upstream commit

Refactor hostkeys_foreach() and dependent code Deal with
 IP addresses (i.e. CheckHostIP) Don't clobber known_hosts when nothing
 changed ok markus@ as part of larger commit

1 files changed, 143 insertions, 76 deletions

diff --git a/hostfile.c b/hostfile.c
index ea6bc6fc8..b235795e6 100644
--- a/hostfile.c
+++ b/hostfile.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: hostfile.c,v 1.63 2015/01/26 13:36:53 djm Exp $ */
+/* $OpenBSD: hostfile.c,v 1.64 2015/02/16 22:08:57 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -184,24 +184,6 @@ hostfile_read_key(char **cpp, u_int *bitsp, struct sshkey *ret)
         return 1;
 }
 
-static int
-hostfile_check_key(int bits, const struct sshkey *key, const char *host,
-    const char *filename, u_long linenum)
-{
-#ifdef WITH_SSH1
-        if (key == NULL || key->type != KEY_RSA1 || key->rsa == NULL)
-                return 1;
-        if (bits != BN_num_bits(key->rsa->n)) {
-                logit("Warning: %s, line %lu: keysize mismatch for host %s: "
-                    "actual %d vs. announced %d.",
-                    filename, linenum, host, BN_num_bits(key->rsa->n), bits);
-                logit("Warning: replace %d with %d in %s, line %lu.",
-                    bits, BN_num_bits(key->rsa->n), filename, linenum);
-        }
-#endif
-        return 1;
-}
-
 static HostkeyMarker
 check_markers(char **cpp)
 {
@@ -295,8 +277,8 @@ load_hostkeys(struct hostkeys *hostkeys, const char *host, const char *path)
         ctx.num_loaded = 0;
         ctx.hostkeys = hostkeys;
 
-        if ((r = hostkeys_foreach(path, record_hostkey, &ctx, host,
-            HKF_WANT_MATCH_HOST|HKF_WANT_PARSE_KEY)) != 0) {
+        if ((r = hostkeys_foreach(path, record_hostkey, &ctx, host, NULL,
+            HKF_WANT_MATCH|HKF_WANT_PARSE_KEY)) != 0) {
                 if (r != SSH_ERR_SYSTEM_ERROR && errno != ENOENT)
                         debug("%s: hostkeys_foreach failed for %s: %s",
                             __func__, path, ssh_err(r));
@@ -433,7 +415,7 @@ lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype,
 }
 
 static int
-write_host_entry(FILE *f, const char *host,
+write_host_entry(FILE *f, const char *host, const char *ip,
     const struct sshkey *key, int store_hash)
 {
         int r, success = 0;
@@ -444,8 +426,11 @@ write_host_entry(FILE *f, const char *host,
                         error("%s: host_hash failed", __func__);
                         return 0;
                 }
-        }
-        fprintf(f, "%s ", store_hash ? hashed_host : host);
+                fprintf(f, "%s ", hashed_host);
+        } else if (ip != NULL)
+                fprintf(f, "%s,%s ", host, ip);
+        else
+                fprintf(f, "%s ", host);
 
         if ((r = sshkey_write(key, f)) == 0)
                 success = 1;
@@ -471,7 +456,7 @@ add_host_to_hostfile(const char *filename, const char *host,
         f = fopen(filename, "a");
         if (!f)
                 return 0;
-        success = write_host_entry(f, host, key, store_hash);
+        success = write_host_entry(f, host, NULL, key, store_hash);
         fclose(f);
         return success;
 }
@@ -480,19 +465,20 @@ struct host_delete_ctx {
         FILE *out;
         int quiet;
         const char *host;
-        int *skip_keys;
+        int *skip_keys; /* XXX split for host/ip? might want to ensure both */
         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_INFO;
+        int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
         size_t i;
 
-        if (l->status == HKF_STATUS_HOST_MATCHED) {
+        if (l->status == HKF_STATUS_MATCHED) {
                 if (l->marker != MRK_NONE) {
                         /* Don't remove CA and revocation lines */
                         fprintf(ctx->out, "%s\n", l->line);
@@ -525,9 +511,10 @@ host_delete(struct hostkey_foreach_line *l, void *_ctx)
                  * 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: Host %s removed",
+                do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s",
                     ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
-                    l->path, l->linenum, ctx->host);
+                    l->path, l->linenum, sshkey_type(l->key), ctx->host);
+                ctx->modified = 1;
                 return 0;
         }
         /* Retain non-matching hosts and invalid lines when deleting */
@@ -541,13 +528,13 @@ host_delete(struct hostkey_foreach_line *l, void *_ctx)
 }
 
 int
-hostfile_replace_entries(const char *filename, const char *host,
-    struct sshkey **keys, size_t nkeys, int store_hash, int quiet)
+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_INFO;
+        int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
         struct host_delete_ctx ctx;
-        char *temp = NULL, *back = NULL;
+        char *fp, *temp = NULL, *back = NULL;
         mode_t omask;
         size_t i;
 
@@ -560,6 +547,7 @@ hostfile_replace_entries(const char *filename, const char *host,
                 return SSH_ERR_ALLOC_FAIL;
         ctx.keys = keys;
         ctx.nkeys = nkeys;
+        ctx.modified = 0;
 
         /*
          * Prepare temporary file for in-place deletion.
@@ -585,7 +573,7 @@ hostfile_replace_entries(const char *filename, const char *host,
         }
 
         /* Remove all entries for the specified host from the file */
-        if ((r = hostkeys_foreach(filename, host_delete, &ctx, host,
+        if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip,
             HKF_WANT_PARSE_KEY)) != 0) {
                 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r));
                 goto fail;
@@ -595,38 +583,54 @@ hostfile_replace_entries(const char *filename, const char *host,
         for (i = 0; i < nkeys; i++) {
                 if (ctx.skip_keys[i])
                         continue;
-                do_log2(loglevel, "%s%sadd %s key to %s",
-                    quiet ? __func__ : "", quiet ? ": " : NULL,
-                    sshkey_type(keys[i]), filename);
-                if (!write_host_entry(ctx.out, host, keys[i], store_hash)) {
+                if ((fp = sshkey_fingerprint(keys[i], hash_alg,
+                    SSH_FP_DEFAULT)) == NULL) {
+                        r = SSH_ERR_ALLOC_FAIL;
+                        goto fail;
+                }
+                do_log2(loglevel, "%s%sAdding new key for %s to %s: %s %s",
+                    quiet ? __func__ : "", quiet ? ": " : "", host, filename,
+                    sshkey_ssh_name(keys[i]), fp);
+                free(fp);
+                if (!write_host_entry(ctx.out, host, ip, keys[i], store_hash)) {
                         r = SSH_ERR_INTERNAL_ERROR;
                         goto fail;
                 }
+                ctx.modified = 1;
         }
         fclose(ctx.out);
         ctx.out = NULL;
 
-        /* Backup the original file and replace it with the temporary */
-        if (unlink(back) == -1 && errno != ENOENT) {
-                oerrno = errno;
-                error("%s: unlink %.100s: %s", __func__, back, strerror(errno));
-                r = SSH_ERR_SYSTEM_ERROR;
-                goto fail;
-        }
-        if (link(filename, back) == -1) {
-                oerrno = errno;
-                error("%s: link %.100s to %.100s: %s", __func__, filename, back,
-                    strerror(errno));
-                r = SSH_ERR_SYSTEM_ERROR;
-                goto fail;
-        }
-        if (rename(temp, filename) == -1) {
-                oerrno = errno;
-                error("%s: rename \"%s\" to \"%s\": %s", __func__,
-                    temp, filename, strerror(errno));
-                r = SSH_ERR_SYSTEM_ERROR;
-                goto fail;
+        if (ctx.modified) {
+                /* Backup the original file and replace it with the temporary */
+                if (unlink(back) == -1 && errno != ENOENT) {
+                        oerrno = errno;
+                        error("%s: unlink %.100s: %s", __func__,
+                            back, strerror(errno));
+                        r = SSH_ERR_SYSTEM_ERROR;
+                        goto fail;
+                }
+                if (link(filename, back) == -1) {
+                        oerrno = errno;
+                        error("%s: link %.100s to %.100s: %s", __func__,
+                            filename, back, strerror(errno));
+                        r = SSH_ERR_SYSTEM_ERROR;
+                        goto fail;
+                }
+                if (rename(temp, filename) == -1) {
+                        oerrno = errno;
+                        error("%s: rename \"%s\" to \"%s\": %s", __func__,
+                            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("%s: unlink \"%s\": %s", __func__,
+                            temp, strerror(errno));
         }
+
         /* success */
         r = 0;
  fail:
@@ -663,18 +667,20 @@ match_maybe_hashed(const char *host, const char *names, int *was_hashed)
 
 int
 hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
-    const char *host, u_int options)
+    const char *host, const char *ip, u_int options)
 {
         FILE *f;
-        char line[8192], oline[8192];
+        char line[8192], oline[8192], 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 l;
 
         memset(&lineinfo, 0, sizeof(lineinfo));
-        if (host == NULL && (options & HKF_WANT_MATCH_HOST) != 0)
+        if (host == NULL && (options & HKF_WANT_MATCH) != 0)
                 return SSH_ERR_INVALID_ARGUMENT;
         if ((f = fopen(path, "r")) == NULL)
                 return SSH_ERR_SYSTEM_ERROR;
@@ -689,13 +695,15 @@ hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
                 lineinfo.path = path;
                 lineinfo.linenum = linenum;
                 lineinfo.line = oline;
+                lineinfo.marker = MRK_NONE;
                 lineinfo.status = HKF_STATUS_OK;
+                lineinfo.keytype = KEY_UNSPEC;
 
                 /* 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_HOST) == 0) {
+                        if ((options & HKF_WANT_MATCH) == 0) {
                                 lineinfo.status = HKF_STATUS_COMMENT;
                                 if ((r = callback(&lineinfo, ctx)) != 0)
                                         break;
@@ -706,7 +714,7 @@ hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
                 if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) {
                         verbose("%s: invalid marker at %s:%lu",
                             __func__, path, linenum);
-                        if ((options & HKF_WANT_MATCH_HOST) == 0)
+                        if ((options & HKF_WANT_MATCH) == 0)
                                 goto bad;
                         continue;
                 }
@@ -719,24 +727,47 @@ hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
 
                 /* Check if the host name matches. */
                 if (host != NULL) {
-                        s = match_maybe_hashed(host, lineinfo.hosts,
-                            &lineinfo.was_hashed);
-                        if (s == 1)
-                                lineinfo.status = HKF_STATUS_HOST_MATCHED;
-                        else if ((options & HKF_WANT_MATCH_HOST) != 0)
-                                continue;
-                        else if (s == -1) {
+                        if ((s = match_maybe_hashed(host, lineinfo.hosts,
+                            &hashed)) == -1) {
                                 debug2("%s: %s:%ld: bad host hash \"%.32s\"",
                                     __func__, 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("%s: %s:%ld: bad ip hash "
+                                            "\"%.32s\"", __func__, 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", path, linenum);
+                        debug2("%s:%ld: truncated before key type",
+                            path, linenum);
                         goto bad;
                 }
                 lineinfo.rawkey = cp = cp2;
@@ -749,7 +780,8 @@ hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
                          */
                         if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) {
                                 error("%s: sshkey_new failed", __func__);
-                                return SSH_ERR_ALLOC_FAIL;
+                                r = SSH_ERR_ALLOC_FAIL;
+                                break;
                         }
                         if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) {
 #ifdef WITH_SSH1
@@ -757,7 +789,8 @@ hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
                                 lineinfo.key = sshkey_new(KEY_RSA1);
                                 if (lineinfo.key  == NULL) {
                                         error("%s: sshkey_new fail", __func__);
-                                        return SSH_ERR_ALLOC_FAIL;
+                                        r = SSH_ERR_ALLOC_FAIL;
+                                        break;
                                 }
                                 if (!hostfile_read_key(&cp, &kbits,
                                     lineinfo.key))
@@ -766,9 +799,43 @@ hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
                                 goto bad;
 #endif
                         }
-                        if (!hostfile_check_key(kbits, lineinfo.key, host,
-                            path, linenum)) {
+                        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);
+#ifdef WITH_SSH1
+                        /*
+                         * Assume RSA1 if the first component is a short
+                         * decimal number.
+                         */
+                        if (lineinfo.keytype == KEY_UNSPEC && l < 8 &&
+                            strspn(ktype, "0123456789") == l)
+                                lineinfo.keytype = KEY_RSA1;
+#endif
+                        /*
+                         * 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;