Accept a trailing space at end of PEM lines

With certs being copy-pasted from webmails and all, this will probably become
more and more common.

ChangeLog

@@ -20,6 +20,7 @@ Bugfix
 Changes
    * Add SSL_MIN_DHM_BYTES configuration parameter in config.h to choose the
      minimum size of Diffie-Hellman parameters accepted by the client.
+   * The PEM parser now accepts a trailing space at end of lines (#226).
 
 = mbed TLS 1.3.11 released 2015-06-04
 

library/pem.c

@@ -236,12 +236,14 @@ int pem_read_buffer( pem_context *ctx, const char *header, const char *footer,
         return( POLARSSL_ERR_PEM_NO_HEADER_FOOTER_PRESENT );
 
     s1 += strlen( header );
+    if( *s1 == ' '  ) s1++;
     if( *s1 == '\r' ) s1++;
     if( *s1 == '\n' ) s1++;
     else return( POLARSSL_ERR_PEM_NO_HEADER_FOOTER_PRESENT );
 
     end = s2;
     end += strlen( footer );
+    if( *end == ' '  ) end++;
     if( *end == '\r' ) end++;
     if( *end == '\n' ) end++;
     *use_len = end - data;

tests/data_files/server7_trailing_space.crt

@@ -0,0 +1,47 @@
+-----BEGIN CERTIFICATE----- 
+MIIDwjCCAaqgAwIBAgIBEDANBgkqhkiG9w0BAQsFADBIMQswCQYDVQQGEwJOTDER 
+MA8GA1UEChMIUG9sYXJTU0wxJjAkBgNVBAMTHVBvbGFyU1NMIFRlc3QgSW50ZXJt 
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+VJaNa2iTQ5Dgic+CW4TYAgj5/9g9X3WfwnDNxrZ0UxxawGElczHXqbrNleTtPaKp 
+a8Si6UK5 
+-----END CERTIFICATE----- 
+-----BEGIN CERTIFICATE----- 
+MIIEATCCA4egAwIBAgIBDjAKBggqhkjOPQQDAjA+MQswCQYDVQQGEwJOTDERMA8G 
+A1UEChMIUG9sYXJTU0wxHDAaBgNVBAMTE1BvbGFyc3NsIFRlc3QgRUMgQ0EwHhcN 
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+Af5cNR8KhzegznL6amRObGGKmX1F 
+-----END CERTIFICATE----- 

tests/suites/test_suite_x509parse.data

@@ -1355,3 +1355,7 @@ x509parse_crt_file:"data_files/server7_pem_space.crt":1
 X509 File parse (all certificates fail)
 depends_on:POLARSSL_ECP_C
 x509parse_crt_file:"data_files/server7_all_space.crt":POLARSSL_ERR_PEM_INVALID_DATA + POLARSSL_ERR_BASE64_INVALID_CHARACTER
+
+X509 File parse (trailing spaces, OK)
+depends_on:POLARSSL_ECP_C:POLARSSL_ECP_DP_SECP256R1_ENABLED
+x509parse_crt_file:"data_files/server7_trailing_space.crt":0