Attachment 1510 Details for Bug 1469 – blacklist patch from Debian 1:4.7p1-12

[patch] blacklist patch from Debian 1:4.7p1-12

openssh-blacklist.diff (text/plain), 30.72 KB, created by Colin Watson on 2008-05-31 08:10:09 AEST

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Creator: Colin Watson

Created: 2008-05-31 08:10:09 AEST

Size: 30.72 KB

patch

obsolete

>--- openssh-4.7p1.orig/auth-rh-rsa.c
>+++ openssh-4.7p1/auth-rh-rsa.c
>@@ -44,6 +44,9 @@
> {
> 	HostStatus host_status;
> 
>+	if (reject_blacklisted_key(client_host_key, 0) == 1)
>+		return 0;
>+
> 	/* Check if we would accept it using rhosts authentication. */
> 	if (!auth_rhosts(pw, cuser))
> 		return 0;
>--- openssh-4.7p1.orig/authfile.h
>+++ openssh-4.7p1/authfile.h
>@@ -23,4 +23,6 @@
> Key	*key_load_private_pem(int, int, const char *, char **);
> int	 key_perm_ok(int, const char *);
> 
>+int	 blacklisted_key(const Key *key, char **fp);
>+
> #endif
>--- openssh-4.7p1.orig/sshd_config.5
>+++ openssh-4.7p1/sshd_config.5
>@@ -563,6 +563,20 @@
> Specifies whether password authentication is allowed.
> The default is
> .Dq yes .
>+.It Cm PermitBlacklistedKeys
>+Specifies whether
>+.Xr sshd 8
>+should allow keys recorded in its blacklist of known-compromised keys (see
>+.Xr ssh-vulnkey 1 ) .
>+If
>+.Dq yes ,
>+then attempts to authenticate with compromised keys will be logged but
>+accepted.
>+If
>+.Dq no ,
>+then attempts to authenticate with compromised keys will be rejected.
>+The default is
>+.Dq no .
> .It Cm PermitEmptyPasswords
> When password authentication is allowed, it specifies whether the
> server allows login to accounts with empty password strings.
>--- openssh-4.7p1.orig/ssh-vulnkey.1
>+++ openssh-4.7p1/ssh-vulnkey.1
>@@ -0,0 +1,242 @@
>+.\" Copyright (c) 2008 Canonical Ltd.  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.
>+.\"
>+.Dd $Mdocdate: May 12 2008 $
>+.Dt SSH-VULNKEY 1
>+.Os
>+.Sh NAME
>+.Nm ssh-vulnkey
>+.Nd check blacklist of compromised keys
>+.Sh SYNOPSIS
>+.Nm
>+.Op Fl q | Fl v
>+.Ar file ...
>+.Nm
>+.Fl a
>+.Sh DESCRIPTION
>+.Nm
>+checks a key against a blacklist of compromised keys.
>+.Pp
>+A substantial number of keys are known to have been generated using a broken
>+version of OpenSSL distributed by Debian which failed to seed its random
>+number generator correctly.
>+Keys generated using these OpenSSL versions should be assumed to be
>+compromised.
>+This tool may be useful in checking for such keys.
>+.Pp
>+Keys that are compromised cannot be repaired; replacements must be generated
>+using
>+.Xr ssh-keygen 1 .
>+Make sure to update
>+.Pa authorized_keys
>+files on all systems where compromised keys were permitted to authenticate.
>+.Pp
>+The argument list will be interpreted as a list of paths to public key files
>+or
>+.Pa authorized_keys
>+files.
>+If no suitable file is found at a given path,
>+.Nm
>+will append
>+.Pa .pub
>+and retry, in case it was given a private key file.
>+If no files are given as arguments,
>+.Nm
>+will check
>+.Pa ~/.ssh/id_rsa ,
>+.Pa ~/.ssh/id_dsa ,
>+.Pa ~/.ssh/identity ,
>+.Pa ~/.ssh/authorized_keys
>+and
>+.Pa ~/.ssh/authorized_keys2 ,
>+as well as the system's host keys if readable.
>+.Pp
>+If
>+.Dq -
>+is given as an argument,
>+.Nm
>+will read from standard input.
>+This can be used to process output from
>+.Xr ssh-keyscan 1 ,
>+for example:
>+.Pp
>+.Dl $ ssh-keyscan -t rsa remote.example.org | ssh-vulnkey -
>+.Pp
>+Unless the
>+.Cm PermitBlacklistedKeys
>+option is used,
>+.Xr sshd 8
>+will reject attempts to authenticate with keys in the compromised list.
>+.Pp
>+The output from
>+.Nm
>+looks like this:
>+.Pp
>+.Bd -literal -offset indent
>+/etc/ssh/ssh_host_key:1: COMPROMISED: RSA1 2048 xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx root@host
>+/home/user/.ssh/id_dsa:1: Not blacklisted: DSA 1024 xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx /home/user/.ssh/id_dsa.pub
>+/home/user/.ssh/authorized_keys:3: Unknown (blacklist file not installed): RSA 1024 xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx user@host
>+.Ed
>+.Pp
>+Each line is of the following format (any lines beginning with
>+.Dq #
>+should be ignored by scripts):
>+.Pp
>+.Dl Ar filename : Ns Ar line : Ar status : Ar type Ar size Ar fingerprint Ar comment
>+.Pp
>+It is important to distinguish between the possible values of
>+.Ar status :
>+.Pp
>+.Bl -tag -width Ds
>+.It COMPROMISED
>+These keys are listed in a blacklist file, normally because their
>+corresponding private keys are well-known.
>+Replacements must be generated using
>+.Xr ssh-keygen 1 .
>+.It Not blacklisted
>+A blacklist file exists for this key type and size, but this key is not
>+listed in it.
>+Unless there is some particular reason to believe otherwise, this key
>+may be used safely.
>+(Note that DSA keys used with the broken version of OpenSSL distributed
>+by Debian may be compromised in the event that anyone captured a network
>+trace, even if they were generated with a secure version of OpenSSL.)
>+.It Unknown (blacklist file not installed)
>+No blacklist file exists for this key type and size.
>+You should find a suitable published blacklist and install it before
>+deciding whether this key is safe to use.
>+.El
>+.Pp
>+The options are as follows:
>+.Bl -tag -width Ds
>+.It Fl a
>+Check keys of all users on the system.
>+You will typically need to run
>+.Nm
>+as root to use this option.
>+For each user,
>+.Nm
>+will check
>+.Pa ~/.ssh/id_rsa ,
>+.Pa ~/.ssh/id_dsa ,
>+.Pa ~/.ssh/identity ,
>+.Pa ~/.ssh/authorized_keys
>+and
>+.Pa ~/.ssh/authorized_keys2 .
>+It will also check the system's host keys.
>+.It Fl q
>+Quiet mode.
>+Normally,
>+.Nm
>+outputs the fingerprint of each key scanned, with a description of its
>+status.
>+This option suppresses that output.
>+.It Fl v
>+Verbose mode.
>+Normally,
>+.Nm
>+does not output anything for keys that are not listed in their corresponding
>+blacklist file (although it still produces output for keys for which there
>+is no blacklist file, since their status is unknown).
>+This option causes
>+.Nm
>+to produce output for all keys.
>+.El
>+.Sh EXIT STATUS
>+.Nm
>+will exit zero if any of the given keys were in the compromised list,
>+otherwise non-zero.
>+.Sh BLACKLIST FILE FORMAT
>+The blacklist file may start with comments, on lines starting with
>+.Dq # .
>+After these initial comments, it must follow a strict format:
>+.Pp
>+.Bl -bullet -offset indent -compact
>+.It
>+All the lines must be exactly the same length (20 characters followed by a
>+newline) and must be in sorted order.
>+.It
>+Each line must consist of the lower-case hexadecimal MD5 key fingerprint,
>+without colons, and with the first 12 characters removed (that is, the least
>+significant 80 bits of the fingerprint).
>+.El
>+.Pp
>+The key fingerprint may be generated using
>+.Xr ssh-keygen 1 :
>+.Pp
>+.Dl $ ssh-keygen -l -f /path/to/key
>+.Pp
>+This strict format is necessary to allow the blacklist file to be checked
>+quickly, using a binary-search algorithm.
>+.Sh FILES
>+.Bl -tag -width Ds
>+.It Pa ~/.ssh/id_rsa
>+If present, contains the protocol version 2 RSA authentication identity of
>+the user.
>+.It Pa ~/.ssh/id_dsa
>+If present, contains the protocol version 2 DSA authentication identity of
>+the user.
>+.It Pa ~/.ssh/identity
>+If present, contains the protocol version 1 RSA authentication identity of
>+the user.
>+.It Pa ~/.ssh/authorized_keys
>+If present, lists the public keys (RSA/DSA) that can be used for logging in
>+as this user.
>+.It Pa ~/.ssh/authorized_keys2
>+Obsolete name for
>+.Pa ~/.ssh/authorized_keys .
>+This file may still be present on some old systems, but should not be
>+created if it is missing.
>+.It Pa /etc/ssh/ssh_host_rsa_key
>+If present, contains the protocol version 2 RSA identity of the system.
>+.It Pa /etc/ssh/ssh_host_dsa_key
>+If present, contains the protocol version 2 DSA identity of the system.
>+.It Pa /etc/ssh/ssh_host_key
>+If present, contains the protocol version 1 RSA identity of the system.
>+.It Pa /usr/share/ssh/blacklist. Ns Ar TYPE Ns Pa - Ns Ar LENGTH
>+If present, lists the blacklisted keys of type
>+.Ar TYPE
>+.Pf ( Dq RSA
>+or
>+.Dq DSA )
>+and bit length
>+.Ar LENGTH .
>+The format of this file is described above.
>+RSA1 keys are converted to RSA before being checked in the blacklist.
>+Note that the fingerprints of RSA1 keys are computed differently, so you
>+will not be able to find them in the blacklist by hand.
>+.It Pa /etc/ssh/blacklist. Ns Ar TYPE Ns Pa - Ns Ar LENGTH
>+Same as
>+.Pa /usr/share/ssh/blacklist. Ns Ar TYPE Ns Pa - Ns Ar LENGTH ,
>+but may be edited by the system administrator to add new blacklist entries.
>+.El
>+.Sh SEE ALSO
>+.Xr ssh-keygen 1 ,
>+.Xr sshd 8
>+.Sh AUTHORS
>+.An -nosplit
>+.An Colin Watson Aq cjwatson@ubuntu.com
>+.Pp
>+Florian Weimer suggested the option to check keys of all users, and the idea
>+of processing
>+.Xr ssh-keyscan 1
>+output.
>--- openssh-4.7p1.orig/auth2-hostbased.c
>+++ openssh-4.7p1/auth2-hostbased.c
>@@ -145,6 +145,9 @@
> 	HostStatus host_status;
> 	int len;
> 
>+	if (reject_blacklisted_key(key, 0) == 1)
>+		return 0;
>+
> 	resolvedname = get_canonical_hostname(options.use_dns);
> 	ipaddr = get_remote_ipaddr();
> 
>--- openssh-4.7p1.orig/sshd.c
>+++ openssh-4.7p1/sshd.c
>@@ -1464,6 +1464,11 @@
> 			sensitive_data.host_keys[i] = NULL;
> 			continue;
> 		}
>+		if (reject_blacklisted_key(key, 1) == 1) {
>+			key_free(key);
>+			sensitive_data.host_keys[i] = NULL;
>+			continue;
>+		}
> 		switch (key->type) {
> 		case KEY_RSA1:
> 			sensitive_data.ssh1_host_key = key;
>--- openssh-4.7p1.orig/authfile.c
>+++ openssh-4.7p1/authfile.c
>@@ -65,6 +65,7 @@
> #include "rsa.h"
> #include "misc.h"
> #include "atomicio.h"
>+#include "pathnames.h"
> 
> /* Version identification string for SSH v1 identity files. */
> static const char authfile_id_string[] =
>@@ -677,3 +678,140 @@
> 	key_free(pub);
> 	return NULL;
> }
>+
>+/* Scan a blacklist of known-vulnerable keys in blacklist_file. */
>+static int
>+blacklisted_key_in_file(const Key *key, const char *blacklist_file, char **fp)
>+{
>+	int fd = -1;
>+	char *dgst_hex = NULL;
>+	char *dgst_packed = NULL, *p;
>+	int i;
>+	size_t line_len;
>+	struct stat st;
>+	char buf[256];
>+	off_t start, lower, upper;
>+	int ret = 0;
>+
>+	debug("Checking blacklist file %s", blacklist_file);
>+	fd = open(blacklist_file, O_RDONLY);
>+	if (fd < 0) {
>+		ret = -1;
>+		goto out;
>+	}
>+
>+	dgst_hex = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
>+	/* Remove all colons */
>+	dgst_packed = xcalloc(1, strlen(dgst_hex) + 1);
>+	for (i = 0, p = dgst_packed; dgst_hex[i]; i++)
>+		if (dgst_hex[i] != ':')
>+			*p++ = dgst_hex[i];
>+	/* Only compare least-significant 80 bits (to keep the blacklist
>+	 * size down)
>+	 */
>+	line_len = strlen(dgst_packed + 12);
>+	if (line_len > 32)
>+		goto out;
>+
>+	/* Skip leading comments */
>+	start = 0;
>+	for (;;) {
>+		ssize_t r;
>+		char *newline;
>+
>+		r = atomicio(read, fd, buf, sizeof(buf));
>+		if (r <= 0)
>+			goto out;
>+		if (buf[0] != '#')
>+			break;
>+
>+		newline = memchr(buf, '\n', sizeof(buf));
>+		if (!newline)
>+			goto out;
>+		start += newline + 1 - buf;
>+		if (lseek(fd, start, SEEK_SET) < 0)
>+			goto out;
>+	}
>+
>+	/* Initialise binary search record numbers */
>+	if (fstat(fd, &st) < 0)
>+		goto out;
>+	lower = 0;
>+	upper = (st.st_size - start) / (line_len + 1);
>+
>+	while (lower != upper) {
>+		off_t cur;
>+		int cmp;
>+
>+		cur = lower + (upper - lower) / 2;
>+
>+		/* Read this line and compare to digest; this is
>+		 * overflow-safe since cur < max(off_t) / (line_len + 1) */
>+		if (lseek(fd, start + cur * (line_len + 1), SEEK_SET) < 0)
>+			break;
>+		if (atomicio(read, fd, buf, line_len) != line_len)
>+			break;
>+		cmp = memcmp(buf, dgst_packed + 12, line_len);
>+		if (cmp < 0) {
>+			if (cur == lower)
>+				break;
>+			lower = cur;
>+		} else if (cmp > 0) {
>+			if (cur == upper)
>+				break;
>+			upper = cur;
>+		} else {
>+			debug("Found %s in blacklist", dgst_hex);
>+			ret = 1;
>+			break;
>+		}
>+	}
>+
>+out:
>+	if (dgst_packed)
>+		xfree(dgst_packed);
>+	if (ret != 1 && dgst_hex) {
>+		xfree(dgst_hex);
>+		dgst_hex = NULL;
>+	}
>+	if (fp)
>+		*fp = dgst_hex;
>+	if (fd >= 0)
>+		close(fd);
>+	return ret;
>+}
>+
>+/*
>+ * Scan blacklists of known-vulnerable keys. If a vulnerable key is found,
>+ * its fingerprint is returned in *fp, unless fp is NULL.
>+ */
>+int
>+blacklisted_key(const Key *key, char **fp)
>+{
>+	Key *public;
>+	char *blacklist_file;
>+	int ret, ret2;
>+
>+	public = key_demote(key);
>+	if (public->type == KEY_RSA1)
>+		public->type = KEY_RSA;
>+
>+	xasprintf(&blacklist_file, "%s.%s-%u",
>+	    _PATH_BLACKLIST, key_type(public), key_size(public));
>+	ret = blacklisted_key_in_file(public, blacklist_file, fp);
>+	xfree(blacklist_file);
>+	if (ret > 0) {
>+		key_free(public);
>+		return ret;
>+	}
>+
>+	xasprintf(&blacklist_file, "%s.%s-%u",
>+	    _PATH_BLACKLIST_CONFIG, key_type(public), key_size(public));
>+	ret2 = blacklisted_key_in_file(public, blacklist_file, fp);
>+	xfree(blacklist_file);
>+	if (ret2 > ret)
>+		ret = ret2;
>+
>+	key_free(public);
>+	return ret;
>+}
>--- openssh-4.7p1.orig/ssh-vulnkey.c
>+++ openssh-4.7p1/ssh-vulnkey.c
>@@ -0,0 +1,360 @@
>+/*
>+ * Copyright (c) 2008 Canonical Ltd.  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 "includes.h"
>+
>+#include <sys/types.h>
>+#include <sys/stat.h>
>+
>+#include <errno.h>
>+#include <string.h>
>+#include <stdio.h>
>+#include <fcntl.h>
>+#include <unistd.h>
>+
>+#include <openssl/evp.h>
>+
>+#include "xmalloc.h"
>+#include "ssh.h"
>+#include "log.h"
>+#include "key.h"
>+#include "authfile.h"
>+#include "pathnames.h"
>+#include "uidswap.h"
>+#include "misc.h"
>+
>+extern char *__progname;
>+
>+/* Default files to check */
>+static char *default_host_files[] = {
>+	_PATH_HOST_RSA_KEY_FILE,
>+	_PATH_HOST_DSA_KEY_FILE,
>+	_PATH_HOST_KEY_FILE,
>+	NULL
>+};
>+static char *default_files[] = {
>+	_PATH_SSH_CLIENT_ID_RSA,
>+	_PATH_SSH_CLIENT_ID_DSA,
>+	_PATH_SSH_CLIENT_IDENTITY,
>+	_PATH_SSH_USER_PERMITTED_KEYS,
>+	_PATH_SSH_USER_PERMITTED_KEYS2,
>+	NULL
>+};
>+
>+static int verbosity = 0;
>+
>+static void
>+usage(void)
>+{
>+	fprintf(stderr, "usage: %s [-aqv] [file ...]\n", __progname);
>+	fprintf(stderr, "Options:\n");
>+	fprintf(stderr, "  -a          Check keys of all users.\n");
>+	fprintf(stderr, "  -q          Quiet mode.\n");
>+	fprintf(stderr, "  -v          Verbose mode.\n");
>+	exit(1);
>+}
>+
>+void
>+describe_key(const char *filename, u_long linenum, const char *msg,
>+    const Key *key, const char *comment, int min_verbosity)
>+{
>+	char *fp;
>+
>+	fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
>+	if (verbosity >= min_verbosity) {
>+		if (strchr(filename, ':'))
>+			printf("\"%s\"", filename);
>+		else
>+			printf("%s", filename);
>+		printf(":%lu: %s: %s %u %s %s\n", linenum, msg,
>+		    key_type(key), key_size(key), fp, comment);
>+	}
>+	xfree(fp);
>+}
>+
>+int
>+do_key(const char *filename, u_long linenum,
>+    const Key *key, const char *comment)
>+{
>+	Key *public;
>+	int blacklist_status;
>+	int ret = 1;
>+
>+	public = key_demote(key);
>+	if (public->type == KEY_RSA1)
>+		public->type = KEY_RSA;
>+
>+	blacklist_status = blacklisted_key(public, NULL);
>+	if (blacklist_status == -1)
>+		describe_key(filename, linenum,
>+		    "Unknown (blacklist file not installed)", key, comment, 0);
>+	else if (blacklist_status == 1) {
>+		describe_key(filename, linenum,
>+		    "COMPROMISED", key, comment, 0);
>+		ret = 0;
>+	} else
>+		describe_key(filename, linenum,
>+		    "Not blacklisted", key, comment, 1);
>+
>+	key_free(public);
>+
>+	return ret;
>+}
>+
>+int
>+do_filename(const char *filename, int quiet_open)
>+{
>+	FILE *f;
>+	char line[SSH_MAX_PUBKEY_BYTES];
>+	char *cp;
>+	u_long linenum = 0;
>+	Key *key;
>+	char *comment = NULL;
>+	int found = 0, ret = 1;
>+
>+	/* Copy much of key_load_public's logic here so that we can read
>+	 * several keys from a single file (e.g. authorized_keys).
>+	 */
>+
>+	if (strcmp(filename, "-") != 0) {
>+		int save_errno;
>+		f = fopen(filename, "r");
>+		save_errno = errno;
>+		if (!f) {
>+			char pubfile[MAXPATHLEN];
>+			if (strlcpy(pubfile, filename, sizeof pubfile) <
>+			    sizeof(pubfile) &&
>+			    strlcat(pubfile, ".pub", sizeof pubfile) <
>+			    sizeof(pubfile))
>+				f = fopen(pubfile, "r");
>+		}
>+		errno = save_errno; /* earlier errno is more useful */
>+		if (!f) {
>+			if (!quiet_open)
>+				perror(filename);
>+			return -1;
>+		}
>+		if (verbosity > 0)
>+			printf("# %s\n", filename);
>+	} else
>+		f = stdin;
>+	while (read_keyfile_line(f, filename, line, sizeof(line),
>+		    &linenum) != -1) {
>+		int i;
>+		char *space;
>+		int type;
>+		char *end;
>+
>+		/* Chop trailing newline. */
>+		i = strlen(line) - 1;
>+		if (line[i] == '\n')
>+			line[i] = '\0';
>+
>+		/* Skip leading whitespace, empty and comment lines. */
>+		for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
>+			;
>+		if (!*cp || *cp == '\n' || *cp == '#')
>+			continue;
>+
>+		/* Cope with ssh-keyscan output and options in
>+		 * authorized_keys files.
>+		 */
>+		space = strchr(cp, ' ');
>+		if (!space)
>+			continue;
>+		*space = '\0';
>+		type = key_type_from_name(cp);
>+		*space = ' ';
>+		/* Leading number (RSA1) or valid type (RSA/DSA) indicates
>+		 * that we have no host name or options to skip.
>+		 */
>+		if ((strtol(cp, &end, 10) == 0 || *end != ' ') &&
>+		    type == KEY_UNSPEC) {
>+			int quoted = 0;
>+
>+			for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
>+				if (*cp == '\\' && cp[1] == '"')
>+					cp++;	/* Skip both */
>+				else if (*cp == '"')
>+					quoted = !quoted;
>+			}
>+			/* Skip remaining whitespace. */
>+			for (; *cp == ' ' || *cp == '\t'; cp++)
>+				;
>+			if (!*cp)
>+				continue;
>+		}
>+
>+		/* Read and process the key itself. */
>+		key = key_new(KEY_RSA1);
>+		if (key_read(key, &cp) == 1) {
>+			while (*cp == ' ' || *cp == '\t')
>+				cp++;
>+			if (!do_key(filename, linenum,
>+			    key, *cp ? cp : filename))
>+				ret = 0;
>+			found = 1;
>+		} else {
>+			key_free(key);
>+			key = key_new(KEY_UNSPEC);
>+			if (key_read(key, &cp) == 1) {
>+				while (*cp == ' ' || *cp == '\t')
>+					cp++;
>+				if (!do_key(filename, linenum,
>+				    key, *cp ? cp : filename))
>+					ret = 0;
>+				found = 1;
>+			}
>+		}
>+		key_free(key);
>+	}
>+	if (f != stdin)
>+		fclose(f);
>+
>+	if (!found && filename) {
>+		key = key_load_public(filename, &comment);
>+		if (key) {
>+			if (!do_key(filename, 1, key, comment))
>+				ret = 0;
>+			found = 1;
>+		}
>+		if (comment)
>+			xfree(comment);
>+	}
>+
>+	return ret;
>+}
>+
>+int
>+do_host(int quiet_open)
>+{
>+	int i;
>+	struct stat st;
>+	int ret = 1;
>+
>+	for (i = 0; default_host_files[i]; i++) {
>+		if (stat(default_host_files[i], &st) < 0 && errno == ENOENT)
>+			continue;
>+		if (!do_filename(default_host_files[i], quiet_open))
>+			ret = 0;
>+	}
>+
>+	return ret;
>+}
>+
>+int
>+do_user(const char *dir)
>+{
>+	int i;
>+	char *file;
>+	struct stat st;
>+	int ret = 1;
>+
>+	for (i = 0; default_files[i]; i++) {
>+		xasprintf(&file, "%s/%s", dir, default_files[i]);
>+		if (stat(file, &st) < 0 && errno == ENOENT) {
>+			xfree(file);
>+			continue;
>+		}
>+		if (!do_filename(file, 0))
>+			ret = 0;
>+		xfree(file);
>+	}
>+
>+	return ret;
>+}
>+
>+int
>+main(int argc, char **argv)
>+{
>+	int opt, all_users = 0;
>+	int ret = 1;
>+	extern int optind;
>+
>+	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
>+	sanitise_stdfd();
>+
>+	__progname = ssh_get_progname(argv[0]);
>+
>+	SSLeay_add_all_algorithms();
>+	log_init(argv[0], SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_USER, 1);
>+
>+	/* We don't need the RNG ourselves, but symbol references here allow
>+	 * ld to link us properly.
>+	 */
>+	init_rng();
>+	seed_rng();
>+
>+	while ((opt = getopt(argc, argv, "ahqv")) != -1) {
>+		switch (opt) {
>+		case 'a':
>+			all_users = 1;
>+			break;
>+		case 'q':
>+			verbosity--;
>+			break;
>+		case 'v':
>+			verbosity++;
>+			break;
>+		case 'h':
>+		default:
>+			usage();
>+		}
>+	}
>+
>+	if (all_users) {
>+		struct passwd *pw;
>+
>+		if (!do_host(0))
>+			ret = 0;
>+
>+		while ((pw = getpwent()) != NULL) {
>+			if (pw->pw_dir) {
>+				temporarily_use_uid(pw);
>+				if (!do_user(pw->pw_dir))
>+					ret = 0;
>+				restore_uid();
>+			}
>+		}
>+	} else if (optind == argc) {
>+		struct passwd *pw;
>+
>+		if (!do_host(1))
>+			ret = 0;
>+
>+		if ((pw = getpwuid(geteuid())) == NULL)
>+			fprintf(stderr, "No user found with uid %u\n",
>+			    (u_int)geteuid());
>+		else {
>+			if (!do_user(pw->pw_dir))
>+				ret = 0;
>+		}
>+	} else {
>+		while (optind < argc)
>+			if (!do_filename(argv[optind++], 0))
>+				ret = 0;
>+	}
>+
>+	return ret;
>+}
>--- openssh-4.7p1.orig/servconf.c
>+++ openssh-4.7p1/servconf.c
>@@ -94,6 +94,7 @@
> 	options->password_authentication = -1;
> 	options->kbd_interactive_authentication = -1;
> 	options->challenge_response_authentication = -1;
>+	options->permit_blacklisted_keys = -1;
> 	options->permit_empty_passwd = -1;
> 	options->permit_user_env = -1;
> 	options->use_login = -1;
>@@ -212,6 +213,8 @@
> 		options->kbd_interactive_authentication = 0;
> 	if (options->challenge_response_authentication == -1)
> 		options->challenge_response_authentication = 1;
>+	if (options->permit_blacklisted_keys == -1)
>+		options->permit_blacklisted_keys = 0;
> 	if (options->permit_empty_passwd == -1)
> 		options->permit_empty_passwd = 0;
> 	if (options->permit_user_env == -1)
>@@ -281,7 +284,7 @@
> 	sListenAddress, sAddressFamily,
> 	sPrintMotd, sPrintLastLog, sIgnoreRhosts,
> 	sX11Forwarding, sX11DisplayOffset, sX11UseLocalhost,
>-	sStrictModes, sEmptyPasswd, sTCPKeepAlive,
>+	sStrictModes, sPermitBlacklistedKeys, sEmptyPasswd, sTCPKeepAlive,
> 	sPermitUserEnvironment, sUseLogin, sAllowTcpForwarding, sCompression,
> 	sAllowUsers, sDenyUsers, sAllowGroups, sDenyGroups,
> 	sIgnoreUserKnownHosts, sCiphers, sMacs, sProtocol, sPidFile,
>@@ -371,6 +374,7 @@
> 	{ "x11uselocalhost", sX11UseLocalhost, SSHCFG_ALL },
> 	{ "xauthlocation", sXAuthLocation, SSHCFG_GLOBAL },
> 	{ "strictmodes", sStrictModes, SSHCFG_GLOBAL },
>+	{ "permitblacklistedkeys", sPermitBlacklistedKeys, SSHCFG_GLOBAL },
> 	{ "permitemptypasswords", sEmptyPasswd, SSHCFG_GLOBAL },
> 	{ "permituserenvironment", sPermitUserEnvironment, SSHCFG_GLOBAL },
> 	{ "uselogin", sUseLogin, SSHCFG_GLOBAL },
>@@ -919,6 +923,10 @@
> 		intptr = &options->tcp_keep_alive;
> 		goto parse_flag;
> 
>+	case sPermitBlacklistedKeys:
>+		intptr = &options->permit_blacklisted_keys;
>+		goto parse_flag;
>+
> 	case sEmptyPasswd:
> 		intptr = &options->permit_empty_passwd;
> 		goto parse_flag;
>--- openssh-4.7p1.orig/auth-rsa.c
>+++ openssh-4.7p1/auth-rsa.c
>@@ -265,6 +265,9 @@
> 			    "actual %d vs. announced %d.",
> 			    file, linenum, BN_num_bits(key->rsa->n), bits);
> 
>+		if (reject_blacklisted_key(key, 0) == 1)
>+			continue;
>+
> 		/* We have found the desired key. */
> 		/*
> 		 * If our options do not allow this key to be used,
>--- openssh-4.7p1.orig/auth.h
>+++ openssh-4.7p1/auth.h
>@@ -173,6 +173,8 @@
> check_key_in_hostfiles(struct passwd *, Key *, const char *,
>     const char *, const char *);
> 
>+int	reject_blacklisted_key(Key *, int);
>+
> /* hostkey handling */
> Key	*get_hostkey_by_index(int);
> Key	*get_hostkey_by_type(int);
>--- openssh-4.7p1.orig/pathnames.h
>+++ openssh-4.7p1/pathnames.h
>@@ -18,6 +18,10 @@
> #define SSHDIR				ETCDIR "/ssh"
> #endif
> 
>+#ifndef _PATH_SSH_DATADIR
>+#define _PATH_SSH_DATADIR		"/usr/share/ssh"
>+#endif
>+
> #ifndef _PATH_SSH_PIDDIR
> #define _PATH_SSH_PIDDIR		"/var/run"
> #endif
>@@ -43,6 +47,9 @@
> /* Backwards compatibility */
> #define _PATH_DH_PRIMES			SSHDIR "/primes"
> 
>+#define _PATH_BLACKLIST			_PATH_SSH_DATADIR "/blacklist"
>+#define _PATH_BLACKLIST_CONFIG		SSHDIR "/blacklist"
>+
> #ifndef _PATH_SSH_PROGRAM
> #define _PATH_SSH_PROGRAM		"/usr/bin/ssh"
> #endif
>--- openssh-4.7p1.orig/servconf.h
>+++ openssh-4.7p1/servconf.h
>@@ -92,6 +92,7 @@
> 						 * authentication. */
> 	int     kbd_interactive_authentication;	/* If true, permit */
> 	int     challenge_response_authentication;
>+	int     permit_blacklisted_keys;	/* If true, permit */
> 	int     permit_empty_passwd;	/* If false, do not permit empty
> 					 * passwords. */
> 	int     permit_user_env;	/* If true, read ~/.ssh/environment */
>--- openssh-4.7p1.orig/auth.c
>+++ openssh-4.7p1/auth.c
>@@ -57,6 +57,7 @@
> #include "servconf.h"
> #include "key.h"
> #include "hostfile.h"
>+#include "authfile.h"
> #include "auth.h"
> #include "auth-options.h"
> #include "canohost.h"
>@@ -397,6 +398,38 @@
> 	return host_status;
> }
> 
>+int
>+reject_blacklisted_key(Key *key, int hostkey)
>+{
>+	char *fp;
>+
>+	if (blacklisted_key(key, &fp) != 1)
>+		return 0;
>+
>+	if (options.permit_blacklisted_keys) {
>+		if (hostkey)
>+			error("Host key %s blacklisted (see "
>+			    "ssh-vulnkey(1)); continuing anyway", fp);
>+		else
>+			logit("Public key %s from %s blacklisted (see "
>+			    "ssh-vulnkey(1)); continuing anyway",
>+			    fp, get_remote_ipaddr());
>+		xfree(fp);
>+	} else {
>+		if (hostkey)
>+			error("Host key %s blacklisted (see "
>+			    "ssh-vulnkey(1))", fp);
>+		else
>+			logit("Public key %s from %s blacklisted (see "
>+			    "ssh-vulnkey(1))",
>+			    fp, get_remote_ipaddr());
>+		xfree(fp);
>+		return 1;
>+	}
>+
>+	return 0;
>+}
>+
> 
> /*
>  * Check a given file for security. This is defined as all components
>--- openssh-4.7p1.orig/auth2-pubkey.c
>+++ openssh-4.7p1/auth2-pubkey.c
>@@ -272,6 +272,9 @@
> 	int success;
> 	char *file;
> 
>+	if (reject_blacklisted_key(key, 0) == 1)
>+		return 0;
>+
> 	file = authorized_keys_file(pw);
> 	success = user_key_allowed2(pw, key, file);
> 	xfree(file);
>--- openssh-4.7p1.orig/Makefile.in
>+++ openssh-4.7p1/Makefile.in
>@@ -26,6 +26,7 @@
> SFTP_SERVER=$(libexecdir)/sftp-server
> SSH_KEYSIGN=$(libexecdir)/ssh-keysign
> RAND_HELPER=$(libexecdir)/ssh-rand-helper
>+SSH_DATADIR=$(datadir)/ssh
> PRIVSEP_PATH=@PRIVSEP_PATH@
> SSH_PRIVSEP_USER=@SSH_PRIVSEP_USER@
> STRIP_OPT=@STRIP_OPT@
>@@ -37,7 +38,8 @@
> 	-D_PATH_SSH_KEY_SIGN=\"$(SSH_KEYSIGN)\" \
> 	-D_PATH_SSH_PIDDIR=\"$(piddir)\" \
> 	-D_PATH_PRIVSEP_CHROOT_DIR=\"$(PRIVSEP_PATH)\" \
>-	-DSSH_RAND_HELPER=\"$(RAND_HELPER)\"
>+	-DSSH_RAND_HELPER=\"$(RAND_HELPER)\" \
>+	-D_PATH_SSH_DATADIR=\"$(SSH_DATADIR)\"
> 
> CC=@CC@
> LD=@LD@
>@@ -60,7 +62,7 @@
> INSTALL_SSH_PRNG_CMDS=@INSTALL_SSH_PRNG_CMDS@
> INSTALL_SSH_RAND_HELPER=@INSTALL_SSH_RAND_HELPER@
> 
>-TARGETS=ssh$(EXEEXT) sshd$(EXEEXT) ssh-add$(EXEEXT) ssh-keygen$(EXEEXT) ssh-keyscan${EXEEXT} ssh-keysign${EXEEXT} ssh-agent$(EXEEXT) scp$(EXEEXT) ssh-rand-helper${EXEEXT} sftp-server$(EXEEXT) sftp$(EXEEXT)
>+TARGETS=ssh$(EXEEXT) sshd$(EXEEXT) ssh-add$(EXEEXT) ssh-keygen$(EXEEXT) ssh-keyscan${EXEEXT} ssh-keysign${EXEEXT} ssh-agent$(EXEEXT) scp$(EXEEXT) ssh-rand-helper${EXEEXT} sftp-server$(EXEEXT) sftp$(EXEEXT) ssh-vulnkey$(EXEEXT)
> 
> LIBSSH_OBJS=acss.o authfd.o authfile.o bufaux.o bufbn.o buffer.o \
> 	canohost.o channels.o cipher.o cipher-acss.o cipher-aes.o \
>@@ -88,8 +90,8 @@
> 	loginrec.o auth-pam.o auth-shadow.o auth-sia.o md5crypt.o \
> 	audit.o audit-bsm.o platform.o
> 
>-MANPAGES	= scp.1.out ssh-add.1.out ssh-agent.1.out ssh-keygen.1.out ssh-keyscan.1.out ssh.1.out sshd.8.out sftp-server.8.out sftp.1.out ssh-rand-helper.8.out ssh-keysign.8.out sshd_config.5.out ssh_config.5.out
>-MANPAGES_IN	= scp.1 ssh-add.1 ssh-agent.1 ssh-keygen.1 ssh-keyscan.1 ssh.1 sshd.8 sftp-server.8 sftp.1 ssh-rand-helper.8 ssh-keysign.8 sshd_config.5 ssh_config.5
>+MANPAGES	= scp.1.out ssh-add.1.out ssh-agent.1.out ssh-keygen.1.out ssh-keyscan.1.out ssh.1.out sshd.8.out sftp-server.8.out sftp.1.out ssh-rand-helper.8.out ssh-keysign.8.out ssh-vulnkey.1.out sshd_config.5.out ssh_config.5.out
>+MANPAGES_IN	= scp.1 ssh-add.1 ssh-agent.1 ssh-keygen.1 ssh-keyscan.1 ssh.1 sshd.8 sftp-server.8 sftp.1 ssh-rand-helper.8 ssh-keysign.8 ssh-vulnkey.1 sshd_config.5 ssh_config.5
> MANTYPE		= @MANTYPE@
> 
> CONFIGFILES=sshd_config.out ssh_config.out moduli.out
>@@ -165,6 +167,9 @@
> ssh-rand-helper${EXEEXT}: $(LIBCOMPAT) libssh.a ssh-rand-helper.o
> 	$(LD) -o $@ ssh-rand-helper.o $(LDFLAGS) -lssh -lopenbsd-compat $(LIBS)
> 
>+ssh-vulnkey$(EXEEXT): $(LIBCOMPAT) libssh.a ssh-vulnkey.o
>+	$(LD) -o $@ ssh-vulnkey.o $(LDFLAGS) -lssh -lopenbsd-compat $(LIBS)
>+
> # test driver for the loginrec code - not built by default
> logintest: logintest.o $(LIBCOMPAT) libssh.a loginrec.o
> 	$(LD) -o $@ logintest.o $(LDFLAGS) loginrec.o -lopenbsd-compat -lssh $(LIBS)
>@@ -264,6 +269,7 @@
> 	$(INSTALL) -m 4711 $(STRIP_OPT) ssh-keysign $(DESTDIR)$(SSH_KEYSIGN)
> 	$(INSTALL) -m 0755 $(STRIP_OPT) sftp $(DESTDIR)$(bindir)/sftp
> 	$(INSTALL) -m 0755 $(STRIP_OPT) sftp-server $(DESTDIR)$(SFTP_SERVER)
>+	$(INSTALL) -m 0755 $(STRIP_OPT) ssh-vulnkey $(DESTDIR)$(bindir)/ssh-vulnkey
> 	$(INSTALL) -m 644 ssh.1.out $(DESTDIR)$(mandir)/$(mansubdir)1/ssh.1
> 	$(INSTALL) -m 644 scp.1.out $(DESTDIR)$(mandir)/$(mansubdir)1/scp.1
> 	$(INSTALL) -m 644 ssh-add.1.out $(DESTDIR)$(mandir)/$(mansubdir)1/ssh-add.1
>@@ -279,6 +285,7 @@
> 	$(INSTALL) -m 644 sftp.1.out $(DESTDIR)$(mandir)/$(mansubdir)1/sftp.1
> 	$(INSTALL) -m 644 sftp-server.8.out $(DESTDIR)$(mandir)/$(mansubdir)8/sftp-server.8
> 	$(INSTALL) -m 644 ssh-keysign.8.out $(DESTDIR)$(mandir)/$(mansubdir)8/ssh-keysign.8
>+	$(INSTALL) -m 644 ssh-vulnkey.1.out $(DESTDIR)$(mandir)/$(mansubdir)1/ssh-vulnkey.1
> 	-rm -f $(DESTDIR)$(bindir)/slogin
> 	ln -s ./ssh$(EXEEXT) $(DESTDIR)$(bindir)/slogin
> 	-rm -f $(DESTDIR)$(mandir)/$(mansubdir)1/slogin.1
>@@ -360,6 +367,7 @@
> 	-rm -f $(DESTDIR)$(bindir)/ssh-agent$(EXEEXT)
> 	-rm -f $(DESTDIR)$(bindir)/ssh-keygen$(EXEEXT)
> 	-rm -f $(DESTDIR)$(bindir)/ssh-keyscan$(EXEEXT)
>+	-rm -f $(DESTDIR)$(bindir)/ssh-vulnkey$(EXEEXT)
> 	-rm -f $(DESTDIR)$(bindir)/sftp$(EXEEXT)
> 	-rm -f $(DESTDIR)$(sbindir)/sshd$(EXEEXT)
> 	-rm -r $(DESTDIR)$(SFTP_SERVER)$(EXEEXT)
>@@ -372,6 +380,7 @@
> 	-rm -f $(DESTDIR)$(mandir)/$(mansubdir)1/ssh-keygen.1
> 	-rm -f $(DESTDIR)$(mandir)/$(mansubdir)1/sftp.1
> 	-rm -f $(DESTDIR)$(mandir)/$(mansubdir)1/ssh-keyscan.1
>+	-rm -f $(DESTDIR)$(mandir)/$(mansubdir)1/ssh-vulnkey.1
> 	-rm -f $(DESTDIR)$(mandir)/$(mansubdir)8/sshd.8
> 	-rm -f $(DESTDIR)$(mandir)/$(mansubdir)8/ssh-rand-helper.8
> 	-rm -f $(DESTDIR)$(mandir)/$(mansubdir)8/sftp-server.8

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Attachments on bug 1469: 1508 | 1510 | 1529 | 1530 | 1531