it exports to the debugger. It currently has two choices: it can use
a compiled-in path (/libexec/ld-elf.so.1) or it can use the path stored
in the interpreter path in the binary being executed. The runtime linker
currently prefers the second. However, this is usually wrong for compat32
binaries since the binary specifies the path of rtld on a 32-bit system
(/libexec/ld-elf.so.1) instead of the actual path (/libexec/ld-elf32.so.1).
For now, always assume the compiled in path (/libexec/ld-elf32.so.1) as
the rtld path and ignore the path in the binary for the 32-bit runtime
linker.
Differential Revision: https://reviews.freebsd.org/D1236
Reviewed by: kib
It is automatically set when -fPIC is passed to the compiler.
Reviewed by: dim, kib
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D1179
Linux LD_ITERATE_PHDR(3):
The dlpi_name field is a null-terminated string giving the
pathname from which the shared object was loaded.
That functionality is much more useful than returning just the short
name.
Approved by: kan
Sponsored by: The FreeBSD Foundation
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
e.g. when a global variable is initialized with a pointer to ifunc.
Add symbol type check and call resolver for STT_GNU_IFUNC symbol types
when processing non-PLT relocations, but only after non-IFUNC
relocations are done. The two-phase proceessing is required since
resolvers may reference other symbols, which must be ready to use when
resolver calls are done.
Restructure reloc_non_plt() on x86 to call find_symdef() and handle
IFUNC in single place.
For non-x86 reloc_non_plt(), check for call for IFUNC relocation and
do nothing, to avoid processing relocs twice.
PR: 193048
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
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
All of the sources for the tests are contained in the
current working directory and the subdirectories
Phabric: D537
Reviewed by: jmmv
Approved by: jmmv (mentor)
Sponsored by: EMC / Isilon Storage Division
build time by using atf_tc_get_config_var(tc, "srcdir"))
This will allow end-users to move the binaries to different locations
after they've been built without having to rebuild the binaries with
the new paths
Phabric: D525 (part of a larger patch)
Reviewed by: jmmv
Approved by: jmmv (co-mentor)
This includes:
o All directories named *ia64*
o All files named *ia64*
o All ia64-specific code guarded by __ia64__
o All ia64-specific makefile logic
o Mention of ia64 in comments and documentation
This excludes:
o Everything under contrib/
o Everything under crypto/
o sys/xen/interface
o sys/sys/elf_common.h
Discussed at: BSDcan
correct stack alignment, however when we have a leaf function that uses
thread local storage it calls __aeabi_read_tp to get the thread pointer.
Neither GCC or clang see this as a function call so will align the stack
to a 4-byte boundary. This may be a problem as _rtld_bind expects to be
on an 8-byte boundary.
The solution is to store a copy of the stack pointer and force the
alignment before calling _rtld_bind.
This fixes a problem with armeb where applications would crash in odd ways.
It should also remove the need for a local patch to clang to force the
stack alignment to an 8-byte boundary, even for leaf functions. Further
testing will be needed before reverting this local change to clang as we
may rely on it in other places.
Reviewed by: jmg@
descriptors in order to relocate RTLD itself. To allocate memory,
we need the pagesizes array initialized, but that happens after
RTLD is relocated. This ordering is important for amd64, but it's
opposite of what ia64 needs. Handle this conflict with the define
called RTLD_INIT_PAGESIZES_EARLY. When defined, obtain the page
sizes before relocating rtld, otherwise do it after.
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 variable allows the loading of shared libraries via directory descriptors
rather than via library paths. If LD_LIBRARY_PATH_FDS=3:4:12, the directories
represented by file descriptors 3, 4 and 12 will searched for shared libraries
before the normal path-based mechanisms are used. This allows us to execute
unprivileged binaries from within a Capsicum sandbox even if they require
shared libraries.
Approved by: rwatson (mentor)
Reviewed by: kib
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]
mode. This allows the binder to be functional in the child after the
fork (assuming no lazy loading of a filter is needed), but other rtld
services which require write lock on rtld_bind_lock cause deadlock, if
called by child.
Change the _rtld_atfork() to lock the bind lock in write mode, making
the rtld fully functional after the fork.
Pre-resolve the symbols which are called by the libthr' fork()
interposer, since dynamic resolution causes deadlock due to the
rtld_bind_lock already owned in the write mode.
Reported and tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
_rtld_debug_postinit(). [1]
- Use __compiler_membar() instead of inline asm in _r_debug_state() and
_r_debug_postinit(). [2]
Pointy hat to: markj [1]
Reported by: attilio [2]
Discussed with: kib
X-MFC-With: r265456
the victim process before its entry point is called, at which point probes
and DOF data are registered with the kernel. The r_debug_state hook cannot
be used for this purpose, as it is called before the program's init routines
are invoked and in particular before DOF data is registered (via drti.o).
Reviewed by: kib
MFC after: 2 weeks
first calls mmap() with the arguments PROT_NONE and MAP_ANON to reserve a
single, contiguous range of virtual addresses for the entire shared library.
Later, rtld calls mmap() with the the shared library's file descriptor
and the argument MAP_FIXED to place the text and data sections within the
reserved range. The rationale for mapping shared libraries in this way is
explained in the commit message for Revision 190885. However, this approach
does have an unintended, negative consequence. Since the first call to
mmap() specifies MAP_ANON and not the shared library's file descriptor, the
kernel has no idea what alignment the vm object backing the file prefers.
As a result, the reserved range's alignment is unlikely to be the same as
the vm object's, and so mapping with superpages becomes impossible. To
address this problem, this revision adds the argument MAP_ALIGNED_SUPER to
the first call to mmap() if the text section is larger than the smallest
superpage size.
To determine if the text section is larger than the smallest superpage
size, rtld must always fetch the page size information. As a result, the
private code for fetching the base page size in rtld's builtin malloc is
redundant. Eliminate it. Requested by: kib
Tested by: zbb (on arm)
Reviewed by: kib (an earlier version)
Discussed with: jhb
Some modules do not align data at least to size of pointer, they uses a
smaller alignment, but our pointer should be aligned to its native
boundary, otherwise on some platforms, hardware alignment checking
will cause bus error.
saving the pointer will overwrite bytes belongs to another memory block
unexpectly, to fix the problem, use (allocated address + sizeof(void *)) as
initial value, and slip to next aligned address, so maximum extra bytes is
sizeof(void *) + align - 1.
Tested by: Andre Albsmeier < mail at ma17 dot ata dot myota dot orgndre >
the max required alignment for the static tls segments, and honor it
when carving the pieces for next module, from the static space. Use
aligned allocator to get properly-aligned dynamic blocks.
Reported by: dt71@gmx.com
Reviewed by: kan
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
On MIPS the .dynamic section is read-only, so the pointer to rtld
information for debuggers cannot be stored there (in DT_DEBUG).
Instead, a special section .rld_map is used.
Sponsored by: DARPA, AFRL
Approved by: re (delphij)
available in 32-bit compatibility mode, unconditional.
Overhaul the man page, which had evolved more by accretion than by design.
Approved by: re (gjb)
MFC after: 3 weeks
PATH_MAX after the token substitution. This is wrong, because
origin_subst_one() performs the substitution on the whole rpath and
similar strings, which contain several pathes separated by colon. As
result, long (but correct) rpath consisting of many path elements is
rejected by the function.
Correct the problem by rewriting the origin_subst_one() to perform two
passes, first pass to calculate the number of substitutions to be
performed, and second pass to generate the resulting string. Second
pass allocates the memory for the result based on the count from the
first pass, without enforcing a limit.
Reported and tested by: pgj
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Normal libraries have base address 0 and are unaffected by this change.
PR: 176216
Submitted by: Damjan Jovanovic <damjan.jov@gmail.com>
Reviewed by: kib
MFC after: 1 week
