encoding/pem: ignore spaces and tabs at the end of header lines.

Fixes #3502.

R=bradfitz
CC=golang-dev
https://golang.org/cl/6011046

src/pkg/encoding/pem/pem.go

@@ -28,9 +28,10 @@ type Block struct {
 }
 
 // getLine results the first \r\n or \n delineated line from the given byte
-// array. The line does not include the \r\n or \n. The remainder of the byte
-// array (also not including the new line bytes) is also returned and this will
-// always be smaller than the original argument.
+// array. The line does not include trailing whitespace or the trailing new
+// line bytes. The remainder of the byte array (also not including the new line
+// bytes) is also returned and this will always be smaller than the original
+// argument.
 func getLine(data []byte) (line, rest []byte) {
 	i := bytes.Index(data, []byte{'\n'})
 	var j int
@@ -43,7 +44,7 @@ func getLine(data []byte) (line, rest []byte) {
 			i--
 		}
 	}
-	return data[0:i], data[j:]
+	return bytes.TrimRight(data[0:i], " \t"), data[j:]
 }
 
 // removeWhitespace returns a copy of its input with all spaces, tab and

src/pkg/encoding/pem/pem_test.go

@@ -127,13 +127,13 @@ Certificate chain
 -----BEGIN CERTIFICATE-----
 testing
 -----BEGIN CERTIFICATE-----
------BEGIN CERTIFICATE-----
+-----BEGIN CERTIFICATE----- 
 MIID6TCCA1ICAQEwDQYJKoZIhvcNAQEFBQAwgYsxCzAJBgNVBAYTAlVTMRMwEQYD
 VQQIEwpDYWxpZm9ybmlhMRYwFAYDVQQHEw1TYW4gRnJhbmNpc2NvMRQwEgYDVQQK
-EwtHb29nbGUgSW5jLjEMMAoGA1UECxMDRW5nMQwwCgYDVQQDEwNhZ2wxHTAbBgkq
-hkiG9w0BCQEWDmFnbEBnb29nbGUuY29tMB4XDTA5MDkwOTIyMDU0M1oXDTEwMDkw
-OTIyMDU0M1owajELMAkGA1UEBhMCQVUxEzARBgNVBAgTClNvbWUtU3RhdGUxITAf
-BgNVBAoTGEludGVybmV0IFdpZGdpdHMgUHR5IEx0ZDEjMCEGA1UEAxMaZXVyb3Bh
+EwtHb29nbGUgSW5jLjEMMAoGA1UECxMDRW5nMQwwCgYDVQQDEwNhZ2wxHTAbBgkq 
+hkiG9w0BCQEWDmFnbEBnb29nbGUuY29tMB4XDTA5MDkwOTIyMDU0M1oXDTEwMDkw  
+OTIyMDU0M1owajELMAkGA1UEBhMCQVUxEzARBgNVBAgTClNvbWUtU3RhdGUxITAf  	  
+BgNVBAoTGEludGVybmV0IFdpZGdpdHMgUHR5IEx0ZDEjMCEGA1UEAxMaZXVyb3Bh		  
 LnNmby5jb3JwLmdvb2dsZS5jb20wggIiMA0GCSqGSIb3DQEBAQUAA4ICDwAwggIK
 AoICAQC6pgYt7/EibBDumASF+S0qvqdL/f+nouJw2T1Qc8GmXF/iiUcrsgzh/Fd8
 pDhz/T96Qg9IyR4ztuc2MXrmPra+zAuSf5bevFReSqvpIt8Duv0HbDbcqs/XKPfB
@@ -149,15 +149,15 @@ Pomjn71GNTtDeWAXibjCgdL6iHACCF6Htbl0zGlG0OAK+bdn0QIDAQABMA0GCSqG
 SIb3DQEBBQUAA4GBAOKnQDtqBV24vVqvesL5dnmyFpFPXBn3WdFfwD6DzEb21UVG
 5krmJiu+ViipORJPGMkgoL6BjU21XI95VQbun5P8vvg8Z+FnFsvRFY3e1CCzAVQY
 ZsUkLw2I7zI/dNlWdB8Xp7v+3w9sX5N3J/WuJ1KOO5m26kRlHQo7EzT3974g
------END CERTIFICATE-----
+-----END CERTIFICATE-----   
  1 s:/C=ZA/O=Ca Inc./CN=CA Inc
 
------BEGIN RSA PRIVATE KEY-----
-Proc-Type: 4,ENCRYPTED
-DEK-Info: DES-EDE3-CBC,80C7C7A09690757A
-
+-----BEGIN RSA PRIVATE KEY-----   	
+Proc-Type: 4,ENCRYPTED	  
+DEK-Info: DES-EDE3-CBC,80C7C7A09690757A  	
+  	
 eQp5ZkH6CyHBz7BZfUPxyLCCmftsBJ7HlqGb8Ld21cSwnzWZ4/SIlhyrUtsfw7VR
-2TTwA+odo9ex7GdxOTaH8oZFumIRoiEjHsk8U7Bhntp+ekkPP79xunnN7hb7hkhr
+2TTwA+odo9ex7GdxOTaH8oZFumIRoiEjHsk8U7Bhntp+ekkPP79xunnN7hb7hkhr   
 yGDQZgA7s2cQHQ71v3gwT2BACAft26jCjbM1wgNzBnJ8M0Rzn68YWqaPtdBu8qb/
 zVR5JB1mnqvTSbFsfF5yMc6o2WQ9jJCl6KypnMl+BpL+dlvdjYVK4l9lYsB1Hs3d
 +zDBbWxos818zzhS8/y6eIfiSG27cqrbhURbmgiSfDXjncK4m/pLcQ7mmBL6mFOr