mirror of
https://github.com/RGBCube/serenity
synced 2025-05-31 10:18:11 +00:00
c05c5a7ff4
Found due to smelly code in InodeFile::absolute_path. In particular, this replaces the following misleading methods: File::absolute_path This method *never* returns an actual path, and if called on an InodeFile (which is impossible), it would VERIFY_NOT_REACHED(). OpenFileDescription::try_serialize_absolute_path OpenFileDescription::absolute_path These methods do not guarantee to return an actual path (just like the other method), and just like Custody::absolute_path they do not guarantee accuracy. In particular, just renaming the method made a TOCTOU bug obvious. The new method signatures use KResultOr, just like try_serialize_absolute_path() already did.
85 lines
2.7 KiB
C++
85 lines
2.7 KiB
C++
/*
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* Copyright (c) 2021, Justin Mietzner <sw1tchbl4d3@sw1tchbl4d3.com>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <Kernel/FileSystem/Custody.h>
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#include <Kernel/FileSystem/VirtualFileSystem.h>
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#include <Kernel/Process.h>
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namespace Kernel {
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KResultOr<FlatPtr> Process::do_statvfs(StringView path, statvfs* buf)
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{
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auto custody = TRY(VirtualFileSystem::the().resolve_path(path, current_directory(), nullptr, 0));
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auto& inode = custody->inode();
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auto& fs = inode.fs();
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statvfs kernelbuf = {};
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kernelbuf.f_bsize = static_cast<u64>(fs.block_size());
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kernelbuf.f_frsize = fs.fragment_size();
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kernelbuf.f_blocks = fs.total_block_count();
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kernelbuf.f_bfree = fs.free_block_count();
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// FIXME: Implement "available blocks" into Filesystem
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kernelbuf.f_bavail = fs.free_block_count();
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kernelbuf.f_files = fs.total_inode_count();
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kernelbuf.f_ffree = fs.free_inode_count();
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kernelbuf.f_favail = fs.free_inode_count(); // FIXME: same as f_bavail
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kernelbuf.f_fsid = 0; // FIXME: Implement "Filesystem ID" into Filesystem
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kernelbuf.f_namemax = 255;
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Custody* current_custody = custody;
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while (current_custody) {
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VirtualFileSystem::the().for_each_mount([&kernelbuf, ¤t_custody](auto& mount) {
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if (¤t_custody->inode() == &mount.guest()) {
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int mountflags = mount.flags();
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int flags = 0;
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if (mountflags & MS_RDONLY)
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flags = flags | ST_RDONLY;
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if (mountflags & MS_NOSUID)
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flags = flags | ST_NOSUID;
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kernelbuf.f_flag = flags;
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current_custody = nullptr;
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return IterationDecision::Break;
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}
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return IterationDecision::Continue;
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});
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if (current_custody) {
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current_custody = current_custody->parent();
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}
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}
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return copy_to_user(buf, &kernelbuf);
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}
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KResultOr<FlatPtr> Process::sys$statvfs(Userspace<const Syscall::SC_statvfs_params*> user_params)
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{
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VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
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REQUIRE_PROMISE(rpath);
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auto params = TRY(copy_typed_from_user(user_params));
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auto path = TRY(get_syscall_path_argument(params.path));
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return do_statvfs(path->view(), params.buf);
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}
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KResultOr<FlatPtr> Process::sys$fstatvfs(int fd, statvfs* buf)
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{
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VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
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REQUIRE_PROMISE(stdio);
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auto description = TRY(fds().open_file_description(fd));
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auto absolute_path = TRY(description->original_absolute_path());
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// FIXME: TOCTOU bug! The file connected to the fd may or may not have been moved, and the name possibly taken by a different file.
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return do_statvfs(absolute_path->view(), buf);
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}
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}
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