Terraform 无法承担启用 MFA 的角色

Question

我很难让 Terraform 承担另一个需要 MFA 的帐户的 IAM 角色。这是我的设置

AWS 配置

[default]
region = us-west-2
output = json

[profile GEHC-000]
region = us-west-2
output = json

....

[profile GEHC-056]
source_profile = GEHC-000
role_arn = arn:aws:iam::~069:role/hc/hc-master
mfa_serial = arn:aws:iam::~183:mfa/username
external_id = ~069

AWS 凭证

[default]
aws_access_key_id = xxx
aws_secret_access_key = xxx


[GEHC-000]
aws_access_key_id = same as above
aws_secret_access_key = same as above

分配给 IAM 用户的策略

STS 政策

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "AssumeRole",
            "Effect": "Allow",
            "Action": [
                "sts:AssumeRole"
            ],
            "Resource": [
                "arn:aws:iam::*:role/hc/hc-master"
            ]
        }
    ]
}

用户政策

{
    "Statement": [
        {
            "Action": [
                "iam:*AccessKey*",
                "iam:*MFA*",
                "iam:*SigningCertificate*",
                "iam:UpdateLoginProfile*",
                "iam:RemoveUserFromGroup*"
            ],
            "Effect": "Allow",
            "Resource": [
                "arn:aws:iam::~183:mfa/${aws:username}",
                "arn:aws:iam::~183:mfa/*/${aws:username}",
                "arn:aws:iam::~183:mfa/*/*/${aws:username}",
                "arn:aws:iam::~183:mfa/*/*/*${aws:username}",
                "arn:aws:iam::~183:user/${aws:username}",
                "arn:aws:iam::~183:user/*/${aws:username}",
                "arn:aws:iam::~183:user/*/*/${aws:username}",
                "arn:aws:iam::~183:user/*/*/*${aws:username}"
            ],
            "Sid": "Write"
        },
        {
            "Action": [
                "iam:*Get*",
                "iam:*List*"
            ],
            "Effect": "Allow",
            "Resource": [
                "*"
            ],
            "Sid": "Read"
        },
        {
            "Action": [
                "iam:CreateUser*",
                "iam:UpdateUser*",
                "iam:AddUserToGroup"
            ],
            "Effect": "Allow",
            "Resource": [
                "*"
            ],
            "Sid": "CreateUser"
        }
    ],
    "Version": "2012-10-17"
}

强制 MFA 政策

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "BlockAnyAccessOtherThanAboveUnlessSignedInWithMFA",
            "Effect": "Deny",
            "NotAction": "iam:*",
            "Resource": "*",
            "Condition": {
                "BoolIfExists": {
                    "aws:MultiFactorAuthPresent": "false"
                }
            }
        }
    ]
}

main.tf

provider "aws" {
  profile                 = "GEHC-056"
  shared_credentials_file = "${pathexpand("~/.aws/config")}"
  region                  = "${var.region}"
}

data "aws_iam_policy_document" "test" {
  statement {
    sid    = "TestAssumeRole"
    effect = "Allow"

    actions = [
      "sts:AssumeRole",
    ]

    principals = {
      type = "AWS"

      identifiers = [
        "arn:aws:iam::~183:role/hc-devops",
      ]
    }

    sid    = "BuUserTrustDocument"
    effect = "Allow"

    principals = {
      type = "Federated"

      identifiers = [
        "arn:aws:iam::~875:saml-provider/ge-saml-for-aws",
      ]
    }

    condition {
      test     = "StringEquals"
      variable = "SAML:aud"
      values   = ["https://signin.aws.amazon.com/saml"]
    }
  }
}

resource "aws_iam_role" "test_role" {
  name               = "test_role"
  path               = "/"
  assume_role_policy = "${data.aws_iam_policy_document.test.json}"
}

获取来电者身份

bash-4.4$ aws --profile GEHC-056 sts get-caller-identity
Enter MFA code for arn:aws:iam::772660252183:mfa/503072343:
{
  "UserId": "AROAIWCCLC2BGRPQMJC7U:botocore-session-1537474244",
  "Account": "730993910069",
  "Arn": "arn:aws:sts::730993910069:assumed-role/hc-master/botocore-session-1537474244"
}

错误：

bash-4.4$ terraform plan
Refreshing Terraform state in-memory prior to plan...
The refreshed state will be used to calculate this plan, but will not be
persisted to local or remote state storage.


Error: Error refreshing state: 1 error(s) occurred:

* provider.aws: Error creating AWS session: AssumeRoleTokenProviderNotSetError: assume role with MFA enabled, but AssumeRoleTokenProvider session option not set.

Answer 1

Terraform 当前不支持在运行时提示输入 MFA 令牌，因为它旨在以尽可能少的交互方式运行并且显然需要大量返工支持此交互式提供程序配置的提供程序结构。 this issue.

中对此有更多讨论

正如那个问题中提到的那样，最好的选择是使用某种形式的 script/tool，它在运行ning Terraform 之前已经承担了这个角色。

我个人使用 AWS-Vault 并编写了一个小的 shim shell 脚本，我从 terraform 符号链接到它（以及我想要的其他东西，例如 aws使用 AWS-Vault 获取凭证）检测它被称为什么，使用 which -a 找到 "real" 二进制文件，然后使用 AWS-Vault 的 exec 运行目标命令指定凭据。

我的脚本如下所示：

#!/bin/bash

set -eo pipefail

# Provides a shim to override target executables so that it is executed through aws-vault
# See https://github.com/99designs/aws-vault/blob/ae56f73f630601fc36f0d68c9df19ac53e987369/USAGE.md#overriding-the-aws-cli-to-use-aws-vault for more information about using it for the AWS CLI.

# Work out what we're shimming and then find the non shim version so we can execute that.
# which -a returns a sorted list of the order of binaries that are on the PATH so we want the second one.
INVOKED=$(basename [=10=])
TARGET=$(which -a ${INVOKED} | tail -n +2 | head -n 1)

if [ -z ${AWS_VAULT} ]; then
    AWS_PROFILE="${AWS_DEFAULT_PROFILE:-read-only}"
    (>&2 echo "Using temporary credentials from ${AWS_PROFILE} profile...")

    exec aws-vault exec "${AWS_PROFILE}" --assume-role-ttl=60m -- "${TARGET}" "$@"
else
    # If AWS_VAULT is already set then we want to just use the existing session instead of nesting them
    exec "${TARGET}" "$@"
fi

它将使用您的 ~/.aws/config 文件中与您设置的 AWS_DEFAULT_PROFILE 环境变量匹配的配置文件，默认为 read-only 配置文件，这可能是也可能不是有用的默认值为你。这确保 AWS-Vault 承担 IAM 角色，获取凭证并将它们设置为目标进程的环境变量。

这意味着就 Terraform 而言，它是通过环境变量获得凭据的，这很有效。

Answer 2

我使用了一个非常简单但可能很脏的解决方案来解决这个问题：

首先，让 TF 从环境变量中选择凭据。那么：

AWS 凭证文件：

[access]
aws_access_key_id = ...
aws_secret_access_key = ...
region = ap-southeast-2
output = json

[target]
role_arn = arn:aws:iam::<target nnn>:role/admin
source_profile = access
mfa_serial = arn:aws:iam::<access nnn>:mfa/my-user

在控制台中

CREDENTIAL=$(aws --profile target sts assume-role \
  --role-arn arn:aws:iam::<target nnn>:role/admin --role-session-name TFsession \
  --output text \
  --query "Credentials.[AccessKeyId,SecretAccessKey,SessionToken,Expiration]")

<enter MFA>

#echo "CREDENTIAL: ${CREDENTIAL}"
export AWS_ACCESS_KEY_ID=$(echo ${CREDENTIAL} | cut -d ' ' -f 1)
export AWS_SECRET_ACCESS_KEY=$(echo ${CREDENTIAL} | cut -d ' ' -f 2)
export AWS_SESSION_TOKEN=$(echo ${CREDENTIAL} | cut -d ' ' -f 3)

terraform plan

更新：更好的解决方案是使用 https://github.com/remind101/assume-role 来获得相同的结果。

Answer 3

另一种方法是使用 credential_process 以使用本地脚本生成凭据并将令牌缓存在新配置文件中（我们称之为 tf_temp）

此脚本将：

检查令牌对个人资料是否仍然有效tf_temp
如果令牌有效，使用aws configure get xxx --profile tf_temp
从现有配置中提取令牌
如果令牌无效，提示使用输入mfa令牌
使用 aws assume-role --token-code xxxx ... --profile your_profile
生成会话令牌
使用 aws configure set xxx --profile tf_temp
设置临时配置文件令牌 tf_temp

你会：

~/.aws/credentials

[prod]
aws_secret_access_key = redacted
aws_access_key_id = redacted

[tf_temp]

[tf]
credential_process = sh -c 'mfa.sh arn:aws:iam::{account_id}:role/{role} arn:aws:iam::{account_id}:mfa/{mfa_entry} prod 2> $(tty)'

mfa.sh

gist

将此脚本移至 /bin/mfa.sh 或 /usr/local/bin/mfa.sh :

#!/bin/sh
set -e

role=
mfa_arn=
profile=
temp_profile=tf_temp

if [ -z $role ]; then echo "no role specified"; exit 1; fi
if [ -z $mfa_arn ]; then echo "no mfa arn specified"; exit 1; fi
if [ -z $profile ]; then echo "no profile specified"; exit 1; fi

resp=$(aws sts get-caller-identity --profile $temp_profile | jq '.UserId')

if [ ! -z $resp ]; then
    echo '{
        "Version": 1,
        "AccessKeyId": "'"$(aws configure get aws_access_key_id --profile $temp_profile)"'",
        "SecretAccessKey": "'"$(aws configure get aws_secret_access_key --profile $temp_profile)"'",
        "SessionToken": "'"$(aws configure get aws_session_token --profile $temp_profile)"'",
        "Expiration": "'"$(aws configure get expiration --profile $temp_profile)"'"
    }'
    exit 0
fi
read -p "Enter MFA token: " mfa_token

if [ -z $mfa_token ]; then echo "MFA token can't be empty"; exit 1; fi

data=$(aws sts assume-role --role-arn $role \
                    --profile $profile \
                    --role-session-name "$(tr -dc A-Za-z0-9 </dev/urandom | head -c 20)" \
                    --serial-number $mfa_arn \
                    --token-code $mfa_token | jq '.Credentials')

aws_access_key_id=$(echo $data | jq -r '.AccessKeyId')
aws_secret_access_key=$(echo $data | jq -r '.SecretAccessKey')
aws_session_token=$(echo $data | jq -r '.SessionToken')
expiration=$(echo $data | jq -r '.Expiration')

aws configure set aws_access_key_id $aws_access_key_id --profile $temp_profile
aws configure set aws_secret_access_key $aws_secret_access_key --profile $temp_profile
aws configure set aws_session_token $aws_session_token --profile $temp_profile
aws configure set expiration $expiration --profile $temp_profile

echo '{
  "Version": 1,
  "AccessKeyId": "'"$aws_access_key_id"'",
  "SecretAccessKey": "'"$aws_secret_access_key"'",
  "SessionToken": "'"$aws_session_token"'",
  "Expiration": "'"$expiration"'"
}'

在提供商设置中使用 tf 配置文件。第一次会提示mfa token :

# terraform apply
Enter MFA token: 428313

此解决方案适用于 terraform and/or terragrunt

Terraform 无法承担启用 MFA 的角色

Terraform unable to assume roles with MFA enabled

amazon-web-services

amazon-iam

terraform

terraform-provider-aws

~/.aws/credentials

mfa.sh