Always enable pointer guard [BZ #18928]
Honoring the LD_POINTER_GUARD environment variable in AT_SECURE mode
has security implications. This commit enables pointer guard
unconditionally, and the environment variable is now ignored.
2015-10-13 Florian Weimer <fweimer@redhat.com>
[BZ #18928]
* sysdeps/generic/ldsodefs.h (struct rtld_global_ro): Remove
_dl_pointer_guard member.
* elf/rtld.c (_rtld_global_ro): Remove _dl_pointer_guard
initializer.
(security_init): Always set up pointer guard.
(process_envvars): Do not process LD_POINTER_GUARD.
@@ -16,10 +16,13 @@ Version 2.23
18265, 18370, 18421, 18480, 18525, 18595, 18589, 18610, 18618, 18647,
18661, 18674, 18675, 18681, 18724, 18757, 18778, 18781, 18787, 18789,
18790, 18795, 18796, 18803, 18820, 18823, 18824, 18825, 18857, 18863,
- 18870, 18872, 18873, 18875, 18887, 18921, 18951, 18952, 18956, 18961,
- 18966, 18967, 18969, 18970, 18977, 18980, 18981, 18985, 19003, 19012,
- 19016, 19018, 19032, 19046, 19049, 19050, 19059, 19071, 19076, 19077,
- 19078, 19079, 19085, 19086, 19088, 19094, 19095.
+ 18870, 18872, 18873, 18875, 18887, 18921, 18928, 18951, 18952, 18956,
+ 18961, 18966, 18967, 18969, 18970, 18977, 18980, 18981, 18985, 19003,
+ 19012, 19016, 19018, 19032, 19046, 19049, 19050, 19059, 19071, 19076,
+ 19077, 19078, 19079, 19085, 19086, 19088, 19094, 19095.
+
+* The LD_POINTER_GUARD environment variable can no longer be used to disable
+ the pointer guard feature. It is always enabled.
* The obsolete header <regexp.h> has been removed. Programs that require
this header must be updated to use <regex.h> instead.
@@ -162,7 +162,6 @@ struct rtld_global_ro _rtld_global_ro attribute_relro =
._dl_hwcap_mask = HWCAP_IMPORTANT,
._dl_lazy = 1,
._dl_fpu_control = _FPU_DEFAULT,
- ._dl_pointer_guard = 1,
._dl_pagesize = EXEC_PAGESIZE,
._dl_inhibit_cache = 0,
@@ -709,15 +708,12 @@ security_init (void)
#endif
/* Set up the pointer guard as well, if necessary. */
- if (GLRO(dl_pointer_guard))
- {
- uintptr_t pointer_chk_guard = _dl_setup_pointer_guard (_dl_random,
- stack_chk_guard);
+ uintptr_t pointer_chk_guard
+ = _dl_setup_pointer_guard (_dl_random, stack_chk_guard);
#ifdef THREAD_SET_POINTER_GUARD
- THREAD_SET_POINTER_GUARD (pointer_chk_guard);
+ THREAD_SET_POINTER_GUARD (pointer_chk_guard);
#endif
- __pointer_chk_guard_local = pointer_chk_guard;
- }
+ __pointer_chk_guard_local = pointer_chk_guard;
/* We do not need the _dl_random value anymore. The less
information we leave behind, the better, so clear the
@@ -2471,9 +2467,6 @@ process_envvars (enum mode *modep)
GLRO(dl_use_load_bias) = envline[14] == '1' ? -1 : 0;
break;
}
-
- if (memcmp (envline, "POINTER_GUARD", 13) == 0)
- GLRO(dl_pointer_guard) = envline[14] != '0';
break;
case 14:
@@ -592,9 +592,6 @@ struct rtld_global_ro
/* List of auditing interfaces. */
struct audit_ifaces *_dl_audit;
unsigned int _dl_naudit;
-
- /* 0 if internal pointer values should not be guarded, 1 if they should. */
- EXTERN int _dl_pointer_guard;
};
# define __rtld_global_attribute__
# if IS_IN (rtld)