Add taint-tracking for syscall

Author: gagliardetto

ql/src/semmle/go/frameworks/Stdlib.qll

@@ -20,6 +20,7 @@ import semmle.go.frameworks.stdlib.PathFilepath
 import semmle.go.frameworks.stdlib.Reflect
 import semmle.go.frameworks.stdlib.Strconv
 import semmle.go.frameworks.stdlib.Strings
+import semmle.go.frameworks.stdlib.Syscall
 import semmle.go.frameworks.stdlib.TextScanner
 import semmle.go.frameworks.stdlib.TextTabwriter
 import semmle.go.frameworks.stdlib.TextTemplate

ql/src/semmle/go/frameworks/stdlib/Syscall.qll

@@ -0,0 +1,66 @@
+/**
+ * Provides classes modeling security-relevant aspects of the `syscall` package.
+ */
+
+import go
+
+/** Provides models of commonly used functions in the `syscall` package. */
+module Syscall {
+  private class FunctionModels extends TaintTracking::FunctionModel {
+    FunctionInput inp;
+    FunctionOutput outp;
+
+    FunctionModels() {
+      // signature: func BytePtrFromString(s string) (*byte, error)
+      hasQualifiedName("syscall", "BytePtrFromString") and
+      (inp.isParameter(0) and outp.isResult(0))
+      or
+      // signature: func ByteSliceFromString(s string) ([]byte, error)
+      hasQualifiedName("syscall", "ByteSliceFromString") and
+      (inp.isParameter(0) and outp.isResult(0))
+      or
+      // signature: func StringBytePtr(s string) *byte
+      hasQualifiedName("syscall", "StringBytePtr") and
+      (inp.isParameter(0) and outp.isResult())
+      or
+      // signature: func StringByteSlice(s string) []byte
+      hasQualifiedName("syscall", "StringByteSlice") and
+      (inp.isParameter(0) and outp.isResult())
+      or
+      // signature: func StringSlicePtr(ss []string) []*byte
+      hasQualifiedName("syscall", "StringSlicePtr") and
+      (inp.isParameter(0) and outp.isResult())
+    }
+
+    override predicate hasTaintFlow(FunctionInput input, FunctionOutput output) {
+      input = inp and output = outp
+    }
+  }
+
+  private class MethodModels extends TaintTracking::FunctionModel, Method {
+    FunctionInput inp;
+    FunctionOutput outp;
+
+    MethodModels() {
+      // signature: func (RawConn).Read(f func(fd uintptr) (done bool)) error
+      this.implements("syscall", "RawConn", "Read") and
+      (inp.isReceiver() and outp.isParameter(0))
+      or
+      // signature: func (Conn).SyscallConn() (RawConn, error)
+      this.implements("syscall", "Conn", "SyscallConn") and
+      (
+        inp.isReceiver() and outp.isResult(0)
+        or
+        inp.isResult(0) and outp.isReceiver()
+      )
+      or
+      // signature: func (RawConn).Write(f func(fd uintptr) (done bool)) error
+      this.implements("syscall", "RawConn", "Write") and
+      (inp.isParameter(0) and outp.isReceiver())
+    }
+
+    override predicate hasTaintFlow(FunctionInput input, FunctionOutput output) {
+      input = inp and output = outp
+    }
+  }
+}