ladybird/Kernel/Syscalls/getuid.cpp
Andreas Kling 90c0f9664e Kernel: Don't keep protected Process data in a separate allocation
The previous architecture had a huge flaw: the pointer to the protected
data was itself unprotected, allowing you to overwrite it at any time.

This patch reorganizes the protected data so it's part of the Process
class itself. (Actually, it's a new ProcessBase helper class.)

We use the first 4 KB of Process objects themselves as the new storage
location for protected data. Then we make Process objects page-aligned
using MAKE_ALIGNED_ALLOCATED.

This allows us to easily turn on/off write-protection for everything in
the ProcessBase portion of Process. :^)

Thanks to @bugaevc for pointing out the flaw! This is still not perfect
but it's an improvement.
2021-03-11 14:21:49 +01:00

88 lines
2.7 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <Kernel/Process.h>
namespace Kernel {
KResultOr<uid_t> Process::sys$getuid()
{
REQUIRE_PROMISE(stdio);
return uid();
}
KResultOr<gid_t> Process::sys$getgid()
{
REQUIRE_PROMISE(stdio);
return gid();
}
KResultOr<uid_t> Process::sys$geteuid()
{
REQUIRE_PROMISE(stdio);
return euid();
}
KResultOr<gid_t> Process::sys$getegid()
{
REQUIRE_PROMISE(stdio);
return egid();
}
KResultOr<int> Process::sys$getresuid(Userspace<uid_t*> ruid, Userspace<uid_t*> euid, Userspace<uid_t*> suid)
{
REQUIRE_PROMISE(stdio);
if (!copy_to_user(ruid, &m_uid) || !copy_to_user(euid, &m_euid) || !copy_to_user(suid, &m_suid))
return EFAULT;
return 0;
}
KResultOr<int> Process::sys$getresgid(Userspace<gid_t*> rgid, Userspace<gid_t*> egid, Userspace<gid_t*> sgid)
{
REQUIRE_PROMISE(stdio);
if (!copy_to_user(rgid, &m_gid) || !copy_to_user(egid, &m_egid) || !copy_to_user(sgid, &m_sgid))
return EFAULT;
return 0;
}
KResultOr<int> Process::sys$getgroups(ssize_t count, Userspace<gid_t*> user_gids)
{
REQUIRE_PROMISE(stdio);
if (count < 0)
return EINVAL;
if (!count)
return extra_gids().size();
if (count != (int)extra_gids().size())
return EINVAL;
if (!copy_to_user(user_gids, extra_gids().data(), sizeof(gid_t) * count))
return EFAULT;
return 0;
}
}