ladybird/Kernel/Syscalls/process.cpp
Brian Gianforcaro 54b9a4ec1e Kernel: Handle promise violations in the syscall handler
Previously we would crash the process immediately when a promise
violation was found during a syscall. This is error prone, as we
don't unwind the stack. This means that in certain cases we can
leak resources, like an OwnPtr / RefPtr tracked on the stack. Or
even leak a lock acquired in a ScopeLockLocker.

To remedy this situation we move the promise violation handling to
the syscall handler, right before we return to user space. This
allows the code to follow the normal unwind path, and grantees
there is no longer any cleanup that needs to occur.

The Process::require_promise() and Process::require_no_promises()
functions were modified to return ErrorOr<void> so we enforce that
the errors are always propagated by the caller.
2021-12-29 18:08:15 +01:00

66 lines
1.9 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Types.h>
#include <Kernel/Process.h>
namespace Kernel {
ErrorOr<FlatPtr> Process::sys$getpid()
{
VERIFY_NO_PROCESS_BIG_LOCK(this)
TRY(require_promise(Pledge::stdio));
return pid().value();
}
ErrorOr<FlatPtr> Process::sys$getppid()
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
TRY(require_promise(Pledge::stdio));
return m_protected_values.ppid.value();
}
ErrorOr<FlatPtr> Process::sys$get_process_name(Userspace<char*> buffer, size_t buffer_size)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
TRY(require_promise(Pledge::stdio));
if (m_name->length() + 1 > buffer_size)
return ENAMETOOLONG;
TRY(copy_to_user(buffer, m_name->characters(), m_name->length() + 1));
return 0;
}
ErrorOr<FlatPtr> Process::sys$set_process_name(Userspace<const char*> user_name, size_t user_name_length)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
TRY(require_promise(Pledge::proc));
if (user_name_length > 256)
return ENAMETOOLONG;
auto name = TRY(try_copy_kstring_from_user(user_name, user_name_length));
// Empty and whitespace-only names only exist to confuse users.
if (name->view().is_whitespace())
return EINVAL;
m_name = move(name);
return 0;
}
ErrorOr<FlatPtr> Process::sys$set_coredump_metadata(Userspace<const Syscall::SC_set_coredump_metadata_params*> user_params)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
auto params = TRY(copy_typed_from_user(user_params));
if (params.key.length == 0 || params.key.length > 16 * KiB)
return EINVAL;
if (params.value.length > 16 * KiB)
return EINVAL;
auto key = TRY(try_copy_kstring_from_user(params.key));
auto value = TRY(try_copy_kstring_from_user(params.value));
TRY(set_coredump_property(move(key), move(value)));
return 0;
}
}