From a9e8373030b39aadfc33af67443085df83e9e344 Mon Sep 17 00:00:00 2001 From: Daniel Berrange Date: Wed, 14 Aug 2013 16:00:56 +0200 Subject: [libusb-compat PATCH] Link with -znodelete to disallow unloading Since libusb-0.1 did not have any init / exit function, code using the libusb-0.1 API will not call libusb_exit. Now, libgphoto uses libusb and will dlopen() and dlclose() it. Unfortunately since there is no way to ensure libusb_close() is called, when libgphoto dlcloses the libusb.so library, the thread from libusbx.so will not be stopped. So a thread will remain running, executing code from a memory region that has now been freed. Crash-tastic results ensue. I don't see a good way to fix this from libusb or libusbx, given the need to preserve the existing API of libusb. If, however, we link libusb.so using -znodelete, we will prevent it from ever being unloaded, despite the dlclose() calls. This is not ideal, but better than allowing it to be unloaded which is a guaranteed crash. Signed-off-by: Hans de Goede --- libusb/Makefile.am | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libusb/Makefile.am b/libusb/Makefile.am index 33a609a..a20fdb5 100644 --- a/libusb/Makefile.am +++ b/libusb/Makefile.am @@ -5,5 +5,5 @@ libusb_la_SOURCES = core.c usbi.h libusb_la_CFLAGS = -fvisibility=hidden $(AM_CFLAGS) $(LIBUSB_1_0_CFLAGS) libusb_la_LIBADD = $(LIBUSB_1_0_LIBS) libusb_la_LDFLAGS = -version-info $(LT_MAJOR):$(LT_REVISION):$(LT_AGE) \ - -release 0.1 + -release 0.1 -Wl,-z -Wl,nodelete --- libusb-compat-0.1.5.orig/libusb/Makefile.in 2013-05-21 00:40:35.000000000 +0100 +++ libusb-compat-0.1.5.orig/libusb/Makefile.in 2013-08-13 22:20:32.831532426 +0100 @@ -297,7 +297,7 @@ libusb_la_SOURCES = core.c usbi.h libusb_la_CFLAGS = -fvisibility=hidden $(AM_CFLAGS) $(LIBUSB_1_0_CFLAGS) libusb_la_LIBADD = $(LIBUSB_1_0_LIBS) libusb_la_LDFLAGS = -version-info $(LT_MAJOR):$(LT_REVISION):$(LT_AGE) \ - -release 0.1 + -release 0.1 -Wl,-z -Wl,nodelete all: all-am -- 1.8.3.1