Implemented unified secrets sanitization and env. redaction options (#15348)

docs/get-started/configuration.md

@@ -746,6 +746,22 @@ their corresponding top-level category object in your `settings.json` file.
   - **Default:** `false`
   - **Requires restart:** Yes
 
+- **`security.environmentVariableRedaction.allowed`** (array):
+  - **Description:** Environment variables to always allow (bypass redaction).
+  - **Default:** `[]`
+  - **Requires restart:** Yes
+
+- **`security.environmentVariableRedaction.blocked`** (array):
+  - **Description:** Environment variables to always redact.
+  - **Default:** `[]`
+  - **Requires restart:** Yes
+
+- **`security.environmentVariableRedaction.enabled`** (boolean):
+  - **Description:** Enable redaction of environment variables that may contain
+    secrets.
+  - **Default:** `false`
+  - **Requires restart:** Yes
+
 - **`security.auth.selectedType`** (string):
   - **Description:** The currently selected authentication type.
   - **Default:** `undefined`
@@ -1171,6 +1187,52 @@ the `advanced.excludedEnvVars` setting in your `settings.json` file.
   - Specifies the endpoint for the code assist server.
   - This is useful for development and testing.
 
+### Environment variable redaction
+
+To prevent accidental leakage of sensitive information, Gemini CLI automatically
+redacts potential secrets from environment variables when executing tools (such
+as shell commands). This "best effort" redaction applies to variables inherited
+from the system or loaded from `.env` files.
+
+**Default Redaction Rules:**
+
+- **By Name:** Variables are redacted if their names contain sensitive terms
+  like `TOKEN`, `SECRET`, `PASSWORD`, `KEY`, `AUTH`, `CREDENTIAL`, `PRIVATE`, or
+  `CERT`.
+- **By Value:** Variables are redacted if their values match known secret
+  patterns, such as:
+  - Private keys (RSA, OpenSSH, PGP, etc.)
+  - Certificates
+  - URLs containing credentials
+  - API keys and tokens (GitHub, Google, AWS, Stripe, Slack, etc.)
+- **Specific Blocklist:** Certain variables like `CLIENT_ID`, `DB_URI`,
+  `DATABASE_URL`, and `CONNECTION_STRING` are always redacted by default.
+
+**Allowlist (Never Redacted):**
+
+- Common system variables (e.g., `PATH`, `HOME`, `USER`, `SHELL`, `TERM`,
+  `LANG`).
+- Variables starting with `GEMINI_CLI_`.
+- GitHub Action specific variables.
+
+**Configuration:**
+
+You can customize this behavior in your `settings.json` file:
+
+- **`security.allowedEnvironmentVariables`**: A list of variable names to
+  _never_ redact, even if they match sensitive patterns.
+- **`security.blockedEnvironmentVariables`**: A list of variable names to
+  _always_ redact, even if they don't match sensitive patterns.
+
+```json
+{
+  "security": {
+    "allowedEnvironmentVariables": ["MY_PUBLIC_KEY", "NOT_A_SECRET_TOKEN"],
+    "blockedEnvironmentVariables": ["INTERNAL_IP_ADDRESS"]
+  }
+}
+```
+
 ## Command-line arguments
 
 Arguments passed directly when running the CLI can override other configurations