diff options
Diffstat (limited to 'elf/rtld.c')
| -rw-r--r-- | elf/rtld.c | 32 |
1 files changed, 31 insertions, 1 deletions
diff --git a/elf/rtld.c b/elf/rtld.c index a89f89b3a5..9ef58bb328 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -90,6 +90,15 @@ INTDEF(_dl_argv) uintptr_t __stack_chk_guard attribute_relro; #endif +/* Only exported for architectures that don't store the pointer guard + value in thread local area. */ +uintptr_t __pointer_chk_guard_local + attribute_relro attribute_hidden __attribute__ ((nocommon)); +#ifndef THREAD_SET_POINTER_GUARD +strong_alias (__pointer_chk_guard_local, __pointer_chk_guard) +#endif + + /* List of auditing DSOs. */ static struct audit_list { @@ -142,6 +151,7 @@ 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, /* Function pointers. */ ._dl_debug_printf = _dl_debug_printf, @@ -1823,6 +1833,20 @@ ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n", __stack_chk_guard = stack_chk_guard; #endif + /* Set up the pointer guard as well, if necessary. */ + if (GLRO(dl_pointer_guard)) + { + // XXX If it is cheap, we should use a separate value. + uintptr_t pointer_chk_guard; + hp_timing_t now; + HP_TIMING_NOW (now); + pointer_chk_guard = stack_chk_guard ^ now; +#ifdef THREAD_SET_POINTER_GUARD + THREAD_SET_POINTER_GUARD (pointer_chk_guard); +#endif + __pointer_chk_guard_local = pointer_chk_guard; + } + if (__builtin_expect (mode, normal) != normal) { /* We were run just to list the shared libraries. It is @@ -2575,7 +2599,13 @@ process_envvars (enum mode *modep) #endif if (!INTUSE(__libc_enable_secure) && memcmp (envline, "USE_LOAD_BIAS", 13) == 0) - GLRO(dl_use_load_bias) = envline[14] == '1' ? -1 : 0; + { + 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: |