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https://github.com/LadybirdBrowser/ladybird.git
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2cb32f8356
First of all, this fixes a dumb info leak where we'd write kernel heap addresses (StringImpl*) into userspace memory when reading a watcher. Instead of trying to pass names to userspace, we now simply pass the child inode index. Nothing in userspace makes use of this yet anyway, so it's not like we're breaking anything. We'll see how this evolves.
114 lines
3.5 KiB
C++
114 lines
3.5 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <AK/Memory.h>
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#include <Kernel/FileSystem/Inode.h>
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#include <Kernel/FileSystem/InodeWatcher.h>
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namespace Kernel {
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NonnullRefPtr<InodeWatcher> InodeWatcher::create(Inode& inode)
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{
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return adopt(*new InodeWatcher(inode));
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}
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InodeWatcher::InodeWatcher(Inode& inode)
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: m_inode(inode.make_weak_ptr())
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{
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inode.register_watcher({}, *this);
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}
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InodeWatcher::~InodeWatcher()
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{
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if (RefPtr<Inode> safe_inode = m_inode.ptr())
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safe_inode->unregister_watcher({}, *this);
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}
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bool InodeWatcher::can_read(const FileDescription&, size_t) const
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{
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return !m_queue.is_empty() || !m_inode;
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}
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bool InodeWatcher::can_write(const FileDescription&, size_t) const
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{
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return true;
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}
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KResultOr<size_t> InodeWatcher::read(FileDescription&, size_t, UserOrKernelBuffer& buffer, size_t buffer_size)
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{
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LOCKER(m_lock);
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ASSERT(!m_queue.is_empty() || !m_inode);
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if (!m_inode)
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return 0;
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auto event = m_queue.dequeue();
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if (buffer_size < sizeof(Event))
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return buffer_size;
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size_t bytes_to_write = min(buffer_size, sizeof(event));
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ssize_t nwritten = buffer.write_buffered<sizeof(event)>(bytes_to_write, [&](u8* data, size_t data_bytes) {
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memcpy(data, &event, bytes_to_write);
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return (ssize_t)data_bytes;
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});
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if (nwritten < 0)
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return KResult(nwritten);
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return bytes_to_write;
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}
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KResultOr<size_t> InodeWatcher::write(FileDescription&, size_t, const UserOrKernelBuffer&, size_t)
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{
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return KResult(-EIO);
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}
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String InodeWatcher::absolute_path(const FileDescription&) const
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{
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if (!m_inode)
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return "InodeWatcher:(gone)";
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return String::format("InodeWatcher:%s", m_inode->identifier().to_string().characters());
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}
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void InodeWatcher::notify_inode_event(Badge<Inode>, Event::Type event_type)
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{
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LOCKER(m_lock);
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m_queue.enqueue({ event_type });
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}
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void InodeWatcher::notify_child_added(Badge<Inode>, const InodeIdentifier& child_id)
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{
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LOCKER(m_lock);
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m_queue.enqueue({ Event::Type::ChildAdded, child_id.index() });
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}
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void InodeWatcher::notify_child_removed(Badge<Inode>, const InodeIdentifier& child_id)
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{
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LOCKER(m_lock);
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m_queue.enqueue({ Event::Type::ChildRemoved, child_id.index() });
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}
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}
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