package/network/services/dropbear/patches/001-fix-MAX_UNAUTH_CLIENTS-regression.patch

   1 From: Matt Johnston <matt@ucc.asn.au>
   2 Date: Wed, 8 Jun 2022 21:26:20 +0800
   3 Subject: Fix MAX_UNAUTH_CLIENTS regression
   4
   5 Since re-exec change in 2022.82 Dropbear count
   6 treat authenticated sessions towards the unauthenticated
   7 session limit. This is fixed by passing the childpipe FD
   8 through to the re-execed process.
   9 ---
  10  runopts.h     |  5 +++--
  11  svr-main.c    | 21 +++++++++++----------
  12  svr-runopts.c | 15 ++++++++++++---
  13  3 files changed, 26 insertions(+), 15 deletions(-)
  14
  15 --- a/runopts.h
  16 +++ b/runopts.h
  17 @@ -79,8 +79,9 @@ typedef struct svr_runopts {
  18         char *addresses[DROPBEAR_MAX_PORTS];
  19
  20         int inetdmode;
  21 -       /* Hidden "-2" flag indicates it's re-executing itself */
  22 -       int reexec_child;
  23 +       /* Hidden "-2 childpipe_fd" flag indicates it's re-executing itself,
  24 +          stores the childpipe preauth file descriptor. Set to -1 otherwise. */
  25 +       int reexec_childpipe;
  26
  27         /* Flags indicating whether to use ipv4 and ipv6 */
  28         /* not used yet
  29 --- a/svr-main.c
  30 +++ b/svr-main.c
  31 @@ -71,7 +71,7 @@ int main(int argc, char ** argv)
  32  #endif
  33
  34  #if DROPBEAR_DO_REEXEC
  35 -       if (svr_opts.reexec_child) {
  36 +       if (svr_opts.reexec_childpipe >= 0) {
  37  #ifdef PR_SET_NAME
  38                 /* Fix the "Name:" in /proc/pid/status, otherwise it's
  39                 a FD number from fexecve.
  40 @@ -102,7 +102,7 @@ static void main_inetd() {
  41
  42         seedrandom();
  43
  44 -       if (!svr_opts.reexec_child) {
  45 +       if (svr_opts.reexec_childpipe < 0) {
  46                 /* In case our inetd was lax in logging source addresses */
  47                 get_socket_address(0, NULL, NULL, &host, &port, 0);
  48                         dropbear_log(LOG_INFO, "Child connection from %s:%s", host, port);
  49 @@ -115,10 +115,8 @@ static void main_inetd() {
  50                 setsid();
  51         }
  52
  53 -       /* Start service program
  54 -        * -1 is a dummy childpipe, just something we can close() without
  55 -        * mattering. */
  56 -       svr_session(0, -1);
  57 +       /* -1 for childpipe in the inetd case is discarded */
  58 +       svr_session(0, svr_opts.reexec_childpipe);
  59
  60         /* notreached */
  61  }
  62 @@ -347,9 +345,10 @@ static void main_noinetd(int argc, char
  63
  64                                 if (execfd >= 0) {
  65  #if DROPBEAR_DO_REEXEC
  66 -                                       /* Add "-2" to the args and re-execute ourself. */
  67 -                                       char **new_argv = m_malloc(sizeof(char*) * (argc+3));
  68 -                                       int pos0 = 0, new_argc = argc+1;
  69 +                                       /* Add "-2 childpipe[1]" to the args and re-execute ourself. */
  70 +                                       char **new_argv = m_malloc(sizeof(char*) * (argc+4));
  71 +                                       char buf[10];
  72 +                                       int pos0 = 0, new_argc = argc+2;
  73
  74                                         /* We need to specially handle "dropbearmulti dropbear". */
  75                                         if (multipath) {
  76 @@ -359,7 +358,9 @@ static void main_noinetd(int argc, char
  77                                         }
  78
  79                                         memcpy(&new_argv[pos0], argv, sizeof(char*) * argc);
  80 -                                       new_argv[new_argc-1] = "-2";
  81 +                                       new_argv[new_argc-2] = "-2";
  82 +                                       snprintf(buf, sizeof(buf), "%d", childpipe[1]);
  83 +                                       new_argv[new_argc-1] = buf;
  84                                         new_argv[new_argc] = NULL;
  85
  86                                         if ((dup2(childsock, STDIN_FILENO) < 0)) {
  87 --- a/svr-runopts.c
  88 +++ b/svr-runopts.c
  89 @@ -138,6 +138,7 @@ void svr_getopts(int argc, char ** argv)
  90         char* keepalive_arg = NULL;
  91         char* idle_timeout_arg = NULL;
  92         char* maxauthtries_arg = NULL;
  93 +       char* reexec_fd_arg = NULL;
  94         char* keyfile = NULL;
  95         char c;
  96  #if DROPBEAR_PLUGIN
  97 @@ -175,6 +176,7 @@ void svr_getopts(int argc, char ** argv)
  98          svr_opts.pubkey_plugin_options = NULL;
  99  #endif
 100         svr_opts.pass_on_env = 0;
 101 +       svr_opts.reexec_childpipe = -1;
 102
 103  #ifndef DISABLE_ZLIB
 104         opts.compress_mode = DROPBEAR_COMPRESS_DELAYED;
 105 @@ -250,12 +252,12 @@ void svr_getopts(int argc, char ** argv)
 106  #if DROPBEAR_DO_REEXEC && NON_INETD_MODE
 107                                 /* For internal use by re-exec */
 108                                 case '2':
 109 -                                       svr_opts.reexec_child = 1;
 110 +                                       next = &reexec_fd_arg;
 111                                         break;
 112  #endif
 113                                 case 'p':
 114 -                                 nextisport = 1;
 115 -                                 break;
 116 +                                       nextisport = 1;
 117 +                                       break;
 118                                 case 'P':
 119                                         next = &svr_opts.pidfile;
 120                                         break;
 121 @@ -426,6 +428,13 @@ void svr_getopts(int argc, char ** argv)
 122                 dropbear_log(LOG_INFO, "Forced command set to '%s'", svr_opts.forced_command);
 123         }
 124
 125 +       if (reexec_fd_arg) {
 126 +               if (m_str_to_uint(reexec_fd_arg, &svr_opts.reexec_childpipe) == DROPBEAR_FAILURE
 127 +                       || svr_opts.reexec_childpipe < 0) {
 128 +                       dropbear_exit("Bad -2");
 129 +               }
 130 +       }
 131 +
 132  #if INETD_MODE
 133         if (svr_opts.inetdmode && (
 134                 opts.usingsyslog == 0