From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 7868) id 4424B3858429; Fri, 29 Jul 2022 13:00:09 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 4424B3858429 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable From: Takashi Yano To: cygwin-cvs@sourceware.org Subject: [newlib-cygwin/cygwin-3_3-branch] Cygwin: console: Avoid accessing NULL pointer via cygheap->ctty. X-Act-Checkin: newlib-cygwin X-Git-Author: Takashi Yano X-Git-Refname: refs/heads/cygwin-3_3-branch X-Git-Oldrev: 28d69dc863a60dc8b997d7f8e025d46d4b57e097 X-Git-Newrev: 69ec3976d609cfebe9acbca34015ece6b6bd4995 Message-Id: <20220729130009.4424B3858429@sourceware.org> Date: Fri, 29 Jul 2022 13:00:09 +0000 (GMT) X-BeenThere: cygwin-cvs@cygwin.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Cygwin core component git logs List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 29 Jul 2022 13:00:09 -0000 https://sourceware.org/git/gitweb.cgi?p=3Dnewlib-cygwin.git;h=3D69ec3976d60= 9cfebe9acbca34015ece6b6bd4995 commit 69ec3976d609cfebe9acbca34015ece6b6bd4995 Author: Takashi Yano Date: Fri Jul 29 21:40:18 2022 +0900 Cygwin: console: Avoid accessing NULL pointer via cygheap->ctty. =20 - 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 = =3D NULL); =20 friend tty_min * tty_list::get_cttyp (); }; diff --git a/winsup/cygwin/fhandler_console.cc b/winsup/cygwin/fhandler_con= sole.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 ()=3D=3D myself->pgid) ? tty::native : tty::rest= ore; 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); } =20 void @@ -984,7 +984,7 @@ fhandler_console::bg_check (int sig, bool dontsignal) if (sig =3D=3D SIGTTIN) { set_input_mode (tty::cygwin, &tc ()->ti, get_handle_set ()); - set_disable_master_thread (false); + set_disable_master_thread (false, this); } if (sig =3D=3D SIGTTOU) set_output_mode (tty::cygwin, &tc ()->ti, get_handle_set ()); @@ -1723,7 +1723,7 @@ fhandler_console::post_open_setup (int fd) if (fd =3D=3D 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 =3D=3D 1 || fd =3D=3D 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); } } =20 @@ -3977,7 +3977,7 @@ fhandler_console::set_console_mode_to_native () termios *cons_ti =3D &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 () } =20 void -fhandler_console::set_disable_master_thread (bool x) +fhandler_console::set_disable_master_thread (bool x, fhandler_console *con= s) { - if (cygheap->ctty->get_major () !=3D DEV_CONS_MAJOR) + if (con.disable_master_thread =3D=3D x) return; - fhandler_console *cons =3D (fhandler_console *) cygheap->ctty; + if (cons =3D=3D NULL) + { + if (cygheap->ctty && cygheap->ctty->get_major () =3D=3D DEV_CONS_MAJ= OR) + cons =3D (fhandler_console *) cygheap->ctty; + else + return; + } cons->acquire_input_mutex (mutex_timeout); con.disable_master_thread =3D x; cons->release_input_mutex ();