Heap use-after-free in htmlParsePubidLiteral and htmlParseSystemiteral
For https://bugzilla.gnome.org/show_bug.cgi?id=760263
* HTMLparser.c: Add BASE_PTR convenience macro.
(htmlParseSystemLiteral): Store length and start position instead
of a pointer while iterating through the public identifier since
the underlying buffer may change, resulting in a stale pointer
being used.
(htmlParsePubidLiteral): Ditto.
diff --git a/HTMLparser.c b/HTMLparser.c
index 0985d1d..d1395fa 100644
--- a/HTMLparser.c
+++ b/HTMLparser.c
@@ -303,6 +303,7 @@
#define UPP(val) (toupper(ctxt->input->cur[(val)]))
#define CUR_PTR ctxt->input->cur
+#define BASE_PTR ctxt->input->base
#define SHRINK if ((ctxt->input->cur - ctxt->input->base > 2 * INPUT_CHUNK) && \
(ctxt->input->end - ctxt->input->cur < 2 * INPUT_CHUNK)) \
@@ -2781,31 +2782,43 @@
static xmlChar *
htmlParseSystemLiteral(htmlParserCtxtPtr ctxt) {
- const xmlChar *q;
+ size_t len = 0, startPosition = 0;
xmlChar *ret = NULL;
if (CUR == '"') {
NEXT;
- q = CUR_PTR;
- while ((IS_CHAR_CH(CUR)) && (CUR != '"'))
+
+ if (CUR_PTR < BASE_PTR)
+ return(ret);
+ startPosition = CUR_PTR - BASE_PTR;
+
+ while ((IS_CHAR_CH(CUR)) && (CUR != '"')) {
NEXT;
+ len++;
+ }
if (!IS_CHAR_CH(CUR)) {
htmlParseErr(ctxt, XML_ERR_LITERAL_NOT_FINISHED,
"Unfinished SystemLiteral\n", NULL, NULL);
} else {
- ret = xmlStrndup(q, CUR_PTR - q);
+ ret = xmlStrndup((BASE_PTR+startPosition), len);
NEXT;
}
} else if (CUR == '\'') {
NEXT;
- q = CUR_PTR;
- while ((IS_CHAR_CH(CUR)) && (CUR != '\''))
+
+ if (CUR_PTR < BASE_PTR)
+ return(ret);
+ startPosition = CUR_PTR - BASE_PTR;
+
+ while ((IS_CHAR_CH(CUR)) && (CUR != '\'')) {
NEXT;
+ len++;
+ }
if (!IS_CHAR_CH(CUR)) {
htmlParseErr(ctxt, XML_ERR_LITERAL_NOT_FINISHED,
"Unfinished SystemLiteral\n", NULL, NULL);
} else {
- ret = xmlStrndup(q, CUR_PTR - q);
+ ret = xmlStrndup((BASE_PTR+startPosition), len);
NEXT;
}
} else {
@@ -2829,32 +2842,47 @@
static xmlChar *
htmlParsePubidLiteral(htmlParserCtxtPtr ctxt) {
- const xmlChar *q;
+ size_t len = 0, startPosition = 0;
xmlChar *ret = NULL;
/*
* Name ::= (Letter | '_') (NameChar)*
*/
if (CUR == '"') {
NEXT;
- q = CUR_PTR;
- while (IS_PUBIDCHAR_CH(CUR)) NEXT;
+
+ if (CUR_PTR < BASE_PTR)
+ return(ret);
+ startPosition = CUR_PTR - BASE_PTR;
+
+ while (IS_PUBIDCHAR_CH(CUR)) {
+ len++;
+ NEXT;
+ }
+
if (CUR != '"') {
htmlParseErr(ctxt, XML_ERR_LITERAL_NOT_FINISHED,
"Unfinished PubidLiteral\n", NULL, NULL);
} else {
- ret = xmlStrndup(q, CUR_PTR - q);
+ ret = xmlStrndup((BASE_PTR + startPosition), len);
NEXT;
}
} else if (CUR == '\'') {
NEXT;
- q = CUR_PTR;
- while ((IS_PUBIDCHAR_CH(CUR)) && (CUR != '\''))
- NEXT;
+
+ if (CUR_PTR < BASE_PTR)
+ return(ret);
+ startPosition = CUR_PTR - BASE_PTR;
+
+ while ((IS_PUBIDCHAR_CH(CUR)) && (CUR != '\'')){
+ len++;
+ NEXT;
+ }
+
if (CUR != '\'') {
htmlParseErr(ctxt, XML_ERR_LITERAL_NOT_FINISHED,
"Unfinished PubidLiteral\n", NULL, NULL);
} else {
- ret = xmlStrndup(q, CUR_PTR - q);
+ ret = xmlStrndup((BASE_PTR + startPosition), len);
NEXT;
}
} else {
