diff options
Diffstat (limited to 'libs/libssh2/src/knownhost.c')
| -rw-r--r-- | libs/libssh2/src/knownhost.c | 1245 |
1 files changed, 1245 insertions, 0 deletions
diff --git a/libs/libssh2/src/knownhost.c b/libs/libssh2/src/knownhost.c new file mode 100644 index 0000000000..a32dcf8764 --- /dev/null +++ b/libs/libssh2/src/knownhost.c @@ -0,0 +1,1245 @@ +/* + * Copyright (c) 2009-2014 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 *key_type_name; /* the (allocated) key type name */ + size_t key_type_len; /* size of key_type_name */ + char *comment; /* the (allocated) optional comment text, may be + NULL */ + size_t comment_len; /* the size of comment */ + + /* 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_type_name) + LIBSSH2_FREE(session, entry->key_type_name); + 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_type_name, size_t key_type_len, + 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_CALLOC(hosts->session, sizeof(struct known_host)))) + return _libssh2_error(hosts->session, LIBSSH2_ERROR_ALLOC, + "Unable to allocate memory for known host " + "entry"); + + 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); + entry->name_len = hostlen; + 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 (key_type_name && ((typemask & LIBSSH2_KNOWNHOST_KEY_MASK) == + LIBSSH2_KNOWNHOST_KEY_UNKNOWN)) { + entry->key_type_name = LIBSSH2_ALLOC(hosts->session, key_type_len+1); + if (!entry->key_type_name) { + rc = _libssh2_error(hosts->session, LIBSSH2_ERROR_ALLOC, + "Unable to allocate memory for key type"); + goto error; + } + memcpy(entry->key_type_name, key_type_name, key_type_len); + entry->key_type_name[key_type_len]=0; + entry->key_type_len = key_type_len; + } + + 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 */ + entry->comment_len = commentlen; + } + 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, NULL, 0, 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, NULL, 0, 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 a port number is given, check for a '[host]:port' first before the + plain 'host' */ + if(port >= 0) { + int len = snprintf(hostbuff, sizeof(hostbuff), "[%s]:%d", hostp, port); + if (len < 0 || len >= (int)sizeof(hostbuff)) { + _libssh2_error(hosts->session, + LIBSSH2_ERROR_BUFFER_TOO_SMALL, + "Known-host write buffer too small"); + return LIBSSH2_KNOWNHOST_CHECK_FAILURE; + } + host = hostbuff; + numcheck = 2; /* check both combos, start with this */ + } + else { + host = hostp; + numcheck = 1; /* only check this host version */ + } + + 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; + } + + 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. + */ + unsigned char hash[SHA_DIGEST_LENGTH]; + libssh2_hmac_ctx ctx; + libssh2_hmac_ctx_init(ctx); + + 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, (unsigned char *)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) { + int host_key_type = typemask & LIBSSH2_KNOWNHOST_KEY_MASK; + int known_key_type = + node->typemask & LIBSSH2_KNOWNHOST_KEY_MASK; + /* match on key type as follows: + - never match on an unknown key type + - if key_type is set to zero, ignore it an match always + - otherwise match when both key types are equal + */ + if ( (host_key_type != LIBSSH2_KNOWNHOST_KEY_UNKNOWN ) && + ( (host_key_type == 0) || + (host_key_type == known_key_type) ) ) { + /* host name and key type 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_type_name, size_t key_type_len, + 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_type_name, key_type_len, + 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_type_name, size_t key_type_len, + 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_type_name, key_type_len, + 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; + const char *key_type_name = NULL; + size_t commentlen = 0; + size_t key_type_len = 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; + + default: + key_type_name = key; + while (keylen && *key && + (*key != ' ') && (*key != '\t')) { + key++; + keylen--; + } + key_type_len = key - key_type_name; + + if (!strncmp(key_type_name, "ssh-dss", key_type_len)) + key_type = LIBSSH2_KNOWNHOST_KEY_SSHDSS; + else if (!strncmp(key_type_name, "ssh-rsa", key_type_len)) + key_type = LIBSSH2_KNOWNHOST_KEY_SSHRSA; + else + key_type = LIBSSH2_KNOWNHOST_KEY_UNKNOWN; + + /* 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; + } + + /* 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_type_name, + key_type_len, key, keylen, key_type, + comment, commentlen); + } + else { + /* |1|[salt]|[hash] */ + return hashed_hostline(hosts, host, hostlen, key_type_name, + key_type_len, 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)) { + num = _libssh2_error(hosts->session, LIBSSH2_ERROR_KNOWN_HOSTS, + "Failed to parse known hosts file"); + 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) +{ + size_t required_size; + + const char *key_type_name; + size_t key_type_len; + + /* 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"); + + switch(node->typemask & LIBSSH2_KNOWNHOST_KEY_MASK) { + case LIBSSH2_KNOWNHOST_KEY_RSA1: + key_type_name = NULL; + key_type_len = 0; + break; + case LIBSSH2_KNOWNHOST_KEY_SSHRSA: + key_type_name = "ssh-rsa"; + key_type_len = 7; + break; + case LIBSSH2_KNOWNHOST_KEY_SSHDSS: + key_type_name = "ssh-dss"; + key_type_len = 7; + break; + case LIBSSH2_KNOWNHOST_KEY_UNKNOWN: + key_type_name = node->key_type_name; + if (key_type_name) { + key_type_len = node->key_type_len; + break; + } + /* otherwise fallback to default and error */ + default: + return _libssh2_error(hosts->session, + LIBSSH2_ERROR_METHOD_NOT_SUPPORTED, + "Unsupported type of known-host entry"); + } + + /* When putting together the host line there are three aspects to consider: + - Hashed (SHA1) or unhashed hostname + - key name or no key name (RSA1) + - comment or no comment + + This means there are 2^3 different formats: + ("|1|%s|%s %s %s %s\n", salt, hashed_host, key_name, key, comment) + ("|1|%s|%s %s %s\n", salt, hashed_host, key_name, key) + ("|1|%s|%s %s %s\n", salt, hashed_host, key, comment) + ("|1|%s|%s %s\n", salt, hashed_host, key) + ("%s %s %s %s\n", host, key_name, key, comment) + ("%s %s %s\n", host, key_name, key) + ("%s %s %s\n", host, key, comment) + ("%s %s\n", host, key) + + Even if the buffer is too small, we have to set outlen to the number of + characters the complete line would have taken. We also don't write + anything to the buffer unless we are sure we can write everything to the + buffer. */ + + required_size = strlen(node->key); + + if(key_type_len) + required_size += key_type_len + 1; /* ' ' = 1 */ + if(node->comment) + required_size += node->comment_len + 1; /* ' ' = 1 */ + + if((node->typemask & LIBSSH2_KNOWNHOST_TYPE_MASK) == + LIBSSH2_KNOWNHOST_TYPE_SHA1) { + char *namealloc; + size_t name_base64_len; + char *saltalloc; + size_t salt_base64_len; + + name_base64_len = _libssh2_base64_encode(hosts->session, node->name, + node->name_len, &namealloc); + if(!name_base64_len) + return _libssh2_error(hosts->session, LIBSSH2_ERROR_ALLOC, + "Unable to allocate memory for " + "base64-encoded host name"); + + salt_base64_len = _libssh2_base64_encode(hosts->session, + node->salt, node->salt_len, + &saltalloc); + if(!salt_base64_len) { + LIBSSH2_FREE(hosts->session, namealloc); + return _libssh2_error(hosts->session, LIBSSH2_ERROR_ALLOC, + "Unable to allocate memory for " + "base64-encoded salt"); + } + + required_size += salt_base64_len + name_base64_len + 7; + /* |1| + | + ' ' + \n + \0 = 7 */ + + if(required_size <= buflen) { + if(node->comment && key_type_len) + snprintf(buf, buflen, "|1|%s|%s %s %s %s\n", saltalloc, + namealloc, key_type_name, node->key, node->comment); + else if (node->comment) + snprintf(buf, buflen, "|1|%s|%s %s %s\n", saltalloc, namealloc, + node->key, node->comment); + else if (key_type_len) + snprintf(buf, buflen, "|1|%s|%s %s %s\n", saltalloc, namealloc, + key_type_name, node->key); + else + snprintf(buf, buflen, "|1|%s|%s %s\n", saltalloc, namealloc, + node->key); + } + + LIBSSH2_FREE(hosts->session, namealloc); + LIBSSH2_FREE(hosts->session, saltalloc); + } + else { + required_size += node->name_len + 3; + /* ' ' + '\n' + \0 = 3 */ + + if(required_size <= buflen) { + if(node->comment && key_type_len) + snprintf(buf, buflen, "%s %s %s %s\n", node->name, + key_type_name, node->key, node->comment); + else if (node->comment) + snprintf(buf, buflen, "%s %s %s\n", node->name, node->key, + node->comment); + else if (key_type_len) + snprintf(buf, buflen, "%s %s %s\n", node->name, key_type_name, + node->key); + else + snprintf(buf, buflen, "%s %s\n", node->name, node->key); + } + } + + /* we report the full length of the data with the trailing zero excluded */ + *outlen = required_size-1; + + if(required_size <= buflen) + return LIBSSH2_ERROR_NONE; + else + return _libssh2_error(hosts->session, LIBSSH2_ERROR_BUFFER_TOO_SMALL, + "Known-host write buffer too small"); +} + +/* + * 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 = 0; + 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; +} |