On 11/28/18 12:56 PM, Rob Herring wrote:
>> diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
>> index ad3fcad4d75b8..f309399deac20 100644
>> --- a/drivers/of/Kconfig
>> +++ b/drivers/of/Kconfig
>> @@ -15,6 +15,7 @@ if OF
>> config OF_UNITTEST
>> bool "Device Tree runtime unit tests"
>> depends on !SPARC
>> + depends on KUNIT
> Unless KUNIT has depends, better to be a select here.
That's just style or taste. I would prefer to use depends
instead of select, but that's also just my preference.
--
~Randy
arm64 has a feature called Top Byte Ignore, which allows to embed pointer
tags into the top byte of each pointer. Userspace programs (such as
HWASan, a memory debugging tool [1]) might use this feature and pass
tagged user pointers to the kernel through syscalls or other interfaces.
Right now the kernel is already able to handle user faults with tagged
pointers, due to these patches:
1. 81cddd65 ("arm64: traps: fix userspace cache maintenance emulation on a
tagged pointer")
2. 7dcd9dd8 ("arm64: hw_breakpoint: fix watchpoint matching for tagged
pointers")
3. 276e9327 ("arm64: entry: improve data abort handling of tagged
pointers")
When passing tagged pointers to syscalls, there's a special case of such a
pointer being passed to one of the memory syscalls (mmap, mprotect, etc.).
These syscalls don't do memory accesses but rather deal with memory
ranges, hence an untagged pointer is better suited.
This patchset extends tagged pointer support to non-memory syscalls. This
is done by reusing the untagged_addr macro to untag user pointers when the
kernel performs pointer checking to find out whether the pointer comes
from userspace (most notably in access_ok). The untagging is done only
when the pointer is being checked, the tag is preserved as the pointer
makes its way through the kernel.
One of the alternative approaches to untagging that was considered is to
completely strip the pointer tag as the pointer enters the kernel with
some kind of a syscall wrapper, but that won't work with the countless
number of different ioctl calls. With this approach we would need a custom
wrapper for each ioctl variation, which doesn't seem practical.
The following testing approaches has been taken to find potential issues
with user pointer untagging:
1. Static testing (with sparse [2] and separately with a custom static
analyzer based on Clang) to track casts of __user pointers to integer
types to find places where untagging needs to be done.
2. Dynamic testing: adding BUG_ON(has_tag(addr)) to find_vma() and running
a modified syzkaller version that passes tagged pointers to the kernel.
Based on the results of the testing the requried patches have been added
to the patchset.
This patchset has been merged into the Pixel 2 kernel tree and is now
being used to enable testing of Pixel 2 phones with HWASan.
This patchset is a prerequisite for ARM's memory tagging hardware feature
support [3].
Thanks!
[1] http://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html
[2] https://github.com/lucvoo/sparse-dev/commit/5f960cb10f56ec2017c128ef9d16060…
[3] https://community.arm.com/processors/b/blog/posts/arm-a-profile-architectur…
Changes in v8:
- Rebased onto 65102238 (4.20-rc1).
- Added a note to the cover letter on why syscall wrappers/shims that untag
user pointers won't work.
- Added a note to the cover letter that this patchset has been merged into
the Pixel 2 kernel tree.
- Documentation fixes, in particular added a list of syscalls that don't
support tagged user pointers.
Changes in v7:
- Rebased onto 17b57b18 (4.19-rc6).
- Dropped the "arm64: untag user address in __do_user_fault" patch, since
the existing patches already handle user faults properly.
- Dropped the "usb, arm64: untag user addresses in devio" patch, since the
passed pointer must come from a vma and therefore be untagged.
- Dropped the "arm64: annotate user pointers casts detected by sparse"
patch (see the discussion to the replies of the v6 of this patchset).
- Added more context to the cover letter.
- Updated Documentation/arm64/tagged-pointers.txt.
Changes in v6:
- Added annotations for user pointer casts found by sparse.
- Rebased onto 050cdc6c (4.19-rc1+).
Changes in v5:
- Added 3 new patches that add untagging to places found with static
analysis.
- Rebased onto 44c929e1 (4.18-rc8).
Changes in v4:
- Added a selftest for checking that passing tagged pointers to the
kernel succeeds.
- Rebased onto 81e97f013 (4.18-rc1+).
Changes in v3:
- Rebased onto e5c51f30 (4.17-rc6+).
- Added linux-arch@ to the list of recipients.
Changes in v2:
- Rebased onto 2d618bdf (4.17-rc3+).
- Removed excessive untagging in gup.c.
- Removed untagging pointers returned from __uaccess_mask_ptr.
Changes in v1:
- Rebased onto 4.17-rc1.
Changes in RFC v2:
- Added "#ifndef untagged_addr..." fallback in linux/uaccess.h instead of
defining it for each arch individually.
- Updated Documentation/arm64/tagged-pointers.txt.
- Dropped "mm, arm64: untag user addresses in memory syscalls".
- Rebased onto 3eb2ce82 (4.16-rc7).
Reviewed-by: Luc Van Oostenryck <luc.vanoostenryck(a)gmail.com>
Signed-off-by: Andrey Konovalov <andreyknvl(a)google.com>
Andrey Konovalov (8):
arm64: add type casts to untagged_addr macro
uaccess: add untagged_addr definition for other arches
arm64: untag user addresses in access_ok and __uaccess_mask_ptr
mm, arm64: untag user addresses in mm/gup.c
lib, arm64: untag addrs passed to strncpy_from_user and strnlen_user
fs, arm64: untag user address in copy_mount_options
arm64: update Documentation/arm64/tagged-pointers.txt
selftests, arm64: add a selftest for passing tagged pointers to kernel
Documentation/arm64/tagged-pointers.txt | 25 +++++++++++--------
arch/arm64/include/asm/uaccess.h | 14 +++++++----
fs/namespace.c | 2 +-
include/linux/uaccess.h | 4 +++
lib/strncpy_from_user.c | 2 ++
lib/strnlen_user.c | 2 ++
mm/gup.c | 4 +++
tools/testing/selftests/arm64/.gitignore | 1 +
tools/testing/selftests/arm64/Makefile | 11 ++++++++
.../testing/selftests/arm64/run_tags_test.sh | 12 +++++++++
tools/testing/selftests/arm64/tags_test.c | 19 ++++++++++++++
11 files changed, 80 insertions(+), 16 deletions(-)
create mode 100644 tools/testing/selftests/arm64/.gitignore
create mode 100644 tools/testing/selftests/arm64/Makefile
create mode 100755 tools/testing/selftests/arm64/run_tags_test.sh
create mode 100644 tools/testing/selftests/arm64/tags_test.c
--
2.19.1.930.g4563a0d9d0-goog
If pkg-config is available, use it to define the CFLAGS and
LDLIBS needed for libmount; else, use the current hard-coded
paths and options.
Using pkg-config is very helpful for cross-compilation
environments, and is sometimes readily available on developer
boxes to ensure we get the right compiler/linker options for
the given package.
Signed-off-by: Daniel Díaz <daniel.diaz(a)linaro.org>
---
tools/testing/selftests/gpio/Makefile | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/gpio/Makefile b/tools/testing/selftests/gpio/Makefile
index 46648427d537..f22b22aef7bf 100644
--- a/tools/testing/selftests/gpio/Makefile
+++ b/tools/testing/selftests/gpio/Makefile
@@ -1,7 +1,13 @@
# SPDX-License-Identifier: GPL-2.0
-CFLAGS += -O2 -g -std=gnu99 -Wall -I../../../../usr/include/
-LDLIBS += -lmount -I/usr/include/libmount
+MOUNT_CFLAGS := $(shell pkg-config --cflags mount 2>/dev/null)
+MOUNT_LDLIBS := $(shell pkg-config --libs mount 2>/dev/null)
+ifeq ($(MOUNT_LDLIBS),)
+MOUNT_LDLIBS := -lmount -I/usr/include/libmount
+endif
+
+CFLAGS += -O2 -g -std=gnu99 -Wall -I../../../../usr/include/ $(MOUNT_CFLAGS)
+LDLIBS += $(MOUNT_LDLIBS)
TEST_PROGS := gpio-mockup.sh
TEST_FILES := gpio-mockup-sysfs.sh
--
2.17.1
Your CC list is so huge that vger.kernel.org dropped all of your postings.
That CC list is not reasonable at all, trim it down to the most minimum
set. Probably 2 or 3 mailing lists, primarily netdev, and maybe a small
handful of specific developers.
Nothing more.
Hi,
The test outputs of those failures in seccomp_bpf as below:
---
m3ulcb:/opt/kselftest/seccomp# ./seccomp_bpf 61
[ RUN ] global.syscall_restart
seccomp_bpf.c:2754:global.syscall_restart:Expected 0x200 (512) == msg (256)
global.syscall_restart: Test terminated by assertion
[ FAIL ] global.syscall_restart
m3ulcb:/opt/kselftest/seccomp# seccomp_bpf.c:2685:global.syscall_restart:Expected 0 (0) == nanosleep(&timeout, ((void *)0)) (-1)
seccomp_bpf.c:2686:global.syscall_restart:Call to nanosleep() failed (errno 38)
seccomp_bpf.c:2690:global.syscall_restart:Expected 1 (1) == read(pipefd[0], &buf, 1) (0)
seccomp_bpf.c:2691:global.syscall_restart:Failed final read() from parent
seccomp_bpf.c:2693:global.syscall_restart:Expected '!' (33) == buf (46)
seccomp_bpf.c:2694:global.syscall_restart:Failed to get final data from read()
m3ulcb:/opt/kselftest/seccomp# ./seccomp_bpf 53
[ RUN ] global.detect_seccomp_filter_flags
seccomp_bpf.c:2104:global.detect_seccomp_filter_flags:Expected 14 (14) == (*__errno_location ()) (22)
seccomp_bpf.c:2106:global.detect_seccomp_filter_flags:Failed to detect that a known-good filter flag (0x4) is supported!
seccomp_bpf.c:2115:global.detect_seccomp_filter_flags:Expected 14 (14) == (*__errno_location ()) (22)
seccomp_bpf.c:2117:global.detect_seccomp_filter_flags:Failed to detect that all known-good filter flags (0x7) are supported!
global.detect_seccomp_filter_flags: Test failed at step #6
[ FAIL ] global.detect_seccomp_filter_flags
m3ulcb:/opt/kselftest/seccomp# ./seccomp_bpf 64
[ RUN ] global.get_metadata
seccomp_bpf.c:2914:global.get_metadata:Expected sizeof(md) (16) == ptrace(0x420d, pid, sizeof(md), &md) (-1)
global.get_metadata: Test terminated by assertion
[ FAIL ] global.get_metadata
---
Although I am not so familiar with SECCOMP and BPF, I checked some related documents and codes.
About the failures above, what the most confused me is that why it always give ENOSYS.
Am I missing something?
Thanks in advance.
PS:
I didn't run "make kselftest-merge" before compiling the kernel that I'm using.
---
The Test Environment:
- Kernel version: v4.14.0
The following configs were enabled.
- CONFIG_HAVE_ARCH_SECCOMP_FILTER=y
- CONFIG_SECCOMP_FILTER=y
- CONFIG_SECCOMP=y
Best regards
Liu
On Wed, Nov 28, 2018 at 12:56 PM Rob Herring <robh(a)kernel.org> wrote:
>
> On Wed, Nov 28, 2018 at 1:38 PM Brendan Higgins
> <brendanhiggins(a)google.com> wrote:
> >
> > Migrate tests without any cleanup, or modifying test logic in anyway to
> > run under KUnit using the KUnit expectation and assertion API.
>
> Nice! You beat me to it. This is probably going to conflict with what
> is in the DT tree for 4.21. Also, please Cc the DT list for
> drivers/of/ changes.
Oh, I thought you were asking me to do it :-) In any case, I am happy to.
Oh yeah, sorry about not CC'ing the list.
Cheers