mirror of
https://github.com/securego/gosec.git
synced 2024-12-25 03:55:54 +00:00
134 lines
3.4 KiB
Go
134 lines
3.4 KiB
Go
// (c) Copyright gosec's authors
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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 analyzers
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import (
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"fmt"
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"regexp"
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"strconv"
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"github.com/securego/gosec/v2/issue"
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"golang.org/x/tools/go/analysis"
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"golang.org/x/tools/go/analysis/passes/buildssa"
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"golang.org/x/tools/go/ssa"
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)
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func newConversionOverflowAnalyzer(id string, description string) *analysis.Analyzer {
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return &analysis.Analyzer{
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Name: id,
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Doc: description,
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Run: runConversionOverflow,
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Requires: []*analysis.Analyzer{buildssa.Analyzer},
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}
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}
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func runConversionOverflow(pass *analysis.Pass) (interface{}, error) {
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ssaResult, err := getSSAResult(pass)
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if err != nil {
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return nil, fmt.Errorf("building ssa representation: %w", err)
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}
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issues := []*issue.Issue{}
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for _, mcall := range ssaResult.SSA.SrcFuncs {
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for _, block := range mcall.DomPreorder() {
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for _, instr := range block.Instrs {
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switch instr := instr.(type) {
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case *ssa.Convert:
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src := instr.X.Type().String()
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dst := instr.Type().String()
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if isIntOverflow(src, dst) {
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issue := newIssue(pass.Analyzer.Name,
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fmt.Sprintf("integer overflow conversion %s -> %s", src, dst),
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pass.Fset,
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instr.Pos(),
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issue.High,
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issue.Medium,
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)
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issues = append(issues, issue)
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}
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}
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}
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}
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}
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if len(issues) > 0 {
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return issues, nil
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}
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return nil, nil
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}
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type integer struct {
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signed bool
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size int
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}
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func parseIntType(intType string) (integer, error) {
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re := regexp.MustCompile(`(?P<type>u?int)(?P<size>\d{2})?`)
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matches := re.FindStringSubmatch(intType)
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if matches == nil {
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return integer{}, fmt.Errorf("no integer type match found for %s", intType)
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}
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it := matches[re.SubexpIndex("type")]
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is := matches[re.SubexpIndex("size")]
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signed := false
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if it == "int" {
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signed = true
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}
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// use default system int type in case size is not present in the type
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intSize := strconv.IntSize
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if is != "" {
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var err error
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intSize, err = strconv.Atoi(is)
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if err != nil {
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return integer{}, fmt.Errorf("failed to parse the integer type size: %w", err)
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}
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}
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return integer{signed: signed, size: intSize}, nil
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}
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func isIntOverflow(src string, dst string) bool {
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srcInt, err := parseIntType(src)
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if err != nil {
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return false
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}
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dstInt, err := parseIntType(dst)
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if err != nil {
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return false
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}
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// converting uint to int of the same size or smaller might lead to overflow
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if !srcInt.signed && dstInt.signed && dstInt.size <= srcInt.size {
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return true
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}
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// converting uint to unit of a smaller size might lead to overflow
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if !srcInt.signed && !dstInt.signed && dstInt.size < srcInt.size {
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return true
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}
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// converting int to int of a smaller size might lead to overflow
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if srcInt.signed && dstInt.signed && dstInt.size < srcInt.size {
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return true
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}
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// converting int to uint of a smaller size might lead to overflow
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if srcInt.signed && !dstInt.signed && dstInt.size < srcInt.size && srcInt.size-dstInt.size > 8 {
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return true
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}
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return false
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}
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