[PATCH v2] Cygwin: console: Fix segfault on shared_console_info access.
Takashi Yano
takashi.yano@nifty.ne.jp
Mon Feb 24 16:12:00 GMT 2020
- Accessing shared_console_info before initialization causes access
violation because it is a NULL pointer. The cause of the problem
reported in https://cygwin.com/ml/cygwin/2020-02/msg00197.html is
this NULL pointer access in request_xterm_mode_output() when it is
called from close(). This patch makes sure that shared_console_info
is not NULL before calling request_xterm_mode_output().
---
winsup/cygwin/fhandler_console.cc | 23 +++++++++++------------
1 file changed, 11 insertions(+), 12 deletions(-)
diff --git a/winsup/cygwin/fhandler_console.cc b/winsup/cygwin/fhandler_console.cc
index 42040a971..328424a7d 100644
--- a/winsup/cygwin/fhandler_console.cc
+++ b/winsup/cygwin/fhandler_console.cc
@@ -1159,18 +1159,17 @@ fhandler_console::close ()
acquire_output_mutex (INFINITE);
- if (shared_console_info && myself->pid == con.owner &&
- wincap.has_con_24bit_colors () && !con_is_legacy)
- request_xterm_mode_output (false);
-
- /* Restore console mode if this is the last closure. */
- OBJECT_BASIC_INFORMATION obi;
- NTSTATUS status;
- status = NtQueryObject (get_handle (), ObjectBasicInformation,
- &obi, sizeof obi, NULL);
- if (NT_SUCCESS (status) && obi.HandleCount == 1)
- if (wincap.has_con_24bit_colors ())
- request_xterm_mode_output (false);
+ if (shared_console_info && wincap.has_con_24bit_colors ())
+ {
+ /* Restore console mode if this is the last closure. */
+ OBJECT_BASIC_INFORMATION obi;
+ NTSTATUS status;
+ status = NtQueryObject (get_handle (), ObjectBasicInformation,
+ &obi, sizeof obi, NULL);
+ if ((NT_SUCCESS (status) && obi.HandleCount == 1)
+ || myself->pid == con.owner)
+ request_xterm_mode_output (false);
+ }
release_output_mutex ();
--
2.21.0
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