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From a014cecd82b71b70a6a843e250e06b541ad524f7 Mon Sep 17 00:00:00 2001
From: Florian Weimer <fweimer@redhat.com>
Date: Thu, 15 Oct 2015 09:23:07 +0200
Subject: [PATCH] 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.
Upstream-Status: Backport
CVE: CVE-2015-8777
[Yocto # 8980]
https://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commit;h=a014cecd82b71b70a6a843e250e06b541ad524f7
Signed-off-by: Armin Kuster <akuster@mvista.com>
---
ChangeLog | 10 ++++++++++
NEWS | 13 ++++++++-----
elf/rtld.c | 15 ++++-----------
sysdeps/generic/ldsodefs.h | 3 ---
4 files changed, 22 insertions(+), 19 deletions(-)
Index: git/elf/rtld.c
===================================================================
--- git.orig/elf/rtld.c
+++ git/elf/rtld.c
@@ -163,7 +163,6 @@ struct rtld_global_ro _rtld_global_ro at
._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,
@@ -710,15 +709,12 @@ 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
@@ -2478,9 +2474,6 @@ 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:
Index: git/sysdeps/generic/ldsodefs.h
===================================================================
--- git.orig/sysdeps/generic/ldsodefs.h
+++ git/sysdeps/generic/ldsodefs.h
@@ -600,9 +600,6 @@ 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)
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