blaze822: blaze822/blaze822_mem: detect line ending before scanning end of header

A mail using CRLF which contained (for some reason) a LFLF pair would
be misparsed as the header was read until the LFLF.

Instead, scan for the first LF, check if it's preceded by CR,
and then search for the proper header terminator only.

Closes #212.

blaze822.c

@@ -420,10 +420,19 @@ unfold_hdr(char *buf, char *end)
 	compress_hdr(l, end);
 }
 
+static int
+is_crlf(char *s, size_t len)
+{
+	char *firsteol = memchr(s, '\n', len);
+
+	return firsteol && firsteol > s && firsteol[-1] == '\r';
+}
+
 struct message *
 blaze822(char *file)
 {
 	int fd;
+	int crlf;
 	ssize_t rd;
 	char *buf;
 	ssize_t bufalloc;
@@ -466,15 +475,21 @@ blaze822(char *file)
 			close(fd);
 			return 0;
 		}
-
-		if ((end = mymemmem(buf-overlap+used, rd+overlap, "\n\n", 2))) {
-			end++;
-			break;
+		if (used == 0) {
+			crlf = is_crlf(buf, rd);
 		}
-		if ((end = mymemmem(buf-overlap+used, rd+overlap, "\r\n\r\n", 4))) {
-			end++;
-			end++;
-			break;
+
+		if (crlf) {
+			if ((end = mymemmem(buf-overlap+used, rd+overlap, "\r\n\r\n", 4))) {
+				end++;
+				end++;
+				break;
+			}
+		} else {
+			if ((end = mymemmem(buf-overlap+used, rd+overlap, "\n\n", 2))) {
+				end++;
+				break;
+			}
 		}
 
 		used += rd;
@@ -502,11 +517,15 @@ blaze822_mem(char *src, size_t len)
 	if (!mesg)
 		return 0;
 
-	if ((end = mymemmem(src, len, "\n\n", 2))) {
-		mesg->body = end+2;
-	} else if ((end = mymemmem(src, len, "\r\n\r\n", 4))) {
-		mesg->body = end+4;
+	if (is_crlf(src, len)) {
+		if ((end = mymemmem(src, len, "\r\n\r\n", 4)))
+			mesg->body = end+4;
 	} else {
+		if ((end = mymemmem(src, len, "\n\n", 2)))
+			mesg->body = end+2;
+	}
+
+	if (!end) {
 		end = src + len;
 		mesg->body = end;
 		mesg->bodyend = end;

t/1701-mshow-regress.t

@@ -0,0 +1,29 @@
+#!/bin/sh -e
+cd ${0%/*}
+. ./lib.sh
+plan 2
+
+# Mail with \n\n and \r\n\r\n
+cr=$(printf '\r')
+cat <<EOF >tmp
+Content-Type: multipart/form-data; boundary=------------------------55a586f81559face$cr
+$cr
+--------------------------55a586f81559face$cr
+Content-Disposition: form-data; name="a"; filename="foo"$cr
+Content-Type: application/octet-stream$cr
+$cr
+foo$cr
+
+previously there are two NL$cr
+$cr
+--------------------------55a586f81559face$cr
+Content-Disposition: form-data; name="a"; filename="bar"$cr
+Content-Type: application/octet-stream$cr
+$cr
+bar$cr
+$cr
+--------------------------55a586f81559face--$cr
+EOF
+
+check 'mail has 3 attachments' 'mshow -t ./tmp | wc -l | grep 4'
+check 'mail attachment foo has size 35' 'mshow -t ./tmp | grep size=35.*name=\"foo\"'