aws_config/
credential_process.rs

1/*
2 * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
3 * SPDX-License-Identifier: Apache-2.0
4 */
5
6#![cfg(feature = "credentials-process")]
7
8//! Credentials Provider for external process
9
10use crate::json_credentials::{json_parse_loop, InvalidJsonCredentials};
11use crate::sensitive_command::CommandWithSensitiveArgs;
12use aws_credential_types::attributes::AccountId;
13use aws_credential_types::credential_feature::AwsCredentialFeature;
14use aws_credential_types::provider::{self, error::CredentialsError, future, ProvideCredentials};
15use aws_credential_types::Credentials;
16use aws_smithy_json::deserialize::Token;
17use std::borrow::Cow;
18use std::process::Command;
19use std::time::SystemTime;
20use time::format_description::well_known::Rfc3339;
21use time::OffsetDateTime;
22
23/// External process credentials provider
24///
25/// This credentials provider runs a configured external process and parses
26/// its output to retrieve credentials.
27///
28/// The external process must exit with status 0 and output the following
29/// JSON format to `stdout` to provide credentials:
30///
31/// ```json
32/// {
33///     "Version:" 1,
34///     "AccessKeyId": "access key id",
35///     "SecretAccessKey": "secret access key",
36///     "SessionToken": "session token",
37///     "Expiration": "time that the expiration will expire"
38/// }
39/// ```
40///
41/// The `Version` must be set to 1. `AccessKeyId` and `SecretAccessKey` are always required.
42/// `SessionToken` must be set if a session token is associated with the `AccessKeyId`.
43/// The `Expiration` is optional, and must be given in the RFC 3339 date time format (e.g.,
44/// `2022-05-26T12:34:56.789Z`).
45///
46/// If the external process exits with a non-zero status, then the contents of `stderr`
47/// will be output as part of the credentials provider error message.
48///
49/// This credentials provider is included in the profile credentials provider, and can be
50/// configured using the `credential_process` attribute. For example:
51///
52/// ```plain
53/// [profile example]
54/// credential_process = /path/to/my/process --some --arguments
55/// ```
56#[derive(Debug)]
57pub struct CredentialProcessProvider {
58    command: CommandWithSensitiveArgs<String>,
59    profile_account_id: Option<AccountId>,
60}
61
62impl ProvideCredentials for CredentialProcessProvider {
63    fn provide_credentials<'a>(&'a self) -> future::ProvideCredentials<'a>
64    where
65        Self: 'a,
66    {
67        future::ProvideCredentials::new(self.credentials())
68    }
69}
70
71impl CredentialProcessProvider {
72    /// Create new [`CredentialProcessProvider`] with the `command` needed to execute the external process.
73    pub fn new(command: String) -> Self {
74        Self {
75            command: CommandWithSensitiveArgs::new(command),
76            profile_account_id: None,
77        }
78    }
79
80    pub(crate) fn builder() -> Builder {
81        Builder::default()
82    }
83
84    async fn credentials(&self) -> provider::Result {
85        // Security: command arguments must be redacted at debug level
86        tracing::debug!(command = %self.command, "loading credentials from external process");
87
88        let command = if cfg!(windows) {
89            let mut command = Command::new("cmd.exe");
90            command.args(["/C", self.command.unredacted()]);
91            command
92        } else {
93            let mut command = Command::new("sh");
94            command.args(["-c", self.command.unredacted()]);
95            command
96        };
97        let output = tokio::process::Command::from(command)
98            .output()
99            .await
100            .map_err(|e| {
101                CredentialsError::provider_error(format!(
102                    "Error retrieving credentials from external process: {e}",
103                ))
104            })?;
105
106        // Security: command arguments can be logged at trace level
107        tracing::trace!(command = ?self.command, status = ?output.status, "executed command (unredacted)");
108
109        if !output.status.success() {
110            let reason =
111                std::str::from_utf8(&output.stderr).unwrap_or("could not decode stderr as UTF-8");
112            return Err(CredentialsError::provider_error(format!(
113                "Error retrieving credentials: external process exited with code {}. Stderr: {}",
114                output.status, reason
115            )));
116        }
117
118        let output = std::str::from_utf8(&output.stdout).map_err(|e| {
119            CredentialsError::provider_error(format!(
120                "Error retrieving credentials from external process: could not decode output as UTF-8: {e}",
121            ))
122        })?;
123
124        parse_credential_process_json_credentials(output, self.profile_account_id.as_ref())
125            .map(|mut creds| {
126                creds
127                    .get_property_mut_or_default::<Vec<AwsCredentialFeature>>()
128                    .push(AwsCredentialFeature::CredentialsProcess);
129                creds
130            })
131            .map_err(|invalid| {
132                CredentialsError::provider_error(format!(
133                "Error retrieving credentials from external process, could not parse response: {invalid}",
134            ))
135            })
136    }
137}
138
139#[derive(Debug, Default)]
140pub(crate) struct Builder {
141    command: Option<CommandWithSensitiveArgs<String>>,
142    profile_account_id: Option<AccountId>,
143}
144
145impl Builder {
146    pub(crate) fn command(mut self, command: CommandWithSensitiveArgs<String>) -> Self {
147        self.command = Some(command);
148        self
149    }
150
151    #[allow(dead_code)] // only used in unit tests
152    pub(crate) fn account_id(mut self, account_id: impl Into<AccountId>) -> Self {
153        self.set_account_id(Some(account_id.into()));
154        self
155    }
156
157    pub(crate) fn set_account_id(&mut self, account_id: Option<AccountId>) {
158        self.profile_account_id = account_id;
159    }
160
161    pub(crate) fn build(self) -> CredentialProcessProvider {
162        CredentialProcessProvider {
163            command: self.command.expect("should be set"),
164            profile_account_id: self.profile_account_id,
165        }
166    }
167}
168
169/// Deserialize a credential_process response from a string
170///
171/// Returns an error if the response cannot be successfully parsed or is missing keys.
172///
173/// Keys are case insensitive.
174/// The function optionally takes `profile_account_id` that originates from the profile section.
175/// If process execution result does not contain an account ID, the function uses it as a fallback.
176pub(crate) fn parse_credential_process_json_credentials(
177    credentials_response: &str,
178    profile_account_id: Option<&AccountId>,
179) -> Result<Credentials, InvalidJsonCredentials> {
180    let mut version = None;
181    let mut access_key_id = None;
182    let mut secret_access_key = None;
183    let mut session_token = None;
184    let mut expiration = None;
185    let mut account_id = profile_account_id
186        .as_ref()
187        .map(|id| Cow::Borrowed(id.as_str()));
188    json_parse_loop(credentials_response.as_bytes(), |key, value| {
189        match (key, value) {
190            /*
191             "Version": 1,
192             "AccessKeyId": "ASIARTESTID",
193             "SecretAccessKey": "TESTSECRETKEY",
194             "SessionToken": "TESTSESSIONTOKEN",
195             "Expiration": "2022-05-02T18:36:00+00:00",
196             "AccountId": "111122223333"
197            */
198            (key, Token::ValueNumber { value, .. }) if key.eq_ignore_ascii_case("Version") => {
199                version = Some(i32::try_from(*value).map_err(|err| {
200                    InvalidJsonCredentials::InvalidField {
201                        field: "Version",
202                        err: err.into(),
203                    }
204                })?);
205            }
206            (key, Token::ValueString { value, .. }) if key.eq_ignore_ascii_case("AccessKeyId") => {
207                access_key_id = Some(value.to_unescaped()?)
208            }
209            (key, Token::ValueString { value, .. })
210                if key.eq_ignore_ascii_case("SecretAccessKey") =>
211            {
212                secret_access_key = Some(value.to_unescaped()?)
213            }
214            (key, Token::ValueString { value, .. }) if key.eq_ignore_ascii_case("SessionToken") => {
215                session_token = Some(value.to_unescaped()?)
216            }
217            (key, Token::ValueString { value, .. }) if key.eq_ignore_ascii_case("Expiration") => {
218                expiration = Some(value.to_unescaped()?)
219            }
220            (key, Token::ValueString { value, .. }) if key.eq_ignore_ascii_case("AccountId") => {
221                account_id = Some(value.to_unescaped()?)
222            }
223
224            _ => {}
225        };
226        Ok(())
227    })?;
228
229    match version {
230        Some(1) => { /* continue */ }
231        None => return Err(InvalidJsonCredentials::MissingField("Version")),
232        Some(version) => {
233            return Err(InvalidJsonCredentials::InvalidField {
234                field: "version",
235                err: format!("unknown version number: {version}").into(),
236            })
237        }
238    }
239
240    let access_key_id = access_key_id.ok_or(InvalidJsonCredentials::MissingField("AccessKeyId"))?;
241    let secret_access_key =
242        secret_access_key.ok_or(InvalidJsonCredentials::MissingField("SecretAccessKey"))?;
243    let expiration = expiration.map(parse_expiration).transpose()?;
244    if expiration.is_none() {
245        tracing::debug!("no expiration provided for credentials provider credentials. these credentials will never be refreshed.")
246    }
247    let mut builder = Credentials::builder()
248        .access_key_id(access_key_id)
249        .secret_access_key(secret_access_key)
250        .provider_name("CredentialProcess");
251    builder.set_session_token(session_token.map(String::from));
252    builder.set_expiry(expiration);
253    builder.set_account_id(account_id.map(AccountId::from));
254    Ok(builder.build())
255}
256
257fn parse_expiration(expiration: impl AsRef<str>) -> Result<SystemTime, InvalidJsonCredentials> {
258    OffsetDateTime::parse(expiration.as_ref(), &Rfc3339)
259        .map(SystemTime::from)
260        .map_err(|err| InvalidJsonCredentials::InvalidField {
261            field: "Expiration",
262            err: err.into(),
263        })
264}
265
266#[cfg(test)]
267mod test {
268    use crate::credential_process::CredentialProcessProvider;
269    use crate::sensitive_command::CommandWithSensitiveArgs;
270    use aws_credential_types::credential_feature::AwsCredentialFeature;
271    use aws_credential_types::provider::ProvideCredentials;
272    use std::time::{Duration, SystemTime};
273    use time::format_description::well_known::Rfc3339;
274    use time::OffsetDateTime;
275    use tokio::time::timeout;
276
277    // TODO(https://github.com/awslabs/aws-sdk-rust/issues/1117) This test is ignored on Windows because it uses Unix-style paths
278    #[tokio::test]
279    #[cfg_attr(windows, ignore)]
280    async fn test_credential_process() {
281        let provider = CredentialProcessProvider::new(String::from(
282            r#"echo '{ "Version": 1, "AccessKeyId": "ASIARTESTID", "SecretAccessKey": "TESTSECRETKEY", "SessionToken": "TESTSESSIONTOKEN", "AccountId": "123456789001", "Expiration": "2022-05-02T18:36:00+00:00" }'"#,
283        ));
284        let creds = provider.provide_credentials().await.expect("valid creds");
285        assert_eq!(creds.access_key_id(), "ASIARTESTID");
286        assert_eq!(creds.secret_access_key(), "TESTSECRETKEY");
287        assert_eq!(creds.session_token(), Some("TESTSESSIONTOKEN"));
288        assert_eq!(creds.account_id().unwrap().as_str(), "123456789001");
289        assert_eq!(
290            creds.expiry(),
291            Some(
292                SystemTime::try_from(
293                    OffsetDateTime::parse("2022-05-02T18:36:00+00:00", &Rfc3339)
294                        .expect("static datetime")
295                )
296                .expect("static datetime")
297            )
298        );
299    }
300
301    // TODO(https://github.com/awslabs/aws-sdk-rust/issues/1117) This test is ignored on Windows because it uses Unix-style paths
302    #[tokio::test]
303    #[cfg_attr(windows, ignore)]
304    async fn test_credential_process_no_expiry() {
305        let provider = CredentialProcessProvider::new(String::from(
306            r#"echo '{ "Version": 1, "AccessKeyId": "ASIARTESTID", "SecretAccessKey": "TESTSECRETKEY" }'"#,
307        ));
308        let creds = provider.provide_credentials().await.expect("valid creds");
309        assert_eq!(creds.access_key_id(), "ASIARTESTID");
310        assert_eq!(creds.secret_access_key(), "TESTSECRETKEY");
311        assert_eq!(creds.session_token(), None);
312        assert_eq!(creds.expiry(), None);
313    }
314
315    #[tokio::test]
316    async fn credentials_process_timeouts() {
317        let provider = CredentialProcessProvider::new(String::from("sleep 1000"));
318        let _creds = timeout(Duration::from_millis(1), provider.provide_credentials())
319            .await
320            .expect_err("timeout forced");
321    }
322
323    #[tokio::test]
324    async fn credentials_with_fallback_account_id() {
325        let provider = CredentialProcessProvider::builder()
326            .command(CommandWithSensitiveArgs::new(String::from(
327                r#"echo '{ "Version": 1, "AccessKeyId": "ASIARTESTID", "SecretAccessKey": "TESTSECRETKEY" }'"#,
328            )))
329            .account_id("012345678901")
330            .build();
331        let creds = provider.provide_credentials().await.unwrap();
332        assert_eq!("012345678901", creds.account_id().unwrap().as_str());
333    }
334
335    #[tokio::test]
336    async fn fallback_account_id_shadowed_by_account_id_in_process_output() {
337        let provider = CredentialProcessProvider::builder()
338            .command(CommandWithSensitiveArgs::new(String::from(
339                r#"echo '{ "Version": 1, "AccessKeyId": "ASIARTESTID", "SecretAccessKey": "TESTSECRETKEY", "AccountId": "111122223333" }'"#,
340            )))
341            .account_id("012345678901")
342            .build();
343        let creds = provider.provide_credentials().await.unwrap();
344        assert_eq!("111122223333", creds.account_id().unwrap().as_str());
345    }
346
347    #[tokio::test]
348    async fn credential_feature() {
349        let provider = CredentialProcessProvider::builder()
350            .command(CommandWithSensitiveArgs::new(String::from(
351                r#"echo '{ "Version": 1, "AccessKeyId": "ASIARTESTID", "SecretAccessKey": "TESTSECRETKEY", "AccountId": "111122223333" }'"#,
352            )))
353            .account_id("012345678901")
354            .build();
355        let creds = provider.provide_credentials().await.unwrap();
356        assert_eq!(
357            &vec![AwsCredentialFeature::CredentialsProcess],
358            creds.get_property::<Vec<AwsCredentialFeature>>().unwrap()
359        );
360    }
361}
aws_config/credential_process.rs

aws_config/
credential_process.rs
