gosec/rules/errors.go

97 lines
2.8 KiB
Go

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