terrascan scan crashes with runtime: goroutine stack exceeds 1000000000-byte limit

[ismailyenigul]

• terrascan version: version: v1.2.0
• Operating System: MacOS

Description

terrascan scan -i terraform -t aws crashes

What I Did

testing terraform code at https://github.com/cloudposse/terraform-aws-vpc-flow-logs-s3-bucket

$ git clone https://github.com/cloudposse/terraform-aws-vpc-flow-logs-s3-bucket
$ cd terraform-aws-vpc-flow-logs-s3-bucket/examples/complete
$ mv fixtures.us-east-2.tfvars terraform.tfvars
$ cat main.tf

provider "aws" {
  region = var.region
}

module "vpc" {
  // https://github.com/cloudposse/terraform-aws-vpc
  source     = "git::https://github.com/cloudposse/terraform-aws-vpc.git?ref=0.17.0"
  enabled    = module.this.enabled
  namespace  = module.this.namespace
  stage      = module.this.stage
  name       = module.this.name
  cidr_block = "172.16.0.0/16"
}

module "flow_logs" {
  source = "../../"

  context = module.this.context
  region  = var.region
  vpc_id  = module.vpc.vpc_id

  // For testing
  force_destroy = true
}
  

$ terraform plan # to verify the code functionality
...
 module.flow_logs.module.s3_bucket.aws_s3_bucket_public_access_block.default[0] will be created
  + resource "aws_s3_bucket_public_access_block" "default" {
      + block_public_acls       = true
      + block_public_policy     = true
      + bucket                  = (known after apply)
      + id                      = (known after apply)
      + ignore_public_acls      = true
      + restrict_public_buckets = true
    }

Plan: 8 to add, 0 to change, 0 to destroy.

then If I issue terrascan scan -i terraform -t aws it crashes after running for a few minutes.
I've seen the following line tens of thousands of times.

2020-11-25T17:58:23.347+0300	debug	v12/variable-references.go:109	resolving variable ref "${var.force_destroy}" in parent module call

$ terrascan scan -i terraform -t aws

...2020-11-25T17:58:23.347+0300 debug v12/variable-references.go:57 extracted variable name "force_destroy" from reference "${var.force_destroy}"
2020-11-25T17:58:23.347+0300 debug v12/variable-references.go:151 resolved str variable ref: '${var.force_destroy}', value: '${var.force_destroy}'
2020-11-25T17:58:23.347+0300 debug v12/variable-references.go:109 resolving variable ref "${var.force_destroy}" in parent module call
2020-11-25T17:58:23.347+0300 debug v12/variable-references.go:57 extracted variable name "force_destroy" from reference "${var.force_destroy}"
2020-11-25T17:58:23.347+0300 debug v12/variable-references.go:151 resolved str variable ref: '${var.force_destroy}', value: '${var.force_destroy}'
2020-11-25T17:58:23.347+0300 debug v12/variable-references.go:109 resolving variable ref "${var.force_destroy}" in parent module call
runtime: goroutine stack exceeds 1000000000-byte limit
runtime: sp=0xc022700388 stack=[0xc022700000, 0xc042700000]
fatal error: stack overflow

runtime stack:
runtime.throw(0x5e72cf2, 0xe)
runtime/panic.go:1116 +0x72
runtime.newstack()
runtime/stack.go:1067 +0x78d
runtime.morestack()
runtime/asm_amd64.s:449 +0x8f

goroutine 1 [running]:
time.tzsetName(0xc0006bc2f8, 0x7, 0x0, 0x0, 0x0, 0x0, 0x0)
time/zoneinfo.go:337 +0x265 fp=0xc022700398 sp=0xc022700390 pc=0x40d4ae5
time.tzset(0xc0006bc2f8, 0x7, 0x7fffffffffffffff, 0x5fbe710f, 0xc0227004e4, 0xe6700, 0x6e52aa9, 0xe523c, 0xe523c, 0x1)
time/zoneinfo.go:253 +0x4d fp=0xc022700490 sp=0xc022700398 pc=0x40d414d
time.(*Location).lookup(0x7048c40, 0x5fbe710f, 0x591, 0xc0227005a0, 0x40584ff, 0x6f16a6f, 0x54)
time/zoneinfo.go:181 +0x197 fp=0xc022700518 sp=0xc022700490 pc=0x40d3db7
time.Time.locabs(0xbfe7ba23d4bbb570, 0x301c019916, 0x7048c40, 0x3900000a89, 0x6f16a6f, 0x6f16a6f, 0x54)
time/time.go:464 +0xf9 fp=0xc022700568 sp=0xc022700518 pc=0x40d03d9
time.Time.AppendFormat(0xbfe7ba23d4bbb570, 0x301c019916, 0x7048c40, 0xc022700778, 0x0, 0x40, 0x5e8de62, 0x1c, 0x3, 0x57ea300, ...)
time/format.go:513 +0x5d fp=0xc022700718 sp=0xc022700568 pc=0x40c77bd
time.Time.Format(0xbfe7ba23d4bbb570, 0x301c019916, 0x7048c40, 0x5e8de62, 0x1c, 0xc000182390, 0xc0017880c0)
time/format.go:505 +0xc5 fp=0xc0227007c8 sp=0xc022700718 pc=0x40c76c5
go.uber.org/zap/zapcore.ISO8601TimeEncoder(0xbfe7ba23d4bbb570, 0x301c019916, 0x7048c40, 0x6201a00, 0xc0017880c0)
go.uber.org/zap@v1.13.0/zapcore/encoder.go:118 +0x54 fp=0xc022700810 sp=0xc0227007c8 pc=0x41ae034
go.uber.org/zap/zapcore.consoleEncoder.EncodeEntry(0xc0006e6db0, 0xff, 0xbfe7ba23d4bbb570, 0x301c019916, 0x7048c40, 0x0, 0x0, 0xc00214f810, 0x4d, 0x1, ...)
go.uber.org/zap@v1.13.0/zapcore/console_encoder.go:77 +0x902 fp=0xc0227008c8 sp=0xc022700810 pc=0x41acda2
go.uber.org/zap/zapcore.(*ioCore).Write(0xc0006e6de0, 0xff, 0xbfe7ba23d4bbb570, 0x301c019916, 0x7048c40, 0x0, 0x0, 0xc00214f810, 0x4d, 0x1, ...)
go.uber.org/zap@v1.13.0/zapcore/core.go:86 +0xa9 fp=0xc0227009a0 sp=0xc0227008c8 pc=0x41ad709
go.uber.org/zap/zapcore.(*CheckedEntry).Write(0xc000c16000, 0x0, 0x0, 0x0)
go.uber.org/zap@v1.13.0/zapcore/entry.go:216 +0x12d fp=0xc022700b40 sp=0xc0227009a0 pc=0x41af40d
go.uber.org/zap.(*SugaredLogger).log(0xc000010438, 0xff, 0x5eb5087, 0x2c, 0xc022700c48, 0x2, 0x2, 0x0, 0x0, 0x0)
go.uber.org/zap@v1.13.0/sugar.go:234 +0xf6 fp=0xc022700b90 sp=0xc022700b40 pc=0x43ce3f6
go.uber.org/zap.(*SugaredLogger).Debugf(...)
go.uber.org/zap@v1.13.0/sugar.go:133
github.com/accurics/terrascan/pkg/iac-providers/terraform/v12.getVarName(0xc0004a2200, 0x14, 0x5ebf10d, 0x2f, 0xc022700eb8, 0x1)
github.com/accurics/terrascan/pkg/iac-providers/terraform/v12/variable-references.go:57 +0x296 fp=0xc022700db8 sp=0xc022700b90 pc=0x57ea596
github.com/accurics/terrascan/pkg/iac-providers/terraform/v12.(*RefResolver).ResolveVarRefFromParentModuleCall(0xc0426ff698, 0xc0004a2200, 0x14, 0x43ce3f6, 0xc000c16000)
github.com/accurics/terrascan/pkg/iac-providers/terraform/v12/variable-references.go:117 +0x116 fp=0xc022700f90 sp=0xc022700db8 pc=0x57eb116
github.com/accurics/terrascan/pkg/iac-providers/terraform/v12.(*RefResolver).ResolveStrRef(0xc0426ff698, 0xc0004a2200, 0x14, 0x2c, 0xc0227011a8)
github.com/accurics/terrascan/pkg/iac-providers/terraform/v12/references.go:147 +0xe5 fp=0xc022701000 sp=0xc022700f90 pc=0x57e9805
github.com/accurics/terrascan/pkg/iac-providers/terraform/v12.(*RefResolver).ResolveVarRefFromParentModuleCall(0xc0426ff698, 0xc0004a2200, 0x14, 0x43ce3f6, 0xc000c16000)
github.com/accurics/terrascan/pkg/iac-providers/terraform/v12/variable-references.go:152 +0x57e fp=0xc0227011d8 sp=0xc022701000 pc=0x57eb57e
github.com/accurics/terrascan/pkg/iac-providers/terraform/v12.(*RefResolver).ResolveStrRef(0xc0426ff698, 0xc0004a2200, 0x14, 0x2c, 0xc0227013f0)
github.com/accurics/terrascan/pkg/iac-providers/terraform/v12/references.go:147 +0xe5 fp=0xc022701248 sp=0xc0227011d8 pc=0x57e9805
github.com/accurics/terrascan/pkg/iac-providers/terraform/v12.(*RefResolver).ResolveVarRefFromParentModuleCall(0xc0426ff698, 0xc0004a2200, 0x14, 0x43ce3f6, 0xc000c16000)
github.com/accurics/terrascan/pkg/iac-providers/terraform/v12/variable-references.go:152 +0x57e fp=0xc022701420 sp=0xc022701248 pc=0x57eb57e
github.com/accurics/terrascan/pkg/iac-providers/terraform/v12.(*RefResolver).ResolveStrRef(0xc0426ff698, 0xc0004a2200, 0x14, 0x2c, 0xc022701638)
github.com/accurics/terrascan/pkg/iac-providers/terraform/v12/references.go:147 +0xe5 fp=0xc022701490 sp=0xc022701420 pc=0x57e9805

[kanchwala-yusuf]

Thanks for creating this issue.

PR #393 should fix this.

[ismailyenigul]

Thanks @kanchwala-yusuf
when can we get the new release to test?