From 9f93e8036e842329863bf20395b8fb8f73834d9e Mon Sep 17 00:00:00 2001 From: Sebastian Pipping 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(-) diff --git a/expat/lib/xmlparse.c b/expat/lib/xmlparse.c index 8f243126..575e73ee 100644 --- a/expat/lib/xmlparse.c +++ b/expat/lib/xmlparse.c @@ -3261,13 +3261,38 @@ storeAtts(XML_Parser parser, const ENCODING *enc, const char *attStr, /* 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) { @@ -3276,6 +3301,17 @@ storeAtts(XML_Parser parser, const ENCODING *enc, const char *attStr, } 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) { @@ -3610,9 +3646,31 @@ storeAtts(XML_Parser parser, const ENCODING *enc, const char *attStr, 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; @@ -3708,6 +3766,21 @@ addBinding(XML_Parser parser, PREFIX *prefix, const ATTRIBUTE_ID *attId, 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) @@ -3720,6 +3793,21 @@ addBinding(XML_Parser parser, PREFIX *prefix, const ATTRIBUTE_ID *attId, 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) { @@ -6141,7 +6229,24 @@ defineAttribute(ELEMENT_TYPE *type, ATTRIBUTE_ID *attId, XML_Bool isCdata, } } 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) @@ -6792,8 +6897,20 @@ lookup(XML_Parser parser, HASH_TABLE *table, KEY name, size_t createSize) { /* 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) @@ -7143,6 +7260,20 @@ 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) @@ -7212,8 +7343,26 @@ 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)