Allow quoted strings to be used to format SQL queries (#240)

* Support stripping vendor paths when matching calls

* Factor out matching of formatter string

* Quoted strings are safe to use with SQL str formatted strings

* Add test for allowing quoted strings with string formatters

* Install the pq package for tests to pass

.travis.yml

@@ -12,6 +12,7 @@ install:
   - go get -u github.com/onsi/ginkgo/ginkgo
   - go get -u github.com/onsi/gomega
   - go get -u golang.org/x/crypto/ssh
+  - go get -u github.com/lib/pq
   - go get -u github.com/securego/gosec/cmd/gosec/...
   - go get -v -t ./...
   - export PATH=$PATH:$HOME/gopath/bin

call_list.go

@@ -15,8 +15,11 @@ package gosec
 
 import (
 	"go/ast"
+	"strings"
 )
 
+const vendorPath = "vendor/"
+
 type set map[string]bool
 
 // CallList is used to check for usage of specific packages
@@ -55,17 +58,27 @@ func (c CallList) Contains(selector, ident string) bool {
 
 // ContainsCallExpr resolves the call expression name and type
 /// or package and determines if it exists within the CallList
-func (c CallList) ContainsCallExpr(n ast.Node, ctx *Context) *ast.CallExpr {
+func (c CallList) ContainsCallExpr(n ast.Node, ctx *Context, stripVendor bool) *ast.CallExpr {
 	selector, ident, err := GetCallInfo(n, ctx)
 	if err != nil {
 		return nil
 	}
 
-	// Use only explicit path to reduce conflicts
+	// Use only explicit path (optionally strip vendor path prefix) to reduce conflicts
-	if path, ok := GetImportPath(selector, ctx); ok && c.Contains(path, ident) {
+	path, ok := GetImportPath(selector, ctx)
-		return n.(*ast.CallExpr)
+	if !ok {
+		return nil
+	}
+	if stripVendor {
+		if vendorIdx := strings.Index(path, vendorPath); vendorIdx >= 0 {
+			path = path[vendorIdx+len(vendorPath):]
+		}
+	}
+	if !c.Contains(path, ident) {
+		return nil
 	}
 
+	return n.(*ast.CallExpr)
 	/*
 		// Try direct resolution
 		if c.Contains(selector, ident) {
@@ -74,5 +87,4 @@ func (c CallList) ContainsCallExpr(n ast.Node, ctx *Context) *ast.CallExpr {
 		}
 	*/
 
-	return nil
 }

call_list_test.go

@@ -73,7 +73,7 @@ var _ = Describe("call list", func() {
 		v := testutils.NewMockVisitor()
 		v.Context = ctx
 		v.Callback = func(n ast.Node, ctx *gosec.Context) bool {
-			if _, ok := n.(*ast.CallExpr); ok && calls.ContainsCallExpr(n, ctx) != nil {
+			if _, ok := n.(*ast.CallExpr); ok && calls.ContainsCallExpr(n, ctx, false) != nil {
 				matched++
 			}
 			return true

rules/archive.go

@@ -19,7 +19,7 @@ func (a *archive) ID() string {
 
 // Match inspects AST nodes to determine if the filepath.Joins uses any argument derived from type zip.File
 func (a *archive) Match(n ast.Node, c *gosec.Context) (*gosec.Issue, error) {
-	if node := a.calls.ContainsCallExpr(n, c); node != nil {
+	if node := a.calls.ContainsCallExpr(n, c, false); node != nil {
 		for _, arg := range node.Args {
 			var argType types.Type
 			if selector, ok := arg.(*ast.SelectorExpr); ok {

rules/bind.go

@@ -33,7 +33,7 @@ func (r *bindsToAllNetworkInterfaces) ID() string {
 }
 
 func (r *bindsToAllNetworkInterfaces) Match(n ast.Node, c *gosec.Context) (*gosec.Issue, error) {
-	callExpr := r.calls.ContainsCallExpr(n, c)
+	callExpr := r.calls.ContainsCallExpr(n, c, false)
 	if callExpr == nil {
 		return nil, nil
 	}

rules/errors.go

@@ -53,7 +53,7 @@ func (r *noErrorCheck) Match(n ast.Node, ctx *gosec.Context) (*gosec.Issue, erro
 	switch stmt := n.(type) {
 	case *ast.AssignStmt:
 		for _, expr := range stmt.Rhs {
-			if callExpr, ok := expr.(*ast.CallExpr); ok && r.whitelist.ContainsCallExpr(expr, ctx) == nil {
+			if callExpr, ok := expr.(*ast.CallExpr); ok && r.whitelist.ContainsCallExpr(expr, ctx, false) == nil {
 				pos := returnsError(callExpr, ctx)
 				if pos < 0 || pos >= len(stmt.Lhs) {
 					return nil, nil
@@ -64,7 +64,7 @@ func (r *noErrorCheck) Match(n ast.Node, ctx *gosec.Context) (*gosec.Issue, erro
 			}
 		}
 	case *ast.ExprStmt:
-		if callExpr, ok := stmt.X.(*ast.CallExpr); ok && r.whitelist.ContainsCallExpr(stmt.X, ctx) == nil {
+		if callExpr, ok := stmt.X.(*ast.CallExpr); ok && r.whitelist.ContainsCallExpr(stmt.X, ctx, false) == nil {
 			pos := returnsError(callExpr, ctx)
 			if pos >= 0 {
 				return gosec.NewIssue(ctx, n, r.ID(), r.What, r.Severity, r.Confidence), nil

rules/readfile.go

@@ -34,7 +34,7 @@ func (r *readfile) ID() string {
 
 // isJoinFunc checks if there is a filepath.Join or other join function
 func (r *readfile) isJoinFunc(n ast.Node, c *gosec.Context) bool {
-	if call := r.pathJoin.ContainsCallExpr(n, c); call != nil {
+	if call := r.pathJoin.ContainsCallExpr(n, c, false); call != nil {
 		for _, arg := range call.Args {
 			// edge case: check if one of the args is a BinaryExpr
 			if binExp, ok := arg.(*ast.BinaryExpr); ok {
@@ -58,7 +58,7 @@ func (r *readfile) isJoinFunc(n ast.Node, c *gosec.Context) bool {
 
 // Match inspects AST nodes to determine if the match the methods `os.Open` or `ioutil.ReadFile`
 func (r *readfile) Match(n ast.Node, c *gosec.Context) (*gosec.Issue, error) {
-	if node := r.ContainsCallExpr(n, c); node != nil {
+	if node := r.ContainsCallExpr(n, c, false); node != nil {
 		for _, arg := range node.Args {
 			// handles path joining functions in Arg
 			// eg. os.Open(filepath.Join("/tmp/", file))

rules/rsa.go

@@ -32,7 +32,7 @@ func (w *weakKeyStrength) ID() string {
 }
 
 func (w *weakKeyStrength) Match(n ast.Node, c *gosec.Context) (*gosec.Issue, error) {
-	if callExpr := w.calls.ContainsCallExpr(n, c); callExpr != nil {
+	if callExpr := w.calls.ContainsCallExpr(n, c, false); callExpr != nil {
 		if bits, err := gosec.GetInt(callExpr.Args[1]); err == nil && bits < (int64)(w.bits) {
 			return gosec.NewIssue(c, n, w.ID(), w.What, w.Severity, w.Confidence), nil
 		}

rules/sql.go

@@ -100,6 +100,7 @@ type sqlStrFormat struct {
 	sqlStatement
 	calls         gosec.CallList
 	noIssue       gosec.CallList
+	noIssueQuoted gosec.CallList
 }
 
 // Looks for "fmt.Sprintf("SELECT * FROM foo where '%s', userInput)"
@@ -109,7 +110,7 @@ func (s *sqlStrFormat) Match(n ast.Node, c *gosec.Context) (*gosec.Issue, error)
 	argIndex := 0
 
 	// TODO(gm) improve confidence if database/sql is being used
-	if node := s.calls.ContainsCallExpr(n, c); node != nil {
+	if node := s.calls.ContainsCallExpr(n, c, false); node != nil {
 		// if the function is fmt.Fprintf, search for SQL statement in Args[1] instead
 		if sel, ok := node.Fun.(*ast.SelectorExpr); ok {
 			if sel.Sel.Name == "Fprintf" {
@@ -125,17 +126,35 @@ func (s *sqlStrFormat) Match(n ast.Node, c *gosec.Context) (*gosec.Issue, error)
 				argIndex = 1
 			}
 		}
+
+		var formatter string
+
 		// concats callexpr arg strings together if needed before regex evaluation
 		if argExpr, ok := node.Args[argIndex].(*ast.BinaryExpr); ok {
 			if fullStr, ok := gosec.ConcatString(argExpr); ok {
-				if s.MatchPatterns(fullStr) {
+				formatter = fullStr
-					return gosec.NewIssue(c, n, s.ID(), s.What, s.Severity, s.Confidence),
-						nil
 			}
+		} else if arg, e := gosec.GetString(node.Args[argIndex]); e == nil {
+			formatter = arg
 		}
+		if len(formatter) <= 0 {
+			return nil, nil
 		}
 
-		if arg, e := gosec.GetString(node.Args[argIndex]); s.MatchPatterns(arg) && e == nil {
+		// If all formatter args are quoted, then the SQL construction is safe
+		if argIndex+1 < len(node.Args) {
+			allQuoted := true
+			for _, arg := range node.Args[argIndex+1:] {
+				if n := s.noIssueQuoted.ContainsCallExpr(arg, c, true); n == nil {
+					allQuoted = false
+					break
+				}
+			}
+			if allQuoted {
+				return nil, nil
+			}
+		}
+		if s.MatchPatterns(formatter) {
 			return gosec.NewIssue(c, n, s.ID(), s.What, s.Severity, s.Confidence), nil
 		}
 	}
@@ -147,6 +166,7 @@ func NewSQLStrFormat(id string, conf gosec.Config) (gosec.Rule, []ast.Node) {
 	rule := &sqlStrFormat{
 		calls:         gosec.NewCallList(),
 		noIssue:       gosec.NewCallList(),
+		noIssueQuoted: gosec.NewCallList(),
 		sqlStatement: sqlStatement{
 			patterns: []*regexp.Regexp{
 				regexp.MustCompile("(?)(SELECT|DELETE|INSERT|UPDATE|INTO|FROM|WHERE) "),
@@ -162,5 +182,6 @@ func NewSQLStrFormat(id string, conf gosec.Config) (gosec.Rule, []ast.Node) {
 	}
 	rule.calls.AddAll("fmt", "Sprint", "Sprintf", "Sprintln", "Fprintf")
 	rule.noIssue.AddAll("os", "Stdout", "Stderr")
+	rule.noIssueQuoted.Add("github.com/lib/pq", "QuoteIdentifier")
 	return rule, []ast.Node{(*ast.CallExpr)(nil)}
 }

rules/ssrf.go

@@ -35,7 +35,7 @@ func (r *ssrf) ResolveVar(n *ast.CallExpr, c *gosec.Context) bool {
 // Match inspects AST nodes to determine if certain net/http methods are called with variable input
 func (r *ssrf) Match(n ast.Node, c *gosec.Context) (*gosec.Issue, error) {
 	// Call expression is using http package directly
-	if node := r.ContainsCallExpr(n, c); node != nil {
+	if node := r.ContainsCallExpr(n, c, false); node != nil {
 		if r.ResolveVar(node, c) {
 			return gosec.NewIssue(c, n, r.ID(), r.What, r.Severity, r.Confidence), nil
 		}

rules/subproc.go

@@ -40,7 +40,7 @@ func (r *subprocess) ID() string {
 //
 // syscall.Exec("echo", "foobar" + tainted)
 func (r *subprocess) Match(n ast.Node, c *gosec.Context) (*gosec.Issue, error) {
-	if node := r.ContainsCallExpr(n, c); node != nil {
+	if node := r.ContainsCallExpr(n, c, false); node != nil {
 		for _, arg := range node.Args {
 			if ident, ok := arg.(*ast.Ident); ok {
 				obj := c.Info.ObjectOf(ident)

rules/tempfiles.go

@@ -32,7 +32,7 @@ func (t *badTempFile) ID() string {
 }
 
 func (t *badTempFile) Match(n ast.Node, c *gosec.Context) (gi *gosec.Issue, err error) {
-	if node := t.calls.ContainsCallExpr(n, c); node != nil {
+	if node := t.calls.ContainsCallExpr(n, c, false); node != nil {
 		if arg, e := gosec.GetString(node.Args[0]); t.args.MatchString(arg) && e == nil {
 			return gosec.NewIssue(c, n, t.ID(), t.What, t.Severity, t.Confidence), nil
 		}

rules/templates.go

@@ -30,7 +30,7 @@ func (t *templateCheck) ID() string {
 }
 
 func (t *templateCheck) Match(n ast.Node, c *gosec.Context) (*gosec.Issue, error) {
-	if node := t.calls.ContainsCallExpr(n, c); node != nil {
+	if node := t.calls.ContainsCallExpr(n, c, false); node != nil {
 		for _, arg := range node.Args {
 			if _, ok := arg.(*ast.BasicLit); !ok { // basic lits are safe
 				return gosec.NewIssue(c, n, t.ID(), t.What, t.Severity, t.Confidence), nil

testutils/source.go

@@ -292,6 +292,27 @@ func main(){
 				panic(err)
 		}
 		defer rows.Close()
+}`, 0}, {`
+// Format string false positive, quoted formatter argument.
+package main
+import (
+	"database/sql"
+	"fmt"
+	"os"
+	"github.com/lib/pq"
+)
+
+func main(){
+	db, err := sql.Open("postgres", "localhost")
+	if err != nil {
+		panic(err)
+	}
+	q := fmt.Sprintf("SELECT * FROM %s where id = 1", pq.QuoteIdentifier(os.Args[1]))
+	rows, err := db.Query(q)
+	if err != nil {
+		panic(err)
+	}
+	defer rows.Close()
 }`, 0}}
 
 	// SampleCodeG202 - SQL query string building via string concatenation