Building binaries as PIE allows the executable itself to be loaded at a
random address when ASLR is enabled (not just its shared libraries).
With this change PIE objects have a .pieo extension and INTERNALLIB
libraries libXXX_pie.a.
MK_PIE is disabled for some kerberos5 tools, Clang, and Subversion, as
they explicitly reference .a libraries in their Makefiles. These can
be addressed on an individual basis later. MK_PIE is also disabled for
rtld-elf because it is already position-independent using bespoke
Makefile rules.
Currently only dynamically linked binaries will be built as PIE.
Discussed with: dim
Reviewed by: kib
MFC after: 1 month
Relnotes: Yes
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D18423
An issue remains with BIND_NOW and processes using threads. For now,
restore libc's BIND_NOW disable, and also disable BIND_NOW in rtld and
libthr.
A patch is in review (D18400) that likely fixes this issue, but just
disable BIND_NOW pending further testing after it is committed.
PR: 233333
Sponsored by: The FreeBSD Foundation
The function reloc_non_plt has complicated variable lifetimes that GCC 6.4.0
(the version currently used by amd64-xtoolchain-gcc) misunderstands and
produces an erroneous warning about. Silence it to allow the -Werror build
to proceed.
Reviewed by: emaste
In particular, the switch statement on the type of dynamic entries
in _rtld_relocate_nonplt_self() needs to not use a jump table since
jump tables on MIPS use local GOT entries which aren't initialized
until after this loop.
Suggested by: arichardson
Reviewed by: emaste
Sponsored by: DARPA / AFRL
directories to SUBDIR.${MK_TESTS} idiom
This is being done to pave the way for future work (and homogenity) in
^/projects/make-check-sandbox .
No functional change intended.
MFC after: 1 weeks
The dependency is needed in PROG_FULL since only the build of PROG_FULL
is using the LDFLAGS and depending on VERSION_MAP. This was not a problem
with MK_DEBUG_FILES==no since it only builds PROG.
This should probably be using bsd.lib.mk instead [1]
Reported by: swills, gjb
Reviewed by: emaste
Noted by: rgrimes [1]
Sponsored by: EMC / Isilon Storage Division
Approved by: re (kib)
MK_TOOLCHAIN==no disables building and installing of pic archives.
c_pic.a is still needed for rtld though so force it to build in lib/libc
and link directly to the objdir version of it for rtld.
Somehow this has been broken since r148725.
Sponsored by: EMC / Isilon Storage Division
the constraints on what needs to be installed in a specific to
maintain consistency during upgrades.
Create a new clibs package containing libraries that are needed
as a bare minimum for consistency.
With much help and input from: kib
Sponsored by: The FreeBSD Foundation
the malloc() + memset() in the local implementation of calloc() into a call
to calloc(), helpfully turning it into an infinite loop. Clean up some
unneeded flags on PPC64 while here.
MFC after: 1 month
"don't know how to make /Versions.def. Stop"
This was trying to define a target in bsd.symver.mk based on LIBCDIR which was
not yet defined. Switching the order of inclusion of bsd.prog.mk and
bsd.symver.mk fixes it and seems fine.
Pointyhat to: bdrewery
Sponsored by: EMC / Isilon Storage Division
The exists(${DESTDIR}...) check runs with DESTDIR being blank. When the
target runs it does have DESTDIR=${STAGE_OBJTOP} via bsd.sys.mk. This
results in the first execution warning that the symlink is missing. The
second run does run fine. However, this chflags is not needed at all
for META_MODE/STAGING since we never had this path being a schg file
while using META_MODE.
Sponsored by: EMC / Isilon Storage Division
rtld on x86 to be hidden. This is a micro-optimization, which allows
intrinsic references inside rtld to be handled without indirection
through PLT. The visibility of rtld symbols for other objects in the
symbol namespace is controlled by a version script.
Reviewed by: kan, jilles
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
the oabi is still in the tree, but it is expected this will be removed
as developers work on surrounding code.
With this commit the ARM EABI is the only supported supported ABI by
FreeBSD on ARMa 32-bit processors.
X-MFC after: never
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D876
1. 50+% of NO_PIE use is fixed by adding -fPIC to INTERNALLIB and other
build-only utility libraries.
2. Another 40% is fixed by generating _pic.a variants of various libraries.
3. Some of the NO_PIE use is a bit absurd as it is disabling PIE (and ASLR)
where it never would work anyhow, such as csu or loader. This suggests
there may be better ways of adding support to the tree. Many of these
cases can be fixed such that -fPIE will work but there is really no
reason to have it in those cases.
4. Some of the uses are working around hacks done to some Makefiles that are
really building libraries but have been using bsd.prog.mk because the code
is cleaner. Had they been using bsd.lib.mk then NO_PIE would not have
been needed.
We likely do want to enable PIE by default (opt-out) for non-tree consumers
(such as ports). For in-tree though we probably want to only enable PIE
(opt-in) for common attack targets such as remote service daemons and setuid
utilities. This is also a great performance compromise since ASLR is expected
to reduce performance. As such it does not make sense to enable it in all
utilities such as ls(1) that have little benefit to having it enabled.
Reported by: kib
Test LD_LIBRARY_PATH_FDS by linking a binary that requires a shared
library that isn't in any of the usual search paths. Ensure this fails
when we don't supply LD_LIBRARY_PATH_FDS or we pass invalid information
in it. Ensure it works when we pass the correct directory in various
places in the variable.
Approved by: rwatson (mentor)
MFC after: 3 weeks
Sponsored by: DARPA/AFRL
This is currently an opt-in build flag. Once ASLR support is ready and stable
it should changed to opt-out and be enabled by default along with ASLR.
Each application Makefile uses opt-out to ensure that ASLR will be enabled by
default in new directories when the system is compiled with PIE/ASLR. [2]
Mark known build failures as NO_PIE for now.
The only known runtime failure was rtld.
[1] http://www.bsdcan.org/2014/schedule/events/452.en.html
Submitted by: Shawn Webb <lattera@gmail.com>
Discussed between: des@ and Shawn Webb [2]
instead of /libexec/ld-elf.so.1. Below in the Makefile we execute
'chflags noschg ${DESTDIR}/usr/libexec/ld-elf.so.1', which follows
symlink and removes 'schg' flag from system's /libexec/ld-elf.so.1
instead of the one in DESTDIR. It is also more friendly to use
replative paths in symlink in case of jail/chroot environments.
Obtained from: WHEEL Systems
MFC after: 2 weeks
particular on ARM, do require working init arrays.
Traditional FreeBSD crt1 calls _init and _fini of the binary, instead
of allowing runtime linker to arrange the calls. This was probably
done to have the same crt code serve both statically and dynamically
linked binaries. Since ABI mandates that first is called preinit
array functions, then init, and then init array functions, the init
have to be called from rtld now.
To provide binary compatibility to old FreeBSD crt1, which calls _init
itself, rtld only calls intializers and finalizers for main binary if
binary has a note indicating that new crt was used for linking. Add
parsing of ELF notes to rtld, and cache p_osrel value since we parsed
it anyway.
The patch is inspired by init_array support for DragonflyBSD, written
by John Marino.
Reviewed by: kan
Tested by: andrew (arm, previous version), flo (sparc64, previous version)
MFC after: 3 weeks
C runtime services, like printf(). Unfortunately, the multithread-safeness
measures in the libc do not work in rtld environment.
Rip the kernel printf() implementation and use it in the rtld instead of
libc version. This printf does not require any shared global data and thus
is mt-safe. Systematically use rtld_printf() and related functions, remove
the calls to err(3).
Note that stdio is still pulled from libc due to libmap implementaion using
fopen(). This is safe but unoptimal, and can be changed later.
Reported and tested by: pgj
Diagnosed and reviewed by: kan (previous version)
Approved by: re (bz)
With r169630 I disabled symbol versioning because it broke rtld. With
r211706 rtld got broken for ia64 & powerpc64. It was fixed for powerpc64
with r212497. In between, r211749 removed the exports table because the
version script handled the exports. But wait, symbol versioning was
disabled on ia64.
With exports controlled by the version script and symbol versioning
disabled, all symbols are exported and too many symbols bind to the
definition in rtld. Let's just say that waird things happen.
So, enable symbol versioning on ia64 and apply a work-around for the
SIGSEGV that triggered r169630 to begin with: when rtld relocates
itself, it comes across r_debug_state and for some reason can't find the
definition. This causes a failure, relocation aborts and null pointers
galore. The work-around is to ignore the missing definition when rtld
is relocating itself and keep going.
Maybe with the next binutils this will all go away. Maybe not, in
which case I still need to figure out why r_debug_state cannot be found.
BTW: r_debug_state is in the symbol map -- I don't think any other rtld
symbols that rtld references are in the symbol map...
and symbol map are required to support various consequences of the dot
symbol scheme:
- Symbols beginning with a dot are reserved, so start private symbols with
an underscore.
- In order to set RTLD breakpoints, gdb must be able to locate the text
entry point, not the data section function descriptor, so add
.r_debug_state to the symbol map on powerpc64.
Obtained from: projects/ppc64
