120 lines
3.4 KiB
Go
120 lines
3.4 KiB
Go
// (c) Copyright 2016 Hewlett Packard Enterprise Development LP
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package rules
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import (
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"go/ast"
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"go/types"
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"github.com/securego/gosec"
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)
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type noErrorCheck struct {
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gosec.MetaData
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whitelist gosec.CallList
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}
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func (r *noErrorCheck) ID() string {
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return r.MetaData.ID
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}
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func returnsError(callExpr *ast.CallExpr, ctx *gosec.Context) int {
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if tv := ctx.Info.TypeOf(callExpr); tv != nil {
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switch t := tv.(type) {
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case *types.Tuple:
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for pos := 0; pos < t.Len(); pos++ {
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variable := t.At(pos)
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if variable != nil && variable.Type().String() == "error" {
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return pos
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}
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}
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case *types.Named:
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if t.String() == "error" {
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return 0
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}
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}
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}
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return -1
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}
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func (r *noErrorCheck) Match(n ast.Node, ctx *gosec.Context) (*gosec.Issue, error) {
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switch stmt := n.(type) {
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case *ast.AssignStmt:
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cfg := ctx.Config
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if enabled, err := cfg.IsGlobalEnabled(gosec.Audit); err == nil && enabled {
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for _, expr := range stmt.Rhs {
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if callExpr, ok := expr.(*ast.CallExpr); ok && r.whitelist.ContainsCallExpr(expr, ctx, false) == nil {
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pos := returnsError(callExpr, ctx)
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if pos < 0 || pos >= len(stmt.Lhs) {
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return nil, nil
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}
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if id, ok := stmt.Lhs[pos].(*ast.Ident); ok && id.Name == "_" {
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return gosec.NewIssue(ctx, n, r.ID(), r.What, r.Severity, r.Confidence), nil
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}
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}
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}
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}
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case *ast.ExprStmt:
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if callExpr, ok := stmt.X.(*ast.CallExpr); ok && r.whitelist.ContainsCallExpr(stmt.X, ctx, false) == nil {
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pos := returnsError(callExpr, ctx)
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if pos >= 0 {
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return gosec.NewIssue(ctx, n, r.ID(), r.What, r.Severity, r.Confidence), nil
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}
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}
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}
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return nil, nil
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}
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// NewNoErrorCheck detects if the returned error is unchecked
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func NewNoErrorCheck(id string, conf gosec.Config) (gosec.Rule, []ast.Node) {
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// TODO(gm) Come up with sensible defaults here. Or flip it to use a
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// black list instead.
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whitelist := gosec.NewCallList()
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whitelist.AddAll("bytes.Buffer", "Write", "WriteByte", "WriteRune", "WriteString")
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whitelist.AddAll("fmt", "Print", "Printf", "Println", "Fprint", "Fprintf", "Fprintln")
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whitelist.AddAll("strings.Builder", "Write", "WriteByte", "WriteRune", "WriteString")
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whitelist.Add("io.PipeWriter", "CloseWithError")
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if configured, ok := conf["G104"]; ok {
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if whitelisted, ok := configured.(map[string]interface{}); ok {
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for pkg, funcs := range whitelisted {
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if funcs, ok := funcs.([]interface{}); ok {
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whitelist.AddAll(pkg, toStringSlice(funcs)...)
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}
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}
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}
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}
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return &noErrorCheck{
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MetaData: gosec.MetaData{
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ID: id,
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Severity: gosec.Low,
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Confidence: gosec.High,
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What: "Errors unhandled.",
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},
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whitelist: whitelist,
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}, []ast.Node{(*ast.AssignStmt)(nil), (*ast.ExprStmt)(nil)}
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}
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func toStringSlice(values []interface{}) []string {
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result := []string{}
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for _, value := range values {
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if value, ok := value.(string); ok {
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result = append(result, value)
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}
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}
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return result
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}
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