feat: add the NOSQL, LOG and PII taint kinds

CHANGELOG.md

@@ -6,6 +6,10 @@
 
 - Two plugins may declare the same symbol: an identical model is registered once and sinks merge their kinds and positions; a real conflict names both plugins instead of failing the run on the first duplicate (#92).
 
+### Analysis
+
+- New taint kinds: `NOSQL` in `TaintKind.ALL`; `LOG` and `PII` outside it, carried only by the values a model marks, so a NoSQL-injection, log-injection or personal-data detector no longer has to share a kind with another rule (#96).
+
 ## 0.2.0 (2026-09-06)
 
 ### Adoption in an existing repository

docs/plugins.md

@@ -101,10 +101,14 @@ class CommandInjectionPlugin(TaintDetector):
 ```
 
 `confidence` defaults to high; a hotspot, a flow behind a guard that mentions the value
-or an authorization decorator, is reported at medium. The taint kinds are `SQL`,
-`COMMAND`, `HTML`, `PATH`, `SSRF`, `CODE`, `DESERIALIZATION`, `REDIRECT`, `ADVISORY`
-(APIs affected by advisories) and `CREDENTIAL`, which only credential-named parameters
-carry so that ordinary input reaching a database write is not a plaintext credential.
+or an authorization decorator, is reported at medium. The taint kinds every source
+carries by default (`TaintKind.ALL`) are `SQL`, `NOSQL`, `COMMAND`, `HTML`, `PATH`,
+`SSRF`, `CODE`, `DESERIALIZATION`, `REDIRECT` and `ADVISORY` (APIs affected by
+advisories). Three kinds are outside `ALL`, so only a value a model marks with them
+reaches their sinks: `CREDENTIAL`, which credential-named parameters carry so that
+ordinary input reaching a database write is not a plaintext credential; `LOG`, for
+values that must not be written to a log as they are; and `PII`, for personal data
+that must not leave the application through a log, a third party or plain storage.
 
 ### Security models: `ModelPlugin`
 

src/coretrace_python/taint/models.py

@@ -30,10 +30,14 @@ class TaintKind(Flag):
     ADVISORY = auto()
     DESERIALIZATION = auto()
     REDIRECT = auto()
-    ALL = SQL | COMMAND | HTML | PATH | SSRF | CODE | ADVISORY | DESERIALIZATION | REDIRECT
-    # Outside ALL on purpose: only credential-named parameters carry it, so a database
-    # write reached by ordinary input is not a plaintext credential.
+    NOSQL = auto()
+    ALL = SQL | COMMAND | HTML | PATH | SSRF | CODE | ADVISORY | DESERIALIZATION | REDIRECT | NOSQL
+    # Outside ALL on purpose: only the values a model marks carry them, so a database
+    # write reached by ordinary input is not a plaintext credential, and ordinary input
+    # reaching a logger is neither log forging nor a personal-data leak.
     CREDENTIAL = auto()
+    LOG = auto()
+    PII = auto()
 
 
 class ModelError(Exception):

tests/test_taint.py

@@ -101,6 +101,38 @@ def test_taint_kinds_form_a_bitset() -> None:
     assert {TaintKind.SQL, TaintKind.COMMAND, TaintKind.HTML, TaintKind.PATH, TaintKind.SSRF} <= set(TaintKind)
 
 
+def test_nosql_is_ordinary_input_while_log_and_pii_are_opt_in() -> None:
+    assert TaintKind.NOSQL in TaintKind.ALL
+    assert TaintKind.LOG not in TaintKind.ALL
+    assert TaintKind.PII not in TaintKind.ALL
+    assert TaintKind.CREDENTIAL not in TaintKind.ALL
+
+
+def test_ordinary_input_reaches_a_nosql_sink_but_not_a_log_sink() -> None:
+    registry = SecurityModelRegistry()
+    registry.register(
+        Source(sym("python.flask.request.args"), HTTP),
+        Source(sym("python.app.record"), "record", TaintKind.LOG),
+        Sink(sym("python.db.find"), TaintKind.NOSQL),
+        Sink(sym("python.logging.info"), TaintKind.LOG),
+    )
+    _, facts = analyze(
+        "from flask import request\n"
+        "import db, logging\n"
+        "from app import record\n\n"
+        "def run():\n"
+        "    db.find(request.args['q'])\n"
+        "    logging.info(request.args['q'])\n"
+        "    logging.info(record())\n",
+        registry.freeze(),
+    )
+
+    assert [(f.sink.symbol, f.kinds) for f in facts.flows] == [
+        (sym("python.db.find"), TaintKind.NOSQL),
+        (sym("python.logging.info"), TaintKind.LOG),
+    ]
+
+
 def test_taint_joins_with_or() -> None:
     a = Taint(TaintKind.SQL, frozenset({Source(sym("python.a"), "a")}))
     b = Taint(TaintKind.HTML, frozenset({Source(sym("python.b"), "b")}))