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* [newlib-cygwin] Cygwin: posix timers: allocate timer_tracker on system heap.
@ 2019-01-22 15:38 Corinna Vinschen
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From: Corinna Vinschen @ 2019-01-22 15:38 UTC (permalink / raw)
To: cygwin-cvs
https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=83c51fffe6bad36a7143c30946ac5445f9ca4c56
commit 83c51fffe6bad36a7143c30946ac5445f9ca4c56
Author: Corinna Vinschen <corinna@vinschen.de>
Date: Tue Jan 22 16:22:45 2019 +0100
Cygwin: posix timers: allocate timer_tracker on system heap.
Allocating on the cygheap would copy information of the tracker into
the child process. A forked child knows the timer id and could simply
still access the (free'd but still valid) timer_tracker on the heap,
which is dangerous and very certainly doesn't reflect POSIX semantics.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Diff:
---
winsup/cygwin/cygheap_malloc.h | 3 +--
winsup/cygwin/posix_timer.cc | 5 +++--
winsup/cygwin/posix_timer.h | 2 +-
3 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/winsup/cygwin/cygheap_malloc.h b/winsup/cygwin/cygheap_malloc.h
index cd545c3..74f0bb6 100644
--- a/winsup/cygwin/cygheap_malloc.h
+++ b/winsup/cygwin/cygheap_malloc.h
@@ -34,8 +34,7 @@ enum cygheap_types
HEAP_2_DLL,
HEAP_MMAP,
HEAP_2_MAX = 200,
- HEAP_3_FHANDLER,
- HEAP_3_TIMER
+ HEAP_3_FHANDLER
};
extern "C" {
diff --git a/winsup/cygwin/posix_timer.cc b/winsup/cygwin/posix_timer.cc
index 8651c22..e969dcc 100644
--- a/winsup/cygwin/posix_timer.cc
+++ b/winsup/cygwin/posix_timer.cc
@@ -414,10 +414,11 @@ timer_tracker::settime (int flags, const itimerspec *new_value,
return ret;
}
-/* The timers are stored on the cygheap. */
+/* The timers are stored on the system heap in order to avoid accidental
+ leaking of timer ids into the child process. */
#define cnew(name, ...) \
({ \
- void* ptr = (void*) ccalloc (HEAP_3_TIMER, 1, sizeof (name)); \
+ void* ptr = (void*) HeapAlloc (GetProcessHeap (), 0, sizeof (name)); \
ptr ? new (ptr) name (__VA_ARGS__) : NULL; \
})
diff --git a/winsup/cygwin/posix_timer.h b/winsup/cygwin/posix_timer.h
index 04a383f..f69a179 100644
--- a/winsup/cygwin/posix_timer.h
+++ b/winsup/cygwin/posix_timer.h
@@ -30,7 +30,7 @@ class timer_tracker
public:
void *operator new (size_t, void *p) __attribute__ ((nothrow)) {return p;}
- void operator delete (void *p) { cfree (p); }
+ void operator delete (void *p) { HeapFree (GetProcessHeap (), 0, p); }
timer_tracker (clockid_t, const sigevent *);
~timer_tracker ();
inline bool is_timer_tracker () const { return magic == TT_MAGIC; }
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