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Code Issues Releases Activity

Modify rule for integer overflow to have more acurate results (#434)

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Signed-off-by: Hiroki Suezawa <suezawa@gmail.com>
This commit is contained in:
Hiroki Suezawa
2020-01-21 18:13:12 +09:00
committed by Cosmin Cojocar
parent a4d7b3628b
commit 459e2d3e91
2 changed files with 25 additions and 13 deletions
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21
rules/integer_overflow.go
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@ -30,32 +30,29 @@ func (i *integerOverflowCheck) ID() string {
}
func (i *integerOverflowCheck) Match(node ast.Node, ctx *gosec.Context) (*gosec.Issue, error) {
var atoiVarName map[string]ast.Node
var atoiVarObj map[*ast.Object]ast.Node
// To check multiple lines, ctx.PassedValues is used to store temporary data.
if _, ok := ctx.PassedValues[i.ID()]; !ok {
atoiVarName = make(map[string]ast.Node)
ctx.PassedValues[i.ID()] = atoiVarName
} else if pv, ok := ctx.PassedValues[i.ID()].(map[string]ast.Node); ok {
atoiVarName = pv
atoiVarObj = make(map[*ast.Object]ast.Node)
ctx.PassedValues[i.ID()] = atoiVarObj
} else if pv, ok := ctx.PassedValues[i.ID()].(map[*ast.Object]ast.Node); ok {
atoiVarObj = pv
} else {
return nil, fmt.Errorf("PassedValues[%s] of Context is not map[string]ast.Node, but %T", i.ID(), ctx.PassedValues[i.ID()])
return nil, fmt.Errorf("PassedValues[%s] of Context is not map[*ast.Object]ast.Node, but %T", i.ID(), ctx.PassedValues[i.ID()])
}
// strconv.Atoi is a common function.
// To reduce false positives, This rule detects code which is converted to int32/int16 only.
switch n := node.(type) {
case *ast.FuncDecl:
// Clear atoiVarName by function
ctx.PassedValues[i.ID()] = make(map[string]ast.Node)
case *ast.AssignStmt:
for _, expr := range n.Rhs {
if callExpr, ok := expr.(*ast.CallExpr); ok && i.calls.ContainsCallExpr(callExpr, ctx, false) != nil {
if idt, ok := n.Lhs[0].(*ast.Ident); ok && idt.Name != "_" {
// Example:
// v, _ := strconv.Atoi("1111")
// Add "v" to atoiVarName map
atoiVarName[idt.Name] = n
// Add v's Obj to atoiVarObj map
atoiVarObj[idt.Obj] = n
}
}
}
@ -63,7 +60,7 @@ func (i *integerOverflowCheck) Match(node ast.Node, ctx *gosec.Context) (*gosec.
if fun, ok := n.Fun.(*ast.Ident); ok {
if fun.Name == "int32" || fun.Name == "int16" {
if idt, ok := n.Args[0].(*ast.Ident); ok {
if n, ok := atoiVarName[idt.Name]; ok {
if n, ok := atoiVarObj[idt.Obj]; ok {
// Detect int32(v) and int16(v)
return gosec.NewIssue(ctx, n, i.ID(), i.What, i.Severity, i.Confidence), nil
}