Mercurial > dropbear

comparison svr-algo.c @ 285:1b9e69c058d2

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propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3) to branch 'au.asn.ucc.matt.dropbear' (head fdf4a7a3b97ae5046139915de7e40399cceb2c01)
author Matt Johnston <matt@ucc.asn.au>
date Wed, 08 Mar 2006 13:23:58 +0000
parents 0cfba3034be5
children 870c63519757
comparison
equal deleted inserted replaced
281:997e6f7dc01e 285:1b9e69c058d2
1 /*
2 * Dropbear - a SSH2 server
3 * SSH client implementation
4 *
5 * Copyright (c) 2002,2003 Matt Johnston
6 * Copyright (c) 2004 by Mihnea Stoenescu
7 * All rights reserved.
8 *
9 * Permission is hereby granted, free of charge, to any person obtaining a copy
10 * of this software and associated documentation files (the "Software"), to deal
11 * in the Software without restriction, including without limitation the rights
12 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
13 * copies of the Software, and to permit persons to whom the Software is
14 * furnished to do so, subject to the following conditions:
15 *
16 * The above copyright notice and this permission notice shall be included in
17 * all copies or substantial portions of the Software.
18 *
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
22 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
24 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
25 * SOFTWARE. */
26
27 #include "algo.h"
28 #include "dbutil.h"
29
30 /* match the first algorithm in the comma-separated list in buf which is
31 * also in localalgos[], or return NULL on failure.
32 * (*goodguess) is set to 1 if the preferred client/server algos match,
33 * 0 otherwise. This is used for checking if the kexalgo/hostkeyalgos are
34 * guessed correctly */
35 algo_type * svr_buf_match_algo(buffer* buf, algo_type localalgos[],
36 int *goodguess)
37 {
38
39 unsigned char * algolist = NULL;
40 unsigned char * remotealgos[MAX_PROPOSED_ALGO];
41 unsigned int len;
42 unsigned int count, i, j;
43 algo_type * ret = NULL;
44
45 *goodguess = 0;
46
47 /* get the comma-separated list from the buffer ie "algo1,algo2,algo3" */
48 algolist = buf_getstring(buf, &len);
49 /* Debug this */
50 TRACE(("buf_match_algo: %s", algolist))
51 if (len > MAX_PROPOSED_ALGO*(MAX_NAME_LEN+1)) {
52 goto out; /* just a sanity check, no other use */
53 }
54
55 /* remotealgos will contain a list of the strings parsed out */
56 /* We will have at least one string (even if it's just "") */
57 remotealgos[0] = algolist;
58 count = 1;
59 /* Iterate through, replacing ','s with NULs, to split it into
60 * words. */
61 for (i = 0; i < len; i++) {
62 if (algolist[i] == '\0') {
63 /* someone is trying something strange */
64 goto out;
65 }
66 if (algolist[i] == ',') {
67 algolist[i] = '\0';
68 remotealgos[count] = &algolist[i+1];
69 count++;
70 }
71 if (count == MAX_PROPOSED_ALGO) {
72 break;
73 }
74 }
75
76 /* iterate and find the first match */
77 for (i = 0; i < count; i++) {
78
79 len = strlen(remotealgos[i]);
80
81 for (j = 0; localalgos[j].name != NULL; j++) {
82 if (localalgos[j].usable) {
83 if (len == strlen(localalgos[j].name) &&
84 strncmp(localalgos[j].name, remotealgos[i], len) == 0) {
85 /* set if it was a good guess */
86 if (i == 0 && j == 0) {
87 *goodguess = 1;
88 }
89 /* set the algo to return */
90 ret = &localalgos[j];
91 goto out;
92 }
93 }
94 }
95 }
96
97 out:
98 m_free(algolist);
99 return ret;
100 }