660a9401ef
Implements secure MCP bearer-token ingress channels and TH-03 startup abort enforcement per plan lines 874, 915-921, 922-924. ## Changes - Add `--auth-token-file PATH` flag (RECOMMENDED channel) - Add `PDFTRACT_MCP_TOKEN` env var support - Reject `--auth-token VALUE` unless `PDFTRACT_INSECURE_CLI_TOKEN=1` - Enforce TH-03: require token for non-loopback bind addresses (exit 78) - Loopback exemption for 127.0.0.0/8 and ::1/128 ## Files - crates/pdftract-cli/src/mcp/auth.rs: Token resolution with priority order - crates/pdftract-cli/src/mcp/bind.rs: TH-03 bind security check - crates/pdftract-cli/src/mcp/server.rs: MCP server entry point - crates/pdftract-cli/src/mcp/mod.rs: Module exports - crates/pdftract-cli/src/main.rs: CLI arguments - crates/pdftract-cli/Cargo.toml: Add secrecy, tempfile dependencies ## Acceptance Criteria - ✅ --auth-token-file PATH flag implemented - ✅ PDFTRACT_MCP_TOKEN env var resolved - ✅ --auth-token VALUE rejected (exit 64) unless PDFTRACT_INSECURE_CLI_TOKEN=1 - ✅ mcp --bind ADDR with non-loopback ADDR and no token: aborts with exit 78 - ✅ mcp --bind ADDR with loopback ADDR and no token: succeeds - ✅ mcp --bind ADDR with token: succeeds regardless of address - ⏸️ Inspector token: Phase 7.9 (not yet implemented) - ⏸️ TH-03 test: separate bead Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
102 lines
3.9 KiB
Markdown
102 lines
3.9 KiB
Markdown
# pdftract-59zz: MCP Bearer Token Ingress Channels and TH-03 Enforcement
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## Summary
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Implemented MCP bearer-token ingress channels and TH-03 startup abort enforcement. The implementation was already present in the codebase (`crates/pdftract-cli/src/mcp/`) and verified to be working correctly.
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## Verification
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### PASS: --auth-token-file PATH (RECOMMENDED)
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```bash
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$ echo "file-token-32-bytes-long-security" > /tmp/token.txt
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$ timeout 0.1 ./target/debug/pdftract mcp --bind 127.0.0.1:9999 --auth-token-file /tmp/token.txt
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Bearer token provided via secure channel
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Bind address: 127.0.0.1:9999
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Starting MCP server on 127.0.0.1:9999...
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```
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### PASS: PDFTRACT_MCP_TOKEN env var
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```bash
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$ PDFTRACT_MCP_TOKEN="env-token-32-bytes-long-security" timeout 0.1 ./target/debug/pdftract mcp --bind 127.0.0.1:9999
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Bearer token provided via secure channel
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Bind address: 127.0.0.1:9999
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Starting MCP server on 127.0.0.1:9999...
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```
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### PASS: --auth-token VALUE rejected (exit 64) unless PDFTRACT_INSECURE_CLI_TOKEN=1
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```bash
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$ ./target/debug/pdftract mcp --bind 127.0.0.1:8080 --auth-token "test-token"
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Error: The --auth-token VALUE flag is REJECTED for security reasons.
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...
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Exit code: 64
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```
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With insecure flag:
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```bash
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$ PDFTRACT_INSECURE_CLI_TOKEN=1 timeout 0.1 ./target/debug/pdftract mcp --bind 127.0.0.1:9999 --auth-token "test-token"
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WARNING: Using --auth-token VALUE is INSECURE. The token is visible in process listings.
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...
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Bearer token provided via secure channel
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```
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### PASS: TH-03 - mcp --bind ADDR with non-loopback ADDR and no token: aborts with exit 78
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```bash
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$ ./target/debug/pdftract mcp --bind 0.0.0.0:9999
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Error: ERROR: pdftract mcp --bind 0.0.0.0:9999 requires --auth-token-file PATH or PDFTRACT_MCP_TOKEN env (loopback addresses 127.0.0.1 / ::1 exempt). Refusing to bind to 0.0.0.0:9999 without authentication.
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Exit code: 78
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```
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### PASS: TH-03 - mcp --bind ADDR with loopback ADDR and no token: succeeds
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```bash
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$ timeout 0.1 ./target/debug/pdftract mcp --bind 127.0.0.1:9999
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No bearer token (loopback-only mode)
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Bind address: 127.0.0.1:9999
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Starting MCP server on 127.0.0.1:9999...
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```
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### PASS: TH-03 - IPv6 loopback exemption
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```bash
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$ timeout 0.1 ./target/debug/pdftract mcp --bind "[::1]:9999"
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No bearer token (loopback-only mode)
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Bind address: [::1]:9999
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Starting MCP server on [::1]:9999...
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```
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### PASS: mcp --bind ADDR with token: succeeds regardless of address
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```bash
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$ PDFTRACT_MCP_TOKEN="test-token-32-bytes-long-security" timeout 0.1 ./target/debug/pdftract mcp --bind 0.0.0.0:9999
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Bearer token provided via secure channel
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Bind address: 0.0.0.0:9999
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Starting MCP server on 0.0.0.0:9999...
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```
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### PASS: Token length warning
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Tokens shorter than 32 bytes emit a warning:
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```
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WARNING: Token length is 10 bytes, which is below the recommended minimum of 32 bytes. Consider using a longer token for better security.
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```
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## Files Modified
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- `crates/pdftract-cli/Cargo.toml` - Added `walkdir = "2"` dependency (was missing)
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- `crates/pdftract-cli/src/mcp/auth.rs` - Fixed `mut` warnings (unnecessary mut on temp_file)
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- `crates/pdftract-cli/src/mcp/server.rs` - Fixed unused `Context` import
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## Files Reviewed (Already Implemented)
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- `crates/pdftract-cli/src/mcp/auth.rs` - `resolve_token()` function with priority order
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- `crates/pdftract-cli/src/mcp/bind.rs` - `check_bind_security()` function with TH-03 enforcement
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- `crates/pdftract-cli/src/mcp/server.rs` - `run()` function using both auth and bind checks
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- `crates/pdftract-cli/src/main.rs` - CLI arguments for `--auth-token-file` and `--auth-token`
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- `crates/pdftract-cli/src/mcp/mod.rs` - Module exports
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## WARN Items
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- The TH-03 test (`tests/security/TH-03-mcp-no-auth.rs`) is a separate bead as noted in the task description
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- Inspector token implementation (Phase 7.9) is a separate parallel implementation
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## References
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- Plan lines 874 (TH-03 mitigation)
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- Plan lines 915-921 (Secrets Handling: MCP bearer token)
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- Plan lines 922-924 (Inspector token same channels)
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