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authorFlorian Weimer <fweimer@redhat.com>2015-10-15 09:23:07 +0200
committerFlorian Weimer <fweimer@redhat.com>2015-10-15 09:23:32 +0200
commita014cecd82b71b70a6a843e250e06b541ad524f7 (patch)
treed402fc41e0212d4feb335c39972752fc5e320d3a
parent0c25f5b5bb48a9d550b5fb403b9a801ba04c146f (diff)
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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.
-rw-r--r--ChangeLog10
-rw-r--r--NEWS13
-rw-r--r--elf/rtld.c15
-rw-r--r--sysdeps/generic/ldsodefs.h3
4 files changed, 22 insertions, 19 deletions
diff --git a/ChangeLog b/ChangeLog
index 997ad13..fa58b30 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.
+
2015-10-14 Joseph Myers <joseph@codesourcery.com>
[BZ #19134]
diff --git a/NEWS b/NEWS
index d4e8b4a..0491a27 100644
--- a/NEWS
+++ b/NEWS
@@ -16,11 +16,14 @@ 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, 19007,
- 19012, 19016, 19018, 19032, 19046, 19049, 19050, 19059, 19071, 19074,
- 19076, 19077, 19078, 19079, 19085, 19086, 19088, 19094, 19095, 19124,
- 19125, 19129, 19134
+ 18870, 18872, 18873, 18875, 18887, 18921, 18928, 18951, 18952, 18956,
+ 18961, 18966, 18967, 18969, 18970, 18977, 18980, 18981, 18985, 19003,
+ 19007, 19012, 19016, 19018, 19032, 19046, 19049, 19050, 19059, 19071,
+ 19074, 19076, 19077, 19078, 19079, 19085, 19086, 19088, 19094, 19095,
+ 19124, 19125, 19129, 19134
+
+* 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.
diff --git a/elf/rtld.c b/elf/rtld.c
index 1474c72..52160df 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 7f7ff72..0625826 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)