On Fri, 27 Feb 2015 10:21:36 +1100 Stephen Rothwell <s...@canb.auug.org.au>
wrote:
> > +/* Not all architectures implement mmap_rnd() */
> > +unsigned long __weak mmap_rnd(void)
> > +{
> > +}
> > +
> > +/*
> > + * Not all architectures use randomize_et_dyn(), so use __weak to let the
> > + * linker omit it from vmlinux
> > + */
> > +unsigned long __weak randomize_et_dyn(unsigned long base)
> > +{
> > + unsigned long ret;
> > +
> > + if ((current->personality & ADDR_NO_RANDOMIZE) ||
> > + !(current->flags & PF_RANDOMIZE))
> > + return base;
> > + ret = base + mmap_rnd();
> > + return max(ret, base);
> > +}
> > +
>
> Didn't we have some trouble with some compilers when the weak function
> (mmap_rnd) was defined and used in the same file i.e. the wrong one was
> used?
I have vague memories, but I forget the details.
This sucks anyway - let's do it properly.
I'm just flinging together trollpatches here. Someone please review,
test and fix this stuff. Kees?
diff -puN
arch/arm/Kconfig~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix-fix-2
arch/arm/Kconfig
---
a/arch/arm/Kconfig~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix-fix-2
+++ a/arch/arm/Kconfig
@@ -5,6 +5,7 @@ config ARM
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_HAVE_CUSTOM_GPIO_H
select ARCH_HAS_GCOV_PROFILE_ALL
+ select ARCH_HAVE_ELF_ASLR
select ARCH_MIGHT_HAVE_PC_PARPORT
select ARCH_SUPPORTS_ATOMIC_RMW
select ARCH_USE_BUILTIN_BSWAP
diff -puN
arch/arm64/Kconfig~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix-fix-2
arch/arm64/Kconfig
---
a/arch/arm64/Kconfig~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix-fix-2
+++ a/arch/arm64/Kconfig
@@ -9,6 +9,7 @@ config ARM64
select ARCH_WANT_OPTIONAL_GPIOLIB
select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
select ARCH_WANT_FRAME_POINTERS
+ select ARCH_HAVE_ELF_ASLR
select ARM_AMBA
select ARM_ARCH_TIMER
select ARM_GIC
diff -puN
arch/mips/Kconfig~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix-fix-2
arch/mips/Kconfig
---
a/arch/mips/Kconfig~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix-fix-2
+++ a/arch/mips/Kconfig
@@ -39,6 +39,7 @@ config MIPS
select HAVE_MEMBLOCK
select HAVE_MEMBLOCK_NODE_MAP
select ARCH_DISCARD_MEMBLOCK
+ select ARCH_HAVE_ELF_ASLR
select GENERIC_SMP_IDLE_THREAD
select BUILDTIME_EXTABLE_SORT
select GENERIC_CLOCKEVENTS
diff -puN
arch/powerpc/Kconfig~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix-fix-2
arch/powerpc/Kconfig
---
a/arch/powerpc/Kconfig~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix-fix-2
+++ a/arch/powerpc/Kconfig
@@ -97,6 +97,7 @@ config PPC
select HAVE_FUNCTION_GRAPH_TRACER
select SYSCTL_EXCEPTION_TRACE
select ARCH_WANT_OPTIONAL_GPIOLIB
+ select ARCH_HAVE_ELF_ASLR
select VIRT_TO_BUS if !PPC64
select HAVE_IDE
select HAVE_IOREMAP_PROT
diff -puN
arch/x86/Kconfig~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix-fix-2
arch/x86/Kconfig
---
a/arch/x86/Kconfig~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix-fix-2
+++ a/arch/x86/Kconfig
@@ -28,6 +28,7 @@ config X86
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_MIGHT_HAVE_PC_PARPORT
select ARCH_MIGHT_HAVE_PC_SERIO
+ select ARCH_HAVE_ELF_ASLR
select HAVE_AOUT if X86_32
select HAVE_UNSTABLE_SCHED_CLOCK
select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
diff -puN
fs/Kconfig~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix-fix-2
fs/Kconfig
--- a/fs/Kconfig~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix-fix-2
+++ a/fs/Kconfig
@@ -50,6 +50,9 @@ config FS_DAX
endif # BLOCK
+config ARCH_HAVE_ELF_ASLR
+ bool
+
# Posix ACL utility routines
#
# Note: Posix ACLs can be implemented without these helpers. Never use
diff -puN
fs/binfmt_elf.c~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix-fix-2
fs/binfmt_elf.c
---
a/fs/binfmt_elf.c~fix-offset2lib-issue-for-x86-arm-powerpc-and-mips-fix-fix-2
+++ a/fs/binfmt_elf.c
@@ -2301,15 +2301,7 @@ out:
#endif /* CONFIG_ELF_CORE */
-/* Not all architectures implement mmap_rnd() */
-unsigned long __weak mmap_rnd(void)
-{
-}
-
-/*
- * Not all architectures use randomize_et_dyn(), but there doesn't seem to be
- * a compile-time way of avoiding its generation.
- */
+#ifdef ARCH_HAVE_ELF_ASLR
unsigned long randomize_et_dyn(unsigned long base)
{
unsigned long ret;
@@ -2320,6 +2312,7 @@ unsigned long randomize_et_dyn(unsigned
ret = base + mmap_rnd();
return max(ret, base);
}
+#endif
static int __init init_elf_binfmt(void)
{
_
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