mirror of
https://github.com/clearml/dropbear
synced 2025-01-31 02:46:58 +00:00
75 lines
1.9 KiB
C
75 lines
1.9 KiB
C
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#include "algo.h"
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#include "dbutil.h"
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/* match the first algorithm in the comma-separated list in buf which is
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* also in localalgos[], or return NULL on failure.
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* (*goodguess) is set to 1 if the preferred client/server algos match,
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* 0 otherwise. This is used for checking if the kexalgo/hostkeyalgos are
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* guessed correctly */
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algo_type * svr_buf_match_algo(buffer* buf, algo_type localalgos[],
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int *goodguess)
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{
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unsigned char * algolist = NULL;
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unsigned char * remotealgos[MAX_PROPOSED_ALGO];
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unsigned int len;
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unsigned int count, i, j;
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algo_type * ret = NULL;
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/* get the comma-separated list from the buffer ie "algo1,algo2,algo3" */
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algolist = buf_getstring(buf, &len);
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/* Debug this */
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TRACE(("buf_match_algo: %s", algolist));
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if (len > MAX_PROPOSED_ALGO*(MAX_NAME_LEN+1)) {
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goto out; /* just a sanity check, no other use */
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}
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/* remotealgos will contain a list of the strings parsed out */
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/* We will have at least one string (even if it's just "") */
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remotealgos[0] = algolist;
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count = 1;
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/* Iterate through, replacing ','s with NULs, to split it into
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* words. */
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for (i = 0; i < len; i++) {
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if (algolist[i] == '\0') {
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/* someone is trying something strange */
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goto out;
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}
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if (algolist[i] == ',') {
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algolist[i] = '\0';
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remotealgos[count] = &algolist[i+1];
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count++;
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}
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if (count == MAX_PROPOSED_ALGO) {
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break;
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}
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}
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/* iterate and find the first match */
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for (i = 0; i < count; i++) {
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len = strlen(remotealgos[i]);
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for (j = 0; localalgos[j].name != NULL; j++) {
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if (localalgos[j].usable) {
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if (len == strlen(localalgos[j].name) &&
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strncmp(localalgos[j].name, remotealgos[i], len) == 0) {
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/* set if it was a good guess */
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if (i == 0 && j == 0) {
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*goodguess = 1;
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} else {
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*goodguess = 0;
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}
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/* set the algo to return */
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ret = &localalgos[j];
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goto out;
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}
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}
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}
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}
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out:
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m_free(algolist);
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return ret;
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}
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