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https://github.com/opencontainers/runc.git
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Aleksa Sarai
42a1e19d67
These helpers will be needed for the compatibility code added in future patches in this series, but because "internal/pathrs" is imported by "libcontainer/utils" we need to move them so that we can avoid circular dependencies. Because the old functions were in a non-internal package it is possible some downstreams use them, so add some wrappers but mark them as deprecated. Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
85 lines
2.9 KiB
Go
85 lines
2.9 KiB
Go
// SPDX-License-Identifier: Apache-2.0
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/*
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* Copyright (C) 2024-2025 Aleksa Sarai <cyphar@cyphar.com>
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* Copyright (C) 2024-2025 SUSE LLC
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package pathrs
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import (
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"os"
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"path/filepath"
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"strings"
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)
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// IsLexicallyInRoot is shorthand for strings.HasPrefix(path+"/", root+"/"),
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// but properly handling the case where path or root have a "/" suffix.
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//
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// NOTE: The return value only make sense if the path is already mostly cleaned
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// (i.e., doesn't contain "..", ".", nor unneeded "/"s).
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func IsLexicallyInRoot(root, path string) bool {
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root = strings.TrimRight(root, "/")
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path = strings.TrimRight(path, "/")
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return strings.HasPrefix(path+"/", root+"/")
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}
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// LexicallyCleanPath makes a path safe for use with filepath.Join. This is
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// done by not only cleaning the path, but also (if the path is relative)
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// adding a leading '/' and cleaning it (then removing the leading '/'). This
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// ensures that a path resulting from prepending another path will always
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// resolve to lexically be a subdirectory of the prefixed path. This is all
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// done lexically, so paths that include symlinks won't be safe as a result of
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// using CleanPath.
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func LexicallyCleanPath(path string) string {
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// Deal with empty strings nicely.
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if path == "" {
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return ""
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}
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// Ensure that all paths are cleaned (especially problematic ones like
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// "/../../../../../" which can cause lots of issues).
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if filepath.IsAbs(path) {
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return filepath.Clean(path)
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}
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// If the path isn't absolute, we need to do more processing to fix paths
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// such as "../../../../<etc>/some/path". We also shouldn't convert absolute
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// paths to relative ones.
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path = filepath.Clean(string(os.PathSeparator) + path)
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// This can't fail, as (by definition) all paths are relative to root.
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path, _ = filepath.Rel(string(os.PathSeparator), path)
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return path
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}
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// LexicallyStripRoot returns the passed path, stripping the root path if it
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// was (lexicially) inside it. Note that both passed paths will always be
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// treated as absolute, and the returned path will also always be absolute. In
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// addition, the paths are cleaned before stripping the root.
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func LexicallyStripRoot(root, path string) string {
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// Make the paths clean and absolute.
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root, path = LexicallyCleanPath("/"+root), LexicallyCleanPath("/"+path)
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switch {
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case path == root:
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path = "/"
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case root == "/":
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// do nothing
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default:
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path = strings.TrimPrefix(path, root+"/")
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}
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return LexicallyCleanPath("/" + path)
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}
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