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fuchsia / third_party / libssh2 / refs/tags/libssh2-1.4.1 / . / src / knownhost.c
blob: c58dfbb20944f1c44f470c909751981d67c469ef [file] [log] [blame]
/*
* Copyright (c) 2009-2011 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_priv.h"
#include "misc.h"
struct known_host {
struct list_node node;
char *name; /* points to the name or the hash (allocated) */
size_t name_len; /* needed for hashed data */
int port; /* if non-zero, a specific port this key is for on this
host */
int typemask; /* plain, sha1, custom, ... */
char *salt; /* points to binary salt (allocated) */
size_t salt_len; /* size of salt */
char *key; /* the (allocated) associated key. This is kept base64
encoded in memory. */
char *comment; /* the (allocated) optional comment text, may be NULL */
/* this is the struct we expose externally */
struct libssh2_knownhost external;
};
struct _LIBSSH2_KNOWNHOSTS
{
LIBSSH2_SESSION *session; /* the session this "belongs to" */
struct list_head head;
};
static void free_host(LIBSSH2_SESSION *session, struct known_host *entry)
{
if(entry) {
if(entry->comment)
LIBSSH2_FREE(session, entry->comment);
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) {
_libssh2_error(session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate memory for known-hosts "
"collection");
return NULL;
}
knh->session = session;
_libssh2_list_init(&knh->head);
return knh;
}
#define KNOWNHOST_MAGIC 0xdeadcafe
/*
* knownhost_to_external()
*
* Copies data from the internal to the external representation struct.
*
*/
static struct libssh2_knownhost *knownhost_to_external(struct known_host *node)
{
struct libssh2_knownhost *ext = &node->external;
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;
return ext;
}
static int
knownhost_add(LIBSSH2_KNOWNHOSTS *hosts,
const char *host, const char *salt,
const char *key, size_t keylen,
const char *comment, size_t commentlen,
int typemask, struct libssh2_knownhost **store)
{
struct known_host *entry;
size_t hostlen = strlen(host);
int rc;
char *ptr;
unsigned int ptrlen;
/* make sure we have a key type set */
if(!(typemask & LIBSSH2_KNOWNHOST_KEY_MASK))
return _libssh2_error(hosts->session, LIBSSH2_ERROR_INVAL,
"No key type set");
if(!(entry = LIBSSH2_ALLOC(hosts->session, sizeof(struct known_host))))
return _libssh2_error(hosts->session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate memory for known host "
"entry");
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->name) {
rc = _libssh2_error(hosts->session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate memory for host name");
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(hosts->session, LIBSSH2_ERROR_METHOD_NOT_SUPPORTED,
"Unknown host name type");
goto error;
}
if(typemask & LIBSSH2_KNOWNHOST_KEYENC_BASE64) {
/* the provided key is base64 encoded already */
if(!keylen)
keylen = strlen(key);
entry->key = LIBSSH2_ALLOC(hosts->session, keylen+1);
if(!entry->key) {
rc = _libssh2_error(hosts->session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate memory for key");
goto error;
}
memcpy(entry->key, key, keylen+1);
entry->key[keylen]=0; /* force a terminating zero trailer */
}
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) {
rc = _libssh2_error(hosts->session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate memory for "
"base64-encoded key");
goto error;
}
entry->key = ptr;
}
if (comment) {
entry->comment = LIBSSH2_ALLOC(hosts->session, commentlen+1);
if(!entry->comment) {
rc = _libssh2_error(hosts->session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate memory for comment");
goto error;
}
memcpy(entry->comment, comment, commentlen+1);
entry->comment[commentlen]=0; /* force a terminating zero trailer */
}
else {
entry->comment = NULL;
}
/* add this new host to the big list of known hosts */
_libssh2_list_add(&hosts->head, &entry->node);
if(store)
*store = knownhost_to_external(entry);
return LIBSSH2_ERROR_NONE;
error:
free_host(hosts->session, entry);
return rc;
}
/*
* 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.
*
* The keylen parameter may be omitted (zero) if the key is provided as a
* NULL-terminated base64-encoded string.
*/
LIBSSH2_API int
libssh2_knownhost_add(LIBSSH2_KNOWNHOSTS *hosts,
const char *host, const char *salt,
const char *key, size_t keylen,
int typemask, struct libssh2_knownhost **store)
{
return knownhost_add(hosts, host, salt, key, keylen, NULL, 0, typemask,
store);
}
/*
* libssh2_knownhost_addc
*
* Add a host and its associated key to the collection of known hosts.
*
* Takes a comment argument that may be NULL. A NULL comment indicates
* there is no comment and the entry will end directly after the key
* when written out to a file. An empty string "" comment will indicate an
* empty comment which will cause a single space to be written after the key.
*
* 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.
*
* The keylen parameter may be omitted (zero) if the key is provided as a
* NULL-terminated base64-encoded string.
*/
LIBSSH2_API int
libssh2_knownhost_addc(LIBSSH2_KNOWNHOSTS *hosts,
const char *host, const char *salt,
const char *key, size_t keylen,
const char *comment, size_t commentlen,
int typemask, struct libssh2_knownhost **store)
{
return knownhost_add(hosts, host, salt, key, keylen, comment, commentlen,
typemask, store);
}
/*
* 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
*/
static int
knownhost_check(LIBSSH2_KNOWNHOSTS *hosts,
const char *hostp, int port,
const char *key, size_t keylen,
int typemask,
struct libssh2_knownhost **ext)
{
struct known_host *node;
struct known_host *badkey = NULL;
int type = typemask & LIBSSH2_KNOWNHOST_TYPE_MASK;
char *keyalloc = NULL;
int rc = LIBSSH2_KNOWNHOST_CHECK_NOTFOUND;
char hostbuff[270]; /* most host names can't be longer than like 256 */
const char *host;
int numcheck; /* number of host combos to check */
int match = 0;
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_KEYENC_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) {
_libssh2_error(hosts->session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate memory for base64-encoded "
"key");
return LIBSSH2_KNOWNHOST_CHECK_FAILURE;
}
/* make the key point to this */
key = keyalloc;
}
/* if a port number is given, check for a '[host]:port' first before the
plain 'host' */
if(port >= 0) {
snprintf(hostbuff, sizeof(hostbuff), "[%s]:%d", hostp, port);
host = hostbuff;
numcheck = 2; /* check both combos, start with this */
}
else {
host = hostp;
numcheck = 1; /* only check this host version */
}
do {
node = _libssh2_list_first(&hosts->head);
while (node) {
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.
*/
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! */
if (ext)
*ext = knownhost_to_external(node);
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;
match = 0; /* don't count this as a match anymore */
}
}
node= _libssh2_list_next(&node->node);
}
host = hostp;
} while(!match && --numcheck);
if(badkey) {
/* key mismatch */
if (ext)
*ext = knownhost_to_external(badkey);
rc = LIBSSH2_KNOWNHOST_CHECK_MISMATCH;
}
if(keyalloc)
LIBSSH2_FREE(hosts->session, keyalloc);
return rc;
}
/*
* 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,
const char *hostp, const char *key, size_t keylen,
int typemask,
struct libssh2_knownhost **ext)
{
return knownhost_check(hosts, hostp, -1, key, keylen,
typemask, ext);
}
/*
* libssh2_knownhost_checkp
*
* Check a host+port and its associated key against the collection of known
* hosts.
*
* Note that if 'port' is specified as greater than zero, the check function
* will be able to check for a dedicated key for this particular host+port
* combo, and if 'port' is negative it only checks for the generic host key.
*
* 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_checkp(LIBSSH2_KNOWNHOSTS *hosts,
const char *hostp, int port,
const char *key, size_t keylen,
int typemask,
struct libssh2_knownhost **ext)
{
return knownhost_check(hosts, hostp, port, key, keylen,
typemask, ext);
}
/*
* 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;
/* check that this was retrieved the right way or get out */
if(!entry || (entry->magic != KNOWNHOST_MAGIC))
return _libssh2_error(hosts->session, LIBSSH2_ERROR_INVAL,
"Invalid host information");
/* get the internal node pointer */
node = entry->node;
/* unlink from the list of all hosts */
_libssh2_list_remove(&node->node);
/* clear the struct now since the memory in which it is allocated is
about to be freed! */
memset(entry, 0, sizeof(struct libssh2_knownhost));
/* 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);
}
/* old style plain text: [name]([,][name])*
for the sake of simplicity, we add them as separate hosts with the same
key
*/
static int oldstyle_hostline(LIBSSH2_KNOWNHOSTS *hosts,
const char *host, size_t hostlen,
const char *key, size_t keylen, int key_type,
const char *comment, size_t commentlen)
{
int rc = 0;
size_t namelen = 0;
const char *name = host + hostlen;
if(hostlen < 1)
return _libssh2_error(hosts->session,
LIBSSH2_ERROR_METHOD_NOT_SUPPORTED,
"Failed to parse known_hosts line "
"(no host names)");
while(name > host) {
--name;
++namelen;
/* when we get the the start or see a comma coming up, add the host
name to the collection */
if((name == host) || (*(name-1) == ',')) {
char hostbuf[256];
/* make sure we don't overflow the buffer */
if(namelen >= sizeof(hostbuf)-1)
return _libssh2_error(hosts->session,
LIBSSH2_ERROR_METHOD_NOT_SUPPORTED,
"Failed to parse known_hosts line "
"(unexpected length)");
/* copy host name to the temp buffer and zero terminate */
memcpy(hostbuf, name, namelen);
hostbuf[namelen]=0;
rc = knownhost_add(hosts, hostbuf, NULL, key, keylen,
comment, commentlen,
key_type | LIBSSH2_KNOWNHOST_TYPE_PLAIN |
LIBSSH2_KNOWNHOST_KEYENC_BASE64, NULL);
if(rc)
return rc;
if(name > host) {
namelen = 0;
--name; /* skip comma */
}
}
}
return rc;
}
/* |1|[salt]|[hash] */
static int hashed_hostline(LIBSSH2_KNOWNHOSTS *hosts,
const char *host, size_t hostlen,
const char *key, size_t keylen, int key_type,
const char *comment, size_t commentlen)
{
const char *p;
char saltbuf[32];
char hostbuf[256];
const char *salt = &host[3]; /* skip the magic marker */
hostlen -= 3; /* deduct the marker */
/* this is where the salt starts, find the end of it */
for(p = salt; *p && (*p != '|'); p++)
;
if(*p=='|') {
const char *hash = NULL;
size_t saltlen = p - salt;
if(saltlen >= (sizeof(saltbuf)-1)) /* weird length */
return _libssh2_error(hosts->session,
LIBSSH2_ERROR_METHOD_NOT_SUPPORTED,
"Failed to parse known_hosts line "
"(unexpectedly long salt)");
memcpy(saltbuf, salt, saltlen);
saltbuf[saltlen] = 0; /* zero terminate */
salt = saltbuf; /* point to the stack based buffer */
hash = p+1; /* the host hash is after the separator */
/* now make the host point to the hash */
host = hash;
hostlen -= saltlen+1; /* deduct the salt and separator */
/* check that the lengths seem sensible */
if(hostlen >= sizeof(hostbuf)-1)
return _libssh2_error(hosts->session,
LIBSSH2_ERROR_METHOD_NOT_SUPPORTED,
"Failed to parse known_hosts line "
"(unexpected length)");
memcpy(hostbuf, host, hostlen);
hostbuf[hostlen]=0;
return knownhost_add(hosts, hostbuf, salt, key, keylen, comment,
commentlen,
key_type | LIBSSH2_KNOWNHOST_TYPE_SHA1 |
LIBSSH2_KNOWNHOST_KEYENC_BASE64, NULL);
}
else
return 0; /* XXX: This should be an error, shouldn't it? */
}
/*
* hostline()
*
* Parse a single known_host line pre-split into host and key.
*
* The key part may include an optional comment which will be parsed here
* for ssh-rsa and ssh-dsa keys. Comments in other key types aren't handled.
*
* The function assumes new-lines have already been removed from the arguments.
*/
static int hostline(LIBSSH2_KNOWNHOSTS *hosts,
const char *host, size_t hostlen,
const char *key, size_t keylen)
{
const char *comment = NULL;
size_t commentlen = 0;
int key_type;
/* make some checks that the lengths seem sensible */
if(keylen < 20)
return _libssh2_error(hosts->session,
LIBSSH2_ERROR_METHOD_NOT_SUPPORTED,
"Failed to parse known_hosts line "
"(key too short)");
switch(key[0]) {
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
key_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))
key_type = LIBSSH2_KNOWNHOST_KEY_SSHDSS;
else if(!strncmp(key, "ssh-rsa", 7))
key_type = LIBSSH2_KNOWNHOST_KEY_SSHRSA;
else
/* unknown key type */
return _libssh2_error(hosts->session,
LIBSSH2_ERROR_METHOD_NOT_SUPPORTED,
"Unknown key type");
key += 7;
keylen -= 7;
/* skip whitespaces */
while((*key ==' ') || (*key == '\t')) {
key++;
keylen--;
}
comment = key;
commentlen = keylen;
/* move over key */
while(commentlen && *comment &&
(*comment != ' ') && (*comment != '\t')) {
comment++;
commentlen--;
}
/* reduce key by comment length */
keylen -= commentlen;
/* Distinguish empty comment (a space) from no comment (no space) */
if (commentlen == 0)
comment = NULL;
/* skip whitespaces */
while(commentlen && *comment &&
((*comment ==' ') || (*comment == '\t'))) {
comment++;
commentlen--;
}
break;
default: /* unknown key format */
return _libssh2_error(hosts->session,
LIBSSH2_ERROR_METHOD_NOT_SUPPORTED,
"Unknown key format");
}
/* Figure out host format */
if((hostlen >2) && memcmp(host, "|1|", 3)) {
/* old style plain text: [name]([,][name])*
for the sake of simplicity, we add them as separate hosts with the
same key
*/
return oldstyle_hostline(hosts, host, hostlen, key, keylen, key_type,
comment, commentlen);
}
else {
/* |1|[salt]|[hash] */
return hashed_hostline(hosts, host, hostlen, key, keylen, key_type,
comment, commentlen);
}
}
/*
* libssh2_knownhost_readline()
*
* Pass in a line of a file of 'type'.
*
* LIBSSH2_KNOWNHOST_FILE_OPENSSH is the only supported type.
*
* OpenSSH line format:
*
* <host> <key>
*
* Where the two parts can be created like:
*
* <host> can be either
* <name> or <hash>
*
* <name> consists of
* [name] optionally followed by [,name] one or more times
*
* <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]
*
*/
LIBSSH2_API int
libssh2_knownhost_readline(LIBSSH2_KNOWNHOSTS *hosts,
const char *line, size_t len, int type)
{
const char *cp;
const char *hostp;
const char *keyp;
size_t hostlen;
size_t keylen;
int rc;
if(type != LIBSSH2_KNOWNHOST_FILE_OPENSSH)
return _libssh2_error(hosts->session,
LIBSSH2_ERROR_METHOD_NOT_SUPPORTED,
"Unsupported type of known-host information "
"store");
cp = line;
/* skip leading whitespaces */
while(len && ((*cp==' ') || (*cp == '\t'))) {
cp++;
len--;
}
if(!len || !*cp || (*cp == '#') || (*cp == '\n'))
/* comment or empty line */
return LIBSSH2_ERROR_NONE;
/* the host part starts here */
hostp = cp;
/* move over the host to the separator */
while(len && *cp && (*cp!=' ') && (*cp != '\t')) {
cp++;
len--;
}
hostlen = cp - hostp;
/* the key starts after the whitespaces */
while(len && *cp && ((*cp==' ') || (*cp == '\t'))) {
cp++;
len--;
}
if(!*cp || !len) /* illegal line */
return _libssh2_error(hosts->session,
LIBSSH2_ERROR_METHOD_NOT_SUPPORTED,
"Failed to parse known_hosts line");
keyp = cp; /* the key starts here */
keylen = len;
/* check if the line (key) ends with a newline and if so kill it */
while(len && *cp && (*cp != '\n')) {
cp++;
len--;
}
/* zero terminate where the newline is */
if(*cp == '\n')
keylen--; /* don't include this in the count */
/* deal with this one host+key line */
rc = hostline(hosts, hostp, hostlen, keyp, keylen);
if(rc)
return rc; /* failed */
return LIBSSH2_ERROR_NONE; /* success */
}
/*
* libssh2_knownhost_readfile
*
* Read hosts+key pairs from a given file.
*
* Returns a negative value for error or number of successfully added hosts.
*
*/
LIBSSH2_API int
libssh2_knownhost_readfile(LIBSSH2_KNOWNHOSTS *hosts,
const char *filename, int type)
{
FILE *file;
int num = 0;
char buf[2048];
if(type != LIBSSH2_KNOWNHOST_FILE_OPENSSH)
return _libssh2_error(hosts->session,
LIBSSH2_ERROR_METHOD_NOT_SUPPORTED,
"Unsupported type of known-host information "
"store");
file = fopen(filename, "r");
if(file) {
while(fgets(buf, sizeof(buf), file)) {
if(libssh2_knownhost_readline(hosts, buf, strlen(buf), type))
break;
num++;
}
fclose(file);
}
else
return _libssh2_error(hosts->session, LIBSSH2_ERROR_FILE,
"Failed to open file");
return num;
}
/*
* knownhost_writeline()
*
* Ask libssh2 to convert a known host to an output line for storage.
*
* Note that this function returns LIBSSH2_ERROR_BUFFER_TOO_SMALL if the given
* output buffer is too small to hold the desired output. The 'outlen' field
* will then contain the size libssh2 wanted to store, which then is the
* smallest sufficient buffer it would require.
*
*/
static int
knownhost_writeline(LIBSSH2_KNOWNHOSTS *hosts,
struct known_host *node,
char *buf, size_t buflen,
size_t *outlen, int type)
{
int rc = LIBSSH2_ERROR_NONE;
int tindex;
const char *keytypes[4]={
"", /* not used */
"", /* this type has no name in the file */
" ssh-rsa",
" ssh-dss"
};
const char *keytype;
size_t nlen;
size_t commentlen = 0;
/* we only support this single file type for now, bail out on all other
attempts */
if(type != LIBSSH2_KNOWNHOST_FILE_OPENSSH)
return _libssh2_error(hosts->session,
LIBSSH2_ERROR_METHOD_NOT_SUPPORTED,
"Unsupported type of known-host information "
"store");
tindex = (node->typemask & LIBSSH2_KNOWNHOST_KEY_MASK) >>
LIBSSH2_KNOWNHOST_KEY_SHIFT;
/* set the string used in the file */
keytype = keytypes[tindex];
/* calculate extra space needed for comment */
if(node->comment)
commentlen = strlen(node->comment) + 1;
if((node->typemask & LIBSSH2_KNOWNHOST_TYPE_MASK) ==
LIBSSH2_KNOWNHOST_TYPE_SHA1) {
char *namealloc;
char *saltalloc;
nlen = _libssh2_base64_encode(hosts->session, node->name,
node->name_len, &namealloc);
if(!nlen)
return _libssh2_error(hosts->session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate memory for "
"base64-encoded host name");
nlen = _libssh2_base64_encode(hosts->session,
node->salt, node->salt_len,
&saltalloc);
if(!nlen) {
free(namealloc);
return _libssh2_error(hosts->session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate memory for "
"base64-encoded salt");
}
nlen = strlen(saltalloc) + strlen(namealloc) + strlen(keytype) +
strlen(node->key) + commentlen + 7;
/* |1| + | + ' ' + \n + \0 = 7 */
if(nlen <= buflen)
if(node->comment)
snprintf(buf, buflen, "|1|%s|%s%s %s %s\n", saltalloc, namealloc,
keytype, node->key, node->comment);
else
snprintf(buf, buflen, "|1|%s|%s%s %s\n", saltalloc, namealloc,
keytype, node->key);
else
rc = _libssh2_error(hosts->session, LIBSSH2_ERROR_BUFFER_TOO_SMALL,
"Known-host write buffer too small");
free(namealloc);
free(saltalloc);
}
else {
nlen = strlen(node->name) + strlen(keytype) + strlen(node->key) +
commentlen + 3;
/* ' ' + '\n' + \0 = 3 */
if(nlen <= buflen)
/* these types have the plain name */
if(node->comment)
snprintf(buf, buflen, "%s%s %s %s\n", node->name, keytype, node->key,
node->comment);
else
snprintf(buf, buflen, "%s%s %s\n", node->name, keytype, node->key);
else
rc = _libssh2_error(hosts->session, LIBSSH2_ERROR_BUFFER_TOO_SMALL,
"Known-host write buffer too small");
}
/* we report the full length of the data with the trailing zero excluded */
*outlen = nlen-1;
return rc;
}
/*
* libssh2_knownhost_writeline()
*
* Ask libssh2 to convert a known host to an output line for storage.
*
* Note that this function returns LIBSSH2_ERROR_BUFFER_TOO_SMALL if the given
* output buffer is too small to hold the desired output.
*/
LIBSSH2_API int
libssh2_knownhost_writeline(LIBSSH2_KNOWNHOSTS *hosts,
struct libssh2_knownhost *known,
char *buffer, size_t buflen,
size_t *outlen, /* the amount of written data */
int type)
{
struct known_host *node;
if(known->magic != KNOWNHOST_MAGIC)
return _libssh2_error(hosts->session, LIBSSH2_ERROR_INVAL,
"Invalid host information");
node = known->node;
return knownhost_writeline(hosts, node, buffer, buflen, outlen, type);
}
/*
* libssh2_knownhost_writefile()
*
* Write hosts+key pairs to the given file.
*/
LIBSSH2_API int
libssh2_knownhost_writefile(LIBSSH2_KNOWNHOSTS *hosts,
const char *filename, int type)
{
struct known_host *node;
FILE *file;
int rc = LIBSSH2_ERROR_NONE;
char buffer[2048];
/* we only support this single file type for now, bail out on all other
attempts */
if(type != LIBSSH2_KNOWNHOST_FILE_OPENSSH)
return _libssh2_error(hosts->session,
LIBSSH2_ERROR_METHOD_NOT_SUPPORTED,
"Unsupported type of known-host information "
"store");
file = fopen(filename, "w");
if(!file)
return _libssh2_error(hosts->session, LIBSSH2_ERROR_FILE,
"Failed to open file");
for(node = _libssh2_list_first(&hosts->head);
node;
node= _libssh2_list_next(&node->node) ) {
size_t wrote;
size_t nwrote;
rc = knownhost_writeline(hosts, node, buffer, sizeof(buffer), &wrote,
type);
if(rc)
break;
nwrote = fwrite(buffer, 1, wrote, file);
if(nwrote != wrote) {
/* failed to write the whole thing, bail out */
rc = _libssh2_error(hosts->session, LIBSSH2_ERROR_FILE,
"Write failed");
break;
}
}
fclose(file);
return rc;
}
/*
* libssh2_knownhost_get()
*
* Traverse the internal list of known hosts. Pass NULL to 'prev' to get
* the first one.
*
* Returns:
* 0 if a fine host was stored in 'store'
* 1 if end of hosts
* [negative] on errors
*/
LIBSSH2_API int
libssh2_knownhost_get(LIBSSH2_KNOWNHOSTS *hosts,
struct libssh2_knownhost **ext,
struct libssh2_knownhost *oprev)
{
struct known_host *node;
if(oprev && oprev->node) {
/* we have a starting point */
struct known_host *prev = oprev->node;
/* get the next node in the list */
node = _libssh2_list_next(&prev->node);
}
else
node = _libssh2_list_first(&hosts->head);
if(!node)
/* no (more) node */
return 1;
*ext = knownhost_to_external(node);
return 0;
}