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split out the knownhost code from hostkey.c into its own separate source file

Browse Source 
now: knownhost.c
This commit is contained in:
Daniel Stenberg
2009-05-07 17:21:56 +00:00
parent 0cee15dc0c
commit d3542e6f7d
3 changed files with 568 additions and 521 deletions
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4
src/Makefile.am
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@@ -1,10 +1,10 @@
# $Id: Makefile.am,v 1.20 2009/05/07 13:09:49 bagder Exp $ # $Id: Makefile.am,v 1.21 2009/05/07 17:21:56 bagder Exp $
AUTOMAKE_OPTIONS = foreign nostdinc AUTOMAKE_OPTIONS = foreign nostdinc
libssh2_la_SOURCES = channel.c comp.c crypt.c hostkey.c kex.c mac.c misc.c \ libssh2_la_SOURCES = channel.c comp.c crypt.c hostkey.c kex.c mac.c misc.c \
packet.c publickey.c scp.c session.c sftp.c userauth.c libssh2_priv.h \ packet.c publickey.c scp.c session.c sftp.c userauth.c libssh2_priv.h \
openssl.h libgcrypt.h transport.c version.c transport.h channel.h comp.h \ openssl.h libgcrypt.h transport.c version.c transport.h channel.h comp.h \
mac.h misc.h mac.h misc.h knownhost.c
if LIBGCRYPT if LIBGCRYPT
libssh2_la_SOURCES += libgcrypt.c pem.c libssh2_la_SOURCES += libgcrypt.c pem.c

519
src/hostkey.c
View File

@@ -457,19 +457,6 @@ libssh2_hostkey_hash(LIBSSH2_SESSION * session, int hash_type)
} }
} }
static void free_host(LIBSSH2_SESSION *session, struct known_host *entry)
{
if(entry) {
if(entry->key)
LIBSSH2_FREE(session, entry->key);
if(entry->salt)
LIBSSH2_FREE(session, entry->salt);
if(entry->name)
LIBSSH2_FREE(session, entry->name);
LIBSSH2_FREE(session, entry);
}
}
/* /*
* libssh2_session_hostkey() * libssh2_session_hostkey()
* *
@@ -489,509 +476,3 @@ libssh2_session_hostkey(LIBSSH2_SESSION *session, size_t *len)
return NULL; return NULL;
} }
/*
* libssh2_knownhost_init
*
* Init a collection of known hosts. Returns the pointer to a collection.
*
*/
LIBSSH2_API LIBSSH2_KNOWNHOSTS *
libssh2_knownhost_init(LIBSSH2_SESSION *session)
{
LIBSSH2_KNOWNHOSTS *knh =
LIBSSH2_ALLOC(session, sizeof(struct _LIBSSH2_KNOWNHOSTS));
if(!knh)
return NULL;
knh->session = session;
_libssh2_list_init(&knh->head);
return knh;
}
/*
* libssh2_knownhost_add
*
* Add a host and its associated key to the collection of known hosts.
*
* The 'type' argument specifies on what format the given host and keys are:
*
* plain - ascii "hostname.domain.tld"
* sha1 - SHA1(<salt> <host>) base64-encoded!
* custom - another hash
*
* If 'sha1' is selected as type, the salt must be provided to the salt
* argument. This too base64 encoded.
*
* The SHA-1 hash is what OpenSSH can be told to use in known_hosts files. If
* a custom type is used, salt is ignored and you must provide the host
* pre-hashed when checking for it in the libssh2_knownhost_check() function.
*
*/
LIBSSH2_API int
libssh2_knownhost_add(LIBSSH2_KNOWNHOSTS *hosts,
char *host, char *salt,
char *key, size_t keylen,
int typemask)
{
struct known_host *entry =
LIBSSH2_ALLOC(hosts->session, sizeof(struct known_host));
size_t hostlen = strlen(host);
int rc = LIBSSH2_ERROR_MEMORY;
char *ptr;
unsigned int ptrlen;
if(!entry)
return rc;
memset(entry, 0, sizeof(struct known_host));
entry->typemask = typemask;
switch(entry->typemask & LIBSSH2_KNOWNHOST_TYPE_MASK) {
case LIBSSH2_KNOWNHOST_TYPE_PLAIN:
case LIBSSH2_KNOWNHOST_TYPE_CUSTOM:
entry->name = LIBSSH2_ALLOC(hosts->session, hostlen+1);
if(!entry)
goto error;
memcpy(entry->name, host, hostlen+1);
break;
case LIBSSH2_KNOWNHOST_TYPE_SHA1:
rc = libssh2_base64_decode(hosts->session, &ptr, &ptrlen,
host, hostlen);
if(rc)
goto error;
entry->name = ptr;
entry->name_len = ptrlen;
rc = libssh2_base64_decode(hosts->session, &ptr, &ptrlen,
salt, strlen(salt));
if(rc)
goto error;
entry->salt = ptr;
entry->salt_len = ptrlen;
break;
default:
rc = LIBSSH2_ERROR_METHOD_NOT_SUPPORTED;
goto error;
}
if(typemask & LIBSSH2_KNOWNHOST_KEY_BASE64) {
/* the provided key is base64 encoded already */
if(!keylen)
keylen = strlen(key);
entry->key = LIBSSH2_ALLOC(hosts->session, keylen+1);
if(!entry)
goto error;
memcpy(entry->key, key, keylen+1);
}
else {
/* key is raw, we base64 encode it and store it as such */
size_t nlen = _libssh2_base64_encode(hosts->session, key, keylen,
&ptr);
if(!nlen)
goto error;
entry->key = ptr;
}
/* add this new host to the big list of known hosts */
_libssh2_list_add(&hosts->head, &entry->node);
return LIBSSH2_ERROR_NONE;
error:
free_host(hosts->session, entry);
return rc;
}
#define KNOWNHOST_MAGIC 0xdeadcafe
/*
* knownhost_to_external()
*
* Copies data from the internal to the external representation struct.
*
*/
static void knownhost_to_external(struct known_host *node,
struct libssh2_knownhost *ext)
{
if(ext) {
ext->magic = KNOWNHOST_MAGIC;
ext->node = node;
ext->name = ((node->typemask & LIBSSH2_KNOWNHOST_TYPE_MASK) ==
LIBSSH2_KNOWNHOST_TYPE_PLAIN)? node->name:NULL;
ext->key = node->key;
ext->typemask = node->typemask;
}
}
/*
* libssh2_knownhost_check
*
* Check a host and its associated key against the collection of known hosts.
*
* The typemask is the type/format of the given host name and key
*
* plain - ascii "hostname.domain.tld"
* sha1 - NOT SUPPORTED AS INPUT
* custom - prehashed base64 encoded. Note that this cannot use any salts.
*
* Returns:
*
* LIBSSH2_KNOWNHOST_CHECK_FAILURE
* LIBSSH2_KNOWNHOST_CHECK_NOTFOUND
* LIBSSH2_KNOWNHOST_CHECK_MATCH
* LIBSSH2_KNOWNHOST_CHECK_MISMATCH
*/
LIBSSH2_API int
libssh2_knownhost_check(LIBSSH2_KNOWNHOSTS *hosts,
char *host, char *key, size_t keylen,
int typemask,
struct libssh2_knownhost *knownhost)
{
struct known_host *node = _libssh2_list_first(&hosts->head);
struct known_host *badkey = NULL;
int type = typemask & LIBSSH2_KNOWNHOST_TYPE_MASK;
char *keyalloc = NULL;
int rc = LIBSSH2_KNOWNHOST_CHECK_NOTFOUND;
if(type == LIBSSH2_KNOWNHOST_TYPE_SHA1)
/* we can't work with a sha1 as given input */
return LIBSSH2_KNOWNHOST_CHECK_MISMATCH;
if(!(typemask & LIBSSH2_KNOWNHOST_KEY_BASE64)) {
/* we got a raw key input, convert it to base64 for the checks below */
size_t nlen = _libssh2_base64_encode(hosts->session, key, keylen,
&keyalloc);
if(!nlen)
return LIBSSH2_KNOWNHOST_CHECK_FAILURE;
/* make the key point to this */
key = keyalloc;
keylen = nlen;
}
while (node) {
int match = 0;
switch(node->typemask & LIBSSH2_KNOWNHOST_TYPE_MASK) {
case LIBSSH2_KNOWNHOST_TYPE_PLAIN:
if(type == LIBSSH2_KNOWNHOST_TYPE_PLAIN)
match = !strcmp(host, node->name);
break;
case LIBSSH2_KNOWNHOST_TYPE_CUSTOM:
if(type == LIBSSH2_KNOWNHOST_TYPE_CUSTOM)
match = !strcmp(host, node->name);
break;
case LIBSSH2_KNOWNHOST_TYPE_SHA1:
if(type == LIBSSH2_KNOWNHOST_TYPE_PLAIN) {
/* when we have the sha1 version stored, we can use a plain
input to produce a hash to compare with the stored hash.
HMAC_Init(&mac_ctx, salt, len, md);
HMAC_Update(&mac_ctx, host, strlen(host));
HMAC_Final(&mac_ctx, result, NULL);
HMAC_cleanup(&mac_ctx);
*/
libssh2_hmac_ctx ctx;
unsigned char hash[SHA_DIGEST_LENGTH];
if(SHA_DIGEST_LENGTH != node->name_len) {
/* the name hash length must be the sha1 size or
we can't match it */
break;
}
libssh2_hmac_sha1_init(&ctx, node->salt, node->salt_len);
libssh2_hmac_update(ctx, (unsigned char *)host, strlen(host));
libssh2_hmac_final(ctx, hash);
libssh2_hmac_cleanup(&ctx);
if(!memcmp(hash, node->name, SHA_DIGEST_LENGTH))
/* this is a node we're interested in */
match = 1;
}
break;
default: /* unsupported type */
break;
}
if(match) {
/* host name match, now compare the keys */
if(!strcmp(key, node->key)) {
/* they match! */
knownhost_to_external(node, knownhost);
badkey = NULL;
rc = LIBSSH2_KNOWNHOST_CHECK_MATCH;
break;
}
else {
/* remember the first node that had a host match but a failed
key match since we continue our search from here */
if(!badkey)
badkey = node;
}
}
node= _libssh2_list_next(&node->node);
}
if(badkey) {
/* key mismatch */
knownhost_to_external(badkey, knownhost);
rc = LIBSSH2_KNOWNHOST_CHECK_MISMATCH;
}
if(keyalloc)
LIBSSH2_FREE(hosts->session, keyalloc);
return rc;
}
/*
* libssh2_knownhost_del
*
* Remove a host from the collection of known hosts.
*
*/
LIBSSH2_API int
libssh2_knownhost_del(LIBSSH2_KNOWNHOSTS *hosts,
struct libssh2_knownhost *entry)
{
struct known_host *node;
if(!entry || (entry->magic != KNOWNHOST_MAGIC))
/* check that this was retrieved the right way or get out */
return -1;
/* get the internal node pointer */
node = entry->node;
/* unlink from the list of all hosts */
_libssh2_list_remove(&node->node);
/* free all resources */
free_host(hosts->session, node);
return 0;
}
/*
* libssh2_knownhost_free
*
* Free an entire collection of known hosts.
*
*/
LIBSSH2_API void
libssh2_knownhost_free(LIBSSH2_KNOWNHOSTS *hosts)
{
struct known_host *node;
struct known_host *next;
for(node = _libssh2_list_first(&hosts->head); node; node = next) {
next = _libssh2_list_next(&node->node);
free_host(hosts->session, node);
}
LIBSSH2_FREE(hosts->session, hosts);
}
/*
* hostline()
*
* Parse a single known_host line pre-split into host and key.
*
* Note: this function assumes that the 'host' pointer points into a temporary
* buffer as it will write to it.
*/
static int hostline(LIBSSH2_KNOWNHOSTS *hosts,
char *host, size_t hostlen,
char *key, size_t keylen)
{
char *p;
char *salt = NULL;
int rc;
int type = LIBSSH2_KNOWNHOST_TYPE_PLAIN;
char *sep = NULL;
/* Figure out host format */
if(strncmp(host, "|1|", 3)) {
/* old style plain text: [name][,][ip-address]
for the sake of simplicity, we add them as two hosts with the same
key
*/
sep = strchr(host, ',');
}
else {
/* |1|[salt]|[hash] */
type = LIBSSH2_KNOWNHOST_TYPE_SHA1;
salt = &host[3]; /* skip the magic marker */
/* this is where the salt starts, find the end of it */
for(p = salt; *p && (*p != '|'); p++)
;
if(*p=='|') {
char *hash = NULL;
*p=0; /* terminate the salt string */
hash = p+1; /* the hash is after the separator */
/* now make the host point to the hash */
hostlen = strlen(hash);
host = hash;
}
else
return 0;
}
if(keylen < 20)
return -1; /* TODO: better return code */
switch(key[0]) {
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
type |= LIBSSH2_KNOWNHOST_KEY_RSA1;
/* Note that the old-style keys (RSA1) aren't truly base64, but we
* claim it is for now since we can get away with strcmp()ing the
* entire anything anyway! We need to check and fix these to make them
* work properly.
*/
break;
case 's': /* ssh-dss or ssh-rsa */
if(!strncmp(key, "ssh-dss", 7))
type |= LIBSSH2_KNOWNHOST_KEY_SSHDSS;
else if(!strncmp(key, "ssh-rsa", 7))
type |= LIBSSH2_KNOWNHOST_KEY_SSHRSA;
else
return -1; /* unknown */
key += 7;
keylen -= 7;
/* skip whitespaces */
while((*key ==' ') || (*key == '\t')) {
key++;
keylen--;
}
break;
default: /* unknown key format */
return -1;
}
if(sep) {
/* this is the second host, add this first */
char *ipaddr;
*sep++ = 0; /* zero terminate the first host name here */
ipaddr = sep;
rc = libssh2_knownhost_add(hosts, ipaddr, salt, key, keylen,
type | LIBSSH2_KNOWNHOST_KEY_BASE64);
if(rc)
return rc;
}
rc = libssh2_knownhost_add(hosts, host, salt, key, keylen,
type | LIBSSH2_KNOWNHOST_KEY_BASE64);
return rc;
}
/*
* libssh2_knownhost_parsefile
*
* Add hosts+key pairs from a given file.
*
* Returns a negative value for error or number of successfully added hosts.
*
* Line format:
*
* <host> <key>
*
* Where the two parts can be created like:
*
* <host> can be either
* <name> or <hash>
*
* <name> consists of
* [name,address] or just [name] or just [address]
*
* <hash> consists of
* |1|<salt>|hash
*
* <key> can be one of:
* [RSA bits] [e] [n as a decimal number]
* 'ssh-dss' [base64-encoded-key]
* 'ssh-rsa' [base64-encoded-key]
*
*/
#define LIBSSH2_KNOWNHOST_FILE_OPENSSH 1
LIBSSH2_API int
libssh2_knownhost_parsefile(LIBSSH2_KNOWNHOSTS *hosts,
const char *filename, int type)
{
FILE *file;
int num = 0;
char buf[2048];
if(type != LIBSSH2_KNOWNHOST_FILE_OPENSSH)
return -1;
file = fopen(filename, "r");
if(file) {
char *cp;
char *hostp;
char *key;
size_t hostlen;
while(fgets(buf, sizeof(buf), file)) {
cp = buf;
/* skip leading whitespaces */
while((*cp==' ') || (*cp == '\t'))
cp++;
if(!*cp || (*cp == '#') || (*cp == '\n'))
/* comment or empty line */
continue;
/* the host part starts here */
hostp = cp;
/* move over the host to the separator */
while(*cp && (*cp!=' ') && (*cp != '\t'))
cp++;
hostlen = cp - hostp;
*cp++ = 0; /* terminate the host string here */
/* the key starts after the whitespaces */
while(*cp && ((*cp==' ') || (*cp == '\t')))
cp++;
if(!*cp)
/* illegal line */
continue;
key = cp; /* the key starts here */
while(*cp && (*cp != '\n'))
cp++;
/* zero terminate where the newline is */
if(*cp == '\n')
*cp = 0;
/* deal with this one host+key line */
if(!hostline(hosts, hostp, hostlen, key, strlen(key)))
num++;
}
fclose(file);
}
else
return -1;
return num;
}

566
src/knownhost.c Normal file
View File

@@ -0,0 +1,566 @@
/*
* Copyright (c) 2009 by Daniel Stenberg
* All rights reserved.
*
* Redistribution and use in source and binary forms,
* with or without modification, are permitted provided
* that the following conditions are met:
*
* Redistributions of source code must retain the above
* copyright notice, this list of conditions and the
* following disclaimer.
*
* Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* Neither the name of the copyright holder nor the names
* of any other contributors may be used to endorse or
* promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
* USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*/
#include "libssh2.h"
#include "libssh2_priv.h"
#include "misc.h"
/* Needed for struct iovec on some platforms */
#ifdef HAVE_SYS_UIO_H
#include <sys/uio.h>
#endif
static void free_host(LIBSSH2_SESSION *session, struct known_host *entry)
{
if(entry) {
if(entry->key)
LIBSSH2_FREE(session, entry->key);
if(entry->salt)
LIBSSH2_FREE(session, entry->salt);
if(entry->name)
LIBSSH2_FREE(session, entry->name);
LIBSSH2_FREE(session, entry);
}
}
/*
* libssh2_knownhost_init
*
* Init a collection of known hosts. Returns the pointer to a collection.
*
*/
LIBSSH2_API LIBSSH2_KNOWNHOSTS *
libssh2_knownhost_init(LIBSSH2_SESSION *session)
{
LIBSSH2_KNOWNHOSTS *knh =
LIBSSH2_ALLOC(session, sizeof(struct _LIBSSH2_KNOWNHOSTS));
if(!knh)
return NULL;
knh->session = session;
_libssh2_list_init(&knh->head);
return knh;
}
/*
* libssh2_knownhost_add
*
* Add a host and its associated key to the collection of known hosts.
*
* The 'type' argument specifies on what format the given host and keys are:
*
* plain - ascii "hostname.domain.tld"
* sha1 - SHA1(<salt> <host>) base64-encoded!
* custom - another hash
*
* If 'sha1' is selected as type, the salt must be provided to the salt
* argument. This too base64 encoded.
*
* The SHA-1 hash is what OpenSSH can be told to use in known_hosts files. If
* a custom type is used, salt is ignored and you must provide the host
* pre-hashed when checking for it in the libssh2_knownhost_check() function.
*
*/
LIBSSH2_API int
libssh2_knownhost_add(LIBSSH2_KNOWNHOSTS *hosts,
char *host, char *salt,
char *key, size_t keylen,
int typemask)
{
struct known_host *entry =
LIBSSH2_ALLOC(hosts->session, sizeof(struct known_host));
size_t hostlen = strlen(host);
int rc = LIBSSH2_ERROR_MEMORY;
char *ptr;
unsigned int ptrlen;
if(!entry)
return rc;
memset(entry, 0, sizeof(struct known_host));
entry->typemask = typemask;
switch(entry->typemask & LIBSSH2_KNOWNHOST_TYPE_MASK) {
case LIBSSH2_KNOWNHOST_TYPE_PLAIN:
case LIBSSH2_KNOWNHOST_TYPE_CUSTOM:
entry->name = LIBSSH2_ALLOC(hosts->session, hostlen+1);
if(!entry)
goto error;
memcpy(entry->name, host, hostlen+1);
break;
case LIBSSH2_KNOWNHOST_TYPE_SHA1:
rc = libssh2_base64_decode(hosts->session, &ptr, &ptrlen,
host, hostlen);
if(rc)
goto error;
entry->name = ptr;
entry->name_len = ptrlen;
rc = libssh2_base64_decode(hosts->session, &ptr, &ptrlen,
salt, strlen(salt));
if(rc)
goto error;
entry->salt = ptr;
entry->salt_len = ptrlen;
break;
default:
rc = LIBSSH2_ERROR_METHOD_NOT_SUPPORTED;
goto error;
}
if(typemask & LIBSSH2_KNOWNHOST_KEY_BASE64) {
/* the provided key is base64 encoded already */
if(!keylen)
keylen = strlen(key);
entry->key = LIBSSH2_ALLOC(hosts->session, keylen+1);
if(!entry)
goto error;
memcpy(entry->key, key, keylen+1);
}
else {
/* key is raw, we base64 encode it and store it as such */
size_t nlen = _libssh2_base64_encode(hosts->session, key, keylen,
&ptr);
if(!nlen)
goto error;
entry->key = ptr;
}
/* add this new host to the big list of known hosts */
_libssh2_list_add(&hosts->head, &entry->node);
return LIBSSH2_ERROR_NONE;
error:
free_host(hosts->session, entry);
return rc;
}
#define KNOWNHOST_MAGIC 0xdeadcafe
/*
* knownhost_to_external()
*
* Copies data from the internal to the external representation struct.
*
*/
static void knownhost_to_external(struct known_host *node,
struct libssh2_knownhost *ext)
{
if(ext) {
ext->magic = KNOWNHOST_MAGIC;
ext->node = node;
ext->name = ((node->typemask & LIBSSH2_KNOWNHOST_TYPE_MASK) ==
LIBSSH2_KNOWNHOST_TYPE_PLAIN)? node->name:NULL;
ext->key = node->key;
ext->typemask = node->typemask;
}
}
/*
* libssh2_knownhost_check
*
* Check a host and its associated key against the collection of known hosts.
*
* The typemask is the type/format of the given host name and key
*
* plain - ascii "hostname.domain.tld"
* sha1 - NOT SUPPORTED AS INPUT
* custom - prehashed base64 encoded. Note that this cannot use any salts.
*
* Returns:
*
* LIBSSH2_KNOWNHOST_CHECK_FAILURE
* LIBSSH2_KNOWNHOST_CHECK_NOTFOUND
* LIBSSH2_KNOWNHOST_CHECK_MATCH
* LIBSSH2_KNOWNHOST_CHECK_MISMATCH
*/
LIBSSH2_API int
libssh2_knownhost_check(LIBSSH2_KNOWNHOSTS *hosts,
char *host, char *key, size_t keylen,
int typemask,
struct libssh2_knownhost *knownhost)
{
struct known_host *node = _libssh2_list_first(&hosts->head);
struct known_host *badkey = NULL;
int type = typemask & LIBSSH2_KNOWNHOST_TYPE_MASK;
char *keyalloc = NULL;
int rc = LIBSSH2_KNOWNHOST_CHECK_NOTFOUND;
if(type == LIBSSH2_KNOWNHOST_TYPE_SHA1)
/* we can't work with a sha1 as given input */
return LIBSSH2_KNOWNHOST_CHECK_MISMATCH;
if(!(typemask & LIBSSH2_KNOWNHOST_KEY_BASE64)) {
/* we got a raw key input, convert it to base64 for the checks below */
size_t nlen = _libssh2_base64_encode(hosts->session, key, keylen,
&keyalloc);
if(!nlen)
return LIBSSH2_KNOWNHOST_CHECK_FAILURE;
/* make the key point to this */
key = keyalloc;
keylen = nlen;
}
while (node) {
int match = 0;
switch(node->typemask & LIBSSH2_KNOWNHOST_TYPE_MASK) {
case LIBSSH2_KNOWNHOST_TYPE_PLAIN:
if(type == LIBSSH2_KNOWNHOST_TYPE_PLAIN)
match = !strcmp(host, node->name);
break;
case LIBSSH2_KNOWNHOST_TYPE_CUSTOM:
if(type == LIBSSH2_KNOWNHOST_TYPE_CUSTOM)
match = !strcmp(host, node->name);
break;
case LIBSSH2_KNOWNHOST_TYPE_SHA1:
if(type == LIBSSH2_KNOWNHOST_TYPE_PLAIN) {
/* when we have the sha1 version stored, we can use a plain
input to produce a hash to compare with the stored hash.
HMAC_Init(&mac_ctx, salt, len, md);
HMAC_Update(&mac_ctx, host, strlen(host));
HMAC_Final(&mac_ctx, result, NULL);
HMAC_cleanup(&mac_ctx);
*/
libssh2_hmac_ctx ctx;
unsigned char hash[SHA_DIGEST_LENGTH];
if(SHA_DIGEST_LENGTH != node->name_len) {
/* the name hash length must be the sha1 size or
we can't match it */
break;
}
libssh2_hmac_sha1_init(&ctx, node->salt, node->salt_len);
libssh2_hmac_update(ctx, (unsigned char *)host, strlen(host));
libssh2_hmac_final(ctx, hash);
libssh2_hmac_cleanup(&ctx);
if(!memcmp(hash, node->name, SHA_DIGEST_LENGTH))
/* this is a node we're interested in */
match = 1;
}
break;
default: /* unsupported type */
break;
}
if(match) {
/* host name match, now compare the keys */
if(!strcmp(key, node->key)) {
/* they match! */
knownhost_to_external(node, knownhost);
badkey = NULL;
rc = LIBSSH2_KNOWNHOST_CHECK_MATCH;
break;
}
else {
/* remember the first node that had a host match but a failed
key match since we continue our search from here */
if(!badkey)
badkey = node;
}
}
node= _libssh2_list_next(&node->node);
}
if(badkey) {
/* key mismatch */
knownhost_to_external(badkey, knownhost);
rc = LIBSSH2_KNOWNHOST_CHECK_MISMATCH;
}
if(keyalloc)
LIBSSH2_FREE(hosts->session, keyalloc);
return rc;
}
/*
* libssh2_knownhost_del
*
* Remove a host from the collection of known hosts.
*
*/
LIBSSH2_API int
libssh2_knownhost_del(LIBSSH2_KNOWNHOSTS *hosts,
struct libssh2_knownhost *entry)
{
struct known_host *node;
if(!entry || (entry->magic != KNOWNHOST_MAGIC))
/* check that this was retrieved the right way or get out */
return -1;
/* get the internal node pointer */
node = entry->node;
/* unlink from the list of all hosts */
_libssh2_list_remove(&node->node);
/* free all resources */
free_host(hosts->session, node);
return 0;
}
/*
* libssh2_knownhost_free
*
* Free an entire collection of known hosts.
*
*/
LIBSSH2_API void
libssh2_knownhost_free(LIBSSH2_KNOWNHOSTS *hosts)
{
struct known_host *node;
struct known_host *next;
for(node = _libssh2_list_first(&hosts->head); node; node = next) {
next = _libssh2_list_next(&node->node);
free_host(hosts->session, node);
}
LIBSSH2_FREE(hosts->session, hosts);
}
/*
* hostline()
*
* Parse a single known_host line pre-split into host and key.
*
* Note: this function assumes that the 'host' pointer points into a temporary
* buffer as it will write to it.
*/
static int hostline(LIBSSH2_KNOWNHOSTS *hosts,
char *host, size_t hostlen,
char *key, size_t keylen)
{
char *p;
char *salt = NULL;
int rc;
int type = LIBSSH2_KNOWNHOST_TYPE_PLAIN;
char *sep = NULL;
/* Figure out host format */
if(strncmp(host, "|1|", 3)) {
/* old style plain text: [name][,][ip-address]
for the sake of simplicity, we add them as two hosts with the same
key
*/
sep = strchr(host, ',');
}
else {
/* |1|[salt]|[hash] */
type = LIBSSH2_KNOWNHOST_TYPE_SHA1;
salt = &host[3]; /* skip the magic marker */
/* this is where the salt starts, find the end of it */
for(p = salt; *p && (*p != '|'); p++)
;
if(*p=='|') {
char *hash = NULL;
*p=0; /* terminate the salt string */
hash = p+1; /* the hash is after the separator */
/* now make the host point to the hash */
hostlen = strlen(hash);
host = hash;
}
else
return 0;
}
if(keylen < 20)
return -1; /* TODO: better return code */
switch(key[0]) {
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
type |= LIBSSH2_KNOWNHOST_KEY_RSA1;
/* Note that the old-style keys (RSA1) aren't truly base64, but we
* claim it is for now since we can get away with strcmp()ing the
* entire anything anyway! We need to check and fix these to make them
* work properly.
*/
break;
case 's': /* ssh-dss or ssh-rsa */
if(!strncmp(key, "ssh-dss", 7))
type |= LIBSSH2_KNOWNHOST_KEY_SSHDSS;
else if(!strncmp(key, "ssh-rsa", 7))
type |= LIBSSH2_KNOWNHOST_KEY_SSHRSA;
else
return -1; /* unknown */
key += 7;
keylen -= 7;
/* skip whitespaces */
while((*key ==' ') || (*key == '\t')) {
key++;
keylen--;
}
break;
default: /* unknown key format */
return -1;
}
if(sep) {
/* this is the second host, add this first */
char *ipaddr;
*sep++ = 0; /* zero terminate the first host name here */
ipaddr = sep;
rc = libssh2_knownhost_add(hosts, ipaddr, salt, key, keylen,
type | LIBSSH2_KNOWNHOST_KEY_BASE64);
if(rc)
return rc;
}
rc = libssh2_knownhost_add(hosts, host, salt, key, keylen,
type | LIBSSH2_KNOWNHOST_KEY_BASE64);
return rc;
}
/*
* libssh2_knownhost_parsefile
*
* Add hosts+key pairs from a given file.
*
* Returns a negative value for error or number of successfully added hosts.
*
* Line format:
*
* <host> <key>
*
* Where the two parts can be created like:
*
* <host> can be either
* <name> or <hash>
*
* <name> consists of
* [name,address] or just [name] or just [address]
*
* <hash> consists of
* |1|<salt>|hash
*
* <key> can be one of:
* [RSA bits] [e] [n as a decimal number]
* 'ssh-dss' [base64-encoded-key]
* 'ssh-rsa' [base64-encoded-key]
*
*/
#define LIBSSH2_KNOWNHOST_FILE_OPENSSH 1
LIBSSH2_API int
libssh2_knownhost_parsefile(LIBSSH2_KNOWNHOSTS *hosts,
const char *filename, int type)
{
FILE *file;
int num = 0;
char buf[2048];
if(type != LIBSSH2_KNOWNHOST_FILE_OPENSSH)
return -1;
file = fopen(filename, "r");
if(file) {
char *cp;
char *hostp;
char *key;
size_t hostlen;
while(fgets(buf, sizeof(buf), file)) {
cp = buf;
/* skip leading whitespaces */
while((*cp==' ') || (*cp == '\t'))
cp++;
if(!*cp || (*cp == '#') || (*cp == '\n'))
/* comment or empty line */
continue;
/* the host part starts here */
hostp = cp;
/* move over the host to the separator */
while(*cp && (*cp!=' ') && (*cp != '\t'))
cp++;
hostlen = cp - hostp;
*cp++ = 0; /* terminate the host string here */
/* the key starts after the whitespaces */
while(*cp && ((*cp==' ') || (*cp == '\t')))
cp++;
if(!*cp)
/* illegal line */
continue;
key = cp; /* the key starts here */
while(*cp && (*cp != '\n'))
cp++;
/* zero terminate where the newline is */
if(*cp == '\n')
*cp = 0;
/* deal with this one host+key line */
if(!hostline(hosts, hostp, hostlen, key, strlen(key)))
num++;
}
fclose(file);
}
else
return -1;
return num;
}