From 13da682b01067428e30b707b7cf64ef3a122984c Mon Sep 17 00:00:00 2001
From: John MacFarlane <jgm@berkeley.edu>
Date: Sat, 8 Nov 2014 15:15:20 -0800
Subject: Added MAX_LINK_LABEL_LENGTH to cmark.h.

Use in link label parsing and reference lookup.
---
 src/cmark.h      |  2 ++
 src/inlines.c    | 24 ++++++++++++++----------
 src/references.c |  3 +++
 3 files changed, 19 insertions(+), 10 deletions(-)

(limited to 'src')

diff --git a/src/cmark.h b/src/cmark.h
index ff2f9a2..a135fa9 100644
--- a/src/cmark.h
+++ b/src/cmark.h
@@ -10,6 +10,8 @@
 #define VERSION "0.1"
 #define CODE_INDENT 4
 
+#define MAX_LINK_LABEL_LENGTH 1000
+
 struct node_inl {
 	enum {
 		INL_STRING,
diff --git a/src/inlines.c b/src/inlines.c
index 7a7ca02..0527d92 100644
--- a/src/inlines.c
+++ b/src/inlines.c
@@ -579,17 +579,24 @@ static node_inl* handle_pointy_brace(subject* subj)
 static int link_label(subject* subj, chunk *raw_label)
 {
 	int startpos = subj->pos;
+	int length = 0;
 
 	advance(subj);  // advance past [
 	unsigned char c;
 	while ((c = peek_char(subj)) && c != '[' && c != ']') {
 		if (c == '\\') {
 			advance(subj);
+			length++;
 			if (ispunct(peek_char(subj))) {
 				advance(subj);
+				length++;
 			}
 		} else {
 			advance(subj);
+			length++;
+		}
+		if (length > MAX_LINK_LABEL_LENGTH) {
+			goto noMatch;
 		}
 	}
 
@@ -597,10 +604,12 @@ static int link_label(subject* subj, chunk *raw_label)
 		*raw_label = chunk_dup(&subj->input, startpos + 1, subj->pos - (startpos + 1));
 		advance(subj);  // advance past ]
 		return 1;
-	} else {
-		subj->pos = startpos; // rewind
-		return 0;
 	}
+
+ noMatch:
+	subj->pos = startpos; // rewind
+	return 0;
+
 }
 
 // Return a link, an image, or a literal close bracket.
@@ -679,16 +688,11 @@ static node_inl* handle_close_bracket(subject* subj, node_inl **last)
 	subj->pos = subj->pos + scan_spacechars(&subj->input, subj->pos);
 	raw_label = chunk_literal("");
 	if (!link_label(subj, &raw_label) || raw_label.len == 0) {
-		// chunk_free(&raw_label);
+		chunk_free(&raw_label);
 		raw_label = chunk_dup(&subj->input, ostack->position, initial_pos - ostack->position - 1);
 	}
 
-	// TODO - document this hard length limit in spec; also impose for creation of refs
-	if (raw_label.len < 1000) {
-		ref = reference_lookup(subj->refmap, &raw_label);
-	} else {
-		ref = NULL;
-	}
+	ref = reference_lookup(subj->refmap, &raw_label);
 	chunk_free(&raw_label);
 
 	if (ref != NULL) { // found
diff --git a/src/references.c b/src/references.c
index 5ba4b24..def4dd8 100644
--- a/src/references.c
+++ b/src/references.c
@@ -100,6 +100,9 @@ reference* reference_lookup(reference_map *map, chunk *label)
 	unsigned char *norm;
 	unsigned int hash;
 
+	if (label->len > MAX_LINK_LABEL_LENGTH)
+		return NULL;
+
 	if (map == NULL)
 		return NULL;
 
-- 
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