provider/aws: Add S3 Bucket name validation

Adds region specific S3 bucket name validation. Currently all regions except for us-east-1 force a dns-compliant naming convention. Thus we cannot utilize the standard `SchemaValidateFunc` interface to validate an S3 bucket name.
 This change creates a helper function outside of the schema validation interface so we can validate S3 bucket names for both naming conventions. At a later date, when the us-east-1 region is updated to conform to a dns-compliant naming scheme, we can refactor the `validateS3BucketName` function to fit the `SchemaValidateFunc` interface.

builtin/providers/aws/resource_aws_s3_bucket.go

@@ -6,6 +6,8 @@ import (
 	"fmt"
 	"log"
 	"net/url"
+	"regexp"
+	"strings"
 	"time"
 
 	"github.com/aws/aws-sdk-go/aws"
@@ -408,6 +410,10 @@ func resourceAwsS3BucketCreate(d *schema.ResourceData, meta interface{}) error {
 		}
 	}
 
+	if err := validateS3BucketName(bucket, awsRegion); err != nil {
+		return fmt.Errorf("Error validating S3 bucket name: %s", err)
+	}
+
 	err := resource.Retry(5*time.Minute, func() *resource.RetryError {
 		log.Printf("[DEBUG] Trying to create new S3 bucket: %q", bucket)
 		_, err := s3conn.CreateBucket(req)
@@ -1728,6 +1734,40 @@ func validateS3BucketRequestPayerType(v interface{}, k string) (ws []string, err
 	return
 }
 
+// validateS3BucketName validates any S3 bucket name that is not inside the us-east-1 region.
+// Buckets outside of this region have to be DNS-compliant. After the same restrictions are
+// applied to buckets in the us-east-1 region, this function can be refactored as a SchemaValidateFunc
+func validateS3BucketName(value string, region string) error {
+	if region != "us-east-1" {
+		if (len(value) < 3) || (len(value) > 63) {
+			return fmt.Errorf("%q must contain from 3 to 63 characters", value)
+		}
+		if !regexp.MustCompile(`^[0-9a-z-.]+$`).MatchString(value) {
+			return fmt.Errorf("only lowercase alphanumeric characters and hyphens allowed in %q", value)
+		}
+		if regexp.MustCompile(`^(?:[0-9]{1,3}\.){3}[0-9]{1,3}$`).MatchString(value) {
+			return fmt.Errorf("%q must not be formatted as an IP address", value)
+		}
+		if strings.HasPrefix(value, `.`) {
+			return fmt.Errorf("%q cannot start with a period", value)
+		}
+		if strings.HasSuffix(value, `.`) {
+			return fmt.Errorf("%q cannot end with a period", value)
+		}
+		if strings.Contains(value, `..`) {
+			return fmt.Errorf("%q can be only one period between labels", value)
+		}
+	} else {
+		if len(value) > 255 {
+			return fmt.Errorf("%q must contain less than 256 characters", value)
+		}
+		if !regexp.MustCompile(`^[0-9a-zA-Z-._]+$`).MatchString(value) {
+			return fmt.Errorf("only alphanumeric characters, hyphens, periods, and underscores allowed in %q", value)
+		}
+	}
+	return nil
+}
+
 func expirationHash(v interface{}) int {
 	var buf bytes.Buffer
 	m := v.(map[string]interface{})

builtin/providers/aws/resource_aws_s3_bucket_test.go

@@ -12,6 +12,8 @@ import (
 	"github.com/hashicorp/terraform/helper/resource"
 	"github.com/hashicorp/terraform/terraform"
 
+	"strings"
+
 	"github.com/aws/aws-sdk-go/aws"
 	"github.com/aws/aws-sdk-go/aws/awserr"
 	"github.com/aws/aws-sdk-go/service/s3"
@@ -690,6 +692,68 @@ func TestAccAWSS3Bucket_ReplicationExpectVersioningValidationError(t *testing.T)
 	})
 }
 
+func TestAWSS3BucketName(t *testing.T) {
+	validDnsNames := []string{
+		"foobar",
+		"foo.bar",
+		"foo.bar.baz",
+		"1234",
+		"foo-bar",
+		strings.Repeat("x", 63),
+	}
+
+	for _, v := range validDnsNames {
+		if err := validateS3BucketName(v, "us-west-2"); err != nil {
+			t.Fatalf("%q should be a valid S3 bucket name", v)
+		}
+	}
+
+	invalidDnsNames := []string{
+		"foo..bar",
+		"Foo.Bar",
+		"192.168.0.1",
+		"127.0.0.1",
+		".foo",
+		"bar.",
+		"foo_bar",
+		strings.Repeat("x", 64),
+	}
+
+	for _, v := range invalidDnsNames {
+		if err := validateS3BucketName(v, "us-west-2"); err == nil {
+			t.Fatalf("%q should not be a valid S3 bucket name", v)
+		}
+	}
+
+	validEastNames := []string{
+		"foobar",
+		"foo_bar",
+		"127.0.0.1",
+		"foo..bar",
+		"foo_bar_baz",
+		"foo.bar.baz",
+		"Foo.Bar",
+		strings.Repeat("x", 255),
+	}
+
+	for _, v := range validEastNames {
+		if err := validateS3BucketName(v, "us-east-1"); err != nil {
+			t.Fatalf("%q should be a valid S3 bucket name", v)
+		}
+	}
+
+	invalidEastNames := []string{
+		"foo;bar",
+		strings.Repeat("x", 256),
+	}
+
+	for _, v := range invalidEastNames {
+		if err := validateS3BucketName(v, "us-east-1"); err == nil {
+			t.Fatalf("%q should not be a valid S3 bucket name", v)
+		}
+	}
+}
+
 func testAccCheckAWSS3BucketDestroy(s *terraform.State) error {
 	return testAccCheckInstanceDestroyWithProvider(s, testAccProvider)
 }