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 ea6bc6fc..b235795e 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;