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/*
* Dropbear - a SSH2 server
* SSH client implementation
*
* Copyright (c) 2002,2003 Matt Johnston
* Copyright (c) 2004 by Mihnea Stoenescu
* All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE. */
#include "algo.h"
#include "dbutil.h"
/* match the first algorithm in the comma-separated list in buf which is
* also in localalgos[], or return NULL on failure.
* (*goodguess) is set to 1 if the preferred client/server algos match,
* 0 otherwise. This is used for checking if the kexalgo/hostkeyalgos are
* guessed correctly */
algo_type * svr_buf_match_algo(buffer* buf, algo_type localalgos[],
int *goodguess)
{
unsigned char * algolist = NULL;
unsigned char * remotealgos[MAX_PROPOSED_ALGO];
unsigned int len;
unsigned int count, i, j;
algo_type * ret = NULL;
*goodguess = 0;
/* get the comma-separated list from the buffer ie "algo1,algo2,algo3" */
algolist = buf_getstring(buf, &len);
/* Debug this */
TRACE(("buf_match_algo: %s", algolist));
if (len > MAX_PROPOSED_ALGO*(MAX_NAME_LEN+1)) {
goto out; /* just a sanity check, no other use */
}
/* remotealgos will contain a list of the strings parsed out */
/* We will have at least one string (even if it's just "") */
remotealgos[0] = algolist;
count = 1;
/* Iterate through, replacing ','s with NULs, to split it into
* words. */
for (i = 0; i < len; i++) {
if (algolist[i] == '\0') {
/* someone is trying something strange */
goto out;
}
if (algolist[i] == ',') {
algolist[i] = '\0';
remotealgos[count] = &algolist[i+1];
count++;
}
if (count == MAX_PROPOSED_ALGO) {
break;
}
}
/* iterate and find the first match */
for (i = 0; i < count; i++) {
len = strlen(remotealgos[i]);
for (j = 0; localalgos[j].name != NULL; j++) {
if (localalgos[j].usable) {
if (len == strlen(localalgos[j].name) &&
strncmp(localalgos[j].name, remotealgos[i], len) == 0) {
/* set if it was a good guess */
if (i == 0 && j == 0) {
*goodguess = 1;
}
/* set the algo to return */
ret = &localalgos[j];
goto out;
}
}
}
}
out:
m_free(algolist);
return ret;
}
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