RCSID("$Id: bufaux.c,v 1.11 2000/04/16 01:18:40 damien Exp $"); |
| |
| #include "ssh.h" |
| |
| #ifdef HAVE_OPENSSL |
| #include <openssl/bn.h> |
| #endif |
| #ifdef HAVE_SSL |
| #include <ssl/bn.h> |
| #endif |
| |
| #include "bufaux.h" |
| #include "xmalloc.h" |
| #include "getput.h" |
| |
| /* |
| * Stores an BIGNUM in the buffer with a 2-byte msb first bit count, followed |
| * by (bits+7)/8 bytes of binary data, msb first. |
| */ |
| void |
| buffer_put_bignum(Buffer *buffer, BIGNUM *value) |
| { |
| int bits = BN_num_bits(value); |
| int bin_size = (bits + 7) / 8; |
| char unsigned *buf = xmalloc(bin_size); |
| int oi; |
| char msg[2]; |
| |
| /* Get the value of in binary */ |
| oi = BN_bn2bin(value, buf); |
| if (oi != bin_size) |
| fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d", |
| oi, bin_size); |
| |
| /* Store the number of bits in the buffer in two bytes, msb first. */ |
| PUT_16BIT(msg, bits); |
| buffer_append(buffer, msg, 2); |
| /* Store the binary data. */ |
| buffer_append(buffer, (char *)buf, oi); |
| |
| memset(buf, 0, bin_size); |
| xfree(buf); |
| } |
| |
| /* |
| * Retrieves an BIGNUM from the buffer. |
| */ |
| int |
| buffer_get_bignum(Buffer *buffer, BIGNUM *value) |
| { |
| int bits, bytes; |
| unsigned char buf[2], *bin; |
| |
| /* Get the number for bits. */ |
| buffer_get(buffer, (char *) buf, 2); |
| bits = GET_16BIT(buf); |
| /* Compute the number of binary bytes that follow. */ |
| bytes = (bits + 7) / 8; |
| if (buffer_len(buffer) < bytes) |
| fatal("buffer_get_bignum: input buffer too small"); |
| bin = (unsigned char*) buffer_ptr(buffer); |
| BN_bin2bn(bin, bytes, value); |
| buffer_consume(buffer, bytes); |
| |
| return 2 + bytes; |
| } |
| |
| /* |
| * Stores an BIGNUM in the buffer in SSH2 format. |
| */ |
| void |
| buffer_put_bignum2(Buffer *buffer, BIGNUM *value) |
| { |
| int bytes = BN_num_bytes(value) + 1; |
| unsigned char *buf = xmalloc(bytes); |
| int oi; |
| int hasnohigh = 0; |
| buf[0] = '\0'; |
| /* Get the value of in binary */ |
| oi = BN_bn2bin(value, buf+1); |
| if (oi != bytes-1) |
| fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d", |
| oi, bytes); |
| hasnohigh = (buf[1] & 0x80) ? 0 : 1; |
| if (value->neg) { |
| /**XXX should be two's-complement */ |
| int i, carry; |
| unsigned char *uc = buf; |
| log("negativ!"); |
| for(i = bytes-1, carry = 1; i>=0; i--) { |
| uc[i] ^= 0xff; |
| if(carry) |
| carry = !++uc[i]; |
| } |
| } |
| buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh); |
| memset(buf, 0, bytes); |
| xfree(buf); |
| } |
| |
| int |
| buffer_get_bignum2(Buffer *buffer, BIGNUM *value) |
| { |
| /**XXX should be two's-complement */ |
| int len; |
| unsigned char *bin = (unsigned char *)buffer_get_string(buffer, (unsigned int *)&len); |
| BN_bin2bn(bin, len, value); |
| xfree(bin); |
| return len; |
| } |
| |
| /* |
| * Returns an integer from the buffer (4 bytes, msb first). |
| */ |
| unsigned int |
| buffer_get_int(Buffer *buffer) |
| { |
| unsigned char buf[4]; |
| buffer_get(buffer, (char *) buf, 4); |
| return GET_32BIT(buf); |
| } |
| |
| /* |
| * Stores an integer in the buffer in 4 bytes, msb first. |
| */ |
| void |
| buffer_put_int(Buffer *buffer, unsigned int value) |
| { |
| char buf[4]; |
| PUT_32BIT(buf, value); |
| buffer_append(buffer, buf, 4); |
| } |
| |
| /* |
| * Returns an arbitrary binary string from the buffer. The string cannot |
| * be longer than 256k. The returned value points to memory allocated |
| * with xmalloc; it is the responsibility of the calling function to free |
| * the data. If length_ptr is non-NULL, the length of the returned data |
| * will be stored there. A null character will be automatically appended |
| * to the returned string, and is not counted in length. |
| */ |
| char * |
| buffer_get_string(Buffer *buffer, unsigned int *length_ptr) |
| { |
| unsigned int len; |
| char *value; |
| /* Get the length. */ |
| len = buffer_get_int(buffer); |
| if (len > 256 * 1024) |
| fatal("Received packet with bad string length %d", len); |
| /* Allocate space for the string. Add one byte for a null character. */ |
| value = xmalloc(len + 1); |
| /* Get the string. */ |
| buffer_get(buffer, value, len); |
| /* Append a null character to make processing easier. */ |
| value[len] = 0; |
| /* Optionally return the length of the string. */ |
| if (length_ptr) |
| *length_ptr = len; |
| return value; |
| } |
| |
| /* |
| * Stores and arbitrary binary string in the buffer. |
| */ |
| void |
| buffer_put_string(Buffer *buffer, const void *buf, unsigned int len) |
| { |
| buffer_put_int(buffer, len); |
| buffer_append(buffer, buf, len); |
| } |
| void |
| buffer_put_cstring(Buffer *buffer, const char *s) |
| { |
| buffer_put_string(buffer, s, strlen(s)); |
| } |
| |
| /* |
| * Returns a character from the buffer (0 - 255). |
| */ |
| int |
| buffer_get_char(Buffer *buffer) |
| { |
| char ch; |
| buffer_get(buffer, &ch, 1); |
| return (unsigned char) ch; |
| } |
| |
| /* |
| * Stores a character in the buffer. |
| */ |
| void |
| buffer_put_char(Buffer *buffer, int value) |
| { |
| char ch = value; |
| buffer_append(buffer, &ch, 1); |
| } |