Add taint-tracking for strconv package; rename module StrConv to Strconv and move into stdlib

Author: gagliardetto

ql/src/Security/CWE-681/IncorrectIntegerConversion.ql

@@ -101,7 +101,7 @@ class ConversionWithoutBoundsCheckConfig extends TaintTracking::Configuration {
         // If we are reading a variable, check if it is
         // `strconv.IntSize`, and use 0 if it is.
         exists(DataFlow::Node rawBitSize | rawBitSize = ip.getTargetBitSizeInput().getNode(c) |
-          if rawBitSize = any(StrConv::IntSize intSize).getARead()
+          if rawBitSize = any(Strconv::IntSize intSize).getARead()
           then apparentBitSize = 0
           else apparentBitSize = rawBitSize.getIntValue()
         )

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

@@ -18,6 +18,8 @@ import semmle.go.frameworks.stdlib.MimeQuotedprintable
 import semmle.go.frameworks.stdlib.Path
 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.TextScanner
 import semmle.go.frameworks.stdlib.TextTabwriter
 import semmle.go.frameworks.stdlib.TextTemplate
@@ -483,41 +485,6 @@ module IntegerParser {
   }
 }
 
-/**
- * Provides classes for some functions in the `strconv` package for
- * converting strings to numbers.
- */
-module StrConv {
-  /** The `Atoi` function. */
-  class Atoi extends IntegerParser::Range {
-    Atoi() { this.hasQualifiedName("strconv", "Atoi") }
-
-    override int getTargetBitSize() { result = 0 }
-  }
-
-  /** The `ParseInt` function. */
-  class ParseInt extends IntegerParser::Range {
-    ParseInt() { this.hasQualifiedName("strconv", "ParseInt") }
-
-    override FunctionInput getTargetBitSizeInput() { result.isParameter(2) }
-  }
-
-  /** The `ParseUint` function. */
-  class ParseUint extends IntegerParser::Range {
-    ParseUint() { this.hasQualifiedName("strconv", "ParseUint") }
-
-    override FunctionInput getTargetBitSizeInput() { result.isParameter(2) }
-  }
-
-  /**
-   * The `IntSize` constant, that gives the size in bits of an `int` or
-   * `uint` value on the current architecture (32 or 64).
-   */
-  class IntSize extends DeclaredConstant {
-    IntSize() { this.hasQualifiedName("strconv", "IntSize") }
-  }
-}
-
 /** Provides models of commonly used functions in the `strings` package. */
 module Strings {
   /** The `Join` function. */

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

@@ -0,0 +1,107 @@
+/**
+ * Provides classes modeling security-relevant aspects of the `strconv` package.
+ */
+
+import go
+
+/** Provides models of commonly used functions in the `strconv` package. */
+module Strconv {
+  /** The `Atoi` function. */
+  class Atoi extends IntegerParser::Range {
+    Atoi() { this.hasQualifiedName("strconv", "Atoi") }
+
+    override int getTargetBitSize() { result = 0 }
+  }
+
+  /** The `ParseInt` function. */
+  class ParseInt extends IntegerParser::Range {
+    ParseInt() { this.hasQualifiedName("strconv", "ParseInt") }
+
+    override FunctionInput getTargetBitSizeInput() { result.isParameter(2) }
+  }
+
+  /** The `ParseUint` function. */
+  class ParseUint extends IntegerParser::Range {
+    ParseUint() { this.hasQualifiedName("strconv", "ParseUint") }
+
+    override FunctionInput getTargetBitSizeInput() { result.isParameter(2) }
+  }
+
+  /**
+   * The `IntSize` constant, that gives the size in bits of an `int` or
+   * `uint` value on the current architecture (32 or 64).
+   */
+  class IntSize extends DeclaredConstant {
+    IntSize() { this.hasQualifiedName("strconv", "IntSize") }
+  }
+
+  private class FunctionModels extends TaintTracking::FunctionModel {
+    FunctionInput inp;
+    FunctionOutput outp;
+
+    FunctionModels() {
+      // signature: func AppendQuote(dst []byte, s string) []byte
+      hasQualifiedName("strconv", "AppendQuote") and
+      (
+        inp.isParameter(_) and outp.isResult()
+        or
+        inp.isParameter(1) and
+        (outp.isParameter(0) or outp.isResult())
+      )
+      or
+      // signature: func AppendQuoteToASCII(dst []byte, s string) []byte
+      hasQualifiedName("strconv", "AppendQuoteToASCII") and
+      (
+        inp.isParameter(_) and outp.isResult()
+        or
+        inp.isParameter(1) and
+        (outp.isParameter(0) or outp.isResult())
+      )
+      or
+      // signature: func AppendQuoteToGraphic(dst []byte, s string) []byte
+      hasQualifiedName("strconv", "AppendQuoteToGraphic") and
+      (
+        inp.isParameter(_) and outp.isResult()
+        or
+        inp.isParameter(1) and
+        (outp.isParameter(0) or outp.isResult())
+      )
+      or
+      // signature: func Quote(s string) string
+      hasQualifiedName("strconv", "Quote") and
+      (inp.isParameter(0) and outp.isResult())
+      or
+      // signature: func QuoteRune(r rune) string
+      hasQualifiedName("strconv", "QuoteRune") and
+      (inp.isParameter(0) and outp.isResult())
+      or
+      // signature: func QuoteRuneToASCII(r rune) string
+      hasQualifiedName("strconv", "QuoteRuneToASCII") and
+      (inp.isParameter(0) and outp.isResult())
+      or
+      // signature: func QuoteRuneToGraphic(r rune) string
+      hasQualifiedName("strconv", "QuoteRuneToGraphic") and
+      (inp.isParameter(0) and outp.isResult())
+      or
+      // signature: func QuoteToASCII(s string) string
+      hasQualifiedName("strconv", "QuoteToASCII") and
+      (inp.isParameter(0) and outp.isResult())
+      or
+      // signature: func QuoteToGraphic(s string) string
+      hasQualifiedName("strconv", "QuoteToGraphic") and
+      (inp.isParameter(0) and outp.isResult())
+      or
+      // signature: func Unquote(s string) (string, error)
+      hasQualifiedName("strconv", "Unquote") and
+      (inp.isParameter(0) and outp.isResult(0))
+      or
+      // signature: func UnquoteChar(s string, quote byte) (value rune, multibyte bool, tail string, err error)
+      hasQualifiedName("strconv", "UnquoteChar") and
+      (inp.isParameter(0) and outp.isResult([0, 2]))
+    }
+
+    override predicate hasTaintFlow(FunctionInput input, FunctionOutput output) {
+      input = inp and output = outp
+    }
+  }
+}