luchunliang commented on code in PR #12151: URL: https://github.com/apache/inlong/pull/12151#discussion_r3533400153
########## inlong-agent/agent-installer/src/main/java/org/apache/inlong/agent/installer/validator/ModuleCommandValidator.java: ########## @@ -0,0 +1,449 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.inlong.agent.installer.validator; + +import lombok.Getter; +import org.apache.commons.lang3.StringUtils; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.File; +import java.nio.file.Path; +import java.nio.file.Paths; +import java.util.ArrayList; +import java.util.Arrays; +import java.util.Collections; +import java.util.HashSet; +import java.util.List; +import java.util.Set; + +/** + * Structured whitelist validator applied to raw command strings coming from + * {@code ModuleConfig}. It enforces four layers of defence: + * + * <ol> + * <li><b>Structured splitting</b>: the raw command is split into sub-commands on {@code ;}, + * each sub-command is further split into pipe segments on {@code |}, and every pipe + * segment is tokenized into an {@code argv[]}. Once split this way, {@code ;} and + * {@code |} are Java-side delimiters instead of shell metacharacters.</li> + * <li><b>Metacharacter blacklist</b>: reject the whole command if it contains a backtick, + * {@code $(}, {@code &&}, {@code ||}, {@code >}, {@code >>}, {@code <}, or a line break + * character. ({@code |} and {@code ;} are already consumed by the previous layer.)</li> + * <li><b>argv[0] whitelist</b>: the first token of every pipe segment must appear in + * {@link #COMMAND_WHITELIST}, otherwise {@link #RULE_NOT_IN_WHITELIST}.</li> + * <li><b>Argument policy</b>: for write-oriented commands, path arguments are tilde-expanded, + * normalized via {@link Path#normalize()}, and then checked with + * {@link AllowedRootsResolver#isUnderAllowedRoot(Path)}; {@code sh}/{@code bash} may not + * receive a {@code -c} flag ({@link #RULE_FORBIDDEN_SH_C_FLAG}).</li> + * </ol> + */ +public final class ModuleCommandValidator { + + /** First-level command whitelist. */ + public static final Set<String> COMMAND_WHITELIST = buildImmutableSet( + "cd", "sh", "bash", "ps", "grep", "awk", "kill", "rm", "mkdir", "cp", "mv", "ln", + "tar", "unzip", "chmod", "chown", "echo", "cat", "test", "[", "true", "false", "java"); + + /** Write-oriented commands whose path arguments must live under an allowed root. */ + public static final Set<String> WRITE_LIKE_COMMANDS = buildImmutableSet( + "rm", "cp", "mv", "mkdir", "ln", "chmod", "chown", "tar", "unzip"); + + private static Set<String> buildImmutableSet(String... items) { + Set<String> s = new HashSet<>(items.length * 2); + Collections.addAll(s, items); + return Collections.unmodifiableSet(s); + } + + /** Substring blacklist for the metacharacter check. */ + private static final String[] META_CHAR_BLACKLIST = new String[]{ + "`", "$(", "&&", "||", ">>", ">", "<" + }; + + public static final String RULE_DISALLOWED_META_CHAR = "DISALLOWED_META_CHAR"; + public static final String RULE_NOT_IN_WHITELIST = "NOT_IN_WHITELIST"; + public static final String RULE_PATH_NOT_UNDER_ALLOWED_ROOT = "PATH_NOT_UNDER_ALLOWED_ROOT"; + public static final String RULE_FORBIDDEN_SH_C_FLAG = "FORBIDDEN_SH_C_FLAG"; + public static final String RULE_EMPTY_COMMAND = "EMPTY_COMMAND"; + + private static final Logger LOGGER = LoggerFactory.getLogger(ModuleCommandValidator.class); + + private final AllowedRootsResolver allowedRootsResolver; + + public ModuleCommandValidator(AllowedRootsResolver allowedRootsResolver) { + this.allowedRootsResolver = allowedRootsResolver; + } + + /** Validate a raw command string. */ + public ValidationResult validate(String rawCmd) { + if (StringUtils.isBlank(rawCmd)) { + return ValidationResult.fail(RULE_EMPTY_COMMAND, rawCmd, "raw command is blank"); + } + + // Scan the whole command for metacharacters first, so a hostile sub-command cannot + // bypass the check by hiding after ';'. + String metaHit = firstMetaCharHit(rawCmd); + if (metaHit != null) { + return ValidationResult.fail(RULE_DISALLOWED_META_CHAR, rawCmd, + "hit meta char: " + metaHit); + } + if (rawCmd.indexOf('\n') >= 0 || rawCmd.indexOf('\r') >= 0) { + return ValidationResult.fail(RULE_DISALLOWED_META_CHAR, rawCmd, + "hit line-break char"); + } + + // split by ';' into sub-commands, then by '|' into pipe segments, then + // tokenize each segment into argv. + List<ParsedSubCmd> subs = new ArrayList<>(); + String[] segments = rawCmd.split(";"); + for (String seg : segments) { + String trimmed = seg == null ? "" : seg.trim(); + if (trimmed.isEmpty()) { + continue; + } + ParsedSubCmd sub = parseSubCmd(trimmed); + if (sub == null) { + return ValidationResult.fail(RULE_EMPTY_COMMAND, trimmed, + "sub-command tokenized to empty"); + } + subs.add(sub); + } + if (subs.isEmpty()) { + return ValidationResult.fail(RULE_EMPTY_COMMAND, rawCmd, + "no sub-command after split by ';'"); + } + + // run the argv[0] whitelist and the argument policy check. + for (ParsedSubCmd sub : subs) { + ValidationResult r = validateSubCmd(sub); + if (!r.isOk()) { + return r; + } + } + + // Absorb 'cd' sub-commands into the working directory of the following sub-command. + List<ParsedSubCmd> parsed = extractCdAndBind(subs); + + return ValidationResult.ok(parsed); + } + + private ValidationResult validateSubCmd(ParsedSubCmd sub) { + for (String[] argv : sub.getPipeline()) { + if (argv == null || argv.length == 0) { + return ValidationResult.fail(RULE_EMPTY_COMMAND, sub.getRawSegment(), + "empty pipeline segment"); + } + String cmd = argv[0]; + + if (!COMMAND_WHITELIST.contains(cmd)) { + return ValidationResult.fail(RULE_NOT_IN_WHITELIST, sub.getRawSegment(), + "command '" + cmd + "' is not in whitelist"); + } + + ValidationResult r = validateArguments(argv, sub.getRawSegment()); + if (!r.isOk()) { + return r; + } + } + return ValidationResult.okPending(); + } + + private ValidationResult validateArguments(String[] argv, String rawSegment) { + String cmd = argv[0]; + + if ("sh".equals(cmd) || "bash".equals(cmd)) { + for (int i = 1; i < argv.length; i++) { + if ("-c".equals(argv[i]) || argv[i].startsWith("-c")) { Review Comment: Duplication. if (argv[i].startsWith("-c")) -- This is an automated message from the Apache Git Service. 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