Go: more models for log.slog

go/ql/lib/change-notes/2026-06-30-model-log-slog.md

@@ -0,0 +1,4 @@
+---
+category: minorAnalysis
+---
+ * Improved models for the `log/slog` package (Go 1.21+), including `*slog.Logger` methods, `With`/`WithGroup`, and `Attr`/`Value` helpers, improving coverage for the `go/log-injection` and `go/clear-text-logging` queries.

go/ql/lib/ext/log.slog.model.yml

@@ -27,3 +27,27 @@ extensions:
       - ["log/slog", "Logger", True, "ErrorContext", "", "", "Argument[1..2]", "log-injection", "manual"]
       - ["log/slog", "Logger", True, "Log", "", "", "Argument[2..3]", "log-injection", "manual"]
       - ["log/slog", "Logger", True, "LogAttrs", "", "", "Argument[2..3]", "log-injection", "manual"]
+      # With/WithGroup add attributes that are included in every subsequent log call.
+      - ["log/slog", "", False, "With", "", "", "Argument[0]", "log-injection", "manual"]
+      - ["log/slog", "Logger", True, "With", "", "", "Argument[0]", "log-injection", "manual"]
+      - ["log/slog", "Logger", True, "WithGroup", "", "", "Argument[0]", "log-injection", "manual"]
+  - addsTo:
+      pack: codeql/go-all
+      extensible: summaryModel
+    data:
+      # Constructors for Attr that can carry a tainted string into the result.
+      - ["log/slog", "", False, "Any", "", "", "Argument[0..1]", "ReturnValue", "taint", "manual"]
+      - ["log/slog", "", False, "Group", "", "", "Argument[0]", "ReturnValue", "taint", "manual"]
+      - ["log/slog", "", False, "Group", "", "", "Argument[1].ArrayElement", "ReturnValue", "taint", "manual"]
+      - ["log/slog", "", False, "GroupAttrs", "", "", "Argument[0]", "ReturnValue", "taint", "manual"]
+      - ["log/slog", "", False, "GroupAttrs", "", "", "Argument[1].ArrayElement", "ReturnValue", "taint", "manual"]
+      - ["log/slog", "", False, "String", "", "", "Argument[0..1]", "ReturnValue", "taint", "manual"]
+      # Constructors for Value that can carry a tainted string into the result.
+      - ["log/slog", "", False, "AnyValue", "", "", "Argument[0]", "ReturnValue", "taint", "manual"]
+      - ["log/slog", "", False, "GroupValue", "", "", "Argument[0].ArrayElement", "ReturnValue", "taint", "manual"]
+      - ["log/slog", "", False, "StringValue", "", "", "Argument[0]", "ReturnValue", "taint", "manual"]
+      # Methods that read a string back out of an Attr or Value.
+      - ["log/slog", "Attr", True, "String", "", "", "Argument[receiver]", "ReturnValue", "taint", "manual"]
+      - ["log/slog", "Value", True, "Any", "", "", "Argument[receiver]", "ReturnValue", "taint", "manual"]
+      - ["log/slog", "Value", True, "Group", "", "", "Argument[receiver]", "ReturnValue.ArrayElement", "taint", "manual"]
+      - ["log/slog", "Value", True, "String", "", "", "Argument[receiver]", "ReturnValue", "taint", "manual"]

go/ql/test/library-tests/semmle/go/concepts/LoggerCall/slog.go

@@ -37,4 +37,9 @@ func slogTest() {
 	slog.InfoContext(ctx, text, key, v)            // $ logger=text logger=key logger=v
 	slog.Log(ctx, slog.LevelInfo, text, key, v)    // $ logger=text logger=key logger=v
 	slog.LogAttrs(ctx, slog.LevelInfo, text, attr) // $ logger=text logger=attr
+
+	// With/WithGroup add attributes that are included in every subsequent log call.
+	logger.With(key, v)    // $ logger=key logger=v
+	logger.WithGroup(text) // $ logger=text
+	slog.With(key, v)      // $ logger=key logger=v
 }

go/ql/test/library-tests/semmle/go/frameworks/Slog/CONSISTENCY/DataFlowConsistency.expected

@@ -0,0 +1,2 @@
+reverseRead
+| test.go:114:21:114:33 | call to Group | Origin of readStep is missing a PostUpdateNode. |

go/ql/test/library-tests/semmle/go/frameworks/Slog/TaintFlows.expected

@@ -0,0 +1,2 @@
+invalidModelRow
+testFailures

go/ql/test/library-tests/semmle/go/frameworks/Slog/TaintFlows.ql

@@ -0,0 +1,14 @@
+import go
+import semmle.go.dataflow.ExternalFlow
+import ModelValidation
+import utils.test.InlineFlowTest
+
+module Config implements DataFlow::ConfigSig {
+  predicate isSource(DataFlow::Node source) {
+    source.(DataFlow::CallNode).getTarget().getName() = ["getUntrustedData", "getUntrustedString"]
+  }
+
+  predicate isSink(DataFlow::Node sink) { sink = any(LoggerCall log).getAMessageComponent() }
+}
+
+import FlowTest<Config, Config>

go/ql/test/library-tests/semmle/go/frameworks/Slog/go.mod

@@ -0,0 +1,3 @@
+module codeql-go-tests/frameworks/slog
+
+go 1.26

go/ql/test/library-tests/semmle/go/frameworks/Slog/test.go

@@ -0,0 +1,115 @@
+package main
+
+import (
+	"context"
+	"log/slog"
+)
+
+func main() {}
+
+func getUntrustedData() interface{} { return nil }
+
+func getUntrustedString() string {
+	return "tainted string"
+}
+
+// Package-level convenience functions.
+
+func testSlogDebug() {
+	slog.Debug(getUntrustedString())                            // $ hasValueFlow="call to getUntrustedString"
+	slog.Debug("msg", "key", getUntrustedData())                // $ hasValueFlow="call to getUntrustedData"
+	slog.Debug("msg", slog.String("key", getUntrustedString())) // $ hasTaintFlow="call to String"
+}
+
+func testSlogInfo() {
+	slog.Info(getUntrustedString())                            // $ hasValueFlow="call to getUntrustedString"
+	slog.Info("msg", slog.Any("key", getUntrustedData()))      // $ hasTaintFlow="call to Any"
+	slog.Info("msg", slog.String("key", getUntrustedString())) // $ hasTaintFlow="call to String"
+}
+
+func testSlogWarn() {
+	slog.Warn(getUntrustedString())                            // $ hasValueFlow="call to getUntrustedString"
+	slog.Warn("msg", slog.String("key", getUntrustedString())) // $ hasTaintFlow="call to String"
+}
+
+func testSlogError() {
+	slog.Error(getUntrustedString())                            // $ hasValueFlow="call to getUntrustedString"
+	slog.Error("msg", slog.String("key", getUntrustedString())) // $ hasTaintFlow="call to String"
+}
+
+func testSlogContextVariants(ctx context.Context) {
+	slog.DebugContext(ctx, getUntrustedString())                           // $ hasValueFlow="call to getUntrustedString"
+	slog.InfoContext(ctx, getUntrustedString())                            // $ hasValueFlow="call to getUntrustedString"
+	slog.WarnContext(ctx, getUntrustedString())                            // $ hasValueFlow="call to getUntrustedString"
+	slog.ErrorContext(ctx, getUntrustedString())                           // $ hasValueFlow="call to getUntrustedString"
+	slog.InfoContext(ctx, "msg", slog.String("key", getUntrustedString())) // $ hasTaintFlow="call to String"
+}
+
+func testSlogLog(ctx context.Context) {
+	slog.Log(ctx, slog.LevelInfo, getUntrustedString())                                 // $ hasValueFlow="call to getUntrustedString"
+	slog.Log(ctx, slog.LevelInfo, "msg", slog.String("key", getUntrustedString()))      // $ hasTaintFlow="call to String"
+	slog.LogAttrs(ctx, slog.LevelInfo, getUntrustedString())                            // $ hasValueFlow="call to getUntrustedString"
+	slog.LogAttrs(ctx, slog.LevelInfo, "msg", slog.String("key", getUntrustedString())) // $ hasTaintFlow="call to String"
+}
+
+// Methods on *slog.Logger.
+
+func testLoggerMethods(logger *slog.Logger, ctx context.Context) {
+	logger.Debug(getUntrustedString())                                                    // $ hasValueFlow="call to getUntrustedString"
+	logger.Info(getUntrustedString())                                                     // $ hasValueFlow="call to getUntrustedString"
+	logger.Warn(getUntrustedString())                                                     // $ hasValueFlow="call to getUntrustedString"
+	logger.Error(getUntrustedString())                                                    // $ hasValueFlow="call to getUntrustedString"
+	logger.Info("msg", slog.Any("key", getUntrustedData()))                               // $ hasTaintFlow="call to Any"
+	logger.InfoContext(ctx, getUntrustedString())                                         // $ hasValueFlow="call to getUntrustedString"
+	logger.Log(ctx, slog.LevelInfo, getUntrustedString())                                 // $ hasValueFlow="call to getUntrustedString"
+	logger.LogAttrs(ctx, slog.LevelInfo, "msg", slog.String("key", getUntrustedString())) // $ hasTaintFlow="call to String"
+}
+
+// With, Logger.With and Logger.WithGroup. Note that for ease of modeling we make these functions
+// sinks, although strictly speaking we should consider logging functions called on the returned
+// loggers as the sinks.
+
+func testWith(logger *slog.Logger) {
+	logger1 := logger.With(slog.String("key", getUntrustedString())) // $ hasTaintFlow="call to String"
+	logger1.Info("hello world")
+	logger2 := logger.With(slog.Any(getUntrustedString(), nil)) // $ hasTaintFlow="call to Any"
+	logger2.Info("hello world")
+	logger.With("key", getUntrustedData()).Info("hello world") // $ hasValueFlow="call to getUntrustedData"
+}
+
+func testPackageWith() {
+	logger := slog.With(slog.String("key", getUntrustedString())) // $ hasTaintFlow="call to String"
+	logger.Info("hello world")
+	slog.With("key", getUntrustedData()).Info("hello world") // $ hasValueFlow="call to getUntrustedData"
+}
+
+func testWithGroup(logger *slog.Logger) {
+	grouped := logger.WithGroup(getUntrustedString()) // $ hasValueFlow="call to getUntrustedString"
+	grouped.Info("hello world")
+}
+
+// Summary models: functions relating to Attr/Value that propagate strings.
+
+func testAttrConstructors(logger *slog.Logger) {
+	logger.Info("msg", slog.Group("group", slog.String("key", getUntrustedString())))      // $ hasTaintFlow="call to Group"
+	logger.Info("msg", slog.GroupAttrs("group", slog.String("key", getUntrustedString()))) // $ hasTaintFlow="call to GroupAttrs"
+}
+
+func testValueConstructors(logger *slog.Logger) {
+	logger.Info("msg", "key", slog.AnyValue(getUntrustedString()))    // $ hasTaintFlow="call to AnyValue"
+	logger.Info("msg", "key", slog.StringValue(getUntrustedString())) // $ hasTaintFlow="call to StringValue"
+	attr := slog.String("key", getUntrustedString())
+	logger.Info("msg", "key", slog.GroupValue(attr)) // $ hasTaintFlow="call to GroupValue"
+}
+
+func testAttrAndValueAccessors(logger *slog.Logger) {
+	attr := slog.String("key", getUntrustedString())
+	logger.Info("msg", "key", attr.String()) // $ hasTaintFlow="call to String"
+
+	v := slog.AnyValue(getUntrustedString())
+	logger.Info("msg", "key", v.Any())    // $ hasTaintFlow="call to Any"
+	logger.Info("msg", "key", v.String()) // $ hasTaintFlow="call to String"
+
+	group := slog.GroupValue(slog.String("key", getUntrustedString()))
+	logger.Info("msg", group.Group()[0]) // $ hasTaintFlow="index expression"
+}