dropbear: cherry-pick upstream commit 544f28a0

Resolves #10081

Reported-By: Chen Minqiang <ptpt52@gmail.com>
Signed-off-by: Konstantin Demin <rockdrilla@gmail.com>

diff --git a/package/network/services/dropbear/patches/001-fix-MAX_UNAUTH_CLIENTS-regression.patch b/package/network/services/dropbear/patches/001-fix-MAX_UNAUTH_CLIENTS-regression.patch
new file mode 100644 (file)
index 0000000..e0dca54
--- /dev/null
+++ b/package/network/services/dropbear/patches/001-fix-MAX_UNAUTH_CLIENTS-regression.patch
@@ -0,0 +1,134 @@
+From: Matt Johnston <matt@ucc.asn.au>
+Date: Wed, 8 Jun 2022 21:26:20 +0800
+Subject: Fix MAX_UNAUTH_CLIENTS regression
+
+Since re-exec change in 2022.82 Dropbear count
+treat authenticated sessions towards the unauthenticated
+session limit. This is fixed by passing the childpipe FD
+through to the re-execed process.
+---
+ runopts.h     |  5 +++--
+ svr-main.c    | 21 +++++++++++----------
+ svr-runopts.c | 15 ++++++++++++---
+ 3 files changed, 26 insertions(+), 15 deletions(-)
+
+--- a/runopts.h
++++ b/runopts.h
+@@ -79,8 +79,9 @@ typedef struct svr_runopts {
+       char *addresses[DROPBEAR_MAX_PORTS];
+ 
+       int inetdmode;
+-      /* Hidden "-2" flag indicates it's re-executing itself */
+-      int reexec_child;
++      /* Hidden "-2 childpipe_fd" flag indicates it's re-executing itself,
++         stores the childpipe preauth file descriptor. Set to -1 otherwise. */
++      int reexec_childpipe;
+ 
+       /* Flags indicating whether to use ipv4 and ipv6 */
+       /* not used yet
+--- a/svr-main.c
++++ b/svr-main.c
+@@ -71,7 +71,7 @@ int main(int argc, char ** argv)
+ #endif
+ 
+ #if DROPBEAR_DO_REEXEC
+-      if (svr_opts.reexec_child) {
++      if (svr_opts.reexec_childpipe >= 0) {
+ #ifdef PR_SET_NAME
+               /* Fix the "Name:" in /proc/pid/status, otherwise it's
+               a FD number from fexecve.
+@@ -102,7 +102,7 @@ static void main_inetd() {
+ 
+       seedrandom();
+ 
+-      if (!svr_opts.reexec_child) {
++      if (svr_opts.reexec_childpipe < 0) {
+               /* In case our inetd was lax in logging source addresses */
+               get_socket_address(0, NULL, NULL, &host, &port, 0);
+                       dropbear_log(LOG_INFO, "Child connection from %s:%s", host, port);
+@@ -115,10 +115,8 @@ static void main_inetd() {
+               setsid();
+       }
+ 
+-      /* Start service program 
+-       * -1 is a dummy childpipe, just something we can close() without 
+-       * mattering. */
+-      svr_session(0, -1);
++      /* -1 for childpipe in the inetd case is discarded */
++      svr_session(0, svr_opts.reexec_childpipe);
+ 
+       /* notreached */
+ }
+@@ -347,9 +345,10 @@ static void main_noinetd(int argc, char
+ 
+                               if (execfd >= 0) {
+ #if DROPBEAR_DO_REEXEC
+-                                      /* Add "-2" to the args and re-execute ourself. */
+-                                      char **new_argv = m_malloc(sizeof(char*) * (argc+3));
+-                                      int pos0 = 0, new_argc = argc+1;
++                                      /* Add "-2 childpipe[1]" to the args and re-execute ourself. */
++                                      char **new_argv = m_malloc(sizeof(char*) * (argc+4));
++                                      char buf[10];
++                                      int pos0 = 0, new_argc = argc+2;
+ 
+                                       /* We need to specially handle "dropbearmulti dropbear". */
+                                       if (multipath) {
+@@ -359,7 +358,9 @@ static void main_noinetd(int argc, char
+                                       }
+ 
+                                       memcpy(&new_argv[pos0], argv, sizeof(char*) * argc);
+-                                      new_argv[new_argc-1] = "-2";
++                                      new_argv[new_argc-2] = "-2";
++                                      snprintf(buf, sizeof(buf), "%d", childpipe[1]);
++                                      new_argv[new_argc-1] = buf;
+                                       new_argv[new_argc] = NULL;
+ 
+                                       if ((dup2(childsock, STDIN_FILENO) < 0)) {
+--- a/svr-runopts.c
++++ b/svr-runopts.c
+@@ -138,6 +138,7 @@ void svr_getopts(int argc, char ** argv)
+       char* keepalive_arg = NULL;
+       char* idle_timeout_arg = NULL;
+       char* maxauthtries_arg = NULL;
++      char* reexec_fd_arg = NULL;
+       char* keyfile = NULL;
+       char c;
+ #if DROPBEAR_PLUGIN
+@@ -175,6 +176,7 @@ void svr_getopts(int argc, char ** argv)
+         svr_opts.pubkey_plugin_options = NULL;
+ #endif
+       svr_opts.pass_on_env = 0;
++      svr_opts.reexec_childpipe = -1;
+ 
+ #ifndef DISABLE_ZLIB
+       opts.compress_mode = DROPBEAR_COMPRESS_DELAYED;
+@@ -250,12 +252,12 @@ void svr_getopts(int argc, char ** argv)
+ #if DROPBEAR_DO_REEXEC && NON_INETD_MODE
+                               /* For internal use by re-exec */
+                               case '2':
+-                                      svr_opts.reexec_child = 1;
++                                      next = &reexec_fd_arg;
+                                       break;
+ #endif
+                               case 'p':
+-                                nextisport = 1;
+-                                break;
++                                      nextisport = 1;
++                                      break;
+                               case 'P':
+                                       next = &svr_opts.pidfile;
+                                       break;
+@@ -426,6 +428,13 @@ void svr_getopts(int argc, char ** argv)
+               dropbear_log(LOG_INFO, "Forced command set to '%s'", svr_opts.forced_command);
+       }
+ 
++      if (reexec_fd_arg) {
++              if (m_str_to_uint(reexec_fd_arg, &svr_opts.reexec_childpipe) == DROPBEAR_FAILURE
++                      || svr_opts.reexec_childpipe < 0) {
++                      dropbear_exit("Bad -2");
++              }
++      }
++
+ #if INETD_MODE
+       if (svr_opts.inetdmode && (
+               opts.usingsyslog == 0