FIX breaking signed content

The strategy is, to not change user supplied eols when
decoding.  If an encoded eol was found, use it.  If not,
go with the one the user gave us.

Author: Sebastian Rose, Hannover, Germany

Base64.xs

@@ -68,7 +68,7 @@ static const unsigned char index_64[256] = {
            ? ((lp = SvCUR(sv)), SvPVX(sv)) : my_sv_2pvbyte(aTHX_ sv, &lp))
        static char *
        my_sv_2pvbyte(pTHX_ register SV *sv, STRLEN *lp)
-       {   
+       {
            sv_utf8_downgrade(sv,0);
            return SvPV(sv,*lp);
        }
@@ -128,7 +128,7 @@ encode_base64(sv,...)
 
 	/* allocate a result buffer */
 	RETVAL = newSV(rlen ? rlen : 1);
-	SvPOK_on(RETVAL);	
+	SvPOK_on(RETVAL);
 	SvCUR_set(RETVAL, rlen);
 	r = SvPVX(RETVAL);
 
@@ -210,7 +210,7 @@ decode_base64(sv)
 		    break;
 		}
             } while (i < 4);
-	
+
 	    if (c[0] == EQ || c[1] == EQ) {
 		break;
             }
@@ -439,6 +439,8 @@ decode_qp(sv)
 	char const* end = str + len;
 	char *r;
 	char *whitespace = 0;
+	/* True, if we indeed did encounter an encoded LF at and of line: */
+	int rfc_nl = 0;
 
         CODE:
 	RETVAL = newSV(len ? len : 1);
@@ -451,13 +453,33 @@ decode_qp(sv)
 		str++;
 	    }
 	    else if (*str == '\r' && (str + 1) < end && str[1] == '\n') {
-		str++;
+		whitespace = 0;
+		if( rfc_nl ) {
+		    /* We've already found an encoded LF.  Hence, we skip the
+		     * original LF found in the document. */
+		    rfc_nl = 0;
+		    str += 2;
+		}
+		else {
+		    /* Otherwise, add the original LF found in the document: */
+		    *r++ = *str++;
+		    *r++ = *str++;
+		}
 	    }
 	    else if (*str == '\n') {
 		whitespace = 0;
-		*r++ = *str++;
+		if( rfc_nl ) {
+		    /* We've already found encoded LF(s) */
+		    str++;
+		    rfc_nl = 0;
+		}
+		else {
+		    /* NOTE: Not canonical LF in MIME-messages! */
+		    *r++ = *str++;
+		}
 	    }
 	    else {
+		rfc_nl = 0;
 		if (whitespace) {
 		    while (whitespace < str) {
 			*r++ = *whitespace++;
@@ -472,6 +494,10 @@ decode_qp(sv)
 		        buf[1] = *str++;
 	                buf[2] = '\0';
 		        *r++ = (char)strtol(buf, 0, 16);
+			if( '0' == buf[0] && ('A' == buf[1] || 'D' == buf[1]) ) {
+			    /* Encoded LF at hand. */
+			    rfc_nl = 1;
+			}
 	            }
 		    else {
 		        /* look for soft line break */

t/quoted-print.t

@@ -233,9 +233,11 @@ print "not " unless decode_qp("foo  \n\nfoo =\n\nfoo=20\n\n") eq
                                 "foo\n\nfoo \nfoo \n\n";
 $testno++; print "ok $testno\n";
 
-# Same test but with "\r\n" terminated lines
+# Same test but with "\r\n" terminated lines.  NOTE: If no encoded eol is found,
+# take the one supplied by the user!  Electronic signatures are destroyed, if we
+# enforce some "standard" eol.
 print "not " unless decode_qp("foo  \r\n\r\nfoo =\r\n\r\nfoo=20\r\n\r\n") eq
-                                "foo\n\nfoo \nfoo \n\n";
+                                "foo\r\n\r\nfoo \r\nfoo \r\n\r\n";
 $testno++; print "ok $testno\n";
 
 # Trailing whitespace
@@ -248,7 +250,7 @@ $testno++; print "ok $testno\n";
 print "not " unless decode_qp("foo = \t\x20\nbar\t\x20\n") eq "foo bar\n";
 $testno++; print "ok $testno\n";
 
-print "not " unless decode_qp("foo = \t\x20\r\nbar\t\x20\r\n") eq "foo bar\n";
+print "not " unless decode_qp("foo = \t\x20\r\nbar\t\x20\r\n") eq "foo bar\r\n";
 $testno++; print "ok $testno\n";
 
 print "not " unless decode_qp("foo = \t\x20\n") eq "foo ";
@@ -257,7 +259,7 @@ $testno++; print "ok $testno\n";
 print "not " unless decode_qp("foo = \t\x20\r\n") eq "foo ";
 $testno++; print "ok $testno\n";
 
-print "not " unless decode_qp("foo = \t\x20y\r\n") eq "foo = \t\x20y\n";
+print "not " unless decode_qp("foo = \t\x20y\r\n") eq "foo = \t\x20y\r\n";
 $testno++; print "ok $testno\n";
 
 print "not " unless decode_qp("foo =xy\n") eq "foo =xy\n";
@@ -359,4 +361,3 @@ print "not " if $] >= 5.006 && (eval 'encode_qp("XXX \x{100}")' || !$@);
 $testno++; print "ok $testno\n";
 
 }
-