Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Implement S609, linux_commands_wildcard_injection #4504

Merged
merged 7 commits into from
Jun 2, 2023
Merged
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Jump to
Jump to file
Failed to load files.
Diff view
Diff view
8 changes: 8 additions & 0 deletions crates/ruff/resources/test/fixtures/flake8_bandit/S609.py
Original file line number Diff line number Diff line change
@@ -0,0 +1,8 @@
import os
import subprocess

os.popen("chmod +w foo*")
subprocess.Popen("/bin/chown root: *", shell=True)
subprocess.Popen(["/usr/local/bin/rsync", "*", "some_where:"], shell=True)
subprocess.Popen("/usr/local/bin/rsync * no_injection_here:")
os.system("tar cf foo.tar bar/*")
1 change: 1 addition & 0 deletions crates/ruff/src/checkers/ast/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -2735,6 +2735,7 @@ where
Rule::StartProcessWithAShell,
Rule::StartProcessWithNoShell,
Rule::StartProcessWithPartialPath,
Rule::UnixCommandWildcardInjection,
charliermarsh marked this conversation as resolved.
Show resolved Hide resolved
]) {
flake8_bandit::rules::shell_injection(self, func, args, keywords);
}
Expand Down
1 change: 1 addition & 0 deletions crates/ruff/src/codes.rs
Original file line number Diff line number Diff line change
Expand Up @@ -529,6 +529,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
(Flake8Bandit, "606") => (RuleGroup::Unspecified, rules::flake8_bandit::rules::StartProcessWithNoShell),
(Flake8Bandit, "607") => (RuleGroup::Unspecified, rules::flake8_bandit::rules::StartProcessWithPartialPath),
(Flake8Bandit, "608") => (RuleGroup::Unspecified, rules::flake8_bandit::rules::HardcodedSQLExpression),
(Flake8Bandit, "609") => (RuleGroup::Unspecified, rules::flake8_bandit::rules::UnixCommandWildcardInjection),
(Flake8Bandit, "612") => (RuleGroup::Unspecified, rules::flake8_bandit::rules::LoggingConfigInsecureListen),
(Flake8Bandit, "701") => (RuleGroup::Unspecified, rules::flake8_bandit::rules::Jinja2AutoescapeFalse),

Expand Down
3 changes: 2 additions & 1 deletion crates/ruff/src/rules/flake8_bandit/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,7 @@ mod tests {
#[test_case(Rule::HashlibInsecureHashFunction, Path::new("S324.py"))]
#[test_case(Rule::Jinja2AutoescapeFalse, Path::new("S701.py"))]
#[test_case(Rule::LoggingConfigInsecureListen, Path::new("S612.py"))]
#[test_case(Rule::ParamikoCall, Path::new("S601.py"))]
#[test_case(Rule::RequestWithNoCertValidation, Path::new("S501.py"))]
#[test_case(Rule::RequestWithoutTimeout, Path::new("S113.py"))]
#[test_case(Rule::SnmpInsecureVersion, Path::new("S508.py"))]
Expand All @@ -41,8 +42,8 @@ mod tests {
#[test_case(Rule::SuspiciousTelnetUsage, Path::new("S312.py"))]
#[test_case(Rule::TryExceptContinue, Path::new("S112.py"))]
#[test_case(Rule::TryExceptPass, Path::new("S110.py"))]
#[test_case(Rule::UnixCommandWildcardInjection, Path::new("S609.py"))]
#[test_case(Rule::UnsafeYAMLLoad, Path::new("S506.py"))]
#[test_case(Rule::ParamikoCall, Path::new("S601.py"))]
fn rules(rule_code: Rule, path: &Path) -> Result<()> {
let snapshot = format!("{}_{}", rule_code.noqa_code(), path.to_string_lossy());
let diagnostics = test_path(
Expand Down
2 changes: 1 addition & 1 deletion crates/ruff/src/rules/flake8_bandit/rules/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,7 @@ pub(crate) use request_without_timeout::{request_without_timeout, RequestWithout
pub(crate) use shell_injection::{
shell_injection, CallWithShellEqualsTrue, StartProcessWithAShell, StartProcessWithNoShell,
StartProcessWithPartialPath, SubprocessPopenWithShellEqualsTrue,
SubprocessWithoutShellEqualsTrue,
SubprocessWithoutShellEqualsTrue, UnixCommandWildcardInjection,
};
pub(crate) use snmp_insecure_version::{snmp_insecure_version, SnmpInsecureVersion};
pub(crate) use snmp_weak_cryptography::{snmp_weak_cryptography, SnmpWeakCryptography};
Expand Down
269 changes: 168 additions & 101 deletions crates/ruff/src/rules/flake8_bandit/rules/shell_injection.rs
Original file line number Diff line number Diff line change
Expand Up @@ -89,106 +89,29 @@ impl Violation for StartProcessWithPartialPath {
}
}

#[derive(Copy, Clone, Debug)]
enum CallKind {
Subprocess,
Shell,
NoShell,
}

/// Return the [`CallKind`] of the given function call.
fn get_call_kind(func: &Expr, model: &SemanticModel) -> Option<CallKind> {
model
.resolve_call_path(func)
.and_then(|call_path| match call_path.as_slice() {
&[module, submodule] => match module {
"os" => match submodule {
"execl" | "execle" | "execlp" | "execlpe" | "execv" | "execve" | "execvp"
| "execvpe" | "spawnl" | "spawnle" | "spawnlp" | "spawnlpe" | "spawnv"
| "spawnve" | "spawnvp" | "spawnvpe" | "startfile" => Some(CallKind::NoShell),
"system" | "popen" | "popen2" | "popen3" | "popen4" => Some(CallKind::Shell),
_ => None,
},
"subprocess" => match submodule {
"Popen" | "call" | "check_call" | "check_output" | "run" => {
Some(CallKind::Subprocess)
}
_ => None,
},
"popen2" => match submodule {
"popen2" | "popen3" | "popen4" | "Popen3" | "Popen4" => Some(CallKind::Shell),
_ => None,
},
"commands" => match submodule {
"getoutput" | "getstatusoutput" => Some(CallKind::Shell),
_ => None,
},
_ => None,
},
_ => None,
})
}

#[derive(Copy, Clone, Debug)]
struct ShellKeyword<'a> {
/// Whether the `shell` keyword argument is set and evaluates to `True`.
truthiness: Truthiness,
/// The `shell` keyword argument.
keyword: &'a Keyword,
}

/// Return the `shell` keyword argument to the given function call, if any.
fn find_shell_keyword<'a>(
model: &SemanticModel,
keywords: &'a [Keyword],
) -> Option<ShellKeyword<'a>> {
keywords
.iter()
.find(|keyword| keyword.arg.as_ref().map_or(false, |arg| arg == "shell"))
.map(|keyword| ShellKeyword {
truthiness: Truthiness::from_expr(&keyword.value, |id| model.is_builtin(id)),
keyword,
})
}

/// Return `true` if the value provided to the `shell` call seems safe. This is based on Bandit's
/// definition: string literals are considered okay, but dynamically-computed values are not.
fn shell_call_seems_safe(arg: &Expr) -> bool {
matches!(
arg,
Expr::Constant(ast::ExprConstant {
value: Constant::Str(_),
..
})
)
}
#[violation]
pub struct UnixCommandWildcardInjection;

/// Return the [`Expr`] as a string literal, if it's a string or a list of strings.
fn try_string_literal(expr: &Expr) -> Option<&str> {
match expr {
Expr::List(ast::ExprList { elts, .. }) => {
if elts.is_empty() {
None
} else {
string_literal(&elts[0])
}
}
_ => string_literal(expr),
impl Violation for UnixCommandWildcardInjection {
#[derive_message_formats]
fn message(&self) -> String {
format!("Possible wildcard injection in call due to `*` usage")
}
}

/// S602, S603, S604, S605, S606, S607
/// S602, S603, S604, S605, S606, S607, S609
pub(crate) fn shell_injection(
checker: &mut Checker,
func: &Expr,
args: &[Expr],
keywords: &[Keyword],
) {
let call_kind = get_call_kind(func, checker.semantic_model());
let shell_keyword = find_shell_keyword(checker.semantic_model(), keywords);

if matches!(call_kind, Some(CallKind::Subprocess)) {
if let Some(arg) = args.first() {
match find_shell_keyword(checker.semantic_model(), keywords) {
match shell_keyword {
// S602
Some(ShellKeyword {
truthiness: Truthiness::Truthy,
Expand Down Expand Up @@ -229,7 +152,7 @@ pub(crate) fn shell_injection(
} else if let Some(ShellKeyword {
truthiness: Truthiness::Truthy,
keyword,
}) = find_shell_keyword(checker.semantic_model(), keywords)
}) = shell_keyword
{
// S604
if checker.enabled(Rule::CallWithShellEqualsTrue) {
Expand All @@ -240,9 +163,9 @@ pub(crate) fn shell_injection(
}

// S605
if matches!(call_kind, Some(CallKind::Shell)) {
if let Some(arg) = args.first() {
if checker.enabled(Rule::StartProcessWithAShell) {
if checker.enabled(Rule::StartProcessWithAShell) {
if matches!(call_kind, Some(CallKind::Shell)) {
if let Some(arg) = args.first() {
checker.diagnostics.push(Diagnostic::new(
StartProcessWithAShell {
seems_safe: shell_call_seems_safe(arg),
Expand All @@ -254,26 +177,170 @@ pub(crate) fn shell_injection(
}

// S606
if matches!(call_kind, Some(CallKind::NoShell)) {
if checker.enabled(Rule::StartProcessWithNoShell) {
if checker.enabled(Rule::StartProcessWithNoShell) {
if matches!(call_kind, Some(CallKind::NoShell)) {
checker
.diagnostics
.push(Diagnostic::new(StartProcessWithNoShell, func.range()));
}
}

// S607
if call_kind.is_some() {
if let Some(arg) = args.first() {
if checker.enabled(Rule::StartProcessWithPartialPath) {
if let Some(value) = try_string_literal(arg) {
if FULL_PATH_REGEX.find(value).is_none() {
checker
.diagnostics
.push(Diagnostic::new(StartProcessWithPartialPath, arg.range()));
}
if checker.enabled(Rule::StartProcessWithPartialPath) {
if call_kind.is_some() {
if let Some(arg) = args.first() {
if is_partial_path(arg) {
checker
.diagnostics
.push(Diagnostic::new(StartProcessWithPartialPath, arg.range()));
}
}
}
}

// S609
if checker.enabled(Rule::UnixCommandWildcardInjection) {
if matches!(call_kind, Some(CallKind::Shell))
|| matches!(
(call_kind, shell_keyword),
(
Some(CallKind::Subprocess),
Some(ShellKeyword {
truthiness: Truthiness::Truthy,
keyword: _,
})
)
)
{
if let Some(arg) = args.first() {
if is_wildcard_command(arg) {
checker
.diagnostics
.push(Diagnostic::new(UnixCommandWildcardInjection, func.range()));
}
}
}
}
}

#[derive(Copy, Clone, Debug)]
enum CallKind {
Subprocess,
Shell,
NoShell,
}

/// Return the [`CallKind`] of the given function call.
fn get_call_kind(func: &Expr, model: &SemanticModel) -> Option<CallKind> {
model
.resolve_call_path(func)
.and_then(|call_path| match call_path.as_slice() {
&[module, submodule] => match module {
"os" => match submodule {
"execl" | "execle" | "execlp" | "execlpe" | "execv" | "execve" | "execvp"
| "execvpe" | "spawnl" | "spawnle" | "spawnlp" | "spawnlpe" | "spawnv"
| "spawnve" | "spawnvp" | "spawnvpe" | "startfile" => Some(CallKind::NoShell),
"system" | "popen" | "popen2" | "popen3" | "popen4" => Some(CallKind::Shell),
_ => None,
},
"subprocess" => match submodule {
"Popen" | "call" | "check_call" | "check_output" | "run" => {
Some(CallKind::Subprocess)
}
_ => None,
},
"popen2" => match submodule {
"popen2" | "popen3" | "popen4" | "Popen3" | "Popen4" => Some(CallKind::Shell),
_ => None,
},
"commands" => match submodule {
"getoutput" | "getstatusoutput" => Some(CallKind::Shell),
_ => None,
},
_ => None,
},
_ => None,
})
}

#[derive(Copy, Clone, Debug)]
struct ShellKeyword<'a> {
/// Whether the `shell` keyword argument is set and evaluates to `True`.
truthiness: Truthiness,
/// The `shell` keyword argument.
keyword: &'a Keyword,
}

/// Return the `shell` keyword argument to the given function call, if any.
fn find_shell_keyword<'a>(
model: &SemanticModel,
keywords: &'a [Keyword],
) -> Option<ShellKeyword<'a>> {
keywords
.iter()
.find(|keyword| keyword.arg.as_ref().map_or(false, |arg| arg == "shell"))
.map(|keyword| ShellKeyword {
truthiness: Truthiness::from_expr(&keyword.value, |id| model.is_builtin(id)),
keyword,
})
}

/// Return `true` if the value provided to the `shell` call seems safe. This is based on Bandit's
/// definition: string literals are considered okay, but dynamically-computed values are not.
fn shell_call_seems_safe(arg: &Expr) -> bool {
matches!(
arg,
Expr::Constant(ast::ExprConstant {
value: Constant::Str(_),
..
})
)
}

/// Return `true` if the [`Expr`] is a string literal or list of string literals that starts with a
/// partial path.
fn is_partial_path(expr: &Expr) -> bool {
let string_literal = match expr {
Expr::List(ast::ExprList { elts, .. }) => elts.first().and_then(string_literal),
_ => string_literal(expr),
};
string_literal.map_or(false, |text| !FULL_PATH_REGEX.is_match(text))
}

/// Return `true` if the [`Expr`] is a wildcard command.
///
/// ## Examples
/// ```python
/// import subprocess
///
/// subprocess.Popen("/bin/chown root: *", shell=True)
/// subprocess.Popen(["/usr/local/bin/rsync", "*", "some_where:"], shell=True)
/// ```
fn is_wildcard_command(expr: &Expr) -> bool {
if let Expr::List(ast::ExprList { elts, .. }) = expr {
let mut has_star = false;
let mut has_command = false;
for elt in elts.iter() {
if let Some(text) = string_literal(elt) {
has_star |= text.contains('*');
has_command |= text.contains("chown")
|| text.contains("chmod")
|| text.contains("tar")
|| text.contains("rsync");
}
if has_star && has_command {
break;
}
}
has_star && has_command
} else {
let string_literal = string_literal(expr);
string_literal.map_or(false, |text| {
text.contains('*')
&& (text.contains("chown")
|| text.contains("chmod")
|| text.contains("tar")
|| text.contains("rsync"))
})
}
}