Program to remove an IP Address from SSHGuard's blacklist

.gitignore

build/

CMakeLists.txt

cmake_minimum_required (VERSION 2.8)
project (sshguard-reprieve)

set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=c99")

include(ExternalProject)
ExternalProject_Add (sshguard
  URL http://downloads.sourceforge.net/project/sshguard/sshguard/sshguard-1.5/sshguard-1.5.tar.bz2
  URL_MD5 11b9f47f9051e25bdfe84a365c961ec1
  CONFIGURE_COMMAND <SOURCE_DIR>/configure --prefix=<INSTALL_DIR> --with-firewall=null
  PATCH_COMMAND patch -p1 < ${CMAKE_SOURCE_DIR}/expose.patch
  BUILD_IN_SOURCE 1
)

ExternalProject_Get_Property(sshguard source_dir)
include_directories(${source_dir}/src)

FILE(WRITE ${source_dir}/src/sshguard_blacklist.o "")
SET_SOURCE_FILES_PROPERTIES(${source_dir}/src/sshguard_blacklist.o PROPERTIES EXTERNAL_OBJECT TRUE)
FILE(WRITE ${source_dir}/src/seekers.o "")
SET_SOURCE_FILES_PROPERTIES(${source_dir}/src/seekers.o PROPERTIES EXTERNAL_OBJECT TRUE)
FILE(WRITE ${source_dir}/src/simclist.o "")
SET_SOURCE_FILES_PROPERTIES(${source_dir}/src/simclist.o PROPERTIES EXTERNAL_OBJECT TRUE)

add_executable(sshguard-reprieve sshguard-reprieve.c ${source_dir}/src/sshguard_blacklist.o
  ${source_dir}/src/simclist.o ${source_dir}/src/seekers.o
)

install(TARGETS sshguard-reprieve DESTINATION bin)

expose.patch

--- a/src/sshguard_blacklist.h	2012-04-27 15:40:11.000000000 -0500
+++ b/src/sshguard_blacklist.h	2012-04-27 15:55:37.000000000 -0500
@@ -25,6 +25,8 @@
 
 #include "sshguard_attack.h"
 
+void *attacker_serializer(const void *restrict el, uint32_t *restrict len);
+
 /**
  * Load the blacklist contained at a given filename.
  *
--- a/src/sshguard_blacklist.c	2012-04-27 15:35:22.000000000 -0500
+++ b/src/sshguard_blacklist.c	2012-04-27 15:55:48.000000000 -0500
@@ -29,7 +29,7 @@
 #include <assert.h>
 
 #include "sshguard_addresskind.h"
-#include "sshguard_log.h"
+#define sshguard_log(...)
 #include "sshguard_blacklist.h"
 
 #define BL_MAXBUF      50
@@ -59,7 +59,7 @@
 }
 */
 
-static void *attacker_serializer(const void *restrict el, uint32_t *restrict len) {
+void *attacker_serializer(const void *restrict el, uint32_t *restrict len) {
     /* buffer for serialization operations */
     char *serialization_buf;
     attacker_t atkr = *(const attacker_t *restrict)el;

sshguard-reprieve.c

#include <stdio.h>
#include <stdlib.h>
#include <libgen.h> // For basename

#include "sshguard_blacklist.h"
#include "seekers.h"

#include <regex.h>
#include "regexlib.h"

int main(int argc, char **argv) {
  if (argc < 3) {
    printf("Usage: %s <blacklist file> <ip address>\n", basename(argv[0]));
    return 1;
  }

  char *filename = argv[1];
  attacker_t *el;
  list_t *blacklist;
  sshg_address_t me;
  regex_t ipreg4, ipreg6;

  if (regcomp(&ipreg4, "^" REGEXLIB_IPV4 "$", REG_EXTENDED) ||
      regcomp(&ipreg6, "^" REGEXLIB_IPV6 "$", REG_EXTENDED)) {
    printf("Failed detecting ip address type: regex compile failed\n");
    return 2;
  }

  if (!regexec(&ipreg4, argv[2], 0, NULL, 0)) {
    me.kind = ADDRKIND_IPv4;
  } else if (!regexec(&ipreg6, argv[2], 0, NULL, 0)) {
    me.kind = ADDRKIND_IPv6;
  } else {
    printf("%s is not a valid ip address\n", argv[2]);
    regfree(&ipreg4);
    regfree(&ipreg6);
    return 2;
  }

  for(int i = 0; *(me.value + i) = *(argv[2] + i); i++);
  regfree(&ipreg4);
  regfree(&ipreg6);

  if (!(blacklist = blacklist_load(filename))) {
      perror("Failed opening blacklist");
      return 3;
  }

  list_attributes_seeker(blacklist, seeker_addr);
  list_attributes_serializer(blacklist, attacker_serializer);

  if ((el = list_seek(blacklist, &me))) {
    list_delete(blacklist, el);

    printf("Removed %s from blacklist\n", me.value);

    if (list_dump_file(blacklist, filename, NULL) == 0) {
      printf("Saved modified blacklist\n");
    } else {
      perror("Failed saving blacklist");
      list_destroy(blacklist);
      free(blacklist);
      return 5;
    }
  } else {
    printf("%s is not in blacklist\n", me.value);
    list_destroy(blacklist);
    free(blacklist);
    return 4;
  }

  list_destroy(blacklist);
  free(blacklist);

  return 0;
}

Great! Thanks.. worked.

cmake ./; make; sudo ./sshguard-reprieve /var/log/sshguard.db 10.0.0.5

https://github.com/shadowbq/sshguard-contrib