Edit
IABSD.fr/src/usr.bin/ssh/hostfile.c
djm
- usr.bin/ssh/hostfile.c
-
/* $OpenBSD: hostfile.c,v 1.100 2025/11/25 00:57:04 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland * All rights reserved * Functions for manipulating the known hosts files. * * As far as I am concerned, the code I have written for this software * can be used freely for any purpose. Any derived versions of this * software must be clearly marked as such, and if the derived work is * incompatible with the protocol description in the RFC file, it must be * called by a name other than "ssh" or "Secure Shell". * * * Copyright (c) 1999, 2000 Markus Friedl. All rights reserved. * Copyright (c) 1999 Niels Provos. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. 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. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 <sys/types.h> #include <sys/stat.h> #include <netinet/in.h> #include <errno.h> #include <resolv.h> #include <stdarg.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include "xmalloc.h" #include "match.h" #include "sshkey.h" #include "hostfile.h" #include "log.h" #include "misc.h" #include "pathnames.h" #include "ssherr.h" #include "digest.h" #include "hmac.h" #include "sshbuf.h" /* XXX hmac is too easy to dictionary attack; use bcrypt? */ static int extract_salt(const char *s, u_int l, u_char *salt, size_t salt_len) { char *p, *b64salt; u_int b64len; int ret; if (l < sizeof(HASH_MAGIC) - 1) { debug2("extract_salt: string too short"); return (-1); } if (strncmp(s, HASH_MAGIC, sizeof(HASH_MAGIC) - 1) != 0) { debug2("extract_salt: invalid magic identifier"); return (-1); } s += sizeof(HASH_MAGIC) - 1; l -= sizeof(HASH_MAGIC) - 1; if ((p = memchr(s, HASH_DELIM, l)) == NULL) { debug2("extract_salt: missing salt termination character"); return (-1); } b64len = p - s; /* Sanity check */ if (b64len == 0 || b64len > 1024) { debug2("extract_salt: bad encoded salt length %u", b64len); return (-1); } b64salt = xmalloc(1 + b64len); memcpy(b64salt, s, b64len); b64salt[b64len] = '\0'; ret = __b64_pton(b64salt, salt, salt_len); free(b64salt); if (ret == -1) { debug2("extract_salt: salt decode error"); return (-1); } if (ret != (int)ssh_hmac_bytes(SSH_DIGEST_SHA1)) { debug2("extract_salt: expected salt len %zd, got %d", ssh_hmac_bytes(SSH_DIGEST_SHA1), ret); return (-1); } return (0); } char * host_hash(const char *host, const char *name_from_hostfile, u_int src_len) { struct ssh_hmac_ctx *ctx; u_char salt[256], result[256]; char uu_salt[512], uu_result[512]; char *encoded = NULL; u_int len; len = ssh_digest_bytes(SSH_DIGEST_SHA1); if (name_from_hostfile == NULL) { /* Create new salt */ arc4random_buf(salt, len); } else { /* Extract salt from known host entry */ if (extract_salt(name_from_hostfile, src_len, salt, sizeof(salt)) == -1) return (NULL); } if ((ctx = ssh_hmac_start(SSH_DIGEST_SHA1)) == NULL || ssh_hmac_init(ctx, salt, len) < 0 || ssh_hmac_update(ctx, host, strlen(host)) < 0 || ssh_hmac_final(ctx, result, sizeof(result))) fatal_f("ssh_hmac failed"); ssh_hmac_free(ctx); if (__b64_ntop(salt, len, uu_salt, sizeof(uu_salt)) == -1 || __b64_ntop(result, len, uu_result, sizeof(uu_result)) == -1) fatal_f("__b64_ntop failed"); xasprintf(&encoded, "%s%s%c%s", HASH_MAGIC, uu_salt, HASH_DELIM, uu_result); return (encoded); } /* * Parses an RSA key from a string. Moves the pointer over the key. * Skips any whitespace at the beginning and at end. */ int hostfile_read_key(char **cpp, u_int *bitsp, struct sshkey *ret) { char *cp; /* Skip leading whitespace. */ for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++) ; if (sshkey_read(ret, &cp) != 0) return 0; /* Skip trailing whitespace. */ for (; *cp == ' ' || *cp == '\t'; cp++) ; /* Return results. */ *cpp = cp; if (bitsp != NULL) *bitsp = sshkey_size(ret); return 1; } static HostkeyMarker check_markers(char **cpp) { char marker[32], *sp, *cp = *cpp; int ret = MRK_NONE; while (*cp == '@') { /* Only one marker is allowed */ if (ret != MRK_NONE) return MRK_ERROR; /* Markers are terminated by whitespace */ if ((sp = strchr(cp, ' ')) == NULL && (sp = strchr(cp, '\t')) == NULL) return MRK_ERROR; /* Extract marker for comparison */ if (sp <= cp + 1 || sp >= cp + sizeof(marker)) return MRK_ERROR; memcpy(marker, cp, sp - cp); marker[sp - cp] = '\0'; if (strcmp(marker, CA_MARKER) == 0) ret = MRK_CA; else if (strcmp(marker, REVOKE_MARKER) == 0) ret = MRK_REVOKE; else return MRK_ERROR; /* Skip past marker and any whitespace that follows it */ cp = sp; for (; *cp == ' ' || *cp == '\t'; cp++) ; } *cpp = cp; return ret; } struct hostkeys * init_hostkeys(void) { struct hostkeys *ret = xcalloc(1, sizeof(*ret)); ret->entries = NULL; return ret; } struct load_callback_ctx { const char *host; u_long num_loaded; struct hostkeys *hostkeys; }; static int record_hostkey(struct hostkey_foreach_line *l, void *_ctx) { struct load_callback_ctx *ctx = (struct load_callback_ctx *)_ctx; struct hostkeys *hostkeys = ctx->hostkeys; struct hostkey_entry *tmp; if (l->status == HKF_STATUS_INVALID) { /* XXX make this verbose() in the future */ debug("%s:%ld: parse error in hostkeys file", l->path, l->linenum); return 0; } debug3_f("found %skey type %s in file %s:%lu", l->marker == MRK_NONE ? "" : (l->marker == MRK_CA ? "ca " : "revoked "), sshkey_type(l->key), l->path, l->linenum); if ((tmp = recallocarray(hostkeys->entries, hostkeys->num_entries, hostkeys->num_entries + 1, sizeof(*hostkeys->entries))) == NULL) return SSH_ERR_ALLOC_FAIL; hostkeys->entries = tmp; hostkeys->entries[hostkeys->num_entries].host = xstrdup(ctx->host); hostkeys->entries[hostkeys->num_entries].file = xstrdup(l->path); hostkeys->entries[hostkeys->num_entries].line = l->linenum; hostkeys->entries[hostkeys->num_entries].key = l->key; l->key = NULL; /* steal it */ hostkeys->entries[hostkeys->num_entries].marker = l->marker; hostkeys->entries[hostkeys->num_entries].note = l->note; hostkeys->num_entries++; ctx->num_loaded++; return 0; } void load_hostkeys_file(struct hostkeys *hostkeys, const char *host, const char *path, FILE *f, u_int note) { int r; struct load_callback_ctx ctx; ctx.host = host; ctx.num_loaded = 0; ctx.hostkeys = hostkeys; if ((r = hostkeys_foreach_file(path, f, record_hostkey, &ctx, host, NULL, HKF_WANT_MATCH|HKF_WANT_PARSE_KEY, note)) != 0) { if (r != SSH_ERR_SYSTEM_ERROR && errno != ENOENT) debug_fr(r, "hostkeys_foreach failed for %s", path); } if (ctx.num_loaded != 0) debug3_f("loaded %lu keys from %s", ctx.num_loaded, host); } void load_hostkeys(struct hostkeys *hostkeys, const char *host, const char *path, u_int note) { FILE *f; if ((f = fopen(path, "r")) == NULL) { debug_f("fopen %s: %s", path, strerror(errno)); return; } load_hostkeys_file(hostkeys, host, path, f, note); fclose(f); } void free_hostkeys(struct hostkeys *hostkeys) { u_int i; for (i = 0; i < hostkeys->num_entries; i++) { free(hostkeys->entries[i].host); free(hostkeys->entries[i].file); sshkey_free(hostkeys->entries[i].key); explicit_bzero(hostkeys->entries + i, sizeof(*hostkeys->entries)); } free(hostkeys->entries); freezero(hostkeys, sizeof(*hostkeys)); } static int check_key_not_revoked(struct hostkeys *hostkeys, struct sshkey *k) { int is_cert = sshkey_is_cert(k); u_int i; for (i = 0; i < hostkeys->num_entries; i++) { if (hostkeys->entries[i].marker != MRK_REVOKE) continue; if (sshkey_equal_public(k, hostkeys->entries[i].key)) return -1; if (is_cert && k != NULL && sshkey_equal_public(k->cert->signature_key, hostkeys->entries[i].key)) return -1; } return 0; } /* * Match keys against a specified key, or look one up by key type. * * If looking for a keytype (key == NULL) and one is found then return * HOST_FOUND, otherwise HOST_NEW. * * If looking for a key (key != NULL): * 1. If the key is a cert and a matching CA is found, return HOST_OK * 2. If the key is not a cert and a matching key is found, return HOST_OK * 3. If no key matches but a key with a different type is found, then * return HOST_CHANGED * 4. If no matching keys are found, then return HOST_NEW. * * Finally, check any found key is not revoked. */ static HostStatus check_hostkeys_by_key_or_type(struct hostkeys *hostkeys, struct sshkey *k, int keytype, int nid, const struct hostkey_entry **found) { u_int i; HostStatus end_return = HOST_NEW; int want_cert = sshkey_is_cert(k); HostkeyMarker want_marker = want_cert ? MRK_CA : MRK_NONE; if (found != NULL) *found = NULL; for (i = 0; i < hostkeys->num_entries; i++) { if (hostkeys->entries[i].marker != want_marker) continue; if (k == NULL) { if (hostkeys->entries[i].key->type != keytype) continue; if (nid != -1 && sshkey_type_plain(keytype) == KEY_ECDSA && hostkeys->entries[i].key->ecdsa_nid != nid) continue; end_return = HOST_FOUND; if (found != NULL) *found = hostkeys->entries + i; k = hostkeys->entries[i].key; break; } if (want_cert) { if (sshkey_equal_public(k->cert->signature_key, hostkeys->entries[i].key)) { /* A matching CA exists */ end_return = HOST_OK; if (found != NULL) *found = hostkeys->entries + i; break; } } else { if (sshkey_equal(k, hostkeys->entries[i].key)) { end_return = HOST_OK; if (found != NULL) *found = hostkeys->entries + i; break; } /* A non-matching key exists */ end_return = HOST_CHANGED; if (found != NULL) *found = hostkeys->entries + i; } } if (check_key_not_revoked(hostkeys, k) != 0) { end_return = HOST_REVOKED; if (found != NULL) *found = NULL; } return end_return; } HostStatus check_key_in_hostkeys(struct hostkeys *hostkeys, struct sshkey *key, const struct hostkey_entry **found) { if (key == NULL) fatal("no key to look up"); return check_hostkeys_by_key_or_type(hostkeys, key, 0, -1, found); } int lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype, int nid, const struct hostkey_entry **found) { return (check_hostkeys_by_key_or_type(hostkeys, NULL, keytype, nid, found) == HOST_FOUND); } int lookup_marker_in_hostkeys(struct hostkeys *hostkeys, int want_marker) { u_int i; for (i = 0; i < hostkeys->num_entries; i++) { if (hostkeys->entries[i].marker == (HostkeyMarker)want_marker) return 1; } return 0; } static int format_host_entry(struct sshbuf *entry, const char *host, const char *ip, const struct sshkey *key, int store_hash) { int r, success = 0; char *hashed_host = NULL, *lhost; lhost = xstrdup(host); lowercase(lhost); if (store_hash) { if ((hashed_host = host_hash(lhost, NULL, 0)) == NULL) { error_f("host_hash failed"); free(lhost); return 0; } if ((r = sshbuf_putf(entry, "%s ", hashed_host)) != 0) fatal_fr(r, "sshbuf_putf"); } else if (ip != NULL) { if ((r = sshbuf_putf(entry, "%s,%s ", lhost, ip)) != 0) fatal_fr(r, "sshbuf_putf"); } else { if ((r = sshbuf_putf(entry, "%s ", lhost)) != 0) fatal_fr(r, "sshbuf_putf"); } free(hashed_host); free(lhost); if ((r = sshkey_format_text(key, entry)) == 0) success = 1; else error_fr(r, "sshkey_write"); if ((r = sshbuf_putf(entry, "\n")) != 0) fatal_fr(r, "sshbuf_putf"); /* If hashing is enabled, the IP address needs to go on its own line */ if (success && store_hash && ip != NULL) success = format_host_entry(entry, ip, NULL, key, 1); return success; } static int write_host_entry(FILE *f, const char *host, const char *ip, const struct sshkey *key, int store_hash) { int r, success = 0; struct sshbuf *entry = NULL; if ((entry = sshbuf_new()) == NULL) fatal_f("allocation failed"); if ((r = format_host_entry(entry, host, ip, key, store_hash)) != 1) { debug_f("failed to format host entry"); goto out; } if ((r = fwrite(sshbuf_ptr(entry), sshbuf_len(entry), 1, f)) != 1) { error_f("fwrite: %s", strerror(errno)); goto out; } success = 1; out: sshbuf_free(entry); return success; } /* * Create user ~/.ssh directory if it doesn't exist and we want to write to it. * If notify is set, a message will be emitted if the directory is created. */ void hostfile_create_user_ssh_dir(const char *filename, int notify) { char *dotsshdir = NULL, *p; size_t len; struct stat st; if ((p = strrchr(filename, '/')) == NULL) return; len = p - filename; dotsshdir = tilde_expand_filename("~/" _PATH_SSH_USER_DIR, getuid()); if (strlen(dotsshdir) > len || strncmp(filename, dotsshdir, len) != 0) goto out; /* not ~/.ssh prefixed */ if (stat(dotsshdir, &st) == 0) goto out; /* dir already exists */ else if (errno != ENOENT) error("Could not stat %s: %s", dotsshdir, strerror(errno)); else { if (mkdir(dotsshdir, 0700) == -1) error("Could not create directory '%.200s' (%s).", dotsshdir, strerror(errno)); else if (notify) logit("Created directory '%s'.", dotsshdir); } out: free(dotsshdir); } /* * Appends an entry to the host file. Returns false if the entry could not * be appended. */ int add_host_to_hostfile(const char *filename, const char *host, const struct sshkey *key, int store_hash) { FILE *f; int success, addnl = 0; if (key == NULL) return 1; /* XXX ? */ hostfile_create_user_ssh_dir(filename, 0); if ((f = fopen(filename, "a+")) == NULL) return 0; setvbuf(f, NULL, _IONBF, 0); /* Make sure we have a terminating newline. */ if (fseek(f, -1L, SEEK_END) == 0 && fgetc(f) != '\n') addnl = 1; if (fseek(f, 0L, SEEK_END) != 0 || (addnl && fputc('\n', f) != '\n')) { error("Failed to add terminating newline to %s: %s", filename, strerror(errno)); fclose(f); return 0; } success = write_host_entry(f, host, NULL, key, store_hash); fclose(f); return success; } struct host_delete_ctx { FILE *out; int quiet; const char *host, *ip; u_int *match_keys; /* mask of HKF_MATCH_* for this key */ struct sshkey * const *keys; size_t nkeys; int modified; }; static int host_delete(struct hostkey_foreach_line *l, void *_ctx) { struct host_delete_ctx *ctx = (struct host_delete_ctx *)_ctx; int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; size_t i; /* Don't remove CA and revocation lines */ if (l->status == HKF_STATUS_MATCHED && l->marker == MRK_NONE) { /* * If this line contains one of the keys that we will be * adding later, then don't change it and mark the key for * skipping. */ for (i = 0; i < ctx->nkeys; i++) { if (!sshkey_equal(ctx->keys[i], l->key)) continue; ctx->match_keys[i] |= l->match; fprintf(ctx->out, "%s\n", l->line); debug3_f("%s key already at %s:%ld", sshkey_type(l->key), l->path, l->linenum); return 0; } /* * Hostname matches and has no CA/revoke marker, delete it * by *not* writing the line to ctx->out. */ do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s", ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", l->path, l->linenum, sshkey_type(l->key), ctx->host); ctx->modified = 1; return 0; } /* Retain non-matching hosts and invalid lines when deleting */ if (l->status == HKF_STATUS_INVALID) { do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry", ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", l->path, l->linenum); } fprintf(ctx->out, "%s\n", l->line); return 0; } int hostfile_replace_entries(const char *filename, const char *host, const char *ip, struct sshkey **keys, size_t nkeys, int store_hash, int quiet, int hash_alg) { int r, fd, oerrno = 0; int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; struct host_delete_ctx ctx; char *fp = NULL, *temp = NULL, *back = NULL; const char *what; mode_t omask; size_t i; u_int want; omask = umask(077); memset(&ctx, 0, sizeof(ctx)); ctx.host = host; ctx.ip = ip; ctx.quiet = quiet; if ((ctx.match_keys = calloc(nkeys, sizeof(*ctx.match_keys))) == NULL) return SSH_ERR_ALLOC_FAIL; ctx.keys = keys; ctx.nkeys = nkeys; ctx.modified = 0; /* * Prepare temporary file for in-place deletion. */ if ((r = asprintf(&temp, "%s.XXXXXXXXXXX", filename)) == -1 || (r = asprintf(&back, "%s.old", filename)) == -1) { r = SSH_ERR_ALLOC_FAIL; goto fail; } if ((fd = mkstemp(temp)) == -1) { oerrno = errno; error_f("mkstemp: %s", strerror(oerrno)); r = SSH_ERR_SYSTEM_ERROR; goto fail; } if ((ctx.out = fdopen(fd, "w")) == NULL) { oerrno = errno; close(fd); error_f("fdopen: %s", strerror(oerrno)); r = SSH_ERR_SYSTEM_ERROR; goto fail; } /* Remove stale/mismatching entries for the specified host */ if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip, HKF_WANT_PARSE_KEY, 0)) != 0) { oerrno = errno; error_fr(r, "hostkeys_foreach"); goto fail; } /* Re-add the requested keys */ want = HKF_MATCH_HOST | (ip == NULL ? 0 : HKF_MATCH_IP); for (i = 0; i < nkeys; i++) { if (keys[i] == NULL || (want & ctx.match_keys[i]) == want) continue; if ((fp = sshkey_fingerprint(keys[i], hash_alg, SSH_FP_DEFAULT)) == NULL) { r = SSH_ERR_ALLOC_FAIL; goto fail; } /* write host/ip */ what = ""; if (ctx.match_keys[i] == 0) { what = "Adding new key"; if (!write_host_entry(ctx.out, host, ip, keys[i], store_hash)) { r = SSH_ERR_INTERNAL_ERROR; goto fail; } } else if ((want & ~ctx.match_keys[i]) == HKF_MATCH_HOST) { what = "Fixing match (hostname)"; if (!write_host_entry(ctx.out, host, NULL, keys[i], store_hash)) { r = SSH_ERR_INTERNAL_ERROR; goto fail; } } else if ((want & ~ctx.match_keys[i]) == HKF_MATCH_IP) { what = "Fixing match (address)"; if (!write_host_entry(ctx.out, ip, NULL, keys[i], store_hash)) { r = SSH_ERR_INTERNAL_ERROR; goto fail; } } do_log2(loglevel, "%s%s%s for %s%s%s to %s: %s %s", quiet ? __func__ : "", quiet ? ": " : "", what, host, ip == NULL ? "" : ",", ip == NULL ? "" : ip, filename, sshkey_ssh_name(keys[i]), fp); free(fp); fp = NULL; ctx.modified = 1; } fclose(ctx.out); ctx.out = NULL; if (ctx.modified) { /* Backup the original file and replace it with the temporary */ if (unlink(back) == -1 && errno != ENOENT) { oerrno = errno; error_f("unlink %.100s: %s", back, strerror(errno)); r = SSH_ERR_SYSTEM_ERROR; goto fail; } if (link(filename, back) == -1) { oerrno = errno; error_f("link %.100s to %.100s: %s", filename, back, strerror(errno)); r = SSH_ERR_SYSTEM_ERROR; goto fail; } if (rename(temp, filename) == -1) { oerrno = errno; error_f("rename \"%s\" to \"%s\": %s", temp, filename, strerror(errno)); r = SSH_ERR_SYSTEM_ERROR; goto fail; } } else { /* No changes made; just delete the temporary file */ if (unlink(temp) != 0) error_f("unlink \"%s\": %s", temp, strerror(errno)); } /* success */ r = 0; fail: if (temp != NULL && r != 0) unlink(temp); free(temp); free(back); free(fp); if (ctx.out != NULL) fclose(ctx.out); free(ctx.match_keys); umask(omask); if (r == SSH_ERR_SYSTEM_ERROR) errno = oerrno; return r; } static int match_maybe_hashed(const char *host, const char *names, int *was_hashed) { int hashed = *names == HASH_DELIM, ret; char *hashed_host = NULL; size_t nlen = strlen(names); if (was_hashed != NULL) *was_hashed = hashed; if (hashed) { if ((hashed_host = host_hash(host, names, nlen)) == NULL) return -1; ret = (nlen == strlen(hashed_host) && strncmp(hashed_host, names, nlen) == 0); free(hashed_host); return ret; } return match_hostname(host, names) == 1; } int hostkeys_foreach_file(const char *path, FILE *f, hostkeys_foreach_fn *callback, void *ctx, const char *host, const char *ip, u_int options, u_int note) { char *line = NULL, ktype[128]; u_long linenum = 0; char *cp, *cp2; u_int kbits; int hashed; int s, r = 0; struct hostkey_foreach_line lineinfo; size_t linesize = 0, l; memset(&lineinfo, 0, sizeof(lineinfo)); if (host == NULL && (options & HKF_WANT_MATCH) != 0) return SSH_ERR_INVALID_ARGUMENT; while (getline(&line, &linesize, f) != -1) { linenum++; line[strcspn(line, "\n")] = '\0'; free(lineinfo.line); sshkey_free(lineinfo.key); memset(&lineinfo, 0, sizeof(lineinfo)); lineinfo.path = path; lineinfo.linenum = linenum; lineinfo.line = xstrdup(line); lineinfo.marker = MRK_NONE; lineinfo.status = HKF_STATUS_OK; lineinfo.keytype = KEY_UNSPEC; lineinfo.note = note; /* Skip any leading whitespace, comments and empty lines. */ for (cp = line; *cp == ' ' || *cp == '\t'; cp++) ; if (!*cp || *cp == '#' || *cp == '\n') { if ((options & HKF_WANT_MATCH) == 0) { lineinfo.status = HKF_STATUS_COMMENT; if ((r = callback(&lineinfo, ctx)) != 0) break; } continue; } if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) { verbose_f("invalid marker at %s:%lu", path, linenum); if ((options & HKF_WANT_MATCH) == 0) goto bad; continue; } /* Find the end of the host name portion. */ for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++) ; if (*cp2 == '\0') { verbose_f("truncated line at %s:%lu", path, linenum); if ((options & HKF_WANT_MATCH) == 0) goto bad; continue; } lineinfo.hosts = cp; *cp2++ = '\0'; /* Check if the host name matches. */ if (host != NULL) { if ((s = match_maybe_hashed(host, lineinfo.hosts, &hashed)) == -1) { debug2_f("%s:%ld: bad host hash \"%.32s\"", path, linenum, lineinfo.hosts); goto bad; } if (s == 1) { lineinfo.status = HKF_STATUS_MATCHED; lineinfo.match |= HKF_MATCH_HOST | (hashed ? HKF_MATCH_HOST_HASHED : 0); } /* Try matching IP address if supplied */ if (ip != NULL) { if ((s = match_maybe_hashed(ip, lineinfo.hosts, &hashed)) == -1) { debug2_f("%s:%ld: bad ip hash " "\"%.32s\"", path, linenum, lineinfo.hosts); goto bad; } if (s == 1) { lineinfo.status = HKF_STATUS_MATCHED; lineinfo.match |= HKF_MATCH_IP | (hashed ? HKF_MATCH_IP_HASHED : 0); } } /* * Skip this line if host matching requested and * neither host nor address matched. */ if ((options & HKF_WANT_MATCH) != 0 && lineinfo.status != HKF_STATUS_MATCHED) continue; } /* Got a match. Skip host name and any following whitespace */ for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) ; if (*cp2 == '\0' || *cp2 == '#') { debug2("%s:%ld: truncated before key type", path, linenum); goto bad; } lineinfo.rawkey = cp = cp2; if ((options & HKF_WANT_PARSE_KEY) != 0) { /* * Extract the key from the line. This will skip * any leading whitespace. Ignore badly formatted * lines. */ if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) { error_f("sshkey_new failed"); r = SSH_ERR_ALLOC_FAIL; break; } if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) { goto bad; } lineinfo.keytype = lineinfo.key->type; lineinfo.comment = cp; } else { /* Extract and parse key type */ l = strcspn(lineinfo.rawkey, " \t"); if (l <= 1 || l >= sizeof(ktype) || lineinfo.rawkey[l] == '\0') goto bad; memcpy(ktype, lineinfo.rawkey, l); ktype[l] = '\0'; lineinfo.keytype = sshkey_type_from_name(ktype); /* * Assume legacy RSA1 if the first component is a short * decimal number. */ if (lineinfo.keytype == KEY_UNSPEC && l < 8 && strspn(ktype, "0123456789") == l) goto bad; /* * Check that something other than whitespace follows * the key type. This won't catch all corruption, but * it does catch trivial truncation. */ cp2 += l; /* Skip past key type */ for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) ; if (*cp2 == '\0' || *cp2 == '#') { debug2("%s:%ld: truncated after key type", path, linenum); lineinfo.keytype = KEY_UNSPEC; } if (lineinfo.keytype == KEY_UNSPEC) { bad: sshkey_free(lineinfo.key); lineinfo.key = NULL; lineinfo.status = HKF_STATUS_INVALID; if ((r = callback(&lineinfo, ctx)) != 0) break; continue; } } if ((r = callback(&lineinfo, ctx)) != 0) break; } sshkey_free(lineinfo.key); free(lineinfo.line); free(line); return r; } int hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx, const char *host, const char *ip, u_int options, u_int note) { FILE *f; int r, oerrno; if ((f = fopen(path, "r")) == NULL) return SSH_ERR_SYSTEM_ERROR; debug3_f("reading file \"%s\"", path); r = hostkeys_foreach_file(path, f, callback, ctx, host, ip, options, note); oerrno = errno; fclose(f); errno = oerrno; return r; }