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#! /bin/sh /usr/share/dpatch/dpatch-run

## blacklist.dpatch by Magnus Holmgren <holmgren@debian.org>

## blacklist.c code copied from OpenSSH's authfile.c and adapted for LSH.

##

## DP: Check keys against openssh-blacklist before accepting for

## DP: pubkey authentication as well as on conversion by lsh-writekey

## DP: and lsh-decode-key.

@DPATCH@

diff -urNad trunk~/src/Makefile.am trunk/src/Makefile.am

--- trunk~/src/Makefile.am      2004-11-18 22:52:16.000000000 +0100

+++ trunk/src/Makefile.am       2009-11-06 01:07:40.000000000 +0100

@@ -72,7 +72,8 @@

        unix_interact.c unix_process.c unix_random.c unix_user.c \

        userauth.c \

        werror.c write_buffer.c write_packet.c \

-       xalloc.c xauth.c zlib.c

+       xalloc.c xauth.c zlib.c \

+       blacklist.c

 liblsh_a_LIBADD = @LIBOBJS@

diff -urNad trunk~/src/Makefile.in trunk/src/Makefile.in

--- trunk~/src/Makefile.in      2009-11-06 01:07:40.000000000 +0100

+++ trunk/src/Makefile.in       2009-11-06 01:07:40.000000000 +0100

@@ -91,7 +91,8 @@

        tty.$(OBJEXT) unix_interact.$(OBJEXT) unix_process.$(OBJEXT) \

        unix_random.$(OBJEXT) unix_user.$(OBJEXT) userauth.$(OBJEXT) \

        werror.$(OBJEXT) write_buffer.$(OBJEXT) write_packet.$(OBJEXT) \

-       xalloc.$(OBJEXT) xauth.$(OBJEXT) zlib.$(OBJEXT)

+       xalloc.$(OBJEXT) xauth.$(OBJEXT) zlib.$(OBJEXT) \

+       blacklist.$(OBJEXT)

 liblsh_a_OBJECTS = $(am_liblsh_a_OBJECTS)

 am__installdirs = "$(DESTDIR)$(bindir)" "$(DESTDIR)$(sbindir)" \

        "$(DESTDIR)$(bindir)"

@@ -510,7 +511,8 @@

        unix_interact.c unix_process.c unix_random.c unix_user.c \

        userauth.c \

        werror.c write_buffer.c write_packet.c \

-       xalloc.c xauth.c zlib.c

+       xalloc.c xauth.c zlib.c \

+       blacklist.c

 liblsh_a_LIBADD = @LIBOBJS@

@@ -705,6 +707,7 @@

 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/algorithms.Po@am__quote@

 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/alist.Po@am__quote@

 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/atoms.Po@am__quote@

+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/blacklist.Po@am__quote@

 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/channel.Po@am__quote@

 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/channel_commands.Po@am__quote@

 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/channel_forward.Po@am__quote@

diff -urNad trunk~/src/blacklist.c trunk/src/blacklist.c

--- trunk~/src/blacklist.c      1970-01-01 01:00:00.000000000 +0100

+++ trunk/src/blacklist.c       2009-11-06 01:07:40.000000000 +0100

@@ -0,0 +1,164 @@

+#if HAVE_CONFIG_H

+#include "config.h"

+#endif

+

+#include <assert.h>

+

+#include "nettle/bignum.h"

+#include "nettle/dsa.h"

+#include "nettle/rsa.h"

+#include "xalloc.h"

+#include "atoms.h"

+#include "format.h"

+#include "lsh_string.h"

+#include "abstract_crypto.h"

+#include "werror.h"

+#include "crypto.h"

+#define GABA_DECLARE

+#include "rsa.c.x"

+#include "dsa.c.x"

+

+#include <sys/types.h>

+#include <sys/stat.h>

+#include <unistd.h>

+#include <fcntl.h>

+#include <string.h>

+

+/* Scan a blacklist of known-vulnerable keys in blacklist_file. */

+static int

+blacklisted_key_in_file(struct lsh_string *lsh_hash, struct lsh_string *blacklist_file)

+{

+  int fd = -1;

+  const char *hash = 0;

+  int i;

+  uint32_t line_len;

+  struct stat st;

+  char buf[256];

+  off_t start, lower, upper;

+  int ret = 0;

+

+  debug("Checking blacklist file %S\n", blacklist_file);

+  fd = open(lsh_get_cstring(blacklist_file), O_RDONLY);

+  if (fd < 0) {

+    ret = -1;

+    goto out;

+  }

+

+  hash = lsh_get_cstring(lsh_hash) + 12;

+  line_len = strlen(hash);

+  if (line_len != 20)

+    goto out;

+

+  /* Skip leading comments */

+  start = 0;

+  for (;;) {

+    ssize_t r;

+    char *newline;

+

+    r = 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 (read(fd, buf, line_len) != line_len)

+      break;

+    cmp = memcmp(buf, hash, line_len);

+    if (cmp < 0) {

+      if (cur == lower)

+       break;

+      lower = cur;

+    } else if (cmp > 0) {

+      if (cur == upper)

+       break;

+      upper = cur;

+    } else {

+      ret = 1;

+      break;

+    }

+  }

+

+out:

+  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(struct verifier *v, int method)

+{

+    size_t keysize;

+    const char *keytype;

+    int ret = -1;

+    const char *paths[] = { "/usr/share/ssh/blacklist", "/etc/ssh/blacklist", NULL };

+    const char **pp;

+    struct lsh_string *lsh_hash = ssh_format("%lfxS",

+                                            hash_string(&crypto_md5_algorithm,

+                                                        PUBLIC_KEY(v), 1));

+

+    switch (method)

+      {

+      case ATOM_SSH_DSS:

+      case ATOM_DSA:

+       {

+         CAST(dsa_verifier, self, v);

+         keytype = "DSA";

+         keysize = mpz_sizeinbase(self->key.p, 2);

+       }

+       break;

+      case ATOM_SSH_RSA:

+      case ATOM_RSA_PKCS1_SHA1:

+      case ATOM_RSA_PKCS1_MD5:

+      case ATOM_RSA_PKCS1:

+       {

+         CAST(rsa_verifier, self, v);

+         keytype = "RSA";

+         keysize = mpz_sizeinbase(self->key.n, 2);

+       } break;

+      default:

+         werror("Unrecognized key type");

+       return 0;

+      }

+

+    for (pp = paths; *pp && ret <= 0; pp++) {

+      struct lsh_string *blacklist_file = ssh_format("%lz.%lz-%di",

+                                                    *pp, keytype, keysize);

+      int r = blacklisted_key_in_file(lsh_hash, blacklist_file);

+      lsh_string_free(blacklist_file);

+      if (r > ret) ret = r;

+    }

+

+    if (ret > 0) {

+       werror("Key is compromised: %z %i %fS\n", keytype, keysize,

+              lsh_string_colonize(lsh_hash, 2, 0));

+    }

+    return ret;

+}

diff -urNad trunk~/src/lsh-decode-key.c trunk/src/lsh-decode-key.c

--- trunk~/src/lsh-decode-key.c 2005-09-06 14:43:15.000000000 +0200

+++ trunk/src/lsh-decode-key.c  2009-11-06 01:07:40.000000000 +0100

@@ -133,6 +133,10 @@

             werror("Invalid dsa key.\n");

             return NULL;

           }

+        else if (blacklisted_key(v, type))

+          {

+            return NULL;

+          }

         else

           return PUBLIC_SPKI_KEY(v, 1);

       }

@@ -150,6 +154,10 @@

               werror("Invalid rsa key.\n");

               return NULL;

             }

+          else if (blacklisted_key(v, type))

+            {

+              return NULL;

+            }

           else

             return PUBLIC_SPKI_KEY(v, 1);

       }      

diff -urNad trunk~/src/lsh-writekey.c trunk/src/lsh-writekey.c

--- trunk~/src/lsh-writekey.c   2004-11-17 11:55:11.000000000 +0100

+++ trunk/src/lsh-writekey.c    2009-11-06 01:11:54.000000000 +0100

@@ -397,14 +397,18 @@

 {

   struct signer *s;

   struct verifier *v;

+  int algorithm_name;

-  s = spki_make_signer(options->signature_algorithms, key, NULL);

+  s = spki_make_signer(options->signature_algorithms, key, &algorithm_name);

   if (!s)

     return NULL;

   v = SIGNER_GET_VERIFIER(s);

   assert(v);

+  if (blacklisted_key(v, algorithm_name)) {

+    return NULL;

+  }

   return PUBLIC_SPKI_KEY(v, 1);

 }

@@ -416,7 +420,8 @@

   int private_fd;

   int public_fd;

   struct lsh_string *input;

-  struct lsh_string *output;

+  struct lsh_string *priv_output;

+  struct lsh_string *pub_output;

   const struct exception *e;

   argp_parse(&main_argp, argc, argv, 0, NULL, options);

@@ -439,16 +444,22 @@

       return EXIT_FAILURE;

     }

-  output = process_private(input, options);

-  if (!output)

+  pub_output = process_public(input, options);

+  if (!pub_output)

+    return EXIT_FAILURE;

+

+  priv_output = process_private(input, options);

+  if (!priv_output)

     return EXIT_FAILURE;

+  lsh_string_free(input);

+

   private_fd = open_file(options->private_file);

   if (private_fd < 0)

     return EXIT_FAILURE;

-  e = write_raw(private_fd, STRING_LD(output));

-  lsh_string_free(output);

+  e = write_raw(private_fd, STRING_LD(priv_output));

+  lsh_string_free(priv_output);

   if (e)

     {

@@ -457,18 +468,12 @@

       return EXIT_FAILURE;

     }

-  output = process_public(input, options);

-  lsh_string_free(input);

-  

-  if (!output)

-    return EXIT_FAILURE;

-

   public_fd = open_file(options->public_file);

   if (public_fd < 0)

     return EXIT_FAILURE;

-  e = write_raw(public_fd, STRING_LD(output));

-  lsh_string_free(output);

+  e = write_raw(public_fd, STRING_LD(pub_output));

+  lsh_string_free(pub_output);

   if (e)

     {

diff -urNad trunk~/src/publickey_crypto.h trunk/src/publickey_crypto.h

--- trunk~/src/publickey_crypto.h       2004-06-15 13:32:51.000000000 +0200

+++ trunk/src/publickey_crypto.h        2009-11-06 01:07:40.000000000 +0100

@@ -203,5 +203,7 @@

 struct verifier *

 make_ssh_dss_verifier(const struct lsh_string *public);

+int

+blacklisted_key(struct verifier *v, int method);

 #endif /* LSH_PUBLICKEY_CRYPTO_H_INCLUDED */

diff -urNad trunk~/src/server_authorization.c trunk/src/server_authorization.c

--- trunk~/src/server_authorization.c   2004-06-08 20:01:15.000000000 +0200

+++ trunk/src/server_authorization.c    2009-11-06 01:07:40.000000000 +0100

@@ -93,7 +93,8 @@

                                    PUBLIC_SPKI_KEY(v, 0),

                                    1));

-  if (USER_FILE_EXISTS(keyholder, filename, 1))

+  if (USER_FILE_EXISTS(keyholder, filename, 1)

+      && blacklisted_key(v, method) < 1)

     return v;

   return NULL;