This patch adds the necessary bionic code for the linker to protect
global data using MTE.
The implementation is described in the MemtagABI addendum to the
AArch64 ELF ABI:
https://github.com/ARM-software/abi-aa/blob/main/memtagabielf64/memtagabielf64.rst
In summary, this patch includes:
1. When MTE globals is requested, the linker maps writable SHF_ALLOC
sections as anonymous pages with PROT_MTE (copying the file contents
into the anonymous mapping), rather than using a file-backed private
mapping. This is required as file-based mappings are not necessarily
backed by the kernel with tag-capable memory. For sections already
mapped by the kernel when the linker is invoked via. PT_INTERP, we
unmap the contents, remap a PROT_MTE+anonymous mapping in its place,
and re-load the file contents from disk.
2. When MTE globals is requested, the linker tags areas of global memory
(as defined in SHT_AARCH64_MEMTAG_GLOBALS_DYNAMIC) with random tags,
but ensuring that adjacent globals are never tagged using the same
memory tag (to provide detemrinistic overflow detection).
3. Changes to RELATIVE, ABS64, and GLOB_DAT relocations to load and
store tags in the right places. This ensures that the address tags are
materialized into the GOT entries as well. These changes are a
functional no-op to existing binaries and/or non-MTE capable hardware.
Bug: N/A
Test: atest bionic-unit-tests CtsBionicTestCases --test-filter=*Memtag*
Change-Id: Id7b1a925339b14949d5a8f607dd86928624bda0e
The search_linked_namespaces parameter to find_library_internal is
always true.
Bug: none
Test: bionic tests
Change-Id: I4b6f48afefca4f52b34ca2c9e0f4335fa895ff34
The executable can be inside a zip file using the same syntax used for
shared objects: path.zip!/libentry.so.
The linker currently requires an absolute path. This restriction could be
loosened, but it didn't seem important? If it allowed non-absolute paths,
we'd need to decide how to handle:
- foo/bar (relative to CWD?)
- foo (search PATH / LD_LIBRARY_PATH, or also relative to CWD?)
- foo.zip!/bar (normalize_path() requires an absolute path)
The linker adjusts the argc/argv passed to main() and to constructor
functions to hide the initial linker argument, but doesn't adjust the auxv
vector or files like /proc/self/{exe,cmdline,auxv,stat}. Those files will
report that the kernel loaded the linker as an executable.
I think the linker_logger.cpp change guarding against (g_argv == NULL)
isn't actually necessary, but it seemed like a good idea given that I'm
delaying initialization of g_argv until after C++ constructors have run.
Bug: http://b/112050209
Test: bionic unit tests
Change-Id: I846faf98b16fd34218946f6167e8b451897debe5
vdso should be available in all namespaces when present. This
bug went undetected because the way libc currently uses vdso (it
does all the lookups itself). This makes it available for the
programs that want to take advantage by dlopening it.
Bug: http://b/73105445
Bug: http://b/79561555
Test: adb shell /data/nativetest/arm/bionic-unit-tests/bionic-unit-tests --gtest_filter=dl.exec_with_ld_config_file
Test: adb shell /data/nativetest/bionic-unit-tests/bionic-unit-tests --gtest_filter=dl*
Change-Id: I8eae0c9848f256190d1c9ec85d10dc6ce383a8bc
We've been using #pragma once for new internal files, but let's be more bold.
Bug: N/A
Test: builds
Change-Id: I7e2ee2730043bd884f9571cdbd8b524043030c07
This change addresses multiple problems introduced by
02586a2a34
1. In the case of unsuccessful dlopen the failure guard is triggered
for two namespaces which leads to double unload.
2. In the case where load_tasks includes libraries from 3 and more
namespaces it results in incorrect linking of libraries shared between
second and third/forth and so on namespaces.
The root cause of these problems was recursive call to find_libraries.
It does not do what it is expected to do. It does not form new load_tasks
list and immediately jumps to linking local_group. Not only this skips
reference counting it also will include unlinked but accessible library
from third (and fourth and fifth) namespaces in invalid local group. The
best case scenario here is that for 3 or more namesapces this will
fail to link. The worse case scenario it will link the library
incorrectly with will lead to very hard to catch bugs.
This change removes recursive call and replaces it with explicit list of
local_groups which should be linked. It also revisits the way we do
reference counting - with this change the reference counts are updated after
after libraries are successfully loaded.
Also update soinfo_free to abort in case when linker tries to free same
soinfo for the second time - this makes linker behavior less undefined.
Test: bionic-unit-tests
Bug: http://b/69787209
Change-Id: Iea25ced181a98c6503cce6e2b832c91d697342d5
With ld.config.txt, we now have multiple built-in namespaces other than
the default namespace. Libs (and their dependents) listed in LD_PRELOAD
must be visible to those additional namespaces as well.
This also adds a debugging only feature: path to the linker config file
can be customized via LD_CONFIG_FILE environment variable. This works
only for debuggable builds.
Bug: 38114603
Bug: 62815515
Test: 1. ./external/compiler-rt/lib/asan/scripts/asan_device_setup --lib
prebuilts/clang/host/linux-x86/clang-stable/lib64/clang/5.0/lib/linux
2. enable talkback shortcut
3. in the home screen, hold vol-up/down together
4. device does not reboots and talkback shortcut is toggled
Test: bionic-unit-tests and linker-unit-tests successful
Change-Id: I9a03591053f4a9caea82f0dcb23e7a3d324bb9bd
This change allows customization of default namespace
configuration for different executables. It also enables
target_sdk_version setup for binaries (note that this
option should explicitly be enabled in ld.config.txt).
Bug: http://b/30706810
Bug: http://b/30435785
Test: run linker-unit-tests/bionic-unit-tests, boot angler
Change-Id: Ibbe87209acf1538fc9cec04944f3d22a190c38f1
Replace public library list with shared lib sonames
which are property of a link between namespaces
This change does not touch any external interfaces
so from outside it behaves almost as it was before
One significant difference is that there is no longer
need to preload public libraries.
Bug: http://b/26833548
Test: bionic-unit-tests --gtest_filter=dl*:Dl*
Change-Id: I57e44e18a9b4f07dcd6556436346be52f52b79d7
Extract linker executable specific code to linker_main.cpp;
this part of code does not have a place in libdl.a/so.
Bug: http://b/14998480
Bug: http://b/30706810
Test: mm && run bionic-unit-tests
Change-Id: I90f7475e93a919b0f9525da22928089ad35b8f6c
