From 1bdda52fe92fd01b424cd6fbb63e3df96a95015c Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Fri, 29 Nov 2019 10:44:59 -0300 Subject: elf: Move vDSO setup to rtld (BZ#24967) This patch moves the vDSO setup from libc to loader code, just after the vDSO link_map setup. For static case the initialization is moved to _dl_non_dynamic_init instead. Instead of using the mangled pointer, the vDSO data is set as attribute_relro (on _rtld_global_ro for shared or _dl_vdso_* for static). It is read-only even with partial relro. It fixes BZ#24967 now that the vDSO pointer is setup earlier than malloc interposition is called. Also, vDSO calls should not be a problem for static dlopen as indicated by BZ#20802. The vDSO pointer would be zero-initialized and the syscall will be issued instead. Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu, arm-linux-gnueabihf, powerpc64le-linux-gnu, powerpc64-linux-gnu, powerpc-linux-gnu, s390x-linux-gnu, sparc64-linux-gnu, and sparcv9-linux-gnu. I also run some tests on mips. Reviewed-by: Siddhesh Poyarekar --- sysdeps/unix/sysv/linux/dl-vdso.c | 48 --------------------------------------- 1 file changed, 48 deletions(-) delete mode 100644 sysdeps/unix/sysv/linux/dl-vdso.c (limited to 'sysdeps/unix/sysv/linux/dl-vdso.c') diff --git a/sysdeps/unix/sysv/linux/dl-vdso.c b/sysdeps/unix/sysv/linux/dl-vdso.c deleted file mode 100644 index 08aefde4a4..0000000000 --- a/sysdeps/unix/sysv/linux/dl-vdso.c +++ /dev/null @@ -1,48 +0,0 @@ -/* ELF symbol resolve functions for VDSO objects. - Copyright (C) 2005-2020 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - . */ - -#include "config.h" -#include - - -void * -_dl_vdso_vsym (const char *name, const struct r_found_version *vers) -{ - struct link_map *map = GLRO (dl_sysinfo_map); - void *value = NULL; - - - if (map != NULL) - { - /* Use a WEAK REF so we don't error out if the symbol is not found. */ - ElfW (Sym) wsym; - memset (&wsym, 0, sizeof (ElfW (Sym))); - wsym.st_info = (unsigned char) ELFW (ST_INFO (STB_WEAK, STT_NOTYPE)); - - /* Search the scope of the vdso map. */ - const ElfW (Sym) *ref = &wsym; - lookup_t result = GLRO (dl_lookup_symbol_x) (name, map, &ref, - map->l_local_scope, - vers, 0, 0, NULL); - - if (ref != NULL) - value = DL_SYMBOL_ADDRESS (result, ref); - } - - return value; -} -- cgit v1.2.3-70-g09d2