Commit graph

23 commits

Author SHA1 Message Date
Brian Gianforcaro
9201a06027 Kernel: Annotate all syscalls with VERIFY_PROCESS_BIG_LOCK_ACQUIRED
Before we start disabling acquisition of the big process lock for
specific syscalls, make sure to document and assert that all the
lock is held during all syscalls.
2021-07-20 03:21:14 +02:00
Liav A
7c87891c06 Kernel: Don't copy a Vector<FileDescriptionAndFlags>
Instead of copying a Vector everytime we need to enumerate a Process'
file descriptions, we can just temporarily lock so it won't change.
2021-06-29 20:53:59 +02:00
Gunnar Beutner
2a78bf8596 Kernel: Fix the return type for syscalls
The Process::Handler type has KResultOr<FlatPtr> as its return type.
Using a different return type with an equally-sized template parameter
sort of works but breaks once that condition is no longer true, e.g.
for KResultOr<int> on x86_64.

Ideally the syscall handlers would also take FlatPtrs as their args
so we can get rid of the reinterpret_cast for the function pointer
but I didn't quite feel like cleaning that up as well.
2021-06-28 22:29:28 +02:00
Gunnar Beutner
bc3076f894 Kernel: Remove various other uses of ssize_t 2021-06-16 21:29:36 +02:00
Brian Gianforcaro
454d2fd42a Kernel: Harden sys$readv / sys$writev Vector usage against OOM. 2021-04-29 20:31:15 +02:00
Brian Gianforcaro
1682f0b760 Everything: Move to SPDX license identifiers in all files.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.

See: https://spdx.dev/resources/use/#identifiers

This was done with the `ambr` search and replace tool.

 ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
2021-04-22 11:22:27 +02:00
Brian Gianforcaro
5f6ab77352 Kernel: Add bitwise operators for Thread::FileBlocker::BlockFlags enum
Switch to using type-safe bitwise operators for the BlockFlags class,
this cleans up a lot of boilerplate casts which are necessary when the
enum is declared as `enum class`.
2021-03-08 18:47:40 +01:00
Andreas Kling
ac71775de5 Kernel: Make all syscall functions return KResultOr<T>
This makes it a lot easier to return errors since we no longer have to
worry about negating EFOO errors and can just return them flat.
2021-03-01 13:54:32 +01:00
Ben Wiederhake
fbb85f9b2f Kernel: Refuse excessively long iovec list, also in readv
This bug is a good example why copy-paste code should eventually be eliminated
from the code base: Apparently the code was copied from read.cpp before
c6027ed7cc, so the same bug got introduced here.

To recap: A malicious program can ask the Kernel to prepare sys-ing to
a huge amount of iovecs. The Kernel must first copy all the vector locations
into 'vecs', and before that allocates an arbitrary amount of memory:
    vecs.resize(iov_count);
This can cause Kernel memory exhaustion, triggered by any malicious userland
program.
2021-02-15 22:09:01 +01:00
AnotherTest
a3a7ab83c4 Kernel+LibC: Implement readv
We already had writev, so let's just add readv too.
2021-02-15 17:32:56 +01:00
AnotherTest
09a43969ba Everywhere: Replace dbgln<flag>(...) with dbgln_if(flag, ...)
Replacement made by `find Kernel Userland -name '*.h' -o -name '*.cpp' | sed -i -Ee 's/dbgln\b<(\w+)>\(/dbgln_if(\1, /g'`
2021-02-08 18:08:55 +01:00
asynts
7cf0c7cc0d Meta: Split debug defines into multiple headers.
The following script was used to make these changes:

    #!/bin/bash
    set -e

    tmp=$(mktemp -d)

    echo "tmp=$tmp"

    find Kernel \( -name '*.cpp' -o -name '*.h' \) | sort > $tmp/Kernel.files
    find . \( -path ./Toolchain -prune -o -path ./Build -prune -o -path ./Kernel -prune \) -o \( -name '*.cpp' -o -name '*.h' \) -print | sort > $tmp/EverythingExceptKernel.files

    cat $tmp/Kernel.files | xargs grep -Eho '[A-Z0-9_]+_DEBUG' | sort | uniq > $tmp/Kernel.macros
    cat $tmp/EverythingExceptKernel.files | xargs grep -Eho '[A-Z0-9_]+_DEBUG' | sort | uniq > $tmp/EverythingExceptKernel.macros

    comm -23 $tmp/Kernel.macros $tmp/EverythingExceptKernel.macros > $tmp/Kernel.unique
    comm -1 $tmp/Kernel.macros $tmp/EverythingExceptKernel.macros > $tmp/EverythingExceptKernel.unique

    cat $tmp/Kernel.unique | awk '{ print "#cmakedefine01 "$1 }' > $tmp/Kernel.header
    cat $tmp/EverythingExceptKernel.unique | awk '{ print "#cmakedefine01 "$1 }' > $tmp/EverythingExceptKernel.header

    for macro in $(cat $tmp/Kernel.unique)
    do
        cat $tmp/Kernel.files | xargs grep -l $macro >> $tmp/Kernel.new-includes ||:
    done
    cat $tmp/Kernel.new-includes | sort > $tmp/Kernel.new-includes.sorted

    for macro in $(cat $tmp/EverythingExceptKernel.unique)
    do
        cat $tmp/Kernel.files | xargs grep -l $macro >> $tmp/Kernel.old-includes ||:
    done
    cat $tmp/Kernel.old-includes | sort > $tmp/Kernel.old-includes.sorted

    comm -23 $tmp/Kernel.new-includes.sorted $tmp/Kernel.old-includes.sorted > $tmp/Kernel.includes.new
    comm -13 $tmp/Kernel.new-includes.sorted $tmp/Kernel.old-includes.sorted > $tmp/Kernel.includes.old
    comm -12 $tmp/Kernel.new-includes.sorted $tmp/Kernel.old-includes.sorted > $tmp/Kernel.includes.mixed

    for file in $(cat $tmp/Kernel.includes.new)
    do
        sed -i -E 's/#include <AK\/Debug\.h>/#include <Kernel\/Debug\.h>/' $file
    done

    for file in $(cat $tmp/Kernel.includes.mixed)
    do
        echo "mixed include in $file, requires manual editing."
    done
2021-01-26 21:20:00 +01:00
asynts
8465683dcf Everywhere: Debug macros instead of constexpr.
This was done with the following script:

    find . \( -name '*.cpp' -o -name '*.h' -o -name '*.in' \) -not -path './Toolchain/*' -not -path './Build/*' -exec sed -i -E 's/dbgln<debug_([a-z_]+)>/dbgln<\U\1_DEBUG>/' {} \;

    find . \( -name '*.cpp' -o -name '*.h' -o -name '*.in' \) -not -path './Toolchain/*' -not -path './Build/*' -exec sed -i -E 's/if constexpr \(debug_([a-z0-9_]+)/if constexpr \(\U\1_DEBUG/' {} \;
2021-01-25 09:47:36 +01:00
asynts
7b0a1a98d9 Everywhere: Replace a bundle of dbg with dbgln.
These changes are arbitrarily divided into multiple commits to make it
easier to find potentially introduced bugs with git bisect.
2021-01-22 22:14:30 +01:00
Lenny Maiorani
e6f907a155 AK: Simplify constructors and conversions from nullptr_t
Problem:
- Many constructors are defined as `{}` rather than using the ` =
  default` compiler-provided constructor.
- Some types provide an implicit conversion operator from `nullptr_t`
  instead of requiring the caller to default construct. This violates
  the C++ Core Guidelines suggestion to declare single-argument
  constructors explicit
  (https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#c46-by-default-declare-single-argument-constructors-explicit).

Solution:
- Change default constructors to use the compiler-provided default
  constructor.
- Remove implicit conversion operators from `nullptr_t` and change
  usage to enforce type consistency without conversion.
2021-01-12 09:11:45 +01:00
Tom
046d6855f5 Kernel: Move block condition evaluation out of the Scheduler
This makes the Scheduler a lot leaner by not having to evaluate
block conditions every time it is invoked. Instead evaluate them as
the states change, and unblock threads at that point.

This also implements some more waitid/waitpid/wait features and
behavior. For example, WUNTRACED and WNOWAIT are now supported. And
wait will now not return EINTR when SIGCHLD is delivered at the
same time.
2020-11-30 13:17:02 +01:00
Tom
c8d9f1b9c9 Kernel: Make copy_to/from_user safe and remove unnecessary checks
Since the CPU already does almost all necessary validation steps
for us, we don't really need to attempt to do this. Doing it
ourselves doesn't really work very reliably, because we'd have to
account for other processors modifying virtual memory, and we'd
have to account for e.g. pages not being able to be allocated
due to insufficient resources.

So change the copy_to/from_user (and associated helper functions)
to use the new safe_memcpy, which will return whether it succeeded
or not. The only manual validation step needed (which the CPU
can't perform for us) is making sure the pointers provided by user
mode aren't pointing to kernel mappings.

To make it easier to read/write from/to either kernel or user mode
data add the UserOrKernelBuffer helper class, which will internally
either use copy_from/to_user or directly memcpy, or pass the data
through directly using a temporary buffer on the stack.

Last but not least we need to keep syscall params trivial as we
need to copy them from/to user mode using copy_from/to_user.
2020-09-13 21:19:15 +02:00
Ben Wiederhake
eac3bbdcee Kernel: Unbreak building with extra debug macros, part 1 2020-08-30 09:43:49 +02:00
Andreas Kling
7a3ab6c517 Kernel: Make File::write() and File::read() return KResultOr<size_t>
Instead of returning a ssize_t where negative values mean error,
we now return KResultOr<size_t> and use the error state to report
errors exclusively.
2020-08-04 18:17:16 +02:00
Tom
f4a5c9b6c2 Kernel: Consolidate timeout logic
Allow passing in an optional timeout to Thread::block and move
the timeout check out of Thread::Blocker. This way all Blockers
implicitly support timeouts and don't need to implement it
themselves. Do however allow them to override timeouts (e.g.
for sockets).
2020-08-03 18:23:00 +02:00
Andreas Kling
628b3badfb Kernel+AK: Add and use Userspace<T>::unsafe_userspace_ptr()
Since we already have the type information in the Userspace template,
it was a bit silly to cast manually everywhere. Just add a sufficiently
scary-sounding getter for a typed pointer.

Thanks @alimpfard for pointing out that I was being silly with tossing
out the type.

In the future we may want to make this API non-public as well.
2020-07-31 20:56:48 +02:00
Andreas Kling
314dbc10d4 Kernel: Use Userspace<T> for sys$read() and sys$stat()
Add validation helper overloads as needed.
2020-07-31 16:28:37 +02:00
Andreas Kling
949aef4aef Kernel: Move syscall implementations out of Process.cpp
This is something I've been meaning to do for a long time, and here we
finally go. This patch moves all sys$foo functions out of Process.cpp
and into files in Kernel/Syscalls/.

It's not exactly one syscall per file (although it could be, but I got
a bit tired of the repetitive work here..)

This makes hacking on individual syscalls a lot less painful since you
don't have to rebuild nearly as much code every time. I'm also hopeful
that this makes it easier to understand individual syscalls. :^)
2020-07-30 23:40:57 +02:00