In general driver system calls are implemented at a subsystem
layer. However, some drivers may have capabilities specific to
the hardware not covered by the subsystem API. Such drivers may
want to define their own system calls.
This macro makes it simple to validate in the driver-specific
system call handlers that not only does the untrusted device
pointer correspond to the expected subsystem, initialization
state, and caller permissions, but also that the device object
is an instance of a specific driver (and not just any driver in
that subsystem).
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
The function that checks if an object is valid is essentially a boolean
function. Just changing its return type to reflect it.
MISRA-C rule 14.4
Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
The builtin function __builtin_umul_overflow returns a boolean and
should not checked as an integer.
Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
According C99 the first 31 characters of an identifier must be unique.
Shortening the namespace of the generated objects to achieve it.
C99 - 5.2.4.1
MISRA-C rule 5.1
Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
MISRA C requires that every controlling expression of and if or while
statement have a boolean type.
Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
Any word started with underscore followed by and uppercase letter or a
second underscore is a reserved word according with C99.
With have *many* violations on Zephyr's code, this commit is tackling
only the violations caused by headers guards. It also takes the
opportunity to normalize them using the filename in uppercase and
replacing dot with underscore. e.g file.h -> FILE_H
Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
We now have functions for handling all the details of copying
data to/from user mode, including C strings and copying data
into resource pool allocations.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
The various macros to do checks in system call handlers all
implictly would generate a kernel oops if a check failed.
This is undesirable for a few reasons:
* System call handlers that acquire resources in the handler
have no good recourse for cleanup if a check fails.
* In some cases we may want to propagate a return value back
to the caller instead of just killing the calling thread,
even though the base API doesn't do these checks.
These macros now all return a value, if nonzero is returned
the check failed. K_OOPS() now wraps these calls to generate
a kernel oops.
At the moment, the policy for all APIs has not changed. They
still all oops upon a failed check/
The macros now use the Z_ notation for private APIs.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Driver APIs might not implement all operations, making it possible for
a user thread to get the kernel to execute a function at 0x00000000.
Perform runtime checks in all the driver handlers, checking if they're
capable of performing the requested operation.
Fixes#6907.
Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>
Rename the nano_internal.h to kernel_internal.h and modify the
header file name accordingly wherever it is used.
Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com>
We also need macros to assert that an object must be in an
uninitialized state. This will be used for validating thread
and stack objects to k_thread_create(), which must not be already
in use.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
It's currently too easy to run out of thread IDs as they
are never re-used on thread exit.
Now the kernel maintains a bitfield of in-use thread IDs,
updated on thread creation and termination. When a thread
exits, the permission bitfield for all kernel objects is
updated to revoke access for that retired thread ID, so that
a new thread re-using that ID will not gain access to objects
that it should not have.
Because of these runtime updates, setting the permission
bitmap for an object to all ones for a "public" object doesn't
work properly any more; a flag is now set for this instead.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
API to assist with re-using objects, such as terminated threads or
kernel objects returned to a pool.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Use some preprocessor trickery to automatically deduce the amount of
arguments for the various _SYSCALL_HANDLERn() macros. Makes the grunt
work of converting a bunch of kernel APIs to system calls slightly
easier.
Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>
Does the opposite of k_object_access_grant(); the provided thread will
lose access to that kernel object.
If invoked from userspace the caller must hace sufficient access
to that object and permission on the thread being revoked access.
Fix documentation for k_object_access_grant() API to reflect that
permission on the thread parameter is needed as well.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
By default, threads are created only having access to their own thread
object and nothing else. This new flag to k_thread_create() gives the
thread access to all objects that the parent had at the time it was
created, with the exception of the parent thread itself.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
We now have macros which should significantly reduce the amount of
boilerplate involved with defining system call handlers.
- Macros which define the proper prototype based on number of arguments
- "SIMPLE" variants which create handlers that don't need anything
other than object verification
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
- Dumping error messages split from _k_object_validate(), to avoid spam
in test cases that are expected to have failure result.
- _k_object_find() prototype moved to syscall_handler.h
- Clean up k_object_access() implementation to avoid double object
lookup and use single validation function
- Added comments, minor whitespace changes
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Computing the total size of the array need to handle the case where
the product overflow a 32-bit unsigned integer.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Instead of boolean arguments to indicate memory read/write
permissions, or init/non-init APIs, new macros are introduced
which bake the semantics directly into the name of the macro.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Expecting stringified expressions to be completely comprehensible to end
users is wishful thinking; we really need to express what a failed
system call verification step means in human terms in most cases.
Memory buffer and kernel object checks now are implemented in terms of
_SYSCALL_VERIFY_MSG.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This API only gets used inside system call handlers and a specific test
case dedicated to it. Move definition to the private kernel header along
with the rest of the defines for system call handlers.
A non-userspace inline variant of this function is unnecessary and has
been deleted.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Everything get passed to handlers as u32_t, make it simpler to check
something that is known to be a pointer, like we already do with
_SYSCALL_IS_OBJ().
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
- syscall.h now contains those APIs needed to support invoking calls
from user code. Some stuff moved out of main kernel.h.
- syscall_handler.h now contains directives useful for implementing
system call handler functions. This header is not pulled in by
kernel.h and is intended to be used by C files implementing kernel
system calls and driver subsystem APIs.
- syscall_list.h now contains the #defines for system call IDs. This
list is expected to grow quite large so it is put in its own header.
This is now an enumerated type instead of defines to make things
easier as we introduce system calls over the new few months. In the
fullness of time when we desire to have a fixed userspace/kernel ABI,
this can always be converted to defines.
Some new code added:
- _SYSCALL_MEMORY() macro added to check memory regions passed up from
userspace in handler functions
- _syscall_invoke{7...10}() inline functions declare for invoking system
calls with more than 6 arguments. 10 was chosen as the limit as that
corresponds to the largest arg list we currently have
which is for k_thread_create()
Other changes
- auto-generated K_SYSCALL_DECLARE* macros documented
- _k_syscall_table in userspace.c is not a placeholder. There's no
strong need to generate it and doing so would require the introduction
of a third build phase.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
