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

docs/cli/settings.md

@@ -98,11 +98,13 @@ they appear in the UI.
 
 ### Security
 
-| UI Label                   | Setting                        | Description                                        | Default |
-| -------------------------- | ------------------------------ | -------------------------------------------------- | ------- |
-| Disable YOLO Mode          | `security.disableYoloMode`     | Disable YOLO mode, even if enabled by a flag.      | `false` |
-| Blocks extensions from Git | `security.blockGitExtensions`  | Blocks installing and loading extensions from Git. | `false` |
-| Folder Trust               | `security.folderTrust.enabled` | Setting to track whether Folder trust is enabled.  | `false` |
+| UI Label                      | Setting                                         | Description                                               | Default |
+| ----------------------------- | ----------------------------------------------- | --------------------------------------------------------- | ------- |
+| Disable YOLO Mode             | `security.disableYoloMode`                      | Disable YOLO mode, even if enabled by a flag.             | `false` |
+| Blocks extensions from Git    | `security.blockGitExtensions`                   | Blocks installing and loading extensions from Git.        | `false` |
+| Folder Trust                  | `security.folderTrust.enabled`                  | Setting to track whether Folder trust is enabled.         | `false` |
+| Allowed Environment Variables | `security.environmentVariableRedaction.allowed` | Environment variables to always allow (bypass redaction). | `[]`    |
+| Blocked Environment Variables | `security.environmentVariableRedaction.blocked` | Environment variables to always redact.                   | `[]`    |
 
 ### Experimental
 

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