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179 lines
6.3 KiB
179 lines
6.3 KiB
From 5cec67e3f8d56e6e5fda2f90e102950cbb09e3d1 Mon Sep 17 00:00:00 2001 |
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From: Daniel Veillard <veillard@redhat.com> |
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Date: Tue, 14 Apr 2015 17:41:48 +0800 |
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Subject: [PATCH] CVE-2015-1819 Enforce the reader to run in constant memory |
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To: libvir-list@redhat.com |
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One of the operation on the reader could resolve entities |
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leading to the classic expansion issue. Make sure the |
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buffer used for xmlreader operation is bounded. |
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Introduce a new allocation type for the buffers for this effect. |
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Signed-off-by: Daniel Veillard <veillard@redhat.com> |
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--- |
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buf.c | 43 ++++++++++++++++++++++++++++++++++++++++++- |
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include/libxml/tree.h | 3 ++- |
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xmlreader.c | 20 +++++++++++++++++++- |
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3 files changed, 63 insertions(+), 3 deletions(-) |
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diff --git a/buf.c b/buf.c |
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index d1756c4..b52e41d 100644 |
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--- a/buf.c |
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+++ b/buf.c |
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@@ -27,6 +27,7 @@ |
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#include <libxml/tree.h> |
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#include <libxml/globals.h> |
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#include <libxml/tree.h> |
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+#include <libxml/parserInternals.h> /* for XML_MAX_TEXT_LENGTH */ |
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#include "buf.h" |
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#define WITH_BUFFER_COMPAT |
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@@ -299,7 +300,8 @@ xmlBufSetAllocationScheme(xmlBufPtr buf, |
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if ((scheme == XML_BUFFER_ALLOC_DOUBLEIT) || |
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(scheme == XML_BUFFER_ALLOC_EXACT) || |
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(scheme == XML_BUFFER_ALLOC_HYBRID) || |
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- (scheme == XML_BUFFER_ALLOC_IMMUTABLE)) { |
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+ (scheme == XML_BUFFER_ALLOC_IMMUTABLE) || |
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+ (scheme == XML_BUFFER_ALLOC_BOUNDED)) { |
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buf->alloc = scheme; |
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if (buf->buffer) |
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buf->buffer->alloc = scheme; |
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@@ -458,6 +460,18 @@ xmlBufGrowInternal(xmlBufPtr buf, size_t len) { |
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size = buf->use + len + 100; |
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#endif |
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+ if (buf->alloc == XML_BUFFER_ALLOC_BOUNDED) { |
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+ /* |
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+ * Used to provide parsing limits |
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+ */ |
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+ if ((buf->use + len >= XML_MAX_TEXT_LENGTH) || |
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+ (buf->size >= XML_MAX_TEXT_LENGTH)) { |
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+ xmlBufMemoryError(buf, "buffer error: text too long\n"); |
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+ return(0); |
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+ } |
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+ if (size >= XML_MAX_TEXT_LENGTH) |
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+ size = XML_MAX_TEXT_LENGTH; |
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+ } |
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if ((buf->alloc == XML_BUFFER_ALLOC_IO) && (buf->contentIO != NULL)) { |
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size_t start_buf = buf->content - buf->contentIO; |
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@@ -739,6 +753,15 @@ xmlBufResize(xmlBufPtr buf, size_t size) |
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CHECK_COMPAT(buf) |
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if (buf->alloc == XML_BUFFER_ALLOC_IMMUTABLE) return(0); |
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+ if (buf->alloc == XML_BUFFER_ALLOC_BOUNDED) { |
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+ /* |
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+ * Used to provide parsing limits |
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+ */ |
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+ if (size >= XML_MAX_TEXT_LENGTH) { |
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+ xmlBufMemoryError(buf, "buffer error: text too long\n"); |
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+ return(0); |
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+ } |
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+ } |
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/* Don't resize if we don't have to */ |
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if (size < buf->size) |
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@@ -867,6 +890,15 @@ xmlBufAdd(xmlBufPtr buf, const xmlChar *str, int len) { |
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needSize = buf->use + len + 2; |
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if (needSize > buf->size){ |
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+ if (buf->alloc == XML_BUFFER_ALLOC_BOUNDED) { |
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+ /* |
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+ * Used to provide parsing limits |
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+ */ |
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+ if (needSize >= XML_MAX_TEXT_LENGTH) { |
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+ xmlBufMemoryError(buf, "buffer error: text too long\n"); |
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+ return(-1); |
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+ } |
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+ } |
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if (!xmlBufResize(buf, needSize)){ |
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xmlBufMemoryError(buf, "growing buffer"); |
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return XML_ERR_NO_MEMORY; |
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@@ -938,6 +970,15 @@ xmlBufAddHead(xmlBufPtr buf, const xmlChar *str, int len) { |
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} |
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needSize = buf->use + len + 2; |
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if (needSize > buf->size){ |
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+ if (buf->alloc == XML_BUFFER_ALLOC_BOUNDED) { |
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+ /* |
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+ * Used to provide parsing limits |
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+ */ |
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+ if (needSize >= XML_MAX_TEXT_LENGTH) { |
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+ xmlBufMemoryError(buf, "buffer error: text too long\n"); |
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+ return(-1); |
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+ } |
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+ } |
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if (!xmlBufResize(buf, needSize)){ |
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xmlBufMemoryError(buf, "growing buffer"); |
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return XML_ERR_NO_MEMORY; |
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diff --git a/include/libxml/tree.h b/include/libxml/tree.h |
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index 7e06686..d904a44 100644 |
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--- a/include/libxml/tree.h |
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+++ b/include/libxml/tree.h |
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@@ -76,7 +76,8 @@ typedef enum { |
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XML_BUFFER_ALLOC_EXACT, /* grow only to the minimal size */ |
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XML_BUFFER_ALLOC_IMMUTABLE, /* immutable buffer */ |
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XML_BUFFER_ALLOC_IO, /* special allocation scheme used for I/O */ |
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- XML_BUFFER_ALLOC_HYBRID /* exact up to a threshold, and doubleit thereafter */ |
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+ XML_BUFFER_ALLOC_HYBRID, /* exact up to a threshold, and doubleit thereafter */ |
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+ XML_BUFFER_ALLOC_BOUNDED /* limit the upper size of the buffer */ |
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} xmlBufferAllocationScheme; |
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/** |
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diff --git a/xmlreader.c b/xmlreader.c |
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index 00083d0..4fabaa9 100644 |
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--- a/xmlreader.c |
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+++ b/xmlreader.c |
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@@ -2077,6 +2077,9 @@ xmlNewTextReader(xmlParserInputBufferPtr input, const char *URI) { |
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"xmlNewTextReader : malloc failed\n"); |
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return(NULL); |
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} |
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+ /* no operation on a reader should require a huge buffer */ |
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+ xmlBufSetAllocationScheme(ret->buffer, |
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+ XML_BUFFER_ALLOC_BOUNDED); |
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ret->sax = (xmlSAXHandler *) xmlMalloc(sizeof(xmlSAXHandler)); |
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if (ret->sax == NULL) { |
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xmlBufFree(ret->buffer); |
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@@ -3602,6 +3605,7 @@ xmlTextReaderConstValue(xmlTextReaderPtr reader) { |
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return(((xmlNsPtr) node)->href); |
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case XML_ATTRIBUTE_NODE:{ |
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xmlAttrPtr attr = (xmlAttrPtr) node; |
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+ const xmlChar *ret; |
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if ((attr->children != NULL) && |
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(attr->children->type == XML_TEXT_NODE) && |
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@@ -3615,10 +3619,21 @@ xmlTextReaderConstValue(xmlTextReaderPtr reader) { |
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"xmlTextReaderSetup : malloc failed\n"); |
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return (NULL); |
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} |
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+ xmlBufSetAllocationScheme(reader->buffer, |
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+ XML_BUFFER_ALLOC_BOUNDED); |
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} else |
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xmlBufEmpty(reader->buffer); |
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xmlBufGetNodeContent(reader->buffer, node); |
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- return(xmlBufContent(reader->buffer)); |
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+ ret = xmlBufContent(reader->buffer); |
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+ if (ret == NULL) { |
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+ /* error on the buffer best to reallocate */ |
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+ xmlBufFree(reader->buffer); |
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+ reader->buffer = xmlBufCreateSize(100); |
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+ xmlBufSetAllocationScheme(reader->buffer, |
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+ XML_BUFFER_ALLOC_BOUNDED); |
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+ ret = BAD_CAST ""; |
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+ } |
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+ return(ret); |
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} |
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break; |
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} |
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@@ -5117,6 +5132,9 @@ xmlTextReaderSetup(xmlTextReaderPtr reader, |
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"xmlTextReaderSetup : malloc failed\n"); |
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return (-1); |
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} |
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+ /* no operation on a reader should require a huge buffer */ |
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+ xmlBufSetAllocationScheme(reader->buffer, |
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+ XML_BUFFER_ALLOC_BOUNDED); |
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if (reader->sax == NULL) |
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reader->sax = (xmlSAXHandler *) xmlMalloc(sizeof(xmlSAXHandler)); |
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if (reader->sax == NULL) { |
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-- |
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2.5.0 |
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