aae6d8080d
This adds an aws-iam auth method type which supports authenticating to Consul using AWS IAM identities. Co-authored-by: R.B. Boyer <4903+rboyer@users.noreply.github.com>
95 lines
3.6 KiB
Go
95 lines
3.6 KiB
Go
package responses
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import (
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"fmt"
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"strings"
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)
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// https://github.com/hashicorp/vault/blob/ba533d006f2244103648785ebfe8a9a9763d2b6e/builtin/credential/aws/path_login.go#L1722-L1744
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type ParsedArn struct {
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Partition string
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AccountNumber string
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Type string
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Path string
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FriendlyName string
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SessionInfo string
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}
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// https://github.com/hashicorp/vault/blob/ba533d006f2244103648785ebfe8a9a9763d2b6e/builtin/credential/aws/path_login.go#L1482-L1530
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// However, instance profiles are not support in Consul.
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func ParseArn(iamArn string) (*ParsedArn, error) {
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// iamArn should look like one of the following:
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// 1. arn:aws:iam::<account_id>:<entity_type>/<UserName>
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// 2. arn:aws:sts::<account_id>:assumed-role/<RoleName>/<RoleSessionName>
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// if we get something like 2, then we want to transform that back to what
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// most people would expect, which is arn:aws:iam::<account_id>:role/<RoleName>
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var entity ParsedArn
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fullParts := strings.Split(iamArn, ":")
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if len(fullParts) != 6 {
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return nil, fmt.Errorf("unrecognized arn: contains %d colon-separated parts, expected 6", len(fullParts))
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}
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if fullParts[0] != "arn" {
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return nil, fmt.Errorf("unrecognized arn: does not begin with \"arn:\"")
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}
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// normally aws, but could be aws-cn or aws-us-gov
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entity.Partition = fullParts[1]
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if entity.Partition == "" {
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return nil, fmt.Errorf("unrecognized arn: %q is missing the partition", iamArn)
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}
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if fullParts[2] != "iam" && fullParts[2] != "sts" {
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return nil, fmt.Errorf("unrecognized service: %v, not one of iam or sts", fullParts[2])
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}
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// fullParts[3] is the region, which doesn't matter for AWS IAM entities
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entity.AccountNumber = fullParts[4]
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if entity.AccountNumber == "" {
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return nil, fmt.Errorf("unrecognized arn: %q is missing the account number", iamArn)
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}
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// fullParts[5] would now be something like user/<UserName> or assumed-role/<RoleName>/<RoleSessionName>
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parts := strings.Split(fullParts[5], "/")
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if len(parts) < 2 {
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return nil, fmt.Errorf("unrecognized arn: %q contains fewer than 2 slash-separated parts", fullParts[5])
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}
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entity.Type = parts[0]
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entity.Path = strings.Join(parts[1:len(parts)-1], "/")
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entity.FriendlyName = parts[len(parts)-1]
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// now, entity.FriendlyName should either be <UserName> or <RoleName>
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switch entity.Type {
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case "assumed-role":
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// Check for three parts for assumed role ARNs
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if len(parts) < 3 {
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return nil, fmt.Errorf("unrecognized arn: %q contains fewer than 3 slash-separated parts", fullParts[5])
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}
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// Assumed roles don't have paths and have a slightly different format
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// parts[2] is <RoleSessionName>
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entity.Path = ""
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entity.FriendlyName = parts[1]
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entity.SessionInfo = parts[2]
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case "user":
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case "role":
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// case "instance-profile":
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default:
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return nil, fmt.Errorf("unrecognized principal type: %q", entity.Type)
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}
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if entity.FriendlyName == "" {
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return nil, fmt.Errorf("unrecognized arn: %q is missing the resource name", iamArn)
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}
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return &entity, nil
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}
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// CanonicalArn returns the canonical ARN for referring to an IAM entity
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func (p *ParsedArn) CanonicalArn() string {
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entityType := p.Type
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// canonicalize "assumed-role" into "role"
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if entityType == "assumed-role" {
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entityType = "role"
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}
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// Annoyingly, the assumed-role entity type doesn't have the Path of the role which was assumed
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// So, we "canonicalize" it by just completely dropping the path. The other option would be to
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// make an AWS API call to look up the role by FriendlyName, which introduces more complexity to
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// code and test, and it also breaks backwards compatibility in an area where we would really want
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// it
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return fmt.Sprintf("arn:%s:iam::%s:%s/%s", p.Partition, p.AccountNumber, entityType, p.FriendlyName)
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}
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