From aafd1ef00c51824b7cc3b11bf24317400d2289ed Mon Sep 17 00:00:00 2001 From: Matti Kosola Date: Sun, 2 Feb 2020 10:57:54 +0200 Subject: [PATCH] Revert "elf: Refuse to dlopen PIE objects [BZ #24323]" This reverts commit 2c75b545de6fe3c44138799c68217a94bc669a88. --- elf/Makefile | 4 +--- elf/dl-load.c | 18 ++++------------ elf/tst-dlopen-pie.c | 49 -------------------------------------------- include/elf.h | 2 +- 4 files changed, 6 insertions(+), 67 deletions(-) delete mode 100644 elf/tst-dlopen-pie.c diff --git a/elf/Makefile b/elf/Makefile index a3eefd1b1f..bc3e092e5a 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -312,7 +312,7 @@ test-xfail-tst-protected1b = yes endif ifeq (yesyes,$(have-fpie)$(build-shared)) modules-names += tst-piemod1 -tests += tst-pie1 tst-pie2 tst-dlopen-pie +tests += tst-pie1 tst-pie2 tests-pie += tst-pie1 tst-pie2 ifeq (yes,$(have-protected-data)) tests += vismain @@ -1086,8 +1086,6 @@ CFLAGS-tst-pie2.c += $(pie-ccflag) $(objpfx)tst-piemod1.so: $(libsupport) $(objpfx)tst-pie1: $(objpfx)tst-piemod1.so -$(objpfx)tst-dlopen-pie: $(libdl) -$(objpfx)tst-dlopen-pie.out: $(objpfx)tst-pie1 ifeq (yes,$(build-shared)) # NB: Please keep cet-built-dso in sysdeps/x86/Makefile in sync with diff --git a/elf/dl-load.c b/elf/dl-load.c index 5abeb867f1..2bbef81b6e 100644 --- a/elf/dl-load.c +++ b/elf/dl-load.c @@ -1158,10 +1158,6 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, goto call_lose; } - /* dlopen of an executable is not valid because it is not possible - to perform proper relocations, handle static TLS, or run the - ELF constructors. For PIE, the check needs the dynamic - section, so there is another check below. */ if (__glibc_unlikely (type != ET_DYN) && __glibc_unlikely ((mode & __RTLD_OPENEXEC) == 0)) { @@ -1198,11 +1194,9 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, elf_get_dynamic_info (l, NULL); /* Make sure we are not dlopen'ing an object that has the - DF_1_NOOPEN flag set, or a PIE object. */ - if ((__glibc_unlikely (l->l_flags_1 & DF_1_NOOPEN) - && (mode & __RTLD_DLOPEN)) - || (__glibc_unlikely (l->l_flags_1 & DF_1_PIE) - && __glibc_unlikely ((mode & __RTLD_OPENEXEC) == 0))) + DF_1_NOOPEN flag set. */ + if (__glibc_unlikely (l->l_flags_1 & DF_1_NOOPEN) + && (mode & __RTLD_DLOPEN)) { /* We are not supposed to load this object. Free all resources. */ _dl_unmap_segments (l); @@ -1213,11 +1207,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, if (l->l_phdr_allocated) free ((void *) l->l_phdr); - if (l->l_flags_1 & DF_1_PIE) - errstring - = N_("cannot dynamically load position-independent executable"); - else - errstring = N_("shared object cannot be dlopen()ed"); + errstring = N_("shared object cannot be dlopen()ed"); goto call_lose; } diff --git a/elf/tst-dlopen-pie.c b/elf/tst-dlopen-pie.c deleted file mode 100644 index 6a41c731cb..0000000000 --- a/elf/tst-dlopen-pie.c +++ /dev/null @@ -1,49 +0,0 @@ -/* dlopen test for PIE objects. - Copyright (C) 2019 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 - . */ - -/* This test attempts to open the (otherwise unrelated) PIE test - program elf/tst-pie1 and expects the attempt to fail. */ - -#include -#include -#include -#include -#include - -static void -test_mode (int mode) -{ - char *pie_path = xasprintf ("%s/elf/tst-pie1", support_objdir_root); - if (dlopen (pie_path, mode) != NULL) - FAIL_EXIT1 ("dlopen succeeded unexpectedly (%d)", mode); - const char *message = dlerror (); - const char *expected - = "cannot dynamically load position-independent executable"; - if (strstr (message, expected) == NULL) - FAIL_EXIT1 ("unexpected error message (mode %d): %s", mode, message); -} - -static int -do_test (void) -{ - test_mode (RTLD_LAZY); - test_mode (RTLD_NOW); - return 0; -} - -#include diff --git a/include/elf.h b/include/elf.h index 14ed67ff67..ab76aafb1e 100644 --- a/include/elf.h +++ b/include/elf.h @@ -23,7 +23,7 @@ # endif # define DT_1_SUPPORTED_MASK \ (DF_1_NOW | DF_1_NODELETE | DF_1_INITFIRST | DF_1_NOOPEN \ - | DF_1_ORIGIN | DF_1_NODEFLIB | DF_1_PIE) + | DF_1_ORIGIN | DF_1_NODEFLIB) #endif /* !_ISOMAC */ #endif /* elf.h */ -- 2.24.1