glibc/elf/ifuncmod5.c
Nick Alcock de6591238b Do not stack-protect ifunc resolvers [BZ ]
When dynamically linking, ifunc resolvers are called before TLS is
initialized, so they cannot be safely stack-protected.

We avoid disabling stack-protection on large numbers of files by
using __attribute__ ((__optimize__ ("-fno-stack-protector")))
to turn it off just for the resolvers themselves.  (We provide
the attribute even when statically linking, because we will later
use it elsewhere too.)
2016-12-26 10:08:41 +01:00

65 lines
1.1 KiB
C

/* Test STT_GNU_IFUNC symbols without direct function call. */
#include "ifunc-sel.h"
int global = -1;
/* Can't use __attribute__((visibility("protected"))) until the GCC bug:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65248
is fixed. */
asm (".protected global");
static int
one (void)
{
return 1;
}
static int
minus_one (void)
{
return -1;
}
static int
zero (void)
{
return 0;
}
void * foo_ifunc (void) __asm__ ("foo");
__asm__(".type foo, %gnu_indirect_function");
void *
inhibit_stack_protector
foo_ifunc (void)
{
return ifunc_sel (one, minus_one, zero);
}
void * foo_hidden_ifunc (void) __asm__ ("foo_hidden");
__asm__(".type foo_hidden, %gnu_indirect_function");
void *
inhibit_stack_protector
foo_hidden_ifunc (void)
{
return ifunc_sel (minus_one, one, zero);
}
void * foo_protected_ifunc (void) __asm__ ("foo_protected");
__asm__(".type foo_protected, %gnu_indirect_function");
void *
inhibit_stack_protector
foo_protected_ifunc (void)
{
return ifunc_sel (one, zero, minus_one);
}
/* Test hidden indirect function. */
__asm__(".hidden foo_hidden");
/* Test protected indirect function. */
__asm__(".protected foo_protected");