Coverage tools like LLVM's source-based coverage or GNU's --coverage
need to be able to write out coverage files from any binary, regardless
of its security posture. Not ignoring these pledges and veils means we
can't get our coverage data out without playing some serious tricks.
However this is pretty terrible for normal exeuction, so only skip these
checks when we explicitly configured userspace for coverage.
Error codes can leak information about veiled paths, if the path
resolution fails with e.g. EACCESS.
This is non-trivial to fix, as there is a group of error codes we want
to propagate to the caller, such as ENOMEM.
VirtualFileSystem::mkdir() relies on resolve_path() returning an error,
since it is only interested in the out_parent passed as a pointer. Since
resolve_path_without_veil returns an error, no process veil validation
is done by resolve_path() in that case. Due to this problem, mkdir()
should use resolve_path_without_veil() and then manually validate if the
parent directory of the to-be-created directory is unveiled with 'c'
permissions.
This fixes a bug where the mkdir syscall would not respect the process
veil at all.
Previously, VirtualFileSystem::resolve_path() could return a non-null
RefPtr<Custody>* out_parent even if the function errored because the
path has been veiled.
If code relies on recieving the parent custody even if the path is
veiled, it should just call resolve_path_without_veil and do the veil
validation manually. This is because it could be that the parent is
unveiled but the child isn't or the other way round.
Before this commit all consume_until overloads aside from the Predicate
one would consume (and ignore) the stop char/string, while the
Predicate overload would not, in order to keep behaviour consistent,
the other overloads no longer consume the stop char/string as well.
This function is an extended version of `chmod(2)` that lets one control
whether to dereference symlinks, and specify a file descriptor to a
directory that will be used as the base for relative paths.
This modifies sys$chown to allow specifying whether or not to follow
symlinks and in which directory.
This was then used to implement lchown and fchownat in LibC and LibCore.
As pointed out by BertalanD on Discord, POSIX specifies that
_SC_SYMLOOP_MAX (implemented in the following commit) always needs to be
equal or more than _POSIX_SYMLOOP_MAX (8, defined in
LibC/bits/posix1_lim.h), hence I've increased it to that value to
comply with the standard.
The move to header is required for the following commit - to make this
constant accessible outside of the VFS class, namely in sysconf.
This fixes at least half of our LibC includes in the kernel. The source
of truth for errno codes and their description strings now lives in
Kernel/API/POSIX/errno.h as an enumeration, which LibC includes.
We now use AK::Error and AK::ErrorOr<T> in both kernel and userspace!
This was a slightly tedious refactoring that took a long time, so it's
not unlikely that some bugs crept in.
Nevertheless, it does pass basic functionality testing, and it's just
real nice to finally see the same pattern in all contexts. :^)
Found due to smelly code in InodeFile::absolute_path.
In particular, this replaces the following misleading methods:
File::absolute_path
This method *never* returns an actual path, and if called on an
InodeFile (which is impossible), it would VERIFY_NOT_REACHED().
OpenFileDescription::try_serialize_absolute_path
OpenFileDescription::absolute_path
These methods do not guarantee to return an actual path (just like the
other method), and just like Custody::absolute_path they do not
guarantee accuracy. In particular, just renaming the method made a
TOCTOU bug obvious.
The new method signatures use KResultOr, just like
try_serialize_absolute_path() already did.
This singleton simplifies many aspects that we struggled with before:
1. There's no need to make derived classes of Device expose the
constructor as public anymore. The singleton is a friend of them, so he
can call the constructor. This solves the issue with try_create_device
helper neatly, hopefully for good.
2. Getting a reference of the NullDevice is now being done from this
singleton, which means that NullDevice no longer needs to use its own
singleton, and we can apply the try_create_device helper on it too :)
3. We can now defer registration completely after the Device constructor
which means the Device constructor is merely assigning the major and
minor numbers of the Device, and the try_create_device helper ensures it
calls the after_inserting method immediately after construction. This
creates a great opportunity to make registration more OOM-safe.
Don't create these device nodes in the Kernel, so we essentially enforce
userspace (SystemServer) to take control of this operation and to decide
how to create these device nodes.
This makes the DevFS to resemble linux devtmpfs, and allows us to remove
a bunch of unneeded overriding implementations of device name creation
in the Kernel.
- Renamed try_create_absolute_path() => try_serialize_absolute_path()
- Use KResultOr and TRY() to propagate errors
- Don't call this when it's only for debug logging
Prior to this change, both uid_t and gid_t were typedef'ed to `u32`.
This made it easy to use them interchangeably. Let's not allow that.
This patch adds UserID and GroupID using the AK::DistinctNumeric
mechanism we've already been employing for pid_t/ProcessID.
This has several benefits:
1) We no longer just blindly derefence a null pointer in various places
2) We will get nicer runtime error messages if the current process does
turn out to be null in the call location
3) GCC no longer complains about possible nullptr dereferences when
compiling without KUBSAN
This is primarily to be able to remove the GenericLexer include out of
Format.h as well. A subsequent commit will add AK::Result to
GenericLexer, which will cause naming conflicts with other structures
named Result. This can be avoided (for now) by preventing nearly every
file in the system from implicitly including GenericLexer.
Other changes in this commit are to add the GenericLexer include to
files where it is missing.
We are not using this for anything and it's just been sitting there
gathering dust for well over a year, so let's stop carrying all this
complexity around for no good reason.
This patch removes KResult::operator int() and deals with the fallout.
This forces a lot of code to be more explicit in its handling of errors,
greatly improving readability.
To count the remaining children, we simply need to traverse the
directory and increment a counter. No need for a custom virtual that
all file systems have to implement. :^)
Previously, VirtualFileSystem::mkdir() would always return ENOENT if
no parent custody was returned by resolve_path(). This is incorrect when
e.g. the user has no search permission in a component of the path
prefix (=> EACCES), or if on component of the path prefix is a file (=>
ENOTDIR). This patch fixes that behavior.
