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/*
* buffer.c - buffer functions
*
* This file is part of the SSH Library
*
* Copyright (c) 2003-2009 by Aris Adamantiadis
*
* The SSH Library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or (at your
* option) any later version.
*
* The SSH Library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with the SSH Library; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
* MA 02111-1307, USA.
*/
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#ifndef _WIN32
#include <arpa/inet.h>
#endif
#include "libssh/priv.h"
#include "libssh/buffer.h"
/** \defgroup ssh_buffer SSH Buffers
* \brief buffer handling
*/
/** \addtogroup ssh_buffer
* @{
*/
/** \brief checks that preconditions and postconditions are valid
* \internal
*/
#ifdef DEBUG_BUFFER
static void buffer_verify(struct buffer_struct *buf){
int doabort=0;
if(buf->data == NULL)
return;
if(buf->used > buf->allocated){
fprintf(stderr,"Buffer error : allocated %u, used %u\n",buf->allocated, buf->used);
doabort=1;
}
if(buf->pos > buf->used){
fprintf(stderr,"Buffer error : position %u, used %u\n",buf->pos, buf->used);
doabort=1;
}
if(buf->pos > buf->allocated){
fprintf(stderr,"Buffer error : position %u, allocated %u\n",buf->pos, buf->allocated);
doabort=1;
}
if(doabort)
abort();
}
#else
#define buffer_verify(x)
#endif
/** \brief creates a new buffer
* \return a new initialized buffer, NULL on error.
*/
struct ssh_buffer_struct *buffer_new(void) {
struct ssh_buffer_struct *buf = malloc(sizeof(struct ssh_buffer_struct));
if (buf == NULL) {
return NULL;
}
memset(buf, 0, sizeof(struct ssh_buffer_struct));
buffer_verify(buf);
return buf;
}
/** \brief deallocate a buffer
* \param buffer buffer to free
*/
void buffer_free(struct ssh_buffer_struct *buffer) {
if (buffer == NULL) {
return;
}
buffer_verify(buffer);
if (buffer->data) {
/* burn the data */
memset(buffer->data, 0, buffer->allocated);
SAFE_FREE(buffer->data);
}
memset(buffer, 'X', sizeof(*buffer));
SAFE_FREE(buffer);
}
static int realloc_buffer(struct ssh_buffer_struct *buffer, size_t needed) {
size_t smallest = 1;
char *new;
buffer_verify(buffer);
/* Find the smallest power of two which is greater or equal to needed */
while(smallest < needed) {
if (smallest == 0) {
return -1;
}
smallest <<= 1;
}
needed = smallest;
new = realloc(buffer->data, needed);
if (new == NULL) {
return -1;
}
buffer->data = new;
buffer->allocated = needed;
buffer_verify(buffer);
return 0;
}
/* \internal
* \brief reinitialize a buffer
* \param buffer buffer
* \return 0 on sucess, < 0 on error
*/
int buffer_reinit(struct ssh_buffer_struct *buffer) {
buffer_verify(buffer);
memset(buffer->data, 0, buffer->used);
buffer->used = 0;
buffer->pos = 0;
if(buffer->allocated > 127) {
if (realloc_buffer(buffer, 127) < 0) {
return -1;
}
}
buffer_verify(buffer);
return 0;
}
/** \internal
* \brief add data at tail of the buffer
* \param buffer buffer
* \param data data pointer
* \param len length of data
*/
int buffer_add_data(struct ssh_buffer_struct *buffer, const void *data, uint32_t len) {
buffer_verify(buffer);
if (buffer->used + len < len)
return -1;
if (buffer->allocated < (buffer->used + len)) {
if (realloc_buffer(buffer, buffer->used + len) < 0) {
return -1;
}
}
memcpy(buffer->data+buffer->used, data, len);
buffer->used+=len;
buffer_verify(buffer);
return 0;
}
/** \internal
* \brief add a SSH string to the tail of buffer
* \param buffer buffer
* \param string SSH String to add
* \return 0 on success, -1 on error.
*/
int buffer_add_ssh_string(struct ssh_buffer_struct *buffer,
struct ssh_string_struct *string) {
uint32_t len = 0;
len = string_len(string);
if (buffer_add_data(buffer, string, len + sizeof(uint32_t)) < 0) {
return -1;
}
return 0;
}
/** \internal
* \brief add a 32 bits unsigned integer to the tail of buffer
* \param buffer buffer
* \param data 32 bits integer
* \return 0 on success, -1 on error.
*/
int buffer_add_u32(struct ssh_buffer_struct *buffer,uint32_t data){
if (buffer_add_data(buffer, &data, sizeof(data)) < 0) {
return -1;
}
return 0;
}
/** \internal
* \brief add a 16 bits unsigned integer to the tail of buffer
* \param buffer buffer
* \param data 16 bits integer
* \return 0 on success, -1 on error.
*/
int buffer_add_u16(struct ssh_buffer_struct *buffer,uint16_t data){
if (buffer_add_data(buffer, &data, sizeof(data)) < 0) {
return -1;
}
return 0;
}
/** \internal
* \brief add a 64 bits unsigned integer to the tail of buffer
* \param buffer buffer
* \param data 64 bits integer
* \return 0 on success, -1 on error.
*/
int buffer_add_u64(struct ssh_buffer_struct *buffer, uint64_t data){
if (buffer_add_data(buffer, &data, sizeof(data)) < 0) {
return -1;
}
return 0;
}
/** \internal
* \brief add a 8 bits unsigned integer to the tail of buffer
* \param buffer buffer
* \param data 8 bits integer
* \return 0 on success, -1 on error.
*/
int buffer_add_u8(struct ssh_buffer_struct *buffer,uint8_t data){
if (buffer_add_data(buffer, &data, sizeof(uint8_t)) < 0) {
return -1;
}
return 0;
}
/** \internal
* \brief add data at head of a buffer
* \param buffer buffer
* \param data data to add
* \param len length of data
* \return 0 on success, -1 on error.
*/
int buffer_prepend_data(struct ssh_buffer_struct *buffer, const void *data,
uint32_t len) {
buffer_verify(buffer);
if (buffer->used + len < len)
return -1;
if (buffer->allocated < (buffer->used + len)) {
if (realloc_buffer(buffer, buffer->used + len) < 0) {
return -1;
}
}
memmove(buffer->data + len, buffer->data, buffer->used);
memcpy(buffer->data, data, len);
buffer->used += len;
buffer_verify(buffer);
return 0;
}
/** \internal
* \brief append data from a buffer to tail of another
* \param buffer destination buffer
* \param source source buffer. Doesn't take position in buffer into account
* \return 0 on success, -1 on error.
*/
int buffer_add_buffer(struct ssh_buffer_struct *buffer,
struct ssh_buffer_struct *source) {
if (buffer_add_data(buffer, buffer_get(source), buffer_get_len(source)) < 0) {
return -1;
}
return 0;
}
/** \brief get a pointer on the head of the buffer
* \param buffer buffer
* \return data pointer on the head. Doesn't take position into account.
* \warning don't expect data to be nul-terminated
* \see buffer_get_rest()
* \see buffer_get_len()
*/
void *buffer_get(struct ssh_buffer_struct *buffer){
return buffer->data;
}
/** \internal
* \brief get a pointer to head of the buffer at current position
* \param buffer buffer
* \return pointer to the data from current position
* \see buffer_get_rest_len()
* \see buffer_get()
*/
void *buffer_get_rest(struct ssh_buffer_struct *buffer){
return buffer->data + buffer->pos;
}
/** \brief get length of the buffer, not counting position
* \param buffer
* \return length of the buffer
* \see buffer_get()
*/
uint32_t buffer_get_len(struct ssh_buffer_struct *buffer){
return buffer->used;
}
/** \internal
* \brief get length of the buffer from the current position
* \param buffer
* \return length of the buffer
* \see buffer_get_rest()
*/
uint32_t buffer_get_rest_len(struct ssh_buffer_struct *buffer){
buffer_verify(buffer);
return buffer->used - buffer->pos;
}
/** \internal
* has effect to "eat" bytes at head of the buffer
* \brief advance the position in the buffer
* \param buffer buffer
* \param len number of bytes to eat
* \return new size of the buffer
*/
uint32_t buffer_pass_bytes(struct ssh_buffer_struct *buffer, uint32_t len){
buffer_verify(buffer);
if (buffer->pos + len < len || buffer->used < buffer->pos + len)
return 0;
buffer->pos+=len;
/* if the buffer is empty after having passed the whole bytes into it, we can clean it */
if(buffer->pos==buffer->used){
buffer->pos=0;
buffer->used=0;
}
buffer_verify(buffer);
return len;
}
/** \internal
* \brief cut the end of the buffer
* \param buffer buffer
* \param len number of bytes to remove from tail
* \return new size of the buffer
*/
uint32_t buffer_pass_bytes_end(struct ssh_buffer_struct *buffer, uint32_t len){
buffer_verify(buffer);
if (buffer->used < len) {
return 0;
}
buffer->used-=len;
buffer_verify(buffer);
return len;
}
/** \internal
* \brief gets remaining data out of the buffer. Adjust the read pointer.
* \param buffer Buffer to read
* \param data data buffer where to store the data
* \param len length to read from the buffer
* \returns 0 if there is not enough data in buffer
* \returns len otherwise.
*/
uint32_t buffer_get_data(struct ssh_buffer_struct *buffer, void *data, uint32_t len){
/*
* Check for a integer overflow first, then check if not enough data is in
* the buffer.
*/
if (buffer->pos + len < len || buffer->pos + len > buffer->used) {
return 0;
}
memcpy(data,buffer->data+buffer->pos,len);
buffer->pos+=len;
return len; /* no yet support for partial reads (is it really needed ?? ) */
}
/** \internal
* \brief gets a 8 bits unsigned int out of the buffer. Adjusts the read pointer.
* \param buffer Buffer to read
* \param data pointer to a uint8_t where to store the data
* \returns 0 if there is not enough data in buffer
* \returns 1 otherwise.
*/
int buffer_get_u8(struct ssh_buffer_struct *buffer, uint8_t *data){
return buffer_get_data(buffer,data,sizeof(uint8_t));
}
/** \internal
* \brief gets a 32 bits unsigned int out of the buffer. Adjusts the read pointer.
* \param buffer Buffer to read
* \param data pointer to a uint32_t where to store the data
* \returns 0 if there is not enough data in buffer
* \returns 4 otherwise.
*/
int buffer_get_u32(struct ssh_buffer_struct *buffer, uint32_t *data){
return buffer_get_data(buffer,data,sizeof(uint32_t));
}
/** \internal
* \brief gets a 64 bits unsigned int out of the buffer. Adjusts the read pointer.
* \param buffer Buffer to read
* \param data pointer to a uint64_t where to store the data
* \returns 0 if there is not enough data in buffer
* \returns 8 otherwise.
*/
int buffer_get_u64(struct ssh_buffer_struct *buffer, uint64_t *data){
return buffer_get_data(buffer,data,sizeof(uint64_t));
}
/** \internal
* \brief gets a SSH String out of the buffer. Adjusts the read pointer.
* \param buffer Buffer to read
* \returns The SSH String read
* \returns NULL otherwise.
*/
struct ssh_string_struct *buffer_get_ssh_string(struct ssh_buffer_struct *buffer) {
uint32_t stringlen;
uint32_t hostlen;
struct ssh_string_struct *str = NULL;
if (buffer_get_u32(buffer, &stringlen) == 0) {
return NULL;
}
hostlen = ntohl(stringlen);
/* verify if there is enough space in buffer to get it */
if (buffer->pos + hostlen < hostlen || buffer->pos + hostlen > buffer->used) {
return NULL; /* it is indeed */
}
str = string_new(hostlen);
if (str == NULL) {
return NULL;
}
if (buffer_get_data(buffer, string_data(str), hostlen) != hostlen) {
/* should never happen */
SAFE_FREE(str);
return NULL;
}
return str;
}
/** \internal
* \brief gets a mpint out of the buffer. Adjusts the read pointer.
* SSH-1 only
* \param buffer Buffer to read
* \returns the SSH String containing the mpint
* \returns NULL otherwise
*/
struct ssh_string_struct *buffer_get_mpint(struct ssh_buffer_struct *buffer) {
uint16_t bits;
uint32_t len;
struct ssh_string_struct *str = NULL;
if (buffer_get_data(buffer, &bits, sizeof(uint16_t)) != sizeof(uint16_t)) {
return NULL;
}
bits = ntohs(bits);
len = (bits + 7) / 8;
if (buffer->pos + len < len || buffer->pos + len > buffer->used) {
return NULL;
}
str = string_new(len);
if (str == NULL) {
return NULL;
}
if (buffer_get_data(buffer, string_data(str), len) != len) {
SAFE_FREE(str);
return NULL;
}
return str;
}
/** @} */
/* vim: set ts=2 sw=2 et cindent: */
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