--- /dev/null
+This patch is against OpenSSH 4.7p1, although should apply to other versions
+without too much difficulty. It makes the following changes:
+
+ * Add key blacklisting support. Keys listed in
+ /etc/ssh/blacklist.TYPE-LENGTH will be rejected for authentication by
+ sshd, unless "PermitBlacklistedKeys yes" is set in /etc/ssh/sshd_config.
+
+ * Add a new program, ssh-vulnkey, which can be used to check keys against
+ these blacklists.
+
+This patch is up to date with respect to Debian openssh 1:4.7p1-10.
+
+--- openssh-4.7p1.orig/sshd_config.5
++++ openssh-4.7p1/sshd_config.5
+@@ -615,6 +615,20 @@
+ 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/sshd.c
++++ openssh-4.7p1/sshd.c
+@@ -1466,6 +1466,21 @@
+
+ for (i = 0; i < options.num_host_key_files; i++) {
+ key = key_load_private(options.host_key_files[i], "", NULL);
++ if (key && blacklisted_key(key)) {
++ char *fp;
++ fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
++ if (options.permit_blacklisted_keys)
++ error("Host key %s blacklisted (see "
++ "ssh-vulnkey(1)); continuing anyway", fp);
++ else
++ error("Host key %s blacklisted (see "
++ "ssh-vulnkey(1))", fp);
++ xfree(fp);
++ if (!options.permit_blacklisted_keys) {
++ sensitive_data.host_keys[i] = NULL;
++ continue;
++ }
++ }
+ sensitive_data.host_keys[i] = key;
+ if (key == NULL) {
+ error("Could not load host key: %s",
+--- openssh-4.7p1.orig/servconf.c
++++ openssh-4.7p1/servconf.c
+@@ -96,6 +96,7 @@
+ 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;
+@@ -218,6 +219,8 @@
+ 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)
+@@ -287,7 +290,7 @@
+ 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,
+@@ -387,6 +390,7 @@
+ { "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 },
+@@ -943,6 +947,10 @@
+ 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/servconf.h
++++ openssh-4.7p1/servconf.h
+@@ -94,6 +94,7 @@
+ * 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/Makefile.in
++++ openssh-4.7p1/Makefile.in
+@@ -60,7 +60,7 @@
+ 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$(EXEEXT)
+
+ LIBSSH_OBJS=acss.o authfd.o authfile.o bufaux.o bufbn.o buffer.o \
+ canohost.o channels.o cipher.o cipher-acss.o cipher-aes.o \
+@@ -88,8 +88,8 @@
+ loginrec.o auth-pam.o auth-shadow.o auth-sia.o md5crypt.o \
+ audit.o audit-bsm.o platform.o
+
+-MANPAGES = scp.1.out ssh-add.1.out ssh-agent.1.out ssh-keygen.1.out ssh-keyscan.1.out ssh.1.out sshd.8.out sftp-server.8.out sftp.1.out ssh-rand-helper.8.out ssh-keysign.8.out sshd_config.5.out ssh_config.5.out
+-MANPAGES_IN = scp.1 ssh-add.1 ssh-agent.1 ssh-keygen.1 ssh-keyscan.1 ssh.1 sshd.8 sftp-server.8 sftp.1 ssh-rand-helper.8 ssh-keysign.8 sshd_config.5 ssh_config.5
++MANPAGES = scp.1.out ssh-add.1.out ssh-agent.1.out ssh-keygen.1.out ssh-keyscan.1.out ssh.1.out sshd.8.out sftp-server.8.out sftp.1.out ssh-rand-helper.8.out ssh-keysign.8.out ssh-vulnkey.1.out sshd_config.5.out ssh_config.5.out
++MANPAGES_IN = scp.1 ssh-add.1 ssh-agent.1 ssh-keygen.1 ssh-keyscan.1 ssh.1 sshd.8 sftp-server.8 sftp.1 ssh-rand-helper.8 ssh-keysign.8 ssh-vulnkey.1 sshd_config.5 ssh_config.5
+ MANTYPE = @MANTYPE@
+
+ CONFIGFILES=sshd_config.out ssh_config.out moduli.out
+@@ -165,6 +165,9 @@
+ ssh-rand-helper${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 +267,7 @@
+ $(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
+@@ -280,6 +284,7 @@
+ $(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
+@@ -361,6 +366,7 @@
+ -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)
+@@ -373,6 +379,7 @@
+ -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
+--- openssh-4.7p1.orig/auth-rh-rsa.c
++++ openssh-4.7p1/auth-rh-rsa.c
+@@ -20,6 +20,7 @@
+ #include <pwd.h>
+ #include <stdarg.h>
+
++#include "xmalloc.h"
+ #include "packet.h"
+ #include "uidswap.h"
+ #include "log.h"
+@@ -27,6 +28,7 @@
+ #include "servconf.h"
+ #include "key.h"
+ #include "hostfile.h"
++#include "authfile.h"
+ #include "pathnames.h"
+ #include "auth.h"
+ #include "canohost.h"
+@@ -42,8 +44,22 @@
+ auth_rhosts_rsa_key_allowed(struct passwd *pw, char *cuser, char *chost,
+ Key *client_host_key)
+ {
++ char *fp;
+ HostStatus host_status;
+
++ if (blacklisted_key(client_host_key)) {
++ fp = key_fingerprint(client_host_key, SSH_FP_MD5, SSH_FP_HEX);
++ if (options.permit_blacklisted_keys)
++ logit("Public key %s blacklisted (see "
++ "ssh-vulnkey(1)); continuing anyway", fp);
++ else
++ logit("Public key %s blacklisted (see "
++ "ssh-vulnkey(1))", fp);
++ xfree(fp);
++ if (!options.permit_blacklisted_keys)
++ 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 +23,7 @@
+ Key *key_load_private_pem(int, int, const char *, char **);
+ int key_perm_ok(int, const char *);
+
++char *blacklist_filename(const Key *key);
++int blacklisted_key(const Key *key);
++
+ #endif
+--- openssh-4.7p1.orig/ssh-vulnkey.1
++++ openssh-4.7p1/ssh-vulnkey.1
+@@ -0,0 +1,187 @@
++.\" 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
++.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
++.Nm
++will exit zero if any of the given keys were in the compromised list,
++otherwise non-zero.
++.Pp
++Unless the
++.Cm PermitBlacklistedKeys
++option is used,
++.Xr sshd 8
++will reject attempts to authenticate with keys in the compromised list.
++.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.
++.El
++.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 /etc/ssh/blacklist. Ns Ar TYPE Ns Pa - Ns Ar LENGTH
++If present, lists the blacklisted keys of type
++.Ar TYPE
++.Pf ( Dq RSA1 ,
++.Dq RSA ,
++or
++.Dq DSA )
++and bit length
++.Ar LENGTH .
++The format of this file is described above.
++.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
+@@ -40,6 +40,7 @@
+ #include "compat.h"
+ #include "key.h"
+ #include "hostfile.h"
++#include "authfile.h"
+ #include "auth.h"
+ #include "canohost.h"
+ #ifdef GSSAPI
+@@ -141,10 +142,24 @@
+ hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost,
+ Key *key)
+ {
++ char *fp;
+ const char *resolvedname, *ipaddr, *lookup;
+ HostStatus host_status;
+ int len;
+
++ if (blacklisted_key(key)) {
++ fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
++ if (options.permit_blacklisted_keys)
++ logit("Public key %s blacklisted (see "
++ "ssh-vulnkey(1)); continuing anyway", fp);
++ else
++ logit("Public key %s blacklisted (see "
++ "ssh-vulnkey(1))", fp);
++ xfree(fp);
++ if (!options.permit_blacklisted_keys)
++ return 0;
++ }
++
+ resolvedname = get_canonical_hostname(options.use_dns);
+ ipaddr = get_remote_ipaddr();
+
+--- 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 +678,113 @@
+ key_free(pub);
+ return NULL;
+ }
++
++char *
++blacklist_filename(const Key *key)
++{
++ char *name;
++
++ xasprintf(&name, "%s.%s-%u",
++ _PATH_BLACKLIST, key_type(key), key_size(key));
++ return name;
++}
++
++/* Scan a blacklist of known-vulnerable keys. */
++int
++blacklisted_key(const Key *key)
++{
++ char *blacklist_file;
++ 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;
++
++ blacklist_file = blacklist_filename(key);
++ debug("Checking blacklist file %s", blacklist_file);
++ fd = open(blacklist_file, O_RDONLY);
++ if (fd < 0)
++ 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, 256);
++ if (r <= 0)
++ goto out;
++ if (buf[0] != '#')
++ break;
++
++ newline = memchr(buf, '\n', 256);
++ 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;
++ char buf[32];
++ 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 (dgst_hex)
++ xfree(dgst_hex);
++ if (fd >= 0)
++ close(fd);
++ xfree(blacklist_file);
++ return ret;
++}
+--- openssh-4.7p1.orig/ssh-vulnkey.c
++++ openssh-4.7p1/ssh-vulnkey.c
+@@ -0,0 +1,325 @@
++/*
++ * 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 <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 "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 quiet = 0;
++
++static void
++usage(void)
++{
++ fprintf(stderr, "usage: %s [-aq] [file ...]\n", __progname);
++ fprintf(stderr, "Options:\n");
++ fprintf(stderr, " -a Check keys of all users.\n");
++ fprintf(stderr, " -q Quiet mode.\n");
++ exit(1);
++}
++
++void
++describe_key(const char *msg, const Key *key, const char *comment)
++{
++ char *fp;
++
++ fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
++ if (!quiet)
++ printf("%s: %u %s %s\n", msg, key_size(key), fp, comment);
++ xfree(fp);
++}
++
++int
++do_key(const Key *key, const char *comment)
++{
++ char *blacklist_file;
++ struct stat st;
++ int ret = 1;
++
++ blacklist_file = blacklist_filename(key);
++ if (stat(blacklist_file, &st) < 0)
++ describe_key("Unknown (no blacklist information)",
++ key, comment);
++ else if (blacklisted_key(key)) {
++ describe_key("COMPROMISED", key, comment);
++ ret = 0;
++ } else
++ describe_key("Not blacklisted", key, comment);
++ xfree(blacklist_file);
++
++ 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) {
++ f = fopen(filename, "r");
++ if (!f) {
++ char pubfile[MAXPATHLEN];
++ if (strlcpy(pubfile, filename, sizeof pubfile) <
++ sizeof(pubfile) &&
++ strlcat(pubfile, ".pub", sizeof pubfile) <
++ sizeof(pubfile))
++ f = fopen(pubfile, "r");
++ }
++ if (!f) {
++ if (!quiet_open)
++ perror(filename);
++ return -1;
++ }
++ } else
++ f = stdin;
++ while (read_keyfile_line(f, filename, line, sizeof(line),
++ &linenum) != -1) {
++ int i;
++ char *space;
++ int type;
++
++ /* 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 (atoi(cp) == 0 && 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(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(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(key, comment))
++ ret = 0;
++ found = 1;
++ }
++ if (comment)
++ xfree(comment);
++ }
++
++ return ret;
++}
++
++int
++do_host(void)
++{
++ int i;
++ struct stat st;
++ int ret = 1;
++
++ for (i = 0; default_host_files[i]; i++) {
++ if (stat(default_host_files[i], &st) < 0)
++ continue;
++ if (!do_filename(default_host_files[i], 1))
++ ret = 0;
++ }
++
++ return ret;
++}
++
++int
++do_user(const char *dir)
++{
++ int i;
++ char buf[MAXPATHLEN];
++ struct stat st;
++ int ret = 1;
++
++ for (i = 0; default_files[i]; i++) {
++ snprintf(buf, sizeof(buf), "%s/%s", dir, default_files[i]);
++ if (stat(buf, &st) < 0)
++ continue;
++ if (!do_filename(buf, 0))
++ ret = 0;
++ }
++
++ 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, "ahq")) != -1) {
++ switch (opt) {
++ case 'a':
++ all_users = 1;
++ break;
++ case 'q':
++ quiet = 1;
++ break;
++ case 'h':
++ default:
++ usage();
++ }
++ }
++
++ if (all_users) {
++ struct passwd *pw;
++
++ if (!do_host())
++ ret = 0;
++
++ while ((pw = getpwent()) != NULL) {
++ if (pw->pw_dir) {
++ if (!do_user(pw->pw_dir))
++ ret = 0;
++ }
++ }
++ } else if (optind == argc) {
++ struct passwd *pw;
++
++ if (!do_host())
++ ret = 0;
++
++ if ((pw = getpwuid(getuid())) == NULL)
++ fprintf(stderr, "No user found with uid %u\n",
++ (u_int)getuid());
++ 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/auth-rsa.c
++++ openssh-4.7p1/auth-rsa.c
+@@ -40,6 +40,7 @@
+ #include "servconf.h"
+ #include "key.h"
+ #include "hostfile.h"
++#include "authfile.h"
+ #include "auth.h"
+ #ifdef GSSAPI
+ #include "ssh-gss.h"
+@@ -221,6 +222,7 @@
+ char *cp;
+ char *key_options;
+ int keybits;
++ char *fp;
+
+ /* Skip leading whitespace, empty and comment lines. */
+ for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
+@@ -265,6 +267,19 @@
+ "actual %d vs. announced %d.",
+ file, linenum, BN_num_bits(key->rsa->n), bits);
+
++ if (blacklisted_key(key)) {
++ fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
++ if (options.permit_blacklisted_keys)
++ logit("Public key %s blacklisted (see "
++ "ssh-vulnkey(1)); continuing anyway", fp);
++ else
++ logit("Public key %s blacklisted (see "
++ "ssh-vulnkey(1))", fp);
++ xfree(fp);
++ if (!options.permit_blacklisted_keys)
++ continue;
++ }
++
+ /* We have found the desired key. */
+ /*
+ * If our options do not allow this key to be used,
+--- openssh-4.7p1.orig/pathnames.h
++++ openssh-4.7p1/pathnames.h
+@@ -43,6 +43,8 @@
+ /* Backwards compatibility */
+ #define _PATH_DH_PRIMES SSHDIR "/primes"
+
++#define _PATH_BLACKLIST SSHDIR "/blacklist"
++
+ #ifndef _PATH_SSH_PROGRAM
+ #define _PATH_SSH_PROGRAM "/usr/bin/ssh"
+ #endif
+--- openssh-4.7p1.orig/auth2-pubkey.c
++++ openssh-4.7p1/auth2-pubkey.c
+@@ -42,6 +42,7 @@
+ #include "compat.h"
+ #include "key.h"
+ #include "hostfile.h"
++#include "authfile.h"
+ #include "auth.h"
+ #include "pathnames.h"
+ #include "uidswap.h"
+@@ -269,9 +270,23 @@
+ int
+ user_key_allowed(struct passwd *pw, Key *key)
+ {
++ char *fp;
+ int success;
+ char *file;
+
++ if (blacklisted_key(key)) {
++ fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
++ if (options.permit_blacklisted_keys)
++ logit("Public key %s blacklisted (see "
++ "ssh-vulnkey(1)); continuing anyway", fp);
++ else
++ logit("Public key %s blacklisted (see "
++ "ssh-vulnkey(1))", fp);
++ xfree(fp);
++ if (!options.permit_blacklisted_keys)
++ return 0;
++ }
++
+ file = authorized_keys_file(pw);
+ success = user_key_allowed2(pw, key, file);
+ xfree(file);
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