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[BZ #1346]

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2005-09-20  Roland McGrath  <roland@redhat.com>
	[BZ #1346]
	* elf/dl-load.c (_dl_map_object_from_fd) [HAVE_Z_RELRO]: Do relro
	magic on __stack_prot only if [SHARED].  Skip mprotect if __stack_prot
	lies outside the page-rounded-down relro region.
This commit is contained in:
Roland McGrath 2005-09-20 07:46:12 +00:00
parent ab209d3a5c
commit e751d28209
1 changed files with 22 additions and 8 deletions
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30
elf/dl-load.c
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@ -1354,22 +1354,36 @@ cannot allocate TLS data structures for initial thread");
if (__builtin_expect ((stack_flags &~ GL(dl_stack_flags)) & PF_X, 0))
{
if (__builtin_expect (__check_caller (RETURN_ADDRESS (0), allow_ldso),
0) != 0)
{
errstring = N_("invalid caller");
goto call_lose;
}
/* The stack is presently not executable, but this module
requires that it be executable. We must change the
protection of the variable which contains the flags used in
the mprotect calls. */
#ifdef HAVE_Z_RELRO
#if defined HAVE_Z_RELRO && defined SHARED
if ((mode & (__RTLD_DLOPEN | __RTLD_AUDIT)) == __RTLD_DLOPEN)
{
uintptr_t p = ((uintptr_t) &__stack_prot) & ~(GLRO(dl_pagesize) - 1);
size_t s = (uintptr_t) &__stack_prot - p + sizeof (int);
const uintptr_t p = (uintptr_t) &__stack_prot & -GLRO(dl_pagesize);
const size_t s = (uintptr_t) (&__stack_prot + 1) - p;
__mprotect ((void *) p, s, PROT_READ|PROT_WRITE);
if (__builtin_expect (__check_caller (RETURN_ADDRESS (0),
allow_ldso) == 0,
0))
struct link_map *const m = &GL(dl_rtld_map);
const uintptr_t relro_end = ((m->l_addr + m->l_relro_addr
+ m->l_relro_size)
& -GLRO(dl_pagesize));
if (__builtin_expect (p + s <= relro_end, 1))
{
/* The variable lies in the region protected by RELRO. */
__mprotect ((void *) p, s, PROT_READ|PROT_WRITE);
__stack_prot |= PROT_READ|PROT_WRITE|PROT_EXEC;
__mprotect ((void *) p, s, PROT_READ);
}
else
__stack_prot |= PROT_READ|PROT_WRITE|PROT_EXEC;
__mprotect ((void *) p, s, PROT_READ);
}
else
#endif