https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=69ec3976d609cfebe9acbca34015ece6b6bd4995
commit 69ec3976d609cfebe9acbca34015ece6b6bd4995 Author: Takashi Yano <[email protected]> Date: Fri Jul 29 21:40:18 2022 +0900 Cygwin: console: Avoid accessing NULL pointer via cygheap->ctty. - Recent commit "Cygwin: console: Add missing input_mutex guard." has a problem that causes NULL pointer access if cygheap->ctty is NULL. This patch fixes the issue. Diff: --- winsup/cygwin/fhandler.h | 2 +- winsup/cygwin/fhandler_console.cc | 22 ++++++++++++++-------- 2 files changed, 15 insertions(+), 9 deletions(-) diff --git a/winsup/cygwin/fhandler.h b/winsup/cygwin/fhandler.h index e47b38e9a..da0e3183e 100644 --- a/winsup/cygwin/fhandler.h +++ b/winsup/cygwin/fhandler.h @@ -2294,7 +2294,7 @@ private: static void cleanup_for_non_cygwin_app (handle_set_t *p); static void set_console_mode_to_native (); bool need_console_handler (); - static void set_disable_master_thread (bool x); + static void set_disable_master_thread (bool x, fhandler_console *cons = NULL); friend tty_min * tty_list::get_cttyp (); }; diff --git a/winsup/cygwin/fhandler_console.cc b/winsup/cygwin/fhandler_console.cc index c7dc8c609..41b3fd6b8 100644 --- a/winsup/cygwin/fhandler_console.cc +++ b/winsup/cygwin/fhandler_console.cc @@ -790,7 +790,7 @@ fhandler_console::setup_for_non_cygwin_app () (get_ttyp ()->getpgid ()== myself->pgid) ? tty::native : tty::restore; set_input_mode (conmode, &tc ()->ti, get_handle_set ()); set_output_mode (conmode, &tc ()->ti, get_handle_set ()); - set_disable_master_thread (true); + set_disable_master_thread (true, this); } void @@ -984,7 +984,7 @@ fhandler_console::bg_check (int sig, bool dontsignal) if (sig == SIGTTIN) { set_input_mode (tty::cygwin, &tc ()->ti, get_handle_set ()); - set_disable_master_thread (false); + set_disable_master_thread (false, this); } if (sig == SIGTTOU) set_output_mode (tty::cygwin, &tc ()->ti, get_handle_set ()); @@ -1723,7 +1723,7 @@ fhandler_console::post_open_setup (int fd) if (fd == 0) { set_input_mode (tty::cygwin, &get_ttyp ()->ti, &handle_set); - set_disable_master_thread (false); + set_disable_master_thread (false, this); } else if (fd == 1 || fd == 2) set_output_mode (tty::cygwin, &get_ttyp ()->ti, &handle_set); @@ -1751,7 +1751,7 @@ fhandler_console::close () /* Cleaning-up console mode for cygwin apps. */ set_output_mode (tty::restore, &get_ttyp ()->ti, &handle_set); set_input_mode (tty::restore, &get_ttyp ()->ti, &handle_set); - set_disable_master_thread (true); + set_disable_master_thread (true, this); } } @@ -3977,7 +3977,7 @@ fhandler_console::set_console_mode_to_native () termios *cons_ti = &cons->tc ()->ti; set_input_mode (tty::native, cons_ti, cons->get_handle_set ()); set_output_mode (tty::native, cons_ti, cons->get_handle_set ()); - set_disable_master_thread (true); + set_disable_master_thread (true, cons); break; } } @@ -4357,11 +4357,17 @@ fhandler_console::need_console_handler () } void -fhandler_console::set_disable_master_thread (bool x) +fhandler_console::set_disable_master_thread (bool x, fhandler_console *cons) { - if (cygheap->ctty->get_major () != DEV_CONS_MAJOR) + if (con.disable_master_thread == x) return; - fhandler_console *cons = (fhandler_console *) cygheap->ctty; + if (cons == NULL) + { + if (cygheap->ctty && cygheap->ctty->get_major () == DEV_CONS_MAJOR) + cons = (fhandler_console *) cygheap->ctty; + else + return; + } cons->acquire_input_mutex (mutex_timeout); con.disable_master_thread = x; cons->release_input_mutex ();
