[PATCH] Protection against stack-based memory corruption errors using SafeStack: compiler-rt runtime support library
csdavec at swan.ac.uk
Tue Nov 4 01:54:15 PST 2014
Comment at: lib/safestack/safestack.cc:42
@@ +41,3 @@
+// all symbols from pthread that we use dynamically
+#define __DECLARE_WRAPPER(fn) __typeof__(fn)* __d_ ## fn = NULL;
> Why not simply force -lpthread in the driver?
The overhead of adding -pthread (-lpthread is non-portable) to single-threaded programs is measurably greater than the overhead of safe stack. We (current hat: FreeBSD) are willing to ship packages with SSP by default and would be very willing to ship packages with safe-stack, but if it forced -pthread then the overhead would be more than we'd be willing to accept.
Comment at: lib/safestack/safestack.cc:51
@@ +50,3 @@
+// The unsafe stack pointer is stored in the TCB structure on these platforms
> I might be missing something, but can't we just use TLS to store the second stack?
C11 TLS does not have a way of attaching destructors. C++11 does (although the standard is undefined in the presence of shared library loading and unloading, which makes it less useful), but does not have any way of ordering the destruction.
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