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Make PowerPC64 default to nonexecutable stack

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Ryan S. Arnold 2010-12-19 22:49:01 -05:00 committed by Ulrich Drepper
parent db753e2cfb
commit 30950a5fd2
13 changed files with 104 additions and 18 deletions
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22
ChangeLog
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@ -1,3 +1,25 @@
2010-12-15 Ryan S. Arnold <rsa@us.ibm.com>
* elf/Makefile: (check-execstack): Replace $(native-compile) with a
similar rule which adds the sysdep directories to the header search in
order to pick up the correct platform stackinfo.h.
* elf/check-execstack.c (main): Check DEFAULT_STACK_PERMS for PF_X and
perform test if it is, otherwise return successfully without testing.
* elf/dl-load.c (_dl_map_object_from_fd): Source stack_flags from
DEFAULT_STACK_PERMS define in stackinfo.h.
* elf/dl-support.c (_dl_stack_flags): Source from DEFAULT_STACK_PERMS
defined in stackinfo.h.
* elf/rtld.c (_dl_starting_up): Source ._dl_stack_flags from
DEFAULT_STACK_PERMS defined in stackinfo.h.
* sysdeps/i386/stackinfo.h: Define DEFAULT_STACK_PERMS with PF_X.
* sysdeps/ia64/stackinfo.h: Likewise.
* sysdeps/s390/stackinfo.h: Likewise.
* sysdeps/sh/stackinfo.h: Likewise.
* sysdeps/sparc/stackinfo.h: Likewise.
* sysdeps/x86_64/stackinfo.h: Likewise.
* sysdeps/powerpc/stackinfo.h: Define DEFAULT_STACK_PERMS without
PF_X for powerpc64. Retain PF_X for powerpc32.
2010-12-19 Ulrich Drepper <drepper@gmail.com>
* sysdeps/unix/readdir_r.c (__READDIR_R): Compute reclen more accurate.

8
elf/Makefile
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@ -899,8 +899,14 @@ $(objpfx)check-textrel: check-textrel.c
$(native-compile)
check-execstack-CFLAGS = -O -Wall -D_XOPEN_SOURCE=600 -D_BSD_SOURCE -std=gnu99
# Perform the same operation as $(native-compile) but add the sysdeps
# directories as header search locations.
$(objpfx)check-execstack: check-execstack.c
$(native-compile)
$(make-target-directory)
$(patsubst %/,cd % &&,$(objpfx)) \
$(BUILD_CC) $($(basename $(<F))-CFLAGS) $(ALL_BUILD_CFLAGS) \
$(addprefix -I$(shell pwd)/,$(sysdirs)) -I$(shell pwd) \
$(firstword $(filter /%,$< $(shell pwd)/$<)) -o $(@F)
check-localplt-CFLAGS = -O -Wall -D_GNU_SOURCE -std=gnu99
$(objpfx)check-localplt: check-localplt.c

13
elf/check-execstack.c
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@ -1,5 +1,5 @@
/* Check for executable stacks in DSOs.
Copyright (C) 2009 Free Software Foundation, Inc.
Copyright (C) 2009, 2010 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contribute by Ulrich Drepper <drepper@redhat.com>. 2009.
@ -26,6 +26,7 @@
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stackinfo.h>
#ifdef BITS
@ -150,9 +151,13 @@ main (int argc, char *argv[])
int cnt;
int result = 0;
for (cnt = 1; cnt < argc; ++cnt)
result |= handle_file (argv[cnt]);
/* We can return successfully, i.e., not fail, if PF_X isn't present. If it
* is present then check for the GNU_STACK header. */
if (DEFAULT_STACK_PERMS & PF_X)
{
for (cnt = 1; cnt < argc; ++cnt)
result |= handle_file (argv[cnt]);
}
return result;
}
#endif

6
elf/dl-load.c
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@ -984,8 +984,10 @@ _dl_map_object_from_fd (const char *name, int fd, struct filebuf *fbp,
}
}
/* Presumed absent PT_GNU_STACK. */
uint_fast16_t stack_flags = PF_R|PF_W|PF_X;
/* On most platforms presume that PT_GNU_STACK is absent and the stack is
* executable. Other platforms default to a nonexecutable stack and don't
* need PT_GNU_STACK to do so. */
uint_fast16_t stack_flags = DEFAULT_STACK_PERMS;
{
/* Scan the program header table, collecting its load commands. */

6
elf/dl-support.c
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@ -32,6 +32,7 @@
#include <dl-procinfo.h>
#include <unsecvars.h>
#include <hp-timing.h>
#include <stackinfo.h>
extern char *__progname;
char **_dl_argv = &__progname; /* This is checked for some error messages. */
@ -134,8 +135,9 @@ uint64_t _dl_hwcap __attribute__ ((nocommon));
setting _dl_hwcap nonzero below, but we do anyway. */
uint64_t _dl_hwcap_mask __attribute__ ((nocommon));
/* Prevailing state of the stack, PF_X indicating it's executable. */
ElfW(Word) _dl_stack_flags = PF_R|PF_W|PF_X;
/* Prevailing state of the stack. Generally this includes PF_X, indicating it's
* executable but this isn't true for all platforms. */
ElfW(Word) _dl_stack_flags = DEFAULT_STACK_PERMS;
/* If loading a shared object requires that we make the stack executable
when it was not, we do it by calling this function.

6
elf/rtld.c
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@ -40,6 +40,7 @@
#include <dl-osinfo.h>
#include <dl-procinfo.h>
#include <tls.h>
#include <stackinfo.h>
#include <assert.h>
@ -122,8 +123,9 @@ INTVARDEF(_dl_starting_up)
(except those which cannot be added for some reason). */
struct rtld_global _rtld_global =
{
/* Default presumption without further information is executable stack. */
._dl_stack_flags = PF_R|PF_W|PF_X,
/* Generally the default presumption without further information is an
* executable stack but this is not true for all platforms. */
._dl_stack_flags = DEFAULT_STACK_PERMS,
#ifdef _LIBC_REENTRANT
._dl_load_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER,
._dl_load_write_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER,

8
sysdeps/i386/stackinfo.h
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@ -1,4 +1,4 @@
/* Copyright (C) 1999, 2009 Free Software Foundation, Inc.
/* Copyright (C) 1999, 2009, 2010 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
@ -22,9 +22,15 @@
#ifndef _STACKINFO_H
#define _STACKINFO_H 1
#include <elf.h>
/* On x86 the stack grows down. */
#define _STACK_GROWS_DOWN 1
/* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK is
* present, but it is presumed absent. */
#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
/* Access to the stack pointer. The macros are used in alloca_account
for which they need to act as barriers as well, hence the additional
(unnecessary) parameters. */

8
sysdeps/ia64/stackinfo.h
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@ -1,4 +1,4 @@
/* Copyright (C) 2001 Free Software Foundation, Inc.
/* Copyright (C) 2001, 2010 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
@ -22,8 +22,14 @@
#ifndef _STACKINFO_H
#define _STACKINFO_H 1
#include <elf.h>
/* On IA-64 the stack grows down. The register stack is of no concern
here. */
#define _STACK_GROWS_DOWN 1
/* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK is
* present, but it is presumed absent. */
#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
#endif /* stackinfo.h */

13
sysdeps/powerpc/stackinfo.h
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@ -1,4 +1,4 @@
/* Copyright (C) 1999 Free Software Foundation, Inc.
/* Copyright (C) 1999, 2010 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
@ -22,7 +22,18 @@
#ifndef _STACKINFO_H
#define _STACKINFO_H 1
#include <elf.h>
/* On PPC the stack grows down. */
#define _STACK_GROWS_DOWN 1
#if __WORDSIZE == 64
/* PPC64 doesn't need an executable stack and doesn't need PT_GNU_STACK
* to make the stack nonexecutable. */
# define DEFAULT_STACK_PERMS (PF_R|PF_W)
#else
/* PF_X can be overridden if PT_GNU_STACK is present but is presumed absent. */
# define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
#endif
#endif /* stackinfo.h */

8
sysdeps/s390/stackinfo.h
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@ -1,4 +1,4 @@
/* Copyright (C) 2000 Free Software Foundation, Inc.
/* Copyright (C) 2000, 2010 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
@ -22,7 +22,13 @@
#ifndef _STACKINFO_H
#define _STACKINFO_H 1
#include <elf.h>
/* On s390 the stack grows down. */
#define _STACK_GROWS_DOWN 1
/* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK is
* present, but it is presumed absent. */
#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
#endif /* stackinfo.h */

8
sysdeps/sh/stackinfo.h
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@ -1,4 +1,4 @@
/* Copyright (C) 2001 Free Software Foundation, Inc.
/* Copyright (C) 2001, 2010 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
@ -22,7 +22,13 @@
#ifndef _STACKINFO_H
#define _STACKINFO_H 1
#include <elf.h>
/* On SH the stack grows down. */
#define _STACK_GROWS_DOWN 1
/* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK is
* present, but it is presumed absent. */
#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
#endif /* stackinfo.h */

8
sysdeps/sparc/stackinfo.h
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@ -1,4 +1,4 @@
/* Copyright (C) 2001 Free Software Foundation, Inc.
/* Copyright (C) 2001, 2010 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
@ -22,7 +22,13 @@
#ifndef _STACKINFO_H
#define _STACKINFO_H 1
#include <elf.h>
/* On sparc the stack grows down. */
#define _STACK_GROWS_DOWN 1
/* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK is
* present, but it is presumed absent. */
#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
#endif /* stackinfo.h */

8
sysdeps/x86_64/stackinfo.h
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@ -1,4 +1,4 @@
/* Copyright (C) 2001, 2009 Free Software Foundation, Inc.
/* Copyright (C) 2001, 2009, 2010 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
@ -22,9 +22,15 @@
#ifndef _STACKINFO_H
#define _STACKINFO_H 1
#include <elf.h>
/* On x86_64 the stack grows down. */
#define _STACK_GROWS_DOWN 1
/* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK is
* present, but it is presumed absent. */
#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
/* Access to the stack pointer. The macros are used in alloca_account
for which they need to act as barriers as well, hence the additional
(unnecessary) parameters. */