From 9f93e8036e842329863bf20395b8fb8f73834d9e Mon Sep 17 00:00:00 2001
From: Sebastian Pipping <sebastian@pipping.org>
Date: Thu, 30 Dec 2021 22:46:03 +0100
Subject: [PATCH] lib: Prevent integer overflow at multiple places
(CVE-2022-22822 to CVE-2022-22827)
The involved functions are:
- addBinding (CVE-2022-22822)
- build_model (CVE-2022-22823)
- defineAttribute (CVE-2022-22824)
- lookup (CVE-2022-22825)
- nextScaffoldPart (CVE-2022-22826)
- storeAtts (CVE-2022-22827)
---
expat/lib/xmlparse.c | 153 ++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 151 insertions(+), 2 deletions(-)
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -3087,13 +3087,38 @@ storeAtts(XML_Parser parser, const ENCOD
/* get the attributes from the tokenizer */
n = XmlGetAttributes(enc, attStr, parser->m_attsSize, parser->m_atts);
+
+ /* Detect and prevent integer overflow */
+ if (n > INT_MAX - nDefaultAtts) {
+ return XML_ERROR_NO_MEMORY;
+ }
+
if (n + nDefaultAtts > parser->m_attsSize) {
int oldAttsSize = parser->m_attsSize;
ATTRIBUTE *temp;
#ifdef XML_ATTR_INFO
XML_AttrInfo *temp2;
#endif
+
+ /* Detect and prevent integer overflow */
+ if ((nDefaultAtts > INT_MAX - INIT_ATTS_SIZE)
+ || (n > INT_MAX - (nDefaultAtts + INIT_ATTS_SIZE))) {
+ return XML_ERROR_NO_MEMORY;
+ }
+
parser->m_attsSize = n + nDefaultAtts + INIT_ATTS_SIZE;
+
+ /* Detect and prevent integer overflow.
+ * The preprocessor guard addresses the "always false" warning
+ * from -Wtype-limits on platforms where
+ * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
+#if UINT_MAX >= SIZE_MAX
+ if ((unsigned)parser->m_attsSize > (size_t)(-1) / sizeof(ATTRIBUTE)) {
+ parser->m_attsSize = oldAttsSize;
+ return XML_ERROR_NO_MEMORY;
+ }
+#endif
+
temp = (ATTRIBUTE *)REALLOC(parser, (void *)parser->m_atts,
parser->m_attsSize * sizeof(ATTRIBUTE));
if (temp == NULL) {
@@ -3102,6 +3127,17 @@ storeAtts(XML_Parser parser, const ENCOD
}
parser->m_atts = temp;
#ifdef XML_ATTR_INFO
+ /* Detect and prevent integer overflow.
+ * The preprocessor guard addresses the "always false" warning
+ * from -Wtype-limits on platforms where
+ * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
+# if UINT_MAX >= SIZE_MAX
+ if ((unsigned)parser->m_attsSize > (size_t)(-1) / sizeof(XML_AttrInfo)) {
+ parser->m_attsSize = oldAttsSize;
+ return XML_ERROR_NO_MEMORY;
+ }
+# endif
+
temp2 = (XML_AttrInfo *)REALLOC(parser, (void *)parser->m_attInfo,
parser->m_attsSize * sizeof(XML_AttrInfo));
if (temp2 == NULL) {
@@ -3436,9 +3472,31 @@ storeAtts(XML_Parser parser, const ENCOD
tagNamePtr->prefixLen = prefixLen;
for (i = 0; localPart[i++];)
; /* i includes null terminator */
+
+ /* Detect and prevent integer overflow */
+ if (binding->uriLen > INT_MAX - prefixLen
+ || i > INT_MAX - (binding->uriLen + prefixLen)) {
+ return XML_ERROR_NO_MEMORY;
+ }
+
n = i + binding->uriLen + prefixLen;
if (n > binding->uriAlloc) {
TAG *p;
+
+ /* Detect and prevent integer overflow */
+ if (n > INT_MAX - EXPAND_SPARE) {
+ return XML_ERROR_NO_MEMORY;
+ }
+ /* Detect and prevent integer overflow.
+ * The preprocessor guard addresses the "always false" warning
+ * from -Wtype-limits on platforms where
+ * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
+#if UINT_MAX >= SIZE_MAX
+ if ((unsigned)(n + EXPAND_SPARE) > (size_t)(-1) / sizeof(XML_Char)) {
+ return XML_ERROR_NO_MEMORY;
+ }
+#endif
+
uri = (XML_Char *)MALLOC(parser, (n + EXPAND_SPARE) * sizeof(XML_Char));
if (! uri)
return XML_ERROR_NO_MEMORY;
@@ -3534,6 +3592,21 @@ addBinding(XML_Parser parser, PREFIX *pr
if (parser->m_freeBindingList) {
b = parser->m_freeBindingList;
if (len > b->uriAlloc) {
+ /* Detect and prevent integer overflow */
+ if (len > INT_MAX - EXPAND_SPARE) {
+ return XML_ERROR_NO_MEMORY;
+ }
+
+ /* Detect and prevent integer overflow.
+ * The preprocessor guard addresses the "always false" warning
+ * from -Wtype-limits on platforms where
+ * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
+#if UINT_MAX >= SIZE_MAX
+ if ((unsigned)(len + EXPAND_SPARE) > (size_t)(-1) / sizeof(XML_Char)) {
+ return XML_ERROR_NO_MEMORY;
+ }
+#endif
+
XML_Char *temp = (XML_Char *)REALLOC(
parser, b->uri, sizeof(XML_Char) * (len + EXPAND_SPARE));
if (temp == NULL)
@@ -3546,6 +3619,21 @@ addBinding(XML_Parser parser, PREFIX *pr
b = (BINDING *)MALLOC(parser, sizeof(BINDING));
if (! b)
return XML_ERROR_NO_MEMORY;
+
+ /* Detect and prevent integer overflow */
+ if (len > INT_MAX - EXPAND_SPARE) {
+ return XML_ERROR_NO_MEMORY;
+ }
+ /* Detect and prevent integer overflow.
+ * The preprocessor guard addresses the "always false" warning
+ * from -Wtype-limits on platforms where
+ * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
+#if UINT_MAX >= SIZE_MAX
+ if ((unsigned)(len + EXPAND_SPARE) > (size_t)(-1) / sizeof(XML_Char)) {
+ return XML_ERROR_NO_MEMORY;
+ }
+#endif
+
b->uri
= (XML_Char *)MALLOC(parser, sizeof(XML_Char) * (len + EXPAND_SPARE));
if (! b->uri) {
@@ -5826,7 +5914,24 @@ defineAttribute(ELEMENT_TYPE *type, ATTR
}
} else {
DEFAULT_ATTRIBUTE *temp;
+
+ /* Detect and prevent integer overflow */
+ if (type->allocDefaultAtts > INT_MAX / 2) {
+ return 0;
+ }
+
int count = type->allocDefaultAtts * 2;
+
+ /* Detect and prevent integer overflow.
+ * The preprocessor guard addresses the "always false" warning
+ * from -Wtype-limits on platforms where
+ * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
+#if UINT_MAX >= SIZE_MAX
+ if ((unsigned)count > (size_t)(-1) / sizeof(DEFAULT_ATTRIBUTE)) {
+ return 0;
+ }
+#endif
+
temp = (DEFAULT_ATTRIBUTE *)REALLOC(parser, type->defaultAtts,
(count * sizeof(DEFAULT_ATTRIBUTE)));
if (temp == NULL)
@@ -6477,8 +6582,20 @@ lookup(XML_Parser parser, HASH_TABLE *ta
/* check for overflow (table is half full) */
if (table->used >> (table->power - 1)) {
unsigned char newPower = table->power + 1;
+
+ /* Detect and prevent invalid shift */
+ if (newPower >= sizeof(unsigned long) * 8 /* bits per byte */) {
+ return NULL;
+ }
+
size_t newSize = (size_t)1 << newPower;
unsigned long newMask = (unsigned long)newSize - 1;
+
+ /* Detect and prevent integer overflow */
+ if (newSize > (size_t)(-1) / sizeof(NAMED *)) {
+ return NULL;
+ }
+
size_t tsize = newSize * sizeof(NAMED *);
NAMED **newV = (NAMED **)table->mem->malloc_fcn(tsize);
if (! newV)
@@ -6828,6 +6945,20 @@ nextScaffoldPart(XML_Parser parser) {
if (dtd->scaffCount >= dtd->scaffSize) {
CONTENT_SCAFFOLD *temp;
if (dtd->scaffold) {
+ /* Detect and prevent integer overflow */
+ if (dtd->scaffSize > UINT_MAX / 2u) {
+ return -1;
+ }
+ /* Detect and prevent integer overflow.
+ * The preprocessor guard addresses the "always false" warning
+ * from -Wtype-limits on platforms where
+ * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
+#if UINT_MAX >= SIZE_MAX
+ if (dtd->scaffSize > (size_t)(-1) / 2u / sizeof(CONTENT_SCAFFOLD)) {
+ return -1;
+ }
+#endif
+
temp = (CONTENT_SCAFFOLD *)REALLOC(
parser, dtd->scaffold, dtd->scaffSize * 2 * sizeof(CONTENT_SCAFFOLD));
if (temp == NULL)
@@ -6897,8 +7028,26 @@ build_model(XML_Parser parser) {
XML_Content *ret;
XML_Content *cpos;
XML_Char *str;
- int allocsize = (dtd->scaffCount * sizeof(XML_Content)
- + (dtd->contentStringLen * sizeof(XML_Char)));
+
+ /* Detect and prevent integer overflow.
+ * The preprocessor guard addresses the "always false" warning
+ * from -Wtype-limits on platforms where
+ * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
+#if UINT_MAX >= SIZE_MAX
+ if (dtd->scaffCount > (size_t)(-1) / sizeof(XML_Content)) {
+ return NULL;
+ }
+ if (dtd->contentStringLen > (size_t)(-1) / sizeof(XML_Char)) {
+ return NULL;
+ }
+#endif
+ if (dtd->scaffCount * sizeof(XML_Content)
+ > (size_t)(-1) - dtd->contentStringLen * sizeof(XML_Char)) {
+ return NULL;
+ }
+
+ const size_t allocsize = (dtd->scaffCount * sizeof(XML_Content)
+ + (dtd->contentStringLen * sizeof(XML_Char)));
ret = (XML_Content *)MALLOC(parser, allocsize);
if (! ret)