| 1 | //! Execpolicy rules loaded from TOML configuration. |
| 2 | //! |
| 3 | //! The legacy Starlark policy engine (`PolicyParser`, `Policy`, `Rule`, the |
| 4 | //! `execpolicy check` CLI verb) was deleted for v0.9.4: the runtime never |
| 5 | //! enforced it, so a green `check` meant nothing. The live policy surface is |
| 6 | //! the TOML `execpolicy.toml` rules here plus this crate's permission engine. |
| 7 | //! |
| 8 | //! Where the file lives is the caller's business — the TUI resolves |
| 9 | //! `~/.deepseek/execpolicy.toml` and hands the parsed [`ExecPolicyConfig`] |
| 10 | //! to its shell tool. |
| 11 | |
| 12 | use std::collections::BTreeMap; |
| 13 | use std::path::Path; |
| 14 | |
| 15 | use anyhow::{Context, Result}; |
| 16 | use serde::Deserialize; |
| 17 | |
| 18 | use crate::command_safety::{prefix_allow_matches, prefix_grant_is_eligible}; |
| 19 | use crate::matcher::pattern_matches; |
| 20 | |
| 21 | /// Verdict of evaluating a command against the TOML rule sets. |
| 22 | /// |
| 23 | /// Distinct from [`crate::ExecPolicyDecision`], which is the permission |
| 24 | /// engine's structured output; this is the file-rules verdict consumed by |
| 25 | /// the shell tool. |
| 26 | #[derive(Debug, Clone, PartialEq, Eq)] |
| 27 | pub enum RuleDecision { |
| 28 | Allow, |
| 29 | Deny(String), |
| 30 | AskUser(String), |
| 31 | } |
| 32 | |
| 33 | #[derive(Debug, Clone, Deserialize, Default)] |
| 34 | pub struct ExecPolicyConfig { |
| 35 | #[serde(default)] |
| 36 | pub rules: BTreeMap<String, RuleSet>, |
| 37 | } |
| 38 | |
| 39 | #[derive(Debug, Clone, Deserialize, Default)] |
| 40 | pub struct RuleSet { |
| 41 | #[serde(default)] |
| 42 | pub allow: Vec<String>, |
| 43 | #[serde(default)] |
| 44 | pub deny: Vec<String>, |
| 45 | } |
| 46 | |
| 47 | impl ExecPolicyConfig { |
| 48 | pub fn parse(contents: &str) -> Result<Self> { |
| 49 | toml::from_str(contents).context("failed to parse execpolicy.toml") |
| 50 | } |
| 51 | |
| 52 | pub fn from_path(path: &Path) -> Result<Self> { |
| 53 | let contents = std::fs::read_to_string(path) |
| 54 | .with_context(|| format!("failed to read execpolicy file {}", path.display()))?; |
| 55 | Self::parse(&contents) |
| 56 | } |
| 57 | |
| 58 | pub fn evaluate(&self, command: &str) -> RuleDecision { |
| 59 | // #security: a deny pattern has to be matched against the commands the |
| 60 | // shell would actually run, not against the text as written. Quoting, |
| 61 | // command substitution (`` `cmd` ``, `$(cmd)`), grouping, chaining and |
| 62 | // wrapper payloads (`bash -c …`, `eval …`, `sudo …`) all produce an |
| 63 | // invocation whose text differs from the rule while its effect does |
| 64 | // not. `expanded_commands` word-splits the way a shell does and returns |
| 65 | // every command line involved, so one deny pattern covers all of the |
| 66 | // spellings instead of one string pattern per metacharacter. |
| 67 | // |
| 68 | // Only the deny loop is widened. The allow loop below still matches the |
| 69 | // command as written, so a broader expansion can never turn into a |
| 70 | // broader auto-approval. |
| 71 | let expansion = crate::shell_expand::expand_command(command); |
| 72 | let prefix_eligible = prefix_grant_is_eligible(command, &expansion); |
| 73 | let deny_targets = expansion.commands; |
| 74 | // A command word only known at run time cannot be checked against a |
| 75 | // deny pattern: fail closed while any deny pattern is configured, and |
| 76 | // never let an allow pattern written for the outer command approve |
| 77 | // nested or unresolved code. |
| 78 | if expansion.dynamic && self.rules.values().any(|rules| !rules.deny.is_empty()) { |
| 79 | return RuleDecision::Deny( |
| 80 | "execpolicy: command word cannot be resolved statically while deny rules are in force" |
| 81 | .to_string(), |
| 82 | ); |
| 83 | } |
| 84 | // A deny pattern names a command prefix, as the permission engine's |
| 85 | // deny rules do: `git push --force` also denies |
| 86 | // `git push --force origin main`. The whole-command glob still |
| 87 | // applies for patterns that spell out `*` wildcards. |
| 88 | for (group, rules) in &self.rules { |
| 89 | for pattern in &rules.deny { |
| 90 | if deny_targets.iter().any(|target| { |
| 91 | crate::denied_prefix_matches(pattern, target) |
| 92 | || pattern_matches(pattern, target) |
| 93 | }) { |
| 94 | return RuleDecision::Deny(format!("execpolicy denied by {group}: {pattern}")); |
| 95 | } |
| 96 | } |
| 97 | } |
| 98 | |
| 99 | if !prefix_eligible { |
| 100 | return RuleDecision::AskUser( |
| 101 | "execpolicy: command syntax or arguments require an exact approval".to_string(), |
| 102 | ); |
| 103 | } |
| 104 | for (group, rules) in &self.rules { |
| 105 | for pattern in &rules.allow { |
| 106 | // Allow rules use arity-aware prefix matching first so that |
| 107 | // `allow = ["git status"]` matches `git status -s` but NOT |
| 108 | // `git push origin main`. Fall back to regex-style |
| 109 | // `pattern_matches` for wildcard patterns (e.g. `cargo *`). |
| 110 | if prefix_allow_matches(pattern, command) || pattern_matches(pattern, command) { |
| 111 | let _ = group; |
| 112 | return RuleDecision::Allow; |
| 113 | } |
| 114 | } |
| 115 | } |
| 116 | |
| 117 | RuleDecision::AskUser("execpolicy: no matching allow rule".to_string()) |
| 118 | } |
| 119 | } |
| 120 | |
| 121 | #[cfg(test)] |
| 122 | mod tests { |
| 123 | use super::*; |
| 124 | |
| 125 | #[test] |
| 126 | fn test_execpolicy_evaluate() { |
| 127 | let config = ExecPolicyConfig { |
| 128 | rules: BTreeMap::from([ |
| 129 | ( |
| 130 | "git".to_string(), |
| 131 | RuleSet { |
| 132 | allow: vec!["git status".to_string(), "git log *".to_string()], |
| 133 | deny: vec!["git push --force".to_string()], |
| 134 | }, |
| 135 | ), |
| 136 | ( |
| 137 | "danger".to_string(), |
| 138 | RuleSet { |
| 139 | allow: vec![], |
| 140 | deny: vec!["rm -rf /".to_string()], |
| 141 | }, |
| 142 | ), |
| 143 | ]), |
| 144 | }; |
| 145 | |
| 146 | assert!(matches!(config.evaluate("git status"), RuleDecision::Allow)); |
| 147 | assert!(matches!( |
| 148 | config.evaluate("git log --oneline"), |
| 149 | RuleDecision::Allow |
| 150 | )); |
| 151 | assert!(matches!( |
| 152 | config.evaluate("git push --force"), |
| 153 | RuleDecision::Deny(_) |
| 154 | )); |
| 155 | assert!(matches!( |
| 156 | config.evaluate("unknown command"), |
| 157 | RuleDecision::AskUser(_) |
| 158 | )); |
| 159 | } |
| 160 | |
| 161 | #[test] |
| 162 | fn test_prefix_rule_allows_git_status_with_flags() { |
| 163 | // Arity-aware: `allow = ["git status"]` must match `git status -s`. |
| 164 | let config = ExecPolicyConfig { |
| 165 | rules: BTreeMap::from([( |
| 166 | "git".to_string(), |
| 167 | RuleSet { |
| 168 | allow: vec!["git status".to_string()], |
| 169 | deny: vec![], |
| 170 | }, |
| 171 | )]), |
| 172 | }; |
| 173 | |
| 174 | assert!(matches!( |
| 175 | config.evaluate("git status -s"), |
| 176 | RuleDecision::Allow |
| 177 | )); |
| 178 | assert!(matches!( |
| 179 | config.evaluate("git status --porcelain"), |
| 180 | RuleDecision::Allow |
| 181 | )); |
| 182 | // Push must NOT match the "git status" allow rule. |
| 183 | assert!(matches!( |
| 184 | config.evaluate("git push origin main"), |
| 185 | RuleDecision::AskUser(_) |
| 186 | )); |
| 187 | } |
| 188 | |
| 189 | fn danger_policy() -> ExecPolicyConfig { |
| 190 | ExecPolicyConfig { |
| 191 | rules: BTreeMap::from([( |
| 192 | "danger".to_string(), |
| 193 | RuleSet { |
| 194 | allow: vec!["echo *".to_string()], |
| 195 | deny: vec!["rm -rf /".to_string()], |
| 196 | }, |
| 197 | )]), |
| 198 | } |
| 199 | } |
| 200 | |
| 201 | /// #security: the deny pattern must survive every way a shell can spell the |
| 202 | /// command it names. A whole-string match saw only the text as typed. |
| 203 | #[test] |
| 204 | fn deny_pattern_covers_every_shell_spelling() { |
| 205 | let config = danger_policy(); |
| 206 | let mut evaded = Vec::new(); |
| 207 | for command in [ |
| 208 | "rm -rf /", |
| 209 | "ls && rm -rf /", |
| 210 | "ls & rm -rf /", |
| 211 | "true; rm -rf /", |
| 212 | "ls | rm -rf /", |
| 213 | "ls\nrm -rf /", |
| 214 | "(rm -rf /)", |
| 215 | "{ rm -rf /; }", |
| 216 | "`rm -rf /`", |
| 217 | "echo `rm -rf /`", |
| 218 | "echo \"`rm -rf /`\"", |
| 219 | "$(rm -rf /)", |
| 220 | "echo $(rm -rf /)", |
| 221 | "x=$(rm -rf /)", |
| 222 | "diff <(rm -rf /) b", |
| 223 | "rm -rf \"/\"", |
| 224 | "rm -rf '/'", |
| 225 | "eval 'rm -rf /'", |
| 226 | "bash -c 'rm -rf /'", |
| 227 | "sh -lc \"rm -rf /\"", |
| 228 | "sudo rm -rf /", |
| 229 | "env rm -rf /", |
| 230 | "timeout 5 rm -rf /", |
| 231 | "xargs rm -rf /", |
| 232 | ] { |
| 233 | if !matches!(config.evaluate(command), RuleDecision::Deny(_)) { |
| 234 | evaded.push(command); |
| 235 | } |
| 236 | } |
| 237 | assert!(evaded.is_empty(), "deny pattern bypassed by: {evaded:#?}"); |
| 238 | } |
| 239 | |
| 240 | #[test] |
| 241 | fn deny_pattern_is_a_command_prefix() { |
| 242 | let config = ExecPolicyConfig { |
| 243 | rules: BTreeMap::from([( |
| 244 | "danger".to_string(), |
| 245 | RuleSet { |
| 246 | allow: vec!["git *".to_string()], |
| 247 | deny: vec!["git push --force".to_string(), "rm -rf /".to_string()], |
| 248 | }, |
| 249 | )]), |
| 250 | }; |
| 251 | for command in [ |
| 252 | "git push --force", |
| 253 | "git push --force origin main", |
| 254 | "git push origin main --force", |
| 255 | "rm -rf / --no-preserve-root", |
| 256 | "git -C . push --force", |
| 257 | "git commit -m 'a\nb' && git push --force", |
| 258 | ] { |
| 259 | assert!( |
| 260 | matches!(config.evaluate(command), RuleDecision::Deny(_)), |
| 261 | "{command:?} must be denied" |
| 262 | ); |
| 263 | } |
| 264 | for command in [ |
| 265 | "git push origin main", |
| 266 | "git push --force-with-lease", |
| 267 | "rm -rf ./x", |
| 268 | ] { |
| 269 | assert!( |
| 270 | !matches!(config.evaluate(command), RuleDecision::Deny(_)), |
| 271 | "{command:?} must not be denied" |
| 272 | ); |
| 273 | } |
| 274 | } |
| 275 | |
| 276 | /// The fix must not deny a command merely for containing a metacharacter. |
| 277 | #[test] |
| 278 | fn deny_pattern_leaves_harmless_metacharacter_uses_alone() { |
| 279 | let config = danger_policy(); |
| 280 | for command in [ |
| 281 | // Substitution of something the rule does not name. |
| 282 | "echo \"built at $(date)\"", |
| 283 | "echo `date`", |
| 284 | // Single quotes are literal: this prints the text, runs nothing. |
| 285 | "echo '`rm -rf /`'", |
| 286 | "echo 'rm -rf /'", |
| 287 | ] { |
| 288 | assert!( |
| 289 | !matches!(config.evaluate(command), RuleDecision::Deny(_)), |
| 290 | "harmless command wrongly denied: {command:?}" |
| 291 | ); |
| 292 | } |
| 293 | } |
| 294 | |
| 295 | #[test] |
| 296 | fn test_prefix_rule_allows_cargo_check_variants() { |
| 297 | let config = ExecPolicyConfig { |
| 298 | rules: BTreeMap::from([( |
| 299 | "cargo".to_string(), |
| 300 | RuleSet { |
| 301 | allow: vec!["cargo check".to_string()], |
| 302 | deny: vec![], |
| 303 | }, |
| 304 | )]), |
| 305 | }; |
| 306 | |
| 307 | assert!(matches!( |
| 308 | config.evaluate("cargo check"), |
| 309 | RuleDecision::Allow |
| 310 | )); |
| 311 | assert!(matches!( |
| 312 | config.evaluate("cargo check --workspace"), |
| 313 | RuleDecision::Allow |
| 314 | )); |
| 315 | assert!(matches!( |
| 316 | config.evaluate("cargo build --release"), |
| 317 | RuleDecision::AskUser(_) |
| 318 | )); |
| 319 | } |
| 320 | } |
| 321 |