* fixed "nobody " -> "nobody" fuckup when getpwnam-ing

* implemented basic blacklisting:
** the file specified with -b <BLACKLIST> is read and added to a blacklist vector
** if an announce hits a torrent in that blacklist vector, add_peer_to_torrent fails
** sending a SIGHUP to the program forces it to reread the blacklists
** the server returns with a 500, which is not exactly nice but does the job for now
** an adaequat "failure reason:" should be delivered... TODO

4 files changed, 93 insertions, 4 deletions

diff --git a/Makefile b/Makefile
index 178a8c8..4a71eb7 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,5 @@
 CC?=gcc
-FEATURES=#-DWANT_IP_FROM_QUERY_STRING -D_DEBUG_HTTPERROR
+FEATURES=-DWANT_BLACKLISTING #-DWANT_IP_FROM_QUERY_STRING -D_DEBUG_HTTPERROR
 OPTS_debug=-g -ggdb #-pg # -fprofile-arcs -ftest-coverage
 OPTS_production=-s -Os
 CFLAGS+=-I../libowfat -Wall -pipe -Wextra #-pedantic #-ansi
diff --git a/opentracker.c b/opentracker.c
index bb3de02..b13dc11 100644
--- a/opentracker.c
+++ b/opentracker.c
@@ -38,6 +38,9 @@ static time_t ot_start_time;
 static const size_t SUCCESS_HTTP_HEADER_LENGTH = 80;
 static const size_t SUCCESS_HTTP_SIZE_OFF = 17;
 static char g_adminip[4] = {0,0,0,0};
+#ifdef WANT_BLACKLISTING
+static char *blacklist_filename = NULL;
+#endif
 
 /* To always have space for error messages ;) */
 
@@ -495,8 +498,11 @@ static void help( char *name ) {
   HELPLINE("-i ip","specify ip to bind to (default: *, you may specify more than one)");
   HELPLINE("-p port","specify tcp port to bind to (default: 6969, you may specify more than one)");
   HELPLINE("-P port","specify udp port to bind to (default: 6969, you may specify more than one)");
-  HELPLINE("-d dir","specify directory containing white- or black listed torrent info_hashes (default: \".\")");
+  HELPLINE("-d dir","specify directory to try to chroot to (default: \".\")");
   HELPLINE("-A ip","bless an ip address as admin address (e.g. to allow syncs from this address)");
+#ifdef WANT_BLACKLISTING
+  HELPLINE("-b file","specify blacklist file.");
+#endif
 
   fprintf( stderr, "\nExample:   ./opentracker -i 127.0.0.1 -p 6969 -P 6969 -i 10.1.1.23 -p 2710 -p 80\n" );
 }
@@ -745,6 +751,43 @@ static void ot_try_bind( char ip[4], uint16 port, int is_tcp ) {
   ++ot_sockets_count;
 }
 
+#ifdef WANT_BLACKLISTING
+/* Read initial black list */
+void read_blacklist_file( int foo ) {
+  FILE *  blacklist_filehandle = fopen( blacklist_filename, "r" );
+  ot_hash infohash;
+  foo = foo;
+
+  /* Free blacklist vector in trackerlogic.c*/
+  blacklist_reset();
+
+  if( blacklist_filehandle == NULL ) {
+    fprintf( stderr, "Warning: Can't open blacklist file: %s (but will try to create it later, if necessary and possible).", blacklist_filename );
+    return;
+  }
+
+  /* We do ignore anything that is not of the form "^[:xdigit:]{40}[^:xdigit:].*" */
+  while( fgets( static_inbuf, sizeof(static_inbuf), blacklist_filehandle ) ) {
+    int i;
+    for( i=0; i<20; ++i ) {
+      int eger = 16 * scan_fromhex( static_inbuf[ 2*i ] ) + scan_fromhex( static_inbuf[ 1 + 2*i ] );
+      if( eger < 0 )
+        goto ignore_line;
+      infohash[i] = eger;
+    }
+    if( scan_fromhex( static_inbuf[ 40 ] ) >= 0 )
+      goto ignore_line;
+
+    /* Append blacklist to blacklist vector */
+    blacklist_addentry( &infohash );
+
+ignore_line:
+    continue;
+  }
+  fclose( blacklist_filehandle );
+}
+#endif
+
 int main( int argc, char **argv ) {
   struct passwd *pws = NULL;
   char serverip[4] = {0,0,0,0};
@@ -752,10 +795,13 @@ int main( int argc, char **argv ) {
   int scanon = 1;
 
   while( scanon ) {
-    switch( getopt( argc, argv, ":i:p:A:P:d:ocbBh" ) ) {
+    switch( getopt( argc, argv, ":i:p:A:P:d:b:h" ) ) {
       case -1 : scanon = 0; break;
       case 'i': scan_ip4( optarg, serverip ); break;
       case 'A': scan_ip4( optarg, g_adminip ); break;
+#ifdef WANT_BLACKLISTING
+      case 'b': blacklist_filename = optarg; break;
+#endif
       case 'p': ot_try_bind( serverip, (uint16)atol( optarg ), 1 ); break;
       case 'P': ot_try_bind( serverip, (uint16)atol( optarg ), 0 ); break;
       case 'd': serverdir = optarg; break;
@@ -771,7 +817,8 @@ int main( int argc, char **argv ) {
     ot_try_bind( serverip, 6969, 0 );
   }
 
-  pws = getpwnam( "nobody ");
+  /* Drop permissions */
+  pws = getpwnam( "nobody" );
   if( !pws ) {
     setegid( (gid_t)-2 ); setuid( (uid_t)-2 );
     setgid( (gid_t)-2 ); seteuid( (uid_t)-2 );
@@ -781,8 +828,17 @@ int main( int argc, char **argv ) {
   }
   endpwent();
 
+#ifdef WANT_BLACKLISTING
+  /* Passing "0" since read_blacklist_file also is SIGHUP handler */
+  if( blacklist_filename ) {
+    read_blacklist_file( 0 );
+    signal( SIGHUP,  read_blacklist_file );
+  }
+#endif
+
   signal( SIGPIPE, SIG_IGN );
   signal( SIGINT,  graceful );
+
   if( init_logic( serverdir ) == -1 )
     panic( "Logic not started" );
 
diff --git a/trackerlogic.c b/trackerlogic.c
index ebfb1f8..98fcef9 100644
--- a/trackerlogic.c
+++ b/trackerlogic.c
@@ -22,6 +22,10 @@
 /* GLOBAL VARIABLES */
 static ot_vector all_torrents[256];
 static ot_vector changeset;
+#ifdef WANT_BLACKLISTING
+static ot_vector blacklist;
+#endif
+
 size_t changeset_size = 0;
 time_t last_clean_time = 0;
 
@@ -155,6 +159,12 @@ ot_torrent *add_peer_to_torrent( ot_hash *hash, ot_peer *peer, int from_changese
   ot_vector  *torrents_list = &all_torrents[*hash[0]], *peer_pool;
   int         base_pool = 0;
 
+#ifdef WANT_BLACKLISTING
+  binary_search( hash, blacklist.data, blacklist.size, OT_HASH_COMPARE_SIZE, OT_HASH_COMPARE_SIZE, &exactmatch );
+  if( exactmatch )
+    return NULL;
+#endif
+
   torrent = vector_find_or_insert( torrents_list, (void*)hash, sizeof( ot_torrent ), OT_HASH_COMPARE_SIZE, &exactmatch );
   if( !torrent ) return NULL;
 
@@ -672,3 +682,22 @@ void deinit_logic( void ) {
   byte_zero( &changeset, sizeof( changeset ) );
   changeset_size = 0;
 }
+
+#ifdef WANT_BLACKLISTING
+void blacklist_reset( void ) {
+  free( blacklist.data );
+  byte_zero( &blacklist, sizeof( blacklist ) );
+}
+
+int blacklist_addentry( ot_hash *infohash ) {
+  int em;
+  void *insert = vector_find_or_insert( &blacklist, infohash, OT_HASH_COMPARE_SIZE, OT_HASH_COMPARE_SIZE, &em );
+
+  if( !insert )
+    return -1;
+
+  memmove( insert, infohash, OT_HASH_COMPARE_SIZE );
+
+  return 0;
+}
+#endif
diff --git a/trackerlogic.h b/trackerlogic.h
index 4fa48eb..eb4d4f6 100644
--- a/trackerlogic.h
+++ b/trackerlogic.h
@@ -97,5 +97,9 @@ size_t return_memstat_for_tracker( char **reply );
 size_t return_changeset_for_tracker( char **reply );
 void   clean_all_torrents( void );
 void   remove_peer_from_torrent( ot_hash *hash, ot_peer *peer );
+#ifdef WANT_BLACKLISTING
+int    blacklist_addentry( ot_hash *hash );
+void   blacklist_reset( void );
+#endif
 
 #endif