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authorJohn MacFarlane <jgm@berkeley.edu>2014-10-26 11:57:43 -0700
committerJohn MacFarlane <jgm@berkeley.edu>2014-10-26 11:57:43 -0700
commitc3f9a7caecbf5239f29b6fd1a7edf47df4fc6d21 (patch)
treefdf0aa4ffb2b8b222015bb60706d4832dd21f30d
parent15422f68253bd5d877f0b308b1bf6caec6e0eb79 (diff)
Add EMPHASIS_STACK_LIMIT.
If we get more than 1000 deep in potential emphasis/strong emphasis openers, we refuse to add more to the stack. This prevents the sort of stack overflow we previously got with python -c 'print "*a **a " * 100000; print " a** a*" * 100000' | ./cmark Partially addresses #166.
-rw-r--r--src/cmark.h1
-rw-r--r--src/inlines.c7
2 files changed, 7 insertions, 1 deletions
diff --git a/src/cmark.h b/src/cmark.h
index ff2f9a2..5e508e4 100644
--- a/src/cmark.h
+++ b/src/cmark.h
@@ -9,6 +9,7 @@
#define VERSION "0.1"
#define CODE_INDENT 4
+#define EMPHASIS_STACK_LIMIT 1000
struct node_inl {
enum {
diff --git a/src/inlines.c b/src/inlines.c
index 7a7f08a..928a3ac 100644
--- a/src/inlines.c
+++ b/src/inlines.c
@@ -23,6 +23,7 @@ typedef struct Subject {
int label_nestlevel;
reference_map *refmap;
inline_stack *emphasis_openers;
+ int number_of_emphasis_openers;
} subject;
static node_inl *parse_chunk_inlines(chunk *chunk, reference_map *refmap);
@@ -177,6 +178,7 @@ static void subject_from_buf(subject *e, strbuf *buffer, reference_map *refmap)
e->label_nestlevel = 0;
e->refmap = refmap;
e->emphasis_openers = NULL;
+ e->number_of_emphasis_openers = 0;
chunk_rtrim(&e->input);
}
@@ -190,6 +192,7 @@ static void subject_from_chunk(subject *e, chunk *chunk, reference_map *refmap)
e->label_nestlevel = 0;
e->refmap = refmap;
e->emphasis_openers = NULL;
+ e->number_of_emphasis_openers = 0;
chunk_rtrim(&e->input);
}
@@ -309,6 +312,7 @@ static void free_openers(subject* subj, inline_stack* istack)
while (subj->emphasis_openers != istack) {
tempstack = subj->emphasis_openers;
subj->emphasis_openers = subj->emphasis_openers->previous;
+ subj->number_of_emphasis_openers--;
free(tempstack);
}
}
@@ -389,7 +393,7 @@ static node_inl* handle_strong_emph(subject* subj, unsigned char c, node_inl **l
cannotClose:
inl_text = make_str(chunk_dup(&subj->input, subj->pos - numdelims, numdelims));
- if (can_open)
+ if (can_open && subj->number_of_emphasis_openers < EMPHASIS_STACK_LIMIT)
{
istack = (inline_stack*)malloc(sizeof(inline_stack));
if (istack == NULL) {
@@ -400,6 +404,7 @@ cannotClose:
istack->first_inline = inl_text;
istack->previous = subj->emphasis_openers;
subj->emphasis_openers = istack;
+ subj->number_of_emphasis_openers++;
}
return inl_text;