gosec/rules/errors.go
2023-02-16 09:45:28 +01:00

122 lines
3.5 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"
"github.com/securego/gosec/v2"
"github.com/securego/gosec/v2/issue"
)
type noErrorCheck struct {
issue.MetaData
whitelist gosec.CallList
}
func (r *noErrorCheck) ID() string {
return r.MetaData.ID
}
func returnsError(callExpr *ast.CallExpr, ctx *gosec.Context) int {
if tv := ctx.Info.TypeOf(callExpr); tv != nil {
switch t := tv.(type) {
case *types.Tuple:
for pos := 0; pos < t.Len(); pos++ {
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 *gosec.Context) (*issue.Issue, error) {
switch stmt := n.(type) {
case *ast.AssignStmt:
cfg := ctx.Config
if enabled, err := cfg.IsGlobalEnabled(gosec.Audit); err == nil && enabled {
for _, expr := range stmt.Rhs {
if callExpr, ok := expr.(*ast.CallExpr); ok && r.whitelist.ContainsCallExpr(expr, ctx) == nil {
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 ctx.NewIssue(n, r.ID(), r.What, r.Severity, r.Confidence), nil
}
}
}
}
case *ast.ExprStmt:
if callExpr, ok := stmt.X.(*ast.CallExpr); ok && r.whitelist.ContainsCallExpr(stmt.X, ctx) == nil {
pos := returnsError(callExpr, ctx)
if pos >= 0 {
return ctx.NewIssue(n, r.ID(), r.What, r.Severity, r.Confidence), nil
}
}
}
return nil, nil
}
// NewNoErrorCheck detects if the returned error is unchecked
func NewNoErrorCheck(id string, conf gosec.Config) (gosec.Rule, []ast.Node) {
// TODO(gm) Come up with sensible defaults here. Or flip it to use a
// black list instead.
whitelist := gosec.NewCallList()
whitelist.AddAll("bytes.Buffer", "Write", "WriteByte", "WriteRune", "WriteString")
whitelist.AddAll("fmt", "Print", "Printf", "Println", "Fprint", "Fprintf", "Fprintln")
whitelist.AddAll("strings.Builder", "Write", "WriteByte", "WriteRune", "WriteString")
whitelist.Add("io.PipeWriter", "CloseWithError")
whitelist.Add("hash.Hash", "Write")
whitelist.Add("os", "Unsetenv")
if configured, ok := conf[id]; ok {
if whitelisted, ok := configured.(map[string]interface{}); ok {
for pkg, funcs := range whitelisted {
if funcs, ok := funcs.([]interface{}); ok {
whitelist.AddAll(pkg, toStringSlice(funcs)...)
}
}
}
}
return &noErrorCheck{
MetaData: issue.MetaData{
ID: id,
Severity: issue.Low,
Confidence: issue.High,
What: "Errors unhandled.",
},
whitelist: whitelist,
}, []ast.Node{(*ast.AssignStmt)(nil), (*ast.ExprStmt)(nil)}
}
func toStringSlice(values []interface{}) []string {
result := []string{}
for _, value := range values {
if value, ok := value.(string); ok {
result = append(result, value)
}
}
return result
}