From: Takashi Yano <takashi.yano@nifty.ne.jp>
To: cygwin-patches@cygwin.com
Subject: [PATCH] Cygwin: console: Avoid accessing NULL pointer via cygheap->ctty.
Date: Fri, 29 Jul 2022 21:50:56 +0900 [thread overview]
Message-ID: <20220729125056.452-1-takashi.yano@nifty.ne.jp> (raw)
- 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.
---
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 a12e907ff..e4f1a2d94 100644
--- a/winsup/cygwin/fhandler.h
+++ b/winsup/cygwin/fhandler.h
@@ -2298,7 +2298,7 @@ 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 37262f638..d17f03acf 100644
--- a/winsup/cygwin/fhandler_console.cc
+++ b/winsup/cygwin/fhandler_console.cc
@@ -791,7 +791,7 @@ 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
@@ -986,7 +986,7 @@ 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 ());
@@ -1721,7 +1721,7 @@ 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);
@@ -1749,7 +1749,7 @@ 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);
}
}
@@ -3975,7 +3975,7 @@ 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;
}
}
@@ -4321,11 +4321,17 @@ 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 ();
--
2.37.1
reply other threads:[~2022-07-29 12:51 UTC|newest]
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