| From 213f1fe0d76d30eaed6e5853057defc43e6df2c9 Mon Sep 17 00:00:00 2001 |
| From: Daniel Veillard <veillard@redhat.com> |
| Date: Tue, 14 Apr 2015 17:41:48 +0800 |
| Subject: [PATCH] CVE-2015-1819 Enforce the reader to run in constant memory |
| |
| One of the operation on the reader could resolve entities |
| leading to the classic expansion issue. Make sure the |
| buffer used for xmlreader operation is bounded. |
| Introduce a new allocation type for the buffers for this effect. |
| |
| Upstream-Status: Backport |
| |
| Signed-off-by: Yue Tao <Yue.Tao@windriver.com> |
| Signed-off-by: Wenzong Fan <wenzong.fan@windriver.com> |
| --- |
| buf.c | 43 ++++++++++++++++++++++++++++++++++++++++++- |
| include/libxml/tree.h | 3 ++- |
| xmlreader.c | 20 +++++++++++++++++++- |
| 3 files changed, 63 insertions(+), 3 deletions(-) |
| |
| diff --git a/buf.c b/buf.c |
| index 6efc7b6..07922ff 100644 |
| --- a/buf.c |
| +++ b/buf.c |
| @@ -27,6 +27,7 @@ |
| #include <libxml/tree.h> |
| #include <libxml/globals.h> |
| #include <libxml/tree.h> |
| +#include <libxml/parserInternals.h> /* for XML_MAX_TEXT_LENGTH */ |
| #include "buf.h" |
| |
| #define WITH_BUFFER_COMPAT |
| @@ -299,7 +300,8 @@ xmlBufSetAllocationScheme(xmlBufPtr buf, |
| if ((scheme == XML_BUFFER_ALLOC_DOUBLEIT) || |
| (scheme == XML_BUFFER_ALLOC_EXACT) || |
| (scheme == XML_BUFFER_ALLOC_HYBRID) || |
| - (scheme == XML_BUFFER_ALLOC_IMMUTABLE)) { |
| + (scheme == XML_BUFFER_ALLOC_IMMUTABLE) || |
| + (scheme == XML_BUFFER_ALLOC_BOUNDED)) { |
| buf->alloc = scheme; |
| if (buf->buffer) |
| buf->buffer->alloc = scheme; |
| @@ -458,6 +460,18 @@ xmlBufGrowInternal(xmlBufPtr buf, size_t len) { |
| size = buf->use + len + 100; |
| #endif |
| |
| + if (buf->alloc == XML_BUFFER_ALLOC_BOUNDED) { |
| + /* |
| + * Used to provide parsing limits |
| + */ |
| + if ((buf->use + len >= XML_MAX_TEXT_LENGTH) || |
| + (buf->size >= XML_MAX_TEXT_LENGTH)) { |
| + xmlBufMemoryError(buf, "buffer error: text too long\n"); |
| + return(0); |
| + } |
| + if (size >= XML_MAX_TEXT_LENGTH) |
| + size = XML_MAX_TEXT_LENGTH; |
| + } |
| if ((buf->alloc == XML_BUFFER_ALLOC_IO) && (buf->contentIO != NULL)) { |
| size_t start_buf = buf->content - buf->contentIO; |
| |
| @@ -739,6 +753,15 @@ xmlBufResize(xmlBufPtr buf, size_t size) |
| CHECK_COMPAT(buf) |
| |
| if (buf->alloc == XML_BUFFER_ALLOC_IMMUTABLE) return(0); |
| + if (buf->alloc == XML_BUFFER_ALLOC_BOUNDED) { |
| + /* |
| + * Used to provide parsing limits |
| + */ |
| + if (size >= XML_MAX_TEXT_LENGTH) { |
| + xmlBufMemoryError(buf, "buffer error: text too long\n"); |
| + return(0); |
| + } |
| + } |
| |
| /* Don't resize if we don't have to */ |
| if (size < buf->size) |
| @@ -867,6 +890,15 @@ xmlBufAdd(xmlBufPtr buf, const xmlChar *str, int len) { |
| |
| needSize = buf->use + len + 2; |
| if (needSize > buf->size){ |
| + if (buf->alloc == XML_BUFFER_ALLOC_BOUNDED) { |
| + /* |
| + * Used to provide parsing limits |
| + */ |
| + if (needSize >= XML_MAX_TEXT_LENGTH) { |
| + xmlBufMemoryError(buf, "buffer error: text too long\n"); |
| + return(-1); |
| + } |
| + } |
| if (!xmlBufResize(buf, needSize)){ |
| xmlBufMemoryError(buf, "growing buffer"); |
| return XML_ERR_NO_MEMORY; |
| @@ -938,6 +970,15 @@ xmlBufAddHead(xmlBufPtr buf, const xmlChar *str, int len) { |
| } |
| needSize = buf->use + len + 2; |
| if (needSize > buf->size){ |
| + if (buf->alloc == XML_BUFFER_ALLOC_BOUNDED) { |
| + /* |
| + * Used to provide parsing limits |
| + */ |
| + if (needSize >= XML_MAX_TEXT_LENGTH) { |
| + xmlBufMemoryError(buf, "buffer error: text too long\n"); |
| + return(-1); |
| + } |
| + } |
| if (!xmlBufResize(buf, needSize)){ |
| xmlBufMemoryError(buf, "growing buffer"); |
| return XML_ERR_NO_MEMORY; |
| diff --git a/include/libxml/tree.h b/include/libxml/tree.h |
| index 2f90717..4a9b3bc 100644 |
| --- a/include/libxml/tree.h |
| +++ b/include/libxml/tree.h |
| @@ -76,7 +76,8 @@ typedef enum { |
| XML_BUFFER_ALLOC_EXACT, /* grow only to the minimal size */ |
| XML_BUFFER_ALLOC_IMMUTABLE, /* immutable buffer */ |
| XML_BUFFER_ALLOC_IO, /* special allocation scheme used for I/O */ |
| - XML_BUFFER_ALLOC_HYBRID /* exact up to a threshold, and doubleit thereafter */ |
| + XML_BUFFER_ALLOC_HYBRID, /* exact up to a threshold, and doubleit thereafter */ |
| + XML_BUFFER_ALLOC_BOUNDED /* limit the upper size of the buffer */ |
| } xmlBufferAllocationScheme; |
| |
| /** |
| diff --git a/xmlreader.c b/xmlreader.c |
| index f19e123..471e7e2 100644 |
| --- a/xmlreader.c |
| +++ b/xmlreader.c |
| @@ -2091,6 +2091,9 @@ xmlNewTextReader(xmlParserInputBufferPtr input, const char *URI) { |
| "xmlNewTextReader : malloc failed\n"); |
| return(NULL); |
| } |
| + /* no operation on a reader should require a huge buffer */ |
| + xmlBufSetAllocationScheme(ret->buffer, |
| + XML_BUFFER_ALLOC_BOUNDED); |
| ret->sax = (xmlSAXHandler *) xmlMalloc(sizeof(xmlSAXHandler)); |
| if (ret->sax == NULL) { |
| xmlBufFree(ret->buffer); |
| @@ -3616,6 +3619,7 @@ xmlTextReaderConstValue(xmlTextReaderPtr reader) { |
| return(((xmlNsPtr) node)->href); |
| case XML_ATTRIBUTE_NODE:{ |
| xmlAttrPtr attr = (xmlAttrPtr) node; |
| + const xmlChar *ret; |
| |
| if ((attr->children != NULL) && |
| (attr->children->type == XML_TEXT_NODE) && |
| @@ -3629,10 +3633,21 @@ xmlTextReaderConstValue(xmlTextReaderPtr reader) { |
| "xmlTextReaderSetup : malloc failed\n"); |
| return (NULL); |
| } |
| + xmlBufSetAllocationScheme(reader->buffer, |
| + XML_BUFFER_ALLOC_BOUNDED); |
| } else |
| xmlBufEmpty(reader->buffer); |
| xmlBufGetNodeContent(reader->buffer, node); |
| - return(xmlBufContent(reader->buffer)); |
| + ret = xmlBufContent(reader->buffer); |
| + if (ret == NULL) { |
| + /* error on the buffer best to reallocate */ |
| + xmlBufFree(reader->buffer); |
| + reader->buffer = xmlBufCreateSize(100); |
| + xmlBufSetAllocationScheme(reader->buffer, |
| + XML_BUFFER_ALLOC_BOUNDED); |
| + ret = BAD_CAST ""; |
| + } |
| + return(ret); |
| } |
| break; |
| } |
| @@ -5131,6 +5146,9 @@ xmlTextReaderSetup(xmlTextReaderPtr reader, |
| "xmlTextReaderSetup : malloc failed\n"); |
| return (-1); |
| } |
| + /* no operation on a reader should require a huge buffer */ |
| + xmlBufSetAllocationScheme(reader->buffer, |
| + XML_BUFFER_ALLOC_BOUNDED); |
| if (reader->sax == NULL) |
| reader->sax = (xmlSAXHandler *) xmlMalloc(sizeof(xmlSAXHandler)); |
| if (reader->sax == NULL) { |
| -- |
| 1.7.9.5 |
| |