libxml2: Fix CVE-2017-9049 and CVE-2017-9050

Fix handling of parameter-entity references

There were two bugs where parameter-entity references could lead to an
unexpected change of the input buffer in xmlParseNameComplex and
xmlDictLookup being called with an invalid pointer.

Fixes bug 781205 and bug 781361

CVE: CVE-2017-9049 CVE-2017-9050
(From OE-Core rev: 2300762fef8fc8e3e56fb07fd4076c1deeba0a9b)

Signed-off-by: Andrej Valek <andrej.valek@siemens.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 291 insertions, 0 deletions

diff --git a/meta/recipes-core/libxml/libxml2/libxml2-CVE-2017-9049_CVE-2017-9050.patch b/meta/recipes-core/libxml/libxml2/libxml2-CVE-2017-9049_CVE-2017-9050.patch
new file mode 100644
index 0000000000..591075de3c
--- /dev/null
+++ b/meta/recipes-core/libxml/libxml2/libxml2-CVE-2017-9049_CVE-2017-9050.patch
@@ -0,0 +1,291 @@
+libxml2-2.9.4: Fix CVE-2017-9049 and CVE-2017-9050
+
+[No upstream tracking] -- https://bugzilla.gnome.org/show_bug.cgi?id=781205
+ -- https://bugzilla.gnome.org/show_bug.cgi?id=781361
+
+parser: Fix handling of parameter-entity references
+
+There were two bugs where parameter-entity references could lead to an
+unexpected change of the input buffer in xmlParseNameComplex and
+xmlDictLookup being called with an invalid pointer.
+
+Percent sign in DTD Names
+=========================
+
+The NEXTL macro used to call xmlParserHandlePEReference. When parsing
+"complex" names inside the DTD, this could result in entity expansion
+which created a new input buffer. The fix is to simply remove the call
+to xmlParserHandlePEReference from the NEXTL macro. This is safe because
+no users of the macro require expansion of parameter entities.
+
+- xmlParseNameComplex
+- xmlParseNCNameComplex
+- xmlParseNmtoken
+
+The percent sign is not allowed in names, which are grammatical tokens.
+
+- xmlParseEntityValue
+
+Parameter-entity references in entity values are expanded but this
+happens in a separate step in this function.
+
+- xmlParseSystemLiteral
+
+Parameter-entity references are ignored in the system literal.
+
+- xmlParseAttValueComplex
+- xmlParseCharDataComplex
+- xmlParseCommentComplex
+- xmlParsePI
+- xmlParseCDSect
+
+Parameter-entity references are ignored outside the DTD.
+
+- xmlLoadEntityContent
+
+This function is only called from xmlStringLenDecodeEntities and
+entities are replaced in a separate step immediately after the function
+call.
+
+This bug could also be triggered with an internal subset and double
+entity expansion.
+
+This fixes bug 766956 initially reported by Wei Lei and independently by
+Chromium's ClusterFuzz, Hanno Böck, and Marco Grassi. Thanks to everyone
+involved.
+
+xmlParseNameComplex with XML_PARSE_OLD10
+========================================
+
+When parsing Names inside an expanded parameter entity with the
+XML_PARSE_OLD10 option, xmlParseNameComplex would call xmlGROW via the
+GROW macro if the input buffer was exhausted. At the end of the
+parameter entity's replacement text, this function would then call
+xmlPopInput which invalidated the input buffer.
+
+There should be no need to invoke GROW in this situation because the
+buffer is grown periodically every XML_PARSER_CHUNK_SIZE characters and,
+at least for UTF-8, in xmlCurrentChar. This also matches the code path
+executed when XML_PARSE_OLD10 is not set.
+
+This fixes bugs 781205 (CVE-2017-9049) and 781361 (CVE-2017-9050).
+Thanks to Marcel Böhme and Thuan Pham for the report.
+
+Additional hardening
+====================
+
+A separate check was added in xmlParseNameComplex to validate the
+buffer size.
+
+Fixes bug 781205 and bug 781361
+
+Upstream-Status: Backport [https://git.gnome.org/browse/libxml2/commit/?id=932cc9896ab41475d4aa429c27d9afd175959d74]
+CVE: CVE-2017-9049 CVE-2017-9050
+Signed-off-by: Andrej Valek <andrej.valek@siemens.com>
+
+diff --git a/Makefile.am b/Makefile.am
+index 9f988b0..dab15a4 100644
+--- a/Makefile.am
++++ b/Makefile.am
+@@ -422,6 +422,24 @@ Errtests : xmllint$(EXEEXT)
+              if [ -n "$$log" ] ; then echo $$name result ; echo $$log ; fi ; \
+              rm result.$$name error.$$name ; \
+          fi ; fi ; done)
++       @echo "## Error cases regression tests (old 1.0)"
++       -@(for i in $(srcdir)/test/errors10/*.xml ; do \
++         name=`basename $$i`; \
++         if [ ! -d $$i ] ; then \
++         if [ ! -f $(srcdir)/result/errors10/$$name ] ; then \
++             echo New test file $$name ; \
++             $(CHECKER) $(top_builddir)/xmllint --oldxml10 $$i \
++                2> $(srcdir)/result/errors10/$$name.err \
++                > $(srcdir)/result/errors10/$$name ; \
++             grep "MORY ALLO" .memdump  | grep -v "MEMORY ALLOCATED : 0"; \
++         else \
++             log=`$(CHECKER) $(top_builddir)/xmllint --oldxml10 $$i 2> error.$$name > result.$$name ; \
++             grep "MORY ALLO" .memdump  | grep -v "MEMORY ALLOCATED : 0"; \
++             diff $(srcdir)/result/errors10/$$name result.$$name ; \
++             diff $(srcdir)/result/errors10/$$name.err error.$$name` ; \
++             if [ -n "$$log" ] ; then echo $$name result ; echo "$$log" ; fi ; \
++             rm result.$$name error.$$name ; \
++         fi ; fi ; done)
+        @echo "## Error cases stream regression tests"
+        -@(for i in $(srcdir)/test/errors/*.xml ; do \
+          name=`basename $$i`; \
+diff --git a/parser.c b/parser.c
+index 609a270..8e11c12 100644
+--- a/parser.c
++++ b/parser.c
+@@ -2115,7 +2115,6 @@ static void xmlGROW (xmlParserCtxtPtr ctxt) {
+        ctxt->input->line++; ctxt->input->col = 1;                      \
+     } else ctxt->input->col++;                                         \
+     ctxt->input->cur += l;                             \
+-    if (*ctxt->input->cur == '%') xmlParserHandlePEReference(ctxt);    \
+   } while (0)
+ 
+ #define CUR_CHAR(l) xmlCurrentChar(ctxt, &l)
+@@ -3406,13 +3405,6 @@ xmlParseNameComplex(xmlParserCtxtPtr ctxt) {
+            len += l;
+            NEXTL(l);
+            c = CUR_CHAR(l);
+-           if (c == 0) {
+-               count = 0;
+-               GROW;
+-                if (ctxt->instate == XML_PARSER_EOF)
+-                    return(NULL);
+-               c = CUR_CHAR(l);
+-           }
+        }
+     }
+     if ((len > XML_MAX_NAME_LENGTH) &&
+@@ -3420,6 +3412,16 @@ xmlParseNameComplex(xmlParserCtxtPtr ctxt) {
+         xmlFatalErr(ctxt, XML_ERR_NAME_TOO_LONG, "Name");
+         return(NULL);
+     }
++    if (ctxt->input->cur - ctxt->input->base < len) {
++        /*
++         * There were a couple of bugs where PERefs lead to to a change
++         * of the buffer. Check the buffer size to avoid passing an invalid
++         * pointer to xmlDictLookup.
++         */
++        xmlFatalErr(ctxt, XML_ERR_INTERNAL_ERROR,
++                    "unexpected change of input buffer");
++        return (NULL);
++    }
+     if ((*ctxt->input->cur == '\n') && (ctxt->input->cur[-1] == '\r'))
+         return(xmlDictLookup(ctxt->dict, ctxt->input->cur - (len + 1), len));
+     return(xmlDictLookup(ctxt->dict, ctxt->input->cur - len, len));
+diff --git a/result/errors10/781205.xml b/result/errors10/781205.xml
+new file mode 100644
+index 0000000..e69de29
+diff --git a/result/errors10/781205.xml.err b/result/errors10/781205.xml.err
+new file mode 100644
+index 0000000..da15c3f
+--- /dev/null
++++ b/result/errors10/781205.xml.err
+@@ -0,0 +1,21 @@
++Entity: line 1: parser error : internal error: xmlParseInternalSubset: error detected in Markup declaration
++
++ %a; 
++    ^
++Entity: line 1: 
++<:0000
++^
++Entity: line 1: parser error : DOCTYPE improperly terminated
++ %a; 
++    ^
++Entity: line 1: 
++<:0000
++^
++namespace error : Failed to parse QName ':0000'
++ %a; 
++    ^
++<:0000
++      ^
++./test/errors10/781205.xml:4: parser error : Couldn't find end of Start Tag :0000 line 1
++
++^
+diff --git a/result/errors10/781361.xml b/result/errors10/781361.xml
+new file mode 100644
+index 0000000..e69de29
+diff --git a/result/errors10/781361.xml.err b/result/errors10/781361.xml.err
+new file mode 100644
+index 0000000..655f41a
+--- /dev/null
++++ b/result/errors10/781361.xml.err
+@@ -0,0 +1,13 @@
++./test/errors10/781361.xml:4: parser error : xmlParseElementDecl: 'EMPTY', 'ANY' or '(' expected
++
++^
++./test/errors10/781361.xml:4: parser error : internal error: xmlParseInternalSubset: error detected in Markup declaration
++
++
++^
++./test/errors10/781361.xml:4: parser error : DOCTYPE improperly terminated
++
++^
++./test/errors10/781361.xml:4: parser error : Start tag expected, '<' not found
++
++^
+diff --git a/result/valid/766956.xml b/result/valid/766956.xml
+new file mode 100644
+index 0000000..e69de29
+diff --git a/result/valid/766956.xml.err b/result/valid/766956.xml.err
+new file mode 100644
+index 0000000..34b1dae
+--- /dev/null
++++ b/result/valid/766956.xml.err
+@@ -0,0 +1,9 @@
++test/valid/dtds/766956.dtd:2: parser error : PEReference: expecting ';'
++%ä%ent;
++   ^
++Entity: line 1: parser error : Content error in the external subset
++ %ent; 
++      ^
++Entity: line 1: 
++value
++^
+diff --git a/result/valid/766956.xml.err.rdr b/result/valid/766956.xml.err.rdr
+new file mode 100644
+index 0000000..7760346
+--- /dev/null
++++ b/result/valid/766956.xml.err.rdr
+@@ -0,0 +1,10 @@
++test/valid/dtds/766956.dtd:2: parser error : PEReference: expecting ';'
++%ä%ent;
++   ^
++Entity: line 1: parser error : Content error in the external subset
++ %ent; 
++      ^
++Entity: line 1: 
++value
++^
++./test/valid/766956.xml : failed to parse
+diff --git a/runtest.c b/runtest.c
+index bb74d2a..63e8c20 100644
+--- a/runtest.c
++++ b/runtest.c
+@@ -4202,6 +4202,9 @@ testDesc testDescriptions[] = {
+     { "Error cases regression tests",
+       errParseTest, "./test/errors/*.xml", "result/errors/", "", ".err",
+       0 },
++    { "Error cases regression tests (old 1.0)",
++      errParseTest, "./test/errors10/*.xml", "result/errors10/", "", ".err",
++      XML_PARSE_OLD10 },
+ #ifdef LIBXML_READER_ENABLED
+     { "Error cases stream regression tests",
+       streamParseTest, "./test/errors/*.xml", "result/errors/", NULL, ".str",
+diff --git a/test/errors10/781205.xml b/test/errors10/781205.xml
+new file mode 100644
+index 0000000..d9e9e83
+--- /dev/null
++++ b/test/errors10/781205.xml
+@@ -0,0 +1,3 @@
++<!DOCTYPE D [
++  <!ENTITY % a "<:0000">
++  %a;
+diff --git a/test/errors10/781361.xml b/test/errors10/781361.xml
+new file mode 100644
+index 0000000..67476bc
+--- /dev/null
++++ b/test/errors10/781361.xml
+@@ -0,0 +1,3 @@
++<!DOCTYPE doc [
++  <!ENTITY % elem "<!ELEMENT e0000000000">
++  %elem;
+diff --git a/test/valid/766956.xml b/test/valid/766956.xml
+new file mode 100644
+index 0000000..19a95a0
+--- /dev/null
++++ b/test/valid/766956.xml
+@@ -0,0 +1,2 @@
++<!DOCTYPE test SYSTEM "dtds/766956.dtd">
++<test/>
+diff --git a/test/valid/dtds/766956.dtd b/test/valid/dtds/766956.dtd
+new file mode 100644
+index 0000000..dddde68
+--- /dev/null
++++ b/test/valid/dtds/766956.dtd
+@@ -0,0 +1,2 @@
++<!ENTITY % ent "value">
++%ä%ent;