mirror of
https://github.com/SerenityOS/serenity
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d4b65f644e
From now on, we don't allow jailed processes to open all device nodes in /dev, but only allow jailed processes to open /dev/full, /dev/zero, /dev/null, and various TTY and PTY devices (and not including virtual consoles) so we basically restrict applications to what they can do when they are in jail. The motivation for this type of restriction is to ensure that even if a remote code execution occurred, the damage that can be done is very small. We also don't restrict reading and writing on device nodes that were already opened, because that limit seems not useful, especially in the case where we do want to provide an OpenFileDescription to such device but nothing further than that.
53 lines
1.7 KiB
C++
53 lines
1.7 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/Badge.h>
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#include <Kernel/Devices/CharacterDevice.h>
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#include <Kernel/DoubleBuffer.h>
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namespace Kernel {
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class SlavePTY;
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class MasterPTY final : public CharacterDevice {
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public:
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static ErrorOr<NonnullLockRefPtr<MasterPTY>> try_create(unsigned index);
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virtual ~MasterPTY() override;
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unsigned index() const { return m_index; }
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ErrorOr<size_t> on_slave_write(UserOrKernelBuffer const&, size_t);
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bool can_write_from_slave() const;
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void notify_slave_closed(Badge<SlavePTY>);
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bool is_closed() const { return m_closed; }
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virtual ErrorOr<NonnullOwnPtr<KString>> pseudo_path(OpenFileDescription const&) const override;
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private:
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explicit MasterPTY(unsigned index, NonnullOwnPtr<DoubleBuffer> buffer);
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// ^Device
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virtual bool is_openable_by_jailed_processes() const override { return true; }
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// ^CharacterDevice
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virtual ErrorOr<size_t> read(OpenFileDescription&, u64, UserOrKernelBuffer&, size_t) override;
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virtual ErrorOr<size_t> write(OpenFileDescription&, u64, UserOrKernelBuffer const&, size_t) override;
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virtual bool can_read(OpenFileDescription const&, u64) const override;
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virtual bool can_write(OpenFileDescription const&, u64) const override;
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virtual ErrorOr<void> close() override;
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virtual bool is_master_pty() const override { return true; }
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virtual ErrorOr<void> ioctl(OpenFileDescription&, unsigned request, Userspace<void*> arg) override;
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virtual StringView class_name() const override { return "MasterPTY"sv; }
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LockRefPtr<SlavePTY> m_slave;
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unsigned m_index;
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bool m_closed { false };
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NonnullOwnPtr<DoubleBuffer> m_buffer;
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};
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}
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