From dc22a1ec157d02529a0b17986679d3f1c122985e Mon Sep 17 00:00:00 2001
From: Florian Weimer <fweimer@redhat.com>
Date: Thu, 15 Oct 2015 09:23:07 +0200
Subject: [PATCH 19/65] 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.
[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.
(cherry picked from commit a014cecd82b71b70a6a843e250e06b541ad524f7)
---
ChangeLog | 10 ++++++++++
NEWS | 5 ++++-
elf/rtld.c | 15 ++++-----------
sysdeps/generic/ldsodefs.h | 3 ---
4 files changed, 18 insertions(+), 15 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 491d5c7..d0d2f56 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2015-10-15 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.
+
2015-10-09 Carlos O'Donell <carlos@redhat.com>
[BZ #18589]
diff --git a/NEWS b/NEWS
index 9b10bff..fa6f58d 100644
--- a/NEWS
+++ b/NEWS
@@ -9,7 +9,10 @@ Version 2.22.1
* The following bugs are resolved with this release:
- 18589, 18778, 18781, 18787, 18796, 18870, 18887, 18921, 18969.
+ 18589, 18778, 18781, 18787, 18796, 18870, 18887, 18921, 18928, 18969.
+
+* The LD_POINTER_GUARD environment variable can no longer be used to
+ disable the pointer guard feature. It is always enabled.
Version 2.22
diff --git a/elf/rtld.c b/elf/rtld.c
index 69873c2..07e741c 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -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:
diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index 7a0fe8d..78e3a97 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -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)
--
2.7.4
