For ARC MPU version 3, the defined partitions are not added to MPU
when appmem_init_app_memory is doning app_bss_zero().
So need to disable mpu first to allow appmem_init_app_memory to
access all partitions.
Signed-off-by: Wayne Ren <wei.ren@synopsys.com>
Prepend the text 'cmake_minimum_required(VERSION 3.8.2)' into the
application and test build scripts.
Modern versions of CMake will spam users with a deprecation warning
when the toplevel CMakeLists.txt does not specify a CMake
version. This is documented in bug #8355.
To resolve this we include a cmake_minimum_required() line into the
toplevel build scripts. Additionally, cmake_minimum_required is
invoked from within boilerplate.cmake. The highest version will be
enforced.
This patch allows us to afterwards change CMake policy CMP000 from OLD
to NEW which in turn finally rids us of the verbose warning.
The extra boilerplate is considered more acceptable than the verbosity
of the CMP0000 policy.
Signed-off-by: Sebastian Bøe <sebastian.boe@nordicsemi.no>
The test read_kobject_user_pipe() is called twice in
the test suite. There is no need of calling same test
twice. Removing the extra call.
Signed-off-by: Spoorthi K <spoorthi.k@intel.com>
Summary: revised attempt at addressing issue 6290. The
following provides an alternative to using
CONFIG_APPLICATION_MEMORY by compartmentalizing data into
Memory Domains. Dependent on MPU limitations, supports
compartmentalized Memory Domains for 1...N logical
applications. This is considered an initial attempt at
designing flexible compartmentalized Memory Domains for
multiple logical applications and, with the provided python
script and edited CMakeLists.txt, provides support for power
of 2 aligned MPU architectures.
Overview: The current patch uses qualifiers to group data into
subsections. The qualifier usage allows for dynamic subsection
creation and affords the developer a large amount of flexibility
in the grouping, naming, and size of the resulting partitions and
domains that are built on these subsections. By additional macro
calls, functions are created that help calculate the size,
address, and permissions for the subsections and enable the
developer to control application data in specified partitions and
memory domains.
Background: Initial attempts focused on creating a single
section in the linker script that then contained internally
grouped variables/data to allow MPU/MMU alignment and protection.
This did not provide additional functionality beyond
CONFIG_APPLICATION_MEMORY as we were unable to reliably group
data or determine their grouping via exported linker symbols.
Thus, the resulting decision was made to dynamically create
subsections using the current qualifier method. An attempt to
group the data by object file was tested, but found that this
broke applications such as ztest where two object files are
created: ztest and main. This also creates an issue of grouping
the two object files together in the same memory domain while
also allowing for compartmenting other data among threads.
Because it is not possible to know a) the name of the partition
and thus the symbol in the linker, b) the size of all the data
in the subsection, nor c) the overall number of partitions
created by the developer, it was not feasible to align the
subsections at compile time without using dynamically generated
linker script for MPU architectures requiring power of 2
alignment.
In order to provide support for MPU architectures that require a
power of 2 alignment, a python script is run at build prior to
when linker_priv_stacks.cmd is generated. This script scans the
built object files for all possible partitions and the names given
to them. It then generates a linker file (app_smem.ld) that is
included in the main linker.ld file. This app_smem.ld allows the
compiler and linker to then create each subsection and align to
the next power of 2.
Usage:
- Requires: app_memory/app_memdomain.h .
- _app_dmem(id) marks a variable to be placed into a data
section for memory partition id.
- _app_bmem(id) marks a variable to be placed into a bss
section for memory partition id.
- These are seen in the linker.map as "data_smem_id" and
"data_smem_idb".
- To create a k_mem_partition, call the macro
app_mem_partition(part0) where "part0" is the name then used to
refer to that partition. This macro only creates a function and
necessary data structures for the later "initialization".
- To create a memory domain for the partition, the macro
app_mem_domain(dom0) is called where "dom0" is the name then
used for the memory domain.
- To initialize the partition (effectively adding the partition
to a linked list), init_part_part0() is called. This is followed
by init_app_memory(), which walks all partitions in the linked
list and calculates the sizes for each partition.
- Once the partition is initialized, the domain can be
initialized with init_domain_dom0(part0) which initializes the
domain with partition part0.
- After the domain has been initialized, the current thread
can be added using add_thread_dom0(k_current_get()).
- The code used in ztests ans kernel/init has been added under
a conditional #ifdef to isolate the code from other tests.
The userspace test CMakeLists.txt file has commands to insert
the CONFIG_APP_SHARED_MEM definition into the required build
targets.
Example:
/* create partition at top of file outside functions */
app_mem_partition(part0);
/* create domain */
app_mem_domain(dom0);
_app_dmem(dom0) int var1;
_app_bmem(dom0) static volatile int var2;
int main()
{
init_part_part0();
init_app_memory();
init_domain_dom0(part0);
add_thread_dom0(k_current_get());
...
}
- If multiple partitions are being created, a variadic
preprocessor macro can be used as provided in
app_macro_support.h:
FOR_EACH(app_mem_partition, part0, part1, part2);
or, for multiple domains, similarly:
FOR_EACH(app_mem_domain, dom0, dom1);
Similarly, the init_part_* can also be used in the macro:
FOR_EACH(init_part, part0, part1, part2);
Testing:
- This has been successfully tested on qemu_x86 and the
ARM frdm_k64f board. It compiles and builds power of 2
aligned subsections for the linker script on the 96b_carbon
boards. These power of 2 alignments have been checked by
hand and are viewable in the zephyr.map file that is
produced during build. However, due to a shortage of
available MPU regions on the 96b_carbon board, we are unable
to test this.
- When run on the 96b_carbon board, the test suite will
enter execution, but each individaul test will fail due to
an MPU FAULT. This is expected as the required number of
MPU regions exceeds the number allowed due to the static
allocation. As the MPU driver does not detect this issue,
the fault occurs because the data being accessed has been
placed outside the active MPU region.
- This now compiles successfully for the ARC boards
em_starterkit_em7d and em_starterkit_em7d_v22. However,
as we lack ARC hardware to run this build on, we are unable
to test this build.
Current known issues:
1) While the script and edited CMakeLists.txt creates the
ability to align to the next power of 2, this does not
address the shortage of available MPU regions on certain
devices (e.g. 96b_carbon). In testing the APB and PPB
regions were commented out.
2) checkpatch.pl lists several issues regarding the
following:
a) Complex macros. The FOR_EACH macros as defined in
app_macro_support.h are listed as complex macros needing
parentheses. Adding parentheses breaks their
functionality, and we have otherwise been unable to
resolve the reported error.
b) __aligned() preferred. The _app_dmem_pad() and
_app_bmem_pad() macros give warnings that __aligned()
is preferred. Prior iterations had this implementation,
which resulted in errors due to "complex macros".
c) Trailing semicolon. The macro init_part(name) has
a trailing semicolon as the semicolon is needed for the
inlined macro call that is generated when this macro
expands.
Update: updated to alternative CONFIG_APPLCATION_MEMORY.
Added config option CONFIG_APP_SHARED_MEM to enable a new section
app_smem to contain the shared memory component. This commit
seperates the Kconfig definition from the definition used for the
conditional code. The change is in response to changes in the
way the build system treats definitions. The python script used
to generate a linker script for app_smem was also midified to
simplify the alignment directives. A default linker script
app_smem.ld was added to remove the conditional includes dependency
on CONFIG_APP_SHARED_MEM. By addining the default linker script
the prebuild stages link properly prior to the python script running
Signed-off-by: Joshua Domagalski <jedomag@tycho.nsa.gov>
Signed-off-by: Shawn Mosley <smmosle@tycho.nsa.gov>
Forthcoming patches will dual-purpose an object's permission
bitfield as also reference tracking for kernel objects, used to
handle automatic freeing of resources.
We do not want to allow user thread A to revoke thread B's access
to some object O if B is in the middle of an API call using O.
However we do want to allow threads to revoke their own access to
an object, so introduce a new API and syscall for that.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
The read/write_kernel_stack tests are confusingly named and incorrectly
implemented for ARM; they are intended to test that user mode threads
cannot read or write their privileged stacks. The privileged stacks
on ARM are not relative to the user stack, and thus their location
cannot be computed from the user stack. To find the privileged stack on
ARM, we have to use _k_priv_stack_find(), which we do during setup
in test_main() rather than from the usermode thread itself. Accessing
thread_stack directly from the test function requires making it
non-static in ztest, so we also give it a ztest_ prefix to avoid
collisions with other test programs. Rename the test functions and
global pointer variable to more accurately reflect their purpose.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
This patch adjusts the calculation of the overflow size for the kernel
stack tests which read/write to areas below the current user stack.
Signed-off-by: Andy Gross <andy.gross@linaro.org>
Check the fault reason against the expected value.
This is presently architecture-specific, and possibly
reflects a bug on ARM (all faults end up with reason 0,
even though ARM does define a separate value for Oops).
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Previously we were handling any fault during test execution as
a pass condition. Explicitly indicate when a fault is expected
and fail the test if we encounter an unexpected fault.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Tests system call memory buffer read/write validation using the
k_pipe_get() and k_pipe_put() calls from a userspace thread.
Specifically, this tests _SYSCALL_MEMORY_READ/WRITE checks
by the system call handler by attempting to read/write to a
kernel object.
write_kobject_user_pipe() attempts to write over a kernel object
by using the kernel object's location as the buffer to place
the data read from the pipe.
read_kobject_user_pipe() attempts to read a kernel object by using
the kernel object's location as the location of data to be placed
into the pipe.
Tested on qemu_x86 and frdm_k64, passes on both.
Signed-off-by: Joshua Domagalski <jedomag@tycho.nsa.gov>
Added three tests for kernel objects focusing on 1) revoking
access to a k_object that the thread does not have
permissions to access, 2) accessing a k_object after
permissions to access it were revoked, and 3) trying to
revoke access to a k_object from a parent thread by a
child thread. Additionally, added a test for
k_thread_user_mode_enter().
revoke_noperms_object() tests by calling
k_object_access_revoke() on a semaphore (kernel object) that it
does not have access to (ksem).
access_after_revoke() tests ability to access a semaphore after
access has been revoked by itself.
revoke_other_thread() tests whether a thread can revoke access
for an object for which it has permissions from a thread for
which it does not have permissions.
user_mode_enter() tests whether k_thread_user_mode_enter()
truly enters user mode.
Tested on qemu_x86 and frdm_k64 with pr-4974 applied, passes
on qemu_x86 but requires small fix for ARM (will submit
separately).
Signed-off-by: Joshua Domagalski <jedomag@tycho.nsa.gov>
Add tests of the ability to read or write the stack of another thread.
Use semaphores for explicit synchronization of the start and end of the
other thread to ensure that the attempted stack access occurs while the
thread is alive. This ensures that the MMU/MPU has been configured at
least once to allow userspace access to the stack, and that any
removal of access upon thread termination has not yet occurred. This
therefore should exercise changing the MMU/MPU configuration to remove
access to the other thread's stack when switching back to our
thread.
Tested on qemu_x86 (pass) and on frdm_k64f (with and without the ARM
userspace patches; with them, the tests pass; without, they fail as
expected). Also, as with most of the other tests, if you replace
ztest_user_unit_test() with ztest_unit_test(), then the tests fail as
expected.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
This patch removes the extraneous priv_insn test as it is a duplicate
of the following test that writes to the control register. For ARM,
unprivileged contexts which access control registers does not result
in a fault. It results in no modification of the register, so we have
to check that a modification occurred.
Signed-off-by: Andy Gross <andy.gross@linaro.org>
This patch fixes the calculation of the privileged stack portion. The
ztest threads have a stack size of 2048. The privileged area resides in
the lowest 512 bytes. So use the definition of the stack size to get to
the right area.
Signed-off-by: Andy Gross <andy.gross@linaro.org>
This is still work-in-progress, but putting it up in case it is
helpful to people working in this area and for early comments.
Add a set of tests to validate the expected security properties
of threads created with K_USER when CONFIG_USERSPACE=y. This can
be used as a regression test for architectures that already implement
this support and as a validation test for others.
I considered incorporating these tests into the existing protection
test, but decided against it since protection does not enable or rely
upon CONFIG_USERSPACE for its existing tests and passes on everything
that provides MPU or MMU support, even without full userspace support.
I also considered incorporating these tests into the existing
obj_validation test, but decided against it since obj_validation only
tests the object validation/permission logic, does not run any user
mode threads (or strictly depend on that support), and passes
on both x86 and arm today, unlike these tests. That said, I have no
strong objections if it would be preferable to fold these into it
(and perhaps rename it to be more general).
The current tests implemented in this test program verify the following
for a thread created with K_USER:
is_usermode: is running in usermode
priv_insn: cannot invoke privileged insns directly
write_control: cannot write to control registers
disable_mmu_mpu: cannot disable memory protections (MMU/MPU)
read_kernram: cannot read from kernel RAM
write_kernram: cannot write to kernel RAM
write_kernro: cannot write to kernel rodata
write_kerntext: cannot write to kernel text
read_kernel_data: cannot read __kernel-marked data
write_kernel_data: cannot write __kernel-marked data
read_kernel_stack: cannot read the kernel/privileged stack
write_kernel_stack: cannot write the kernel/privileged stack
pass_user_object: cannot pass a non-kernel object to a syscall
pass_noperms_object: cannot pass an object to a syscall without a grant
start_kernel_thread: cannot start a kernel (non-user) thread
Some of the tests overlap and could possibly be dropped, but it
seems harmless to retain them. The particular targets of read/write
tests are arbitrary other than meeting the test criteria and can be
changed (e.g. in data, rodata, or text) if desired to avoid coupling
to kernel implementation details that may change in the future.
On qemu_x86, all of the tests pass. And, if you replace all
occurrences of ztest_user_unit_test() with ztest_unit_test(), then
all of the tests fail (i.e. when the tests are run in kernel mode,
they all fail as expected). On frdm_k64f presently (w/o the arm
userspace patches), all of the tests fail except for write_kernro and
write_kerntext, as expected.
ToDo:
- Verify that a user thread cannot access data in another memory domain.
- Verify that a user thread cannot access another thread's stack.
- Verify that a user thread cannot access another thread's kobject.
- Verify that k_thread_user_mode_enter() transitions correctly.
- Verify that k_object_access_revoke() is enforced.
- Verify that syscalls return to user mode upon completion.
- Verify that a user thread cannot abuse other svc calls (ARM-specific).
- Other suggested properties we should be testing?
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
