Patchwork Expat upate and regression fix for core-updates

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Submitter Leo Famulari
Date Sept. 13, 2016, 2:03 a.m.
Message ID <20160913020340.GA22383@jasmine>
Download mbox | patch
Permalink /patch/15560/
State New
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Comments

Leo Famulari - Sept. 13, 2016, 2:03 a.m.
This updates Expat to the latest release, 2.2.0, and applies the
upstream patch for a regression caused by the fix for CVE-2016-0718.

It's the same patch that I sent earlier in a patch for the master
branch.
From 69611d71dc4718040bc7bc55117bd2705bad4612 Mon Sep 17 00:00:00 2001
From: Leo Famulari <leo@famulari.name>
Date: Mon, 12 Sep 2016 13:26:51 -0400
Subject: [PATCH] gnu: expat: Update to 2.2.0.

* gnu/packages/xml.scm (expat): Update to 2.2.0.
[source]: Use 'expat-CVE-2016-0718-fix-regression.patch'. Remove obsolete
patches.
* gnu/packages/patches/expat-CVE-2016-0718-fix-regression.patch: New file.
* gnu/packages/patches/expat-CVE-2012-6702-and-CVE-2016-5300.patch,
gnu/packages/patches/expat-CVE-2015-1283-refix.patch,
gnu/packages/patches/expat-CVE-2016-0718.patch: Delete files.
* gnu/local.mk (dist_patch_DATA): Add and remove patches.
---
 gnu/local.mk                                       |   4 +-
 .../expat-CVE-2012-6702-and-CVE-2016-5300.patch    | 142 ----
 .../patches/expat-CVE-2015-1283-refix.patch        |  39 --
 .../expat-CVE-2016-0718-fix-regression.patch       |  35 +
 gnu/packages/patches/expat-CVE-2016-0718.patch     | 761 ---------------------
 gnu/packages/xml.scm                               |   9 +-
 6 files changed, 40 insertions(+), 950 deletions(-)
 delete mode 100644 gnu/packages/patches/expat-CVE-2012-6702-and-CVE-2016-5300.patch
 delete mode 100644 gnu/packages/patches/expat-CVE-2015-1283-refix.patch
 create mode 100644 gnu/packages/patches/expat-CVE-2016-0718-fix-regression.patch
 delete mode 100644 gnu/packages/patches/expat-CVE-2016-0718.patch
Ludovic Courtès - Sept. 13, 2016, 9:55 p.m.
Leo Famulari <leo@famulari.name> skribis:

> This updates Expat to the latest release, 2.2.0, and applies the
> upstream patch for a regression caused by the fix for CVE-2016-0718.
>
> It's the same patch that I sent earlier in a patch for the master
> branch.
>
> From 69611d71dc4718040bc7bc55117bd2705bad4612 Mon Sep 17 00:00:00 2001
> From: Leo Famulari <leo@famulari.name>
> Date: Mon, 12 Sep 2016 13:26:51 -0400
> Subject: [PATCH] gnu: expat: Update to 2.2.0.
>
> * gnu/packages/xml.scm (expat): Update to 2.2.0.
> [source]: Use 'expat-CVE-2016-0718-fix-regression.patch'. Remove obsolete
> patches.
> * gnu/packages/patches/expat-CVE-2016-0718-fix-regression.patch: New file.
> * gnu/packages/patches/expat-CVE-2012-6702-and-CVE-2016-5300.patch,
> gnu/packages/patches/expat-CVE-2015-1283-refix.patch,
> gnu/packages/patches/expat-CVE-2016-0718.patch: Delete files.
> * gnu/local.mk (dist_patch_DATA): Add and remove patches.

OK for core-updates, thank you!

Ludo’.
Leo Famulari - Sept. 14, 2016, 12:38 a.m.
On Tue, Sep 13, 2016 at 11:55:14PM +0200, Ludovic Courtès wrote:
> > From 69611d71dc4718040bc7bc55117bd2705bad4612 Mon Sep 17 00:00:00 2001
> > From: Leo Famulari <leo@famulari.name>
> > Date: Mon, 12 Sep 2016 13:26:51 -0400
> > Subject: [PATCH] gnu: expat: Update to 2.2.0.
> >
> > * gnu/packages/xml.scm (expat): Update to 2.2.0.
> > [source]: Use 'expat-CVE-2016-0718-fix-regression.patch'. Remove obsolete
> > patches.
> > * gnu/packages/patches/expat-CVE-2016-0718-fix-regression.patch: New file.
> > * gnu/packages/patches/expat-CVE-2012-6702-and-CVE-2016-5300.patch,
> > gnu/packages/patches/expat-CVE-2015-1283-refix.patch,
> > gnu/packages/patches/expat-CVE-2016-0718.patch: Delete files.
> > * gnu/local.mk (dist_patch_DATA): Add and remove patches.
> 
> OK for core-updates, thank you!

Pushed as b1a782b11aae2fa2bf8450c228638a0fd5cc9c83

Patch

diff --git a/gnu/local.mk b/gnu/local.mk
index 58be68f..8247e8b 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -495,9 +495,7 @@  dist_patch_DATA =						\
   %D%/packages/patches/emacs-source-date-epoch.patch		\
   %D%/packages/patches/eudev-rules-directory.patch		\
   %D%/packages/patches/evilwm-lost-focus-bug.patch		\
-  %D%/packages/patches/expat-CVE-2012-6702-and-CVE-2016-5300.patch	\
-  %D%/packages/patches/expat-CVE-2015-1283-refix.patch		\
-  %D%/packages/patches/expat-CVE-2016-0718.patch		\
+  %D%/packages/patches/expat-CVE-2016-0718-fix-regression.patch	\
   %D%/packages/patches/fastcap-mulGlobal.patch			\
   %D%/packages/patches/fastcap-mulSetup.patch			\
   %D%/packages/patches/fasthenry-spAllocate.patch		\
diff --git a/gnu/packages/patches/expat-CVE-2012-6702-and-CVE-2016-5300.patch b/gnu/packages/patches/expat-CVE-2012-6702-and-CVE-2016-5300.patch
deleted file mode 100644
index edc43f8..0000000
--- a/gnu/packages/patches/expat-CVE-2012-6702-and-CVE-2016-5300.patch
+++ /dev/null
@@ -1,142 +0,0 @@ 
-Fix CVE-2012-6702 and CVE-2016-5300.
-
-https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-6702
-https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-5300
-
-Patch copied from:
-https://sources.debian.net/src/expat/2.1.0-6%2Bdeb8u3/debian/patches/cve-2012-6702-plus-cve-2016-5300-v1.patch/
-
-From cb31522769d11a375078a073cba94e7176cb48a4 Mon Sep 17 00:00:00 2001
-From: Sebastian Pipping <sebastian@pipping.org>
-Date: Wed, 16 Mar 2016 15:30:12 +0100
-Subject: [PATCH] Resolve call to srand, use more entropy (patch version 1.0)
-
-Squashed backport against vanilla Expat 2.1.1, addressing:
-* CVE-2012-6702 -- unanticipated internal calls to srand
-* CVE-2016-5300 -- use of too little entropy
-
-Since commit e3e81a6d9f0885ea02d3979151c358f314bf3d6d
-(released with Expat 2.1.0) Expat called srand by itself
-from inside generate_hash_secret_salt for an instance
-of XML_Parser if XML_SetHashSalt was either (a) not called
-for that instance or if (b) salt 0 was passed to XML_SetHashSalt
-prior to parsing.  That call to srand passed (rather litle)
-entropy extracted from the current time as a seed for srand.
-
-That call to srand (1) broke repeatability for code calling
-srand with a non-random seed prior to parsing with Expat,
-and (2) resulted in a rather small set of hashing salts in
-Expat in total.
-
-For a short- to mid-term fix, the new approach avoids calling
-srand altogether, extracts more entropy out of the clock and
-other sources, too.
-
-For a long term fix, we may want to read sizeof(long) bytes
-from a source like getrandom(..) on Linux, and from similar
-sources on other supported architectures.
-
-https://bugzilla.redhat.com/show_bug.cgi?id=1197087
----
- CMakeLists.txt |  3 +++
- lib/xmlparse.c | 48 +++++++++++++++++++++++++++++++++++++++++-------
- 2 files changed, 44 insertions(+), 7 deletions(-)
-
-diff --git a/CMakeLists.txt b/CMakeLists.txt
-index 353627e..524d514 100755
---- a/CMakeLists.txt
-+++ b/CMakeLists.txt
-@@ -41,6 +41,9 @@ include_directories(${CMAKE_BINARY_DIR} ${CMAKE_SOURCE_DIR}/lib)
- if(MSVC)

-     add_definitions(-D_CRT_SECURE_NO_WARNINGS -wd4996)

- endif(MSVC)

-+if(WIN32)

-+    add_definitions(-DCOMPILED_FROM_DSP)

-+endif(WIN32)

- 

- set(expat_SRCS

-     lib/xmlparse.c

-diff --git a/lib/xmlparse.c b/lib/xmlparse.c
-index e308c79..c5f942f 100644
---- a/lib/xmlparse.c
-+++ b/lib/xmlparse.c
-@@ -6,7 +6,14 @@
- #include <string.h>                     /* memset(), memcpy() */
- #include <assert.h>
- #include <limits.h>                     /* UINT_MAX */
--#include <time.h>                       /* time() */
-+
-+#ifdef COMPILED_FROM_DSP
-+#define getpid GetCurrentProcessId
-+#else
-+#include <sys/time.h>                   /* gettimeofday() */
-+#include <sys/types.h>                  /* getpid() */
-+#include <unistd.h>                     /* getpid() */
-+#endif
- 
- #define XML_BUILDING_EXPAT 1
- 
-@@ -432,7 +439,7 @@ static ELEMENT_TYPE *
- getElementType(XML_Parser parser, const ENCODING *enc,
-                const char *ptr, const char *end);
- 
--static unsigned long generate_hash_secret_salt(void);
-+static unsigned long generate_hash_secret_salt(XML_Parser parser);
- static XML_Bool startParsing(XML_Parser parser);
- 
- static XML_Parser
-@@ -691,11 +698,38 @@ static const XML_Char implicitContext[] = {
- };
- 
- static unsigned long
--generate_hash_secret_salt(void)
-+gather_time_entropy(void)
- {
--  unsigned int seed = time(NULL) % UINT_MAX;
--  srand(seed);
--  return rand();
-+#ifdef COMPILED_FROM_DSP
-+  FILETIME ft;
-+  GetSystemTimeAsFileTime(&ft); /* never fails */
-+  return ft.dwHighDateTime ^ ft.dwLowDateTime;
-+#else
-+  struct timeval tv;
-+  int gettimeofday_res;
-+
-+  gettimeofday_res = gettimeofday(&tv, NULL);
-+  assert (gettimeofday_res == 0);
-+
-+  /* Microseconds time is <20 bits entropy */
-+  return tv.tv_usec;
-+#endif
-+}
-+
-+static unsigned long
-+generate_hash_secret_salt(XML_Parser parser)
-+{
-+  /* Process ID is 0 bits entropy if attacker has local access
-+   * XML_Parser address is few bits of entropy if attacker has local access */
-+  const unsigned long entropy =
-+      gather_time_entropy() ^ getpid() ^ (unsigned long)parser;
-+
-+  /* Factors are 2^31-1 and 2^61-1 (Mersenne primes M31 and M61) */
-+  if (sizeof(unsigned long) == 4) {
-+    return entropy * 2147483647;
-+  } else {
-+    return entropy * 2305843009213693951;
-+  }
- }
- 
- static XML_Bool  /* only valid for root parser */
-@@ -703,7 +737,7 @@ startParsing(XML_Parser parser)
- {
-     /* hash functions must be initialized before setContext() is called */
-     if (hash_secret_salt == 0)
--      hash_secret_salt = generate_hash_secret_salt();
-+      hash_secret_salt = generate_hash_secret_salt(parser);
-     if (ns) {
-       /* implicit context only set for root parser, since child
-          parsers (i.e. external entity parsers) will inherit it
--- 
-2.8.2
-
diff --git a/gnu/packages/patches/expat-CVE-2015-1283-refix.patch b/gnu/packages/patches/expat-CVE-2015-1283-refix.patch
deleted file mode 100644
index fc8d629..0000000
--- a/gnu/packages/patches/expat-CVE-2015-1283-refix.patch
+++ /dev/null
@@ -1,39 +0,0 @@ 
-Follow-up upstream fix for CVE-2015-1283 to not rely on undefined
-behavior.
-
-Adapted from a patch from Debian (found in Debian package version
-2.1.0-6+deb8u2) to apply to upstream code:
-
-https://sources.debian.net/src/expat/2.1.0-6%2Bdeb8u2/debian/patches/CVE-2015-1283-refix.patch/
-
----
- lib/xmlparse.c | 6 ++++--
- 1 file changed, 4 insertions(+), 2 deletions(-)
-
-diff --git a/lib/xmlparse.c b/lib/xmlparse.c
-index 0f6f4cd..5c70c17 100644
---- a/lib/xmlparse.c
-+++ b/lib/xmlparse.c
-@@ -1727,7 +1727,8 @@ XML_GetBuffer(XML_Parser parser, int len)
-   }
- 
-   if (len > bufferLim - bufferEnd) {
--    int neededSize = len + (int)(bufferEnd - bufferPtr);
-+    /* Do not invoke signed arithmetic overflow: */
-+    int neededSize = (int) ((unsigned)len + (unsigned)(bufferEnd - bufferPtr));
-     if (neededSize < 0) {
-       errorCode = XML_ERROR_NO_MEMORY;
-       return NULL;
-@@ -1759,7 +1760,8 @@ XML_GetBuffer(XML_Parser parser, int len)
-       if (bufferSize == 0)
-         bufferSize = INIT_BUFFER_SIZE;
-       do {
--        bufferSize *= 2;
-+        /* Do not invoke signed arithmetic overflow: */
-+        bufferSize = (int) (2U * (unsigned) bufferSize);
-       } while (bufferSize < neededSize && bufferSize > 0);
-       if (bufferSize <= 0) {
-         errorCode = XML_ERROR_NO_MEMORY;
--- 
-2.8.3
-
diff --git a/gnu/packages/patches/expat-CVE-2016-0718-fix-regression.patch b/gnu/packages/patches/expat-CVE-2016-0718-fix-regression.patch
new file mode 100644
index 0000000..b489401
--- /dev/null
+++ b/gnu/packages/patches/expat-CVE-2016-0718-fix-regression.patch
@@ -0,0 +1,35 @@ 
+Fix regression caused by fix for CVE-2016-0718 when building with -DXML_UNICODE.
+
+Discussion:
+
+https://sourceforge.net/p/expat/bugs/539/
+
+Patch copied from upstream source repository:
+
+https://sourceforge.net/p/expat/code_git/ci/af507cef2c93cb8d40062a0abe43a4f4e9158fb2/
+
+From af507cef2c93cb8d40062a0abe43a4f4e9158fb2 Mon Sep 17 00:00:00 2001
+From: Sebastian Pipping <sebastian@pipping.org>
+Date: Sun, 17 Jul 2016 20:22:29 +0200
+Subject: [PATCH 1/2] Fix regression bug #539 (needs -DXML_UNICODE)
+
+Thanks to Andy Wang and Karl Waclawek!
+---
+ expat/lib/xmlparse.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/expat/lib/xmlparse.c b/expat/lib/xmlparse.c
+index b308e67..0d5dd7b 100644
+--- a/lib/xmlparse.c
++++ b/lib/xmlparse.c
+@@ -2468,7 +2468,7 @@ doContent(XML_Parser parser,
+                        &fromPtr, rawNameEnd,
+                        (ICHAR **)&toPtr, (ICHAR *)tag->bufEnd - 1);
+             convLen = (int)(toPtr - (XML_Char *)tag->buf);
+-            if ((convert_res == XML_CONVERT_COMPLETED) || (convert_res == XML_CONVERT_INPUT_INCOMPLETE)) {
++            if ((fromPtr >= rawNameEnd) || (convert_res == XML_CONVERT_INPUT_INCOMPLETE)) {
+               tag->name.strLen = convLen;
+               break;
+             }
+-- 
+2.10.0
diff --git a/gnu/packages/patches/expat-CVE-2016-0718.patch b/gnu/packages/patches/expat-CVE-2016-0718.patch
deleted file mode 100644
index 22436c2..0000000
--- a/gnu/packages/patches/expat-CVE-2016-0718.patch
+++ /dev/null
@@ -1,761 +0,0 @@ 
-Fix CVE-2016-0718.
-
-Copied from Debian, as found in Debian package version 2.1.0-6+deb8u2.
-
-https://sources.debian.net/src/expat/2.1.0-6%2Bdeb8u2/debian/patches/CVE-2016-0718-v2-2-1.patch/
-
-From cdfcb1b5c95e93b00ae9e9d25708b4a3bee72c15 Mon Sep 17 00:00:00 2001
-From: Sebastian Pipping <sebastian@pipping.org>
-Date: Mon, 2 May 2016 00:02:44 +0200
-Subject: [PATCH] Address CVE-2016-0718 (/patch/ version 2.2.1)
-
-* Out of bounds memory access when doing text conversion on malformed input
-* Integer overflow related to memory allocation
-
-Reported by Gustavo Grieco
-
-Patch credits go to
-* Christian Heimes
-* Karl Waclawek
-* Gustavo Grieco
-* Sebastian Pipping
-* Pascal Cuoq
----
- expat/lib/xmlparse.c    |  34 +++++++++-----
- expat/lib/xmltok.c      | 115 +++++++++++++++++++++++++++++++++++-------------
- expat/lib/xmltok.h      |  10 ++++-
- expat/lib/xmltok_impl.c |  62 +++++++++++++-------------
- 4 files changed, 146 insertions(+), 75 deletions(-)
-
-diff --git a/lib/xmlparse.c b/lib/xmlparse.c
-index e308c79..13e080d 100644
---- a/lib/xmlparse.c
-+++ b/lib/xmlparse.c
-@@ -2436,11 +2436,11 @@ doContent(XML_Parser parser,
-           for (;;) {
-             int bufSize;
-             int convLen;
--            XmlConvert(enc,
-+            const enum XML_Convert_Result convert_res = XmlConvert(enc,
-                        &fromPtr, rawNameEnd,
-                        (ICHAR **)&toPtr, (ICHAR *)tag->bufEnd - 1);
-             convLen = (int)(toPtr - (XML_Char *)tag->buf);
--            if (fromPtr == rawNameEnd) {
-+            if ((convert_res == XML_CONVERT_COMPLETED) || (convert_res == XML_CONVERT_INPUT_INCOMPLETE)) {
-               tag->name.strLen = convLen;
-               break;
-             }
-@@ -2661,11 +2661,11 @@ doContent(XML_Parser parser,
-           if (MUST_CONVERT(enc, s)) {
-             for (;;) {
-               ICHAR *dataPtr = (ICHAR *)dataBuf;
--              XmlConvert(enc, &s, next, &dataPtr, (ICHAR *)dataBufEnd);
-+              const enum XML_Convert_Result convert_res = XmlConvert(enc, &s, next, &dataPtr, (ICHAR *)dataBufEnd);
-               *eventEndPP = s;
-               charDataHandler(handlerArg, dataBuf,
-                               (int)(dataPtr - (ICHAR *)dataBuf));
--              if (s == next)
-+              if ((convert_res == XML_CONVERT_COMPLETED) || (convert_res == XML_CONVERT_INPUT_INCOMPLETE))
-                 break;
-               *eventPP = s;
-             }
-@@ -3269,11 +3269,11 @@ doCdataSection(XML_Parser parser,
-           if (MUST_CONVERT(enc, s)) {
-             for (;;) {
-               ICHAR *dataPtr = (ICHAR *)dataBuf;
--              XmlConvert(enc, &s, next, &dataPtr, (ICHAR *)dataBufEnd);
-+              const enum XML_Convert_Result convert_res = XmlConvert(enc, &s, next, &dataPtr, (ICHAR *)dataBufEnd);
-               *eventEndPP = next;
-               charDataHandler(handlerArg, dataBuf,
-                               (int)(dataPtr - (ICHAR *)dataBuf));
--              if (s == next)
-+              if ((convert_res == XML_CONVERT_COMPLETED) || (convert_res == XML_CONVERT_INPUT_INCOMPLETE))
-                 break;
-               *eventPP = s;
-             }
-@@ -5350,6 +5350,7 @@ reportDefault(XML_Parser parser, const ENCODING *enc,
-               const char *s, const char *end)
- {
-   if (MUST_CONVERT(enc, s)) {
-+    enum XML_Convert_Result convert_res;
-     const char **eventPP;
-     const char **eventEndPP;
-     if (enc == encoding) {
-@@ -5362,11 +5363,11 @@ reportDefault(XML_Parser parser, const ENCODING *enc,
-     }
-     do {
-       ICHAR *dataPtr = (ICHAR *)dataBuf;
--      XmlConvert(enc, &s, end, &dataPtr, (ICHAR *)dataBufEnd);
-+      convert_res = XmlConvert(enc, &s, end, &dataPtr, (ICHAR *)dataBufEnd);
-       *eventEndPP = s;
-       defaultHandler(handlerArg, dataBuf, (int)(dataPtr - (ICHAR *)dataBuf));
-       *eventPP = s;
--    } while (s != end);
-+    } while ((convert_res != XML_CONVERT_COMPLETED) && (convert_res != XML_CONVERT_INPUT_INCOMPLETE));
-   }
-   else
-     defaultHandler(handlerArg, (XML_Char *)s, (int)((XML_Char *)end - (XML_Char *)s));
-@@ -6169,8 +6170,8 @@ poolAppend(STRING_POOL *pool, const ENCODING *enc,
-   if (!pool->ptr && !poolGrow(pool))
-     return NULL;
-   for (;;) {
--    XmlConvert(enc, &ptr, end, (ICHAR **)&(pool->ptr), (ICHAR *)pool->end);
--    if (ptr == end)
-+    const enum XML_Convert_Result convert_res = XmlConvert(enc, &ptr, end, (ICHAR **)&(pool->ptr), (ICHAR *)pool->end);
-+    if ((convert_res == XML_CONVERT_COMPLETED) || (convert_res == XML_CONVERT_INPUT_INCOMPLETE))
-       break;
-     if (!poolGrow(pool))
-       return NULL;
-@@ -6254,8 +6255,13 @@ poolGrow(STRING_POOL *pool)
-     }
-   }
-   if (pool->blocks && pool->start == pool->blocks->s) {
--    int blockSize = (int)(pool->end - pool->start)*2;
--    BLOCK *temp = (BLOCK *)
-+    BLOCK *temp;
-+    int blockSize = (int)((unsigned)(pool->end - pool->start)*2U);
-+
-+    if (blockSize < 0)
-+      return XML_FALSE;
-+
-+    temp = (BLOCK *)
-       pool->mem->realloc_fcn(pool->blocks,
-                              (offsetof(BLOCK, s)
-                               + blockSize * sizeof(XML_Char)));
-@@ -6270,6 +6276,10 @@ poolGrow(STRING_POOL *pool)
-   else {
-     BLOCK *tem;
-     int blockSize = (int)(pool->end - pool->start);
-+
-+    if (blockSize < 0)
-+      return XML_FALSE;
-+
-     if (blockSize < INIT_BLOCK_SIZE)
-       blockSize = INIT_BLOCK_SIZE;
-     else
-diff --git a/lib/xmltok.c b/lib/xmltok.c
-index bf09dfc..cb98ce1 100644
---- a/lib/xmltok.c
-+++ b/lib/xmltok.c
-@@ -318,39 +318,55 @@ enum {  /* UTF8_cvalN is value of masked first byte of N byte sequence */
-   UTF8_cval4 = 0xf0
- };
- 
--static void PTRCALL
-+static enum XML_Convert_Result PTRCALL
- utf8_toUtf8(const ENCODING *enc,
-             const char **fromP, const char *fromLim,
-             char **toP, const char *toLim)
- {
-+  enum XML_Convert_Result res = XML_CONVERT_COMPLETED;
-   char *to;
-   const char *from;
-   if (fromLim - *fromP > toLim - *toP) {
-     /* Avoid copying partial characters. */
-+    res = XML_CONVERT_OUTPUT_EXHAUSTED;
-     for (fromLim = *fromP + (toLim - *toP); fromLim > *fromP; fromLim--)
-       if (((unsigned char)fromLim[-1] & 0xc0) != 0x80)
-         break;
-   }
--  for (to = *toP, from = *fromP; from != fromLim; from++, to++)
-+  for (to = *toP, from = *fromP; (from < fromLim) && (to < toLim); from++, to++)
-     *to = *from;
-   *fromP = from;
-   *toP = to;
-+
-+  if ((to == toLim) && (from < fromLim))
-+    return XML_CONVERT_OUTPUT_EXHAUSTED;
-+  else
-+    return res;
- }
- 
--static void PTRCALL
-+static enum XML_Convert_Result PTRCALL
- utf8_toUtf16(const ENCODING *enc,
-              const char **fromP, const char *fromLim,
-              unsigned short **toP, const unsigned short *toLim)
- {
-+  enum XML_Convert_Result res = XML_CONVERT_COMPLETED;
-   unsigned short *to = *toP;
-   const char *from = *fromP;
--  while (from != fromLim && to != toLim) {
-+  while (from < fromLim && to < toLim) {
-     switch (((struct normal_encoding *)enc)->type[(unsigned char)*from]) {
-     case BT_LEAD2:
-+      if (fromLim - from < 2) {
-+        res = XML_CONVERT_INPUT_INCOMPLETE;
-+        break;
-+      }
-       *to++ = (unsigned short)(((from[0] & 0x1f) << 6) | (from[1] & 0x3f));
-       from += 2;
-       break;
-     case BT_LEAD3:
-+      if (fromLim - from < 3) {
-+        res = XML_CONVERT_INPUT_INCOMPLETE;
-+        break;
-+      }
-       *to++ = (unsigned short)(((from[0] & 0xf) << 12)
-                                | ((from[1] & 0x3f) << 6) | (from[2] & 0x3f));
-       from += 3;
-@@ -358,8 +374,14 @@ utf8_toUtf16(const ENCODING *enc,
-     case BT_LEAD4:
-       {
-         unsigned long n;
--        if (to + 1 == toLim)
-+        if (toLim - to < 2) {
-+          res = XML_CONVERT_OUTPUT_EXHAUSTED;
-           goto after;
-+        }
-+        if (fromLim - from < 4) {
-+          res = XML_CONVERT_INPUT_INCOMPLETE;
-+          goto after;
-+        }
-         n = ((from[0] & 0x7) << 18) | ((from[1] & 0x3f) << 12)
-             | ((from[2] & 0x3f) << 6) | (from[3] & 0x3f);
-         n -= 0x10000;
-@@ -377,6 +399,7 @@ utf8_toUtf16(const ENCODING *enc,
- after:
-   *fromP = from;
-   *toP = to;
-+  return res;
- }
- 
- #ifdef XML_NS
-@@ -425,7 +448,7 @@ static const struct normal_encoding internal_utf8_encoding = {
-   STANDARD_VTABLE(sb_) NORMAL_VTABLE(utf8_)
- };
- 
--static void PTRCALL
-+static enum XML_Convert_Result PTRCALL
- latin1_toUtf8(const ENCODING *enc,
-               const char **fromP, const char *fromLim,
-               char **toP, const char *toLim)
-@@ -433,30 +456,35 @@ latin1_toUtf8(const ENCODING *enc,
-   for (;;) {
-     unsigned char c;
-     if (*fromP == fromLim)
--      break;
-+      return XML_CONVERT_COMPLETED;
-     c = (unsigned char)**fromP;
-     if (c & 0x80) {
-       if (toLim - *toP < 2)
--        break;
-+        return XML_CONVERT_OUTPUT_EXHAUSTED;
-       *(*toP)++ = (char)((c >> 6) | UTF8_cval2);
-       *(*toP)++ = (char)((c & 0x3f) | 0x80);
-       (*fromP)++;
-     }
-     else {
-       if (*toP == toLim)
--        break;
-+        return XML_CONVERT_OUTPUT_EXHAUSTED;
-       *(*toP)++ = *(*fromP)++;
-     }
-   }
- }
- 
--static void PTRCALL
-+static enum XML_Convert_Result PTRCALL
- latin1_toUtf16(const ENCODING *enc,
-                const char **fromP, const char *fromLim,
-                unsigned short **toP, const unsigned short *toLim)
- {
--  while (*fromP != fromLim && *toP != toLim)
-+  while (*fromP < fromLim && *toP < toLim)
-     *(*toP)++ = (unsigned char)*(*fromP)++;
-+
-+  if ((*toP == toLim) && (*fromP < fromLim))
-+    return XML_CONVERT_OUTPUT_EXHAUSTED;
-+  else
-+    return XML_CONVERT_COMPLETED;
- }
- 
- #ifdef XML_NS
-@@ -483,13 +511,18 @@ static const struct normal_encoding latin1_encoding = {
-   STANDARD_VTABLE(sb_)
- };
- 
--static void PTRCALL
-+static enum XML_Convert_Result PTRCALL
- ascii_toUtf8(const ENCODING *enc,
-              const char **fromP, const char *fromLim,
-              char **toP, const char *toLim)
- {
--  while (*fromP != fromLim && *toP != toLim)
-+  while (*fromP < fromLim && *toP < toLim)
-     *(*toP)++ = *(*fromP)++;
-+
-+  if ((*toP == toLim) && (*fromP < fromLim))
-+    return XML_CONVERT_OUTPUT_EXHAUSTED;
-+  else
-+    return XML_CONVERT_COMPLETED;
- }
- 
- #ifdef XML_NS
-@@ -536,13 +569,14 @@ unicode_byte_type(char hi, char lo)
- }
- 
- #define DEFINE_UTF16_TO_UTF8(E) \
--static void  PTRCALL \
-+static enum XML_Convert_Result  PTRCALL \
- E ## toUtf8(const ENCODING *enc, \
-             const char **fromP, const char *fromLim, \
-             char **toP, const char *toLim) \
- { \
--  const char *from; \
--  for (from = *fromP; from != fromLim; from += 2) { \
-+  const char *from = *fromP; \
-+  fromLim = from + (((fromLim - from) >> 1) << 1);  /* shrink to even */ \
-+  for (; from < fromLim; from += 2) { \
-     int plane; \
-     unsigned char lo2; \
-     unsigned char lo = GET_LO(from); \
-@@ -552,7 +586,7 @@ E ## toUtf8(const ENCODING *enc, \
-       if (lo < 0x80) { \
-         if (*toP == toLim) { \
-           *fromP = from; \
--          return; \
-+          return XML_CONVERT_OUTPUT_EXHAUSTED; \
-         } \
-         *(*toP)++ = lo; \
-         break; \
-@@ -562,7 +596,7 @@ E ## toUtf8(const ENCODING *enc, \
-     case 0x4: case 0x5: case 0x6: case 0x7: \
-       if (toLim -  *toP < 2) { \
-         *fromP = from; \
--        return; \
-+        return XML_CONVERT_OUTPUT_EXHAUSTED; \
-       } \
-       *(*toP)++ = ((lo >> 6) | (hi << 2) |  UTF8_cval2); \
-       *(*toP)++ = ((lo & 0x3f) | 0x80); \
-@@ -570,7 +604,7 @@ E ## toUtf8(const ENCODING *enc, \
-     default: \
-       if (toLim -  *toP < 3)  { \
-         *fromP = from; \
--        return; \
-+        return XML_CONVERT_OUTPUT_EXHAUSTED; \
-       } \
-       /* 16 bits divided 4, 6, 6 amongst 3 bytes */ \
-       *(*toP)++ = ((hi >> 4) | UTF8_cval3); \
-@@ -580,7 +614,11 @@ E ## toUtf8(const ENCODING *enc, \
-     case 0xD8: case 0xD9: case 0xDA: case 0xDB: \
-       if (toLim -  *toP < 4) { \
-         *fromP = from; \
--        return; \
-+        return XML_CONVERT_OUTPUT_EXHAUSTED; \
-+      } \
-+      if (fromLim - from < 4) { \
-+        *fromP = from; \
-+        return XML_CONVERT_INPUT_INCOMPLETE; \
-       } \
-       plane = (((hi & 0x3) << 2) | ((lo >> 6) & 0x3)) + 1; \
-       *(*toP)++ = ((plane >> 2) | UTF8_cval4); \
-@@ -596,20 +634,32 @@ E ## toUtf8(const ENCODING *enc, \
-     } \
-   } \
-   *fromP = from; \
-+  if (from < fromLim) \
-+    return XML_CONVERT_INPUT_INCOMPLETE; \
-+  else \
-+    return XML_CONVERT_COMPLETED; \
- }
- 
- #define DEFINE_UTF16_TO_UTF16(E) \
--static void  PTRCALL \
-+static enum XML_Convert_Result  PTRCALL \
- E ## toUtf16(const ENCODING *enc, \
-              const char **fromP, const char *fromLim, \
-              unsigned short **toP, const unsigned short *toLim) \
- { \
-+  enum XML_Convert_Result res = XML_CONVERT_COMPLETED; \
-+  fromLim = *fromP + (((fromLim - *fromP) >> 1) << 1);  /* shrink to even */ \
-   /* Avoid copying first half only of surrogate */ \
-   if (fromLim - *fromP > ((toLim - *toP) << 1) \
--      && (GET_HI(fromLim - 2) & 0xF8) == 0xD8) \
-+      && (GET_HI(fromLim - 2) & 0xF8) == 0xD8) { \
-     fromLim -= 2; \
--  for (; *fromP != fromLim && *toP != toLim; *fromP += 2) \
-+    res = XML_CONVERT_INPUT_INCOMPLETE; \
-+  } \
-+  for (; *fromP < fromLim && *toP < toLim; *fromP += 2) \
-     *(*toP)++ = (GET_HI(*fromP) << 8) | GET_LO(*fromP); \
-+  if ((*toP == toLim) && (*fromP < fromLim)) \
-+    return XML_CONVERT_OUTPUT_EXHAUSTED; \
-+  else \
-+    return res; \
- }
- 
- #define SET2(ptr, ch) \
-@@ -1288,7 +1338,7 @@ unknown_isInvalid(const ENCODING *enc, const char *p)
-   return (c & ~0xFFFF) || checkCharRefNumber(c) < 0;
- }
- 
--static void PTRCALL
-+static enum XML_Convert_Result PTRCALL
- unknown_toUtf8(const ENCODING *enc,
-                const char **fromP, const char *fromLim,
-                char **toP, const char *toLim)
-@@ -1299,21 +1349,21 @@ unknown_toUtf8(const ENCODING *enc,
-     const char *utf8;
-     int n;
-     if (*fromP == fromLim)
--      break;
-+      return XML_CONVERT_COMPLETED;
-     utf8 = uenc->utf8[(unsigned char)**fromP];
-     n = *utf8++;
-     if (n == 0) {
-       int c = uenc->convert(uenc->userData, *fromP);
-       n = XmlUtf8Encode(c, buf);
-       if (n > toLim - *toP)
--        break;
-+        return XML_CONVERT_OUTPUT_EXHAUSTED;
-       utf8 = buf;
-       *fromP += (AS_NORMAL_ENCODING(enc)->type[(unsigned char)**fromP]
-                  - (BT_LEAD2 - 2));
-     }
-     else {
-       if (n > toLim - *toP)
--        break;
-+        return XML_CONVERT_OUTPUT_EXHAUSTED;
-       (*fromP)++;
-     }
-     do {
-@@ -1322,13 +1372,13 @@ unknown_toUtf8(const ENCODING *enc,
-   }
- }
- 
--static void PTRCALL
-+static enum XML_Convert_Result PTRCALL
- unknown_toUtf16(const ENCODING *enc,
-                 const char **fromP, const char *fromLim,
-                 unsigned short **toP, const unsigned short *toLim)
- {
-   const struct unknown_encoding *uenc = AS_UNKNOWN_ENCODING(enc);
--  while (*fromP != fromLim && *toP != toLim) {
-+  while (*fromP < fromLim && *toP < toLim) {
-     unsigned short c = uenc->utf16[(unsigned char)**fromP];
-     if (c == 0) {
-       c = (unsigned short)
-@@ -1340,6 +1390,11 @@ unknown_toUtf16(const ENCODING *enc,
-       (*fromP)++;
-     *(*toP)++ = c;
-   }
-+
-+  if ((*toP == toLim) && (*fromP < fromLim))
-+    return XML_CONVERT_OUTPUT_EXHAUSTED;
-+  else
-+    return XML_CONVERT_COMPLETED;
- }
- 
- ENCODING *
-@@ -1503,7 +1558,7 @@ initScan(const ENCODING * const *encodingTable,
- {
-   const ENCODING **encPtr;
- 
--  if (ptr == end)
-+  if (ptr >= end)
-     return XML_TOK_NONE;
-   encPtr = enc->encPtr;
-   if (ptr + 1 == end) {
-diff --git a/lib/xmltok.h b/lib/xmltok.h
-index ca867aa..752007e 100644
---- a/lib/xmltok.h
-+++ b/lib/xmltok.h
-@@ -130,6 +130,12 @@ typedef int (PTRCALL *SCANNER)(const ENCODING *,
-                                const char *,
-                                const char **);
- 
-+enum XML_Convert_Result {
-+  XML_CONVERT_COMPLETED = 0,
-+  XML_CONVERT_INPUT_INCOMPLETE = 1,
-+  XML_CONVERT_OUTPUT_EXHAUSTED = 2  /* and therefore potentially input remaining as well */
-+};
-+
- struct encoding {
-   SCANNER scanners[XML_N_STATES];
-   SCANNER literalScanners[XML_N_LITERAL_TYPES];
-@@ -158,12 +164,12 @@ struct encoding {
-                             const char *ptr,
-                             const char *end,
-                             const char **badPtr);
--  void (PTRCALL *utf8Convert)(const ENCODING *enc,
-+  enum XML_Convert_Result (PTRCALL *utf8Convert)(const ENCODING *enc,
-                               const char **fromP,
-                               const char *fromLim,
-                               char **toP,
-                               const char *toLim);
--  void (PTRCALL *utf16Convert)(const ENCODING *enc,
-+  enum XML_Convert_Result (PTRCALL *utf16Convert)(const ENCODING *enc,
-                                const char **fromP,
-                                const char *fromLim,
-                                unsigned short **toP,
-diff --git a/lib/xmltok_impl.c b/lib/xmltok_impl.c
-index 9c2895b..6c5a3ba 100644
---- a/lib/xmltok_impl.c
-+++ b/lib/xmltok_impl.c
-@@ -93,13 +93,13 @@ static int PTRCALL
- PREFIX(scanComment)(const ENCODING *enc, const char *ptr,
-                     const char *end, const char **nextTokPtr)
- {
--  if (ptr != end) {
-+  if (ptr < end) {
-     if (!CHAR_MATCHES(enc, ptr, ASCII_MINUS)) {
-       *nextTokPtr = ptr;
-       return XML_TOK_INVALID;
-     }
-     ptr += MINBPC(enc);
--    while (ptr != end) {
-+    while (ptr < end) {
-       switch (BYTE_TYPE(enc, ptr)) {
-       INVALID_CASES(ptr, nextTokPtr)
-       case BT_MINUS:
-@@ -147,7 +147,7 @@ PREFIX(scanDecl)(const ENCODING *enc, const char *ptr,
-     *nextTokPtr = ptr;
-     return XML_TOK_INVALID;
-   }
--  while (ptr != end) {
-+  while (ptr < end) {
-     switch (BYTE_TYPE(enc, ptr)) {
-     case BT_PERCNT:
-       if (ptr + MINBPC(enc) == end)
-@@ -233,7 +233,7 @@ PREFIX(scanPi)(const ENCODING *enc, const char *ptr,
-     *nextTokPtr = ptr;
-     return XML_TOK_INVALID;
-   }
--  while (ptr != end) {
-+  while (ptr < end) {
-     switch (BYTE_TYPE(enc, ptr)) {
-     CHECK_NAME_CASES(enc, ptr, end, nextTokPtr)
-     case BT_S: case BT_CR: case BT_LF:
-@@ -242,7 +242,7 @@ PREFIX(scanPi)(const ENCODING *enc, const char *ptr,
-         return XML_TOK_INVALID;
-       }
-       ptr += MINBPC(enc);
--      while (ptr != end) {
-+      while (ptr < end) {
-         switch (BYTE_TYPE(enc, ptr)) {
-         INVALID_CASES(ptr, nextTokPtr)
-         case BT_QUEST:
-@@ -305,7 +305,7 @@ static int PTRCALL
- PREFIX(cdataSectionTok)(const ENCODING *enc, const char *ptr,
-                         const char *end, const char **nextTokPtr)
- {
--  if (ptr == end)
-+  if (ptr >= end)
-     return XML_TOK_NONE;
-   if (MINBPC(enc) > 1) {
-     size_t n = end - ptr;
-@@ -348,7 +348,7 @@ PREFIX(cdataSectionTok)(const ENCODING *enc, const char *ptr,
-     ptr += MINBPC(enc);
-     break;
-   }
--  while (ptr != end) {
-+  while (ptr < end) {
-     switch (BYTE_TYPE(enc, ptr)) {
- #define LEAD_CASE(n) \
-     case BT_LEAD ## n: \
-@@ -391,11 +391,11 @@ PREFIX(scanEndTag)(const ENCODING *enc, const char *ptr,
-     *nextTokPtr = ptr;
-     return XML_TOK_INVALID;
-   }
--  while (ptr != end) {
-+  while (ptr < end) {
-     switch (BYTE_TYPE(enc, ptr)) {
-     CHECK_NAME_CASES(enc, ptr, end, nextTokPtr)
-     case BT_S: case BT_CR: case BT_LF:
--      for (ptr += MINBPC(enc); ptr != end; ptr += MINBPC(enc)) {
-+      for (ptr += MINBPC(enc); ptr < end; ptr += MINBPC(enc)) {
-         switch (BYTE_TYPE(enc, ptr)) {
-         case BT_S: case BT_CR: case BT_LF:
-           break;
-@@ -432,7 +432,7 @@ static int PTRCALL
- PREFIX(scanHexCharRef)(const ENCODING *enc, const char *ptr,
-                        const char *end, const char **nextTokPtr)
- {
--  if (ptr != end) {
-+  if (ptr < end) {
-     switch (BYTE_TYPE(enc, ptr)) {
-     case BT_DIGIT:
-     case BT_HEX:
-@@ -441,7 +441,7 @@ PREFIX(scanHexCharRef)(const ENCODING *enc, const char *ptr,
-       *nextTokPtr = ptr;
-       return XML_TOK_INVALID;
-     }
--    for (ptr += MINBPC(enc); ptr != end; ptr += MINBPC(enc)) {
-+    for (ptr += MINBPC(enc); ptr < end; ptr += MINBPC(enc)) {
-       switch (BYTE_TYPE(enc, ptr)) {
-       case BT_DIGIT:
-       case BT_HEX:
-@@ -464,7 +464,7 @@ static int PTRCALL
- PREFIX(scanCharRef)(const ENCODING *enc, const char *ptr,
-                     const char *end, const char **nextTokPtr)
- {
--  if (ptr != end) {
-+  if (ptr < end) {
-     if (CHAR_MATCHES(enc, ptr, ASCII_x))
-       return PREFIX(scanHexCharRef)(enc, ptr + MINBPC(enc), end, nextTokPtr);
-     switch (BYTE_TYPE(enc, ptr)) {
-@@ -474,7 +474,7 @@ PREFIX(scanCharRef)(const ENCODING *enc, const char *ptr,
-       *nextTokPtr = ptr;
-       return XML_TOK_INVALID;
-     }
--    for (ptr += MINBPC(enc); ptr != end; ptr += MINBPC(enc)) {
-+    for (ptr += MINBPC(enc); ptr < end; ptr += MINBPC(enc)) {
-       switch (BYTE_TYPE(enc, ptr)) {
-       case BT_DIGIT:
-         break;
-@@ -506,7 +506,7 @@ PREFIX(scanRef)(const ENCODING *enc, const char *ptr, const char *end,
-     *nextTokPtr = ptr;
-     return XML_TOK_INVALID;
-   }
--  while (ptr != end) {
-+  while (ptr < end) {
-     switch (BYTE_TYPE(enc, ptr)) {
-     CHECK_NAME_CASES(enc, ptr, end, nextTokPtr)
-     case BT_SEMI:
-@@ -529,7 +529,7 @@ PREFIX(scanAtts)(const ENCODING *enc, const char *ptr, const char *end,
- #ifdef XML_NS
-   int hadColon = 0;
- #endif
--  while (ptr != end) {
-+  while (ptr < end) {
-     switch (BYTE_TYPE(enc, ptr)) {
-     CHECK_NAME_CASES(enc, ptr, end, nextTokPtr)
- #ifdef XML_NS
-@@ -716,7 +716,7 @@ PREFIX(scanLt)(const ENCODING *enc, const char *ptr, const char *end,
-   hadColon = 0;
- #endif
-   /* we have a start-tag */
--  while (ptr != end) {
-+  while (ptr < end) {
-     switch (BYTE_TYPE(enc, ptr)) {
-     CHECK_NAME_CASES(enc, ptr, end, nextTokPtr)
- #ifdef XML_NS
-@@ -740,7 +740,7 @@ PREFIX(scanLt)(const ENCODING *enc, const char *ptr, const char *end,
-     case BT_S: case BT_CR: case BT_LF:
-       {
-         ptr += MINBPC(enc);
--        while (ptr != end) {
-+        while (ptr < end) {
-           switch (BYTE_TYPE(enc, ptr)) {
-           CHECK_NMSTRT_CASES(enc, ptr, end, nextTokPtr)
-           case BT_GT:
-@@ -785,7 +785,7 @@ static int PTRCALL
- PREFIX(contentTok)(const ENCODING *enc, const char *ptr, const char *end,
-                    const char **nextTokPtr)
- {
--  if (ptr == end)
-+  if (ptr >= end)
-     return XML_TOK_NONE;
-   if (MINBPC(enc) > 1) {
-     size_t n = end - ptr;
-@@ -832,7 +832,7 @@ PREFIX(contentTok)(const ENCODING *enc, const char *ptr, const char *end,
-     ptr += MINBPC(enc);
-     break;
-   }
--  while (ptr != end) {
-+  while (ptr < end) {
-     switch (BYTE_TYPE(enc, ptr)) {
- #define LEAD_CASE(n) \
-     case BT_LEAD ## n: \
-@@ -895,7 +895,7 @@ PREFIX(scanPercent)(const ENCODING *enc, const char *ptr, const char *end,
-     *nextTokPtr = ptr;
-     return XML_TOK_INVALID;
-   }
--  while (ptr != end) {
-+  while (ptr < end) {
-     switch (BYTE_TYPE(enc, ptr)) {
-     CHECK_NAME_CASES(enc, ptr, end, nextTokPtr)
-     case BT_SEMI:
-@@ -921,7 +921,7 @@ PREFIX(scanPoundName)(const ENCODING *enc, const char *ptr, const char *end,
-     *nextTokPtr = ptr;
-     return XML_TOK_INVALID;
-   }
--  while (ptr != end) {
-+  while (ptr < end) {
-     switch (BYTE_TYPE(enc, ptr)) {
-     CHECK_NAME_CASES(enc, ptr, end, nextTokPtr)
-     case BT_CR: case BT_LF: case BT_S:
-@@ -941,7 +941,7 @@ PREFIX(scanLit)(int open, const ENCODING *enc,
-                 const char *ptr, const char *end,
-                 const char **nextTokPtr)
- {
--  while (ptr != end) {
-+  while (ptr < end) {
-     int t = BYTE_TYPE(enc, ptr);
-     switch (t) {
-     INVALID_CASES(ptr, nextTokPtr)
-@@ -973,7 +973,7 @@ PREFIX(prologTok)(const ENCODING *enc, const char *ptr, const char *end,
-                   const char **nextTokPtr)
- {
-   int tok;
--  if (ptr == end)
-+  if (ptr >= end)
-     return XML_TOK_NONE;
-   if (MINBPC(enc) > 1) {
-     size_t n = end - ptr;
-@@ -1141,7 +1141,7 @@ PREFIX(prologTok)(const ENCODING *enc, const char *ptr, const char *end,
-     *nextTokPtr = ptr;
-     return XML_TOK_INVALID;
-   }
--  while (ptr != end) {
-+  while (ptr < end) {
-     switch (BYTE_TYPE(enc, ptr)) {
-     CHECK_NAME_CASES(enc, ptr, end, nextTokPtr)
-     case BT_GT: case BT_RPAR: case BT_COMMA:
-@@ -1204,10 +1204,10 @@ PREFIX(attributeValueTok)(const ENCODING *enc, const char *ptr,
-                           const char *end, const char **nextTokPtr)
- {
-   const char *start;
--  if (ptr == end)
-+  if (ptr >= end)
-     return XML_TOK_NONE;
-   start = ptr;
--  while (ptr != end) {
-+  while (ptr < end) {
-     switch (BYTE_TYPE(enc, ptr)) {
- #define LEAD_CASE(n) \
-     case BT_LEAD ## n: ptr += n; break;
-@@ -1262,10 +1262,10 @@ PREFIX(entityValueTok)(const ENCODING *enc, const char *ptr,
-                        const char *end, const char **nextTokPtr)
- {
-   const char *start;
--  if (ptr == end)
-+  if (ptr >= end)
-     return XML_TOK_NONE;
-   start = ptr;
--  while (ptr != end) {
-+  while (ptr < end) {
-     switch (BYTE_TYPE(enc, ptr)) {
- #define LEAD_CASE(n) \
-     case BT_LEAD ## n: ptr += n; break;
-@@ -1326,7 +1326,7 @@ PREFIX(ignoreSectionTok)(const ENCODING *enc, const char *ptr,
-       end = ptr + n;
-     }
-   }
--  while (ptr != end) {
-+  while (ptr < end) {
-     switch (BYTE_TYPE(enc, ptr)) {
-     INVALID_CASES(ptr, nextTokPtr)
-     case BT_LT:
-@@ -1373,7 +1373,7 @@ PREFIX(isPublicId)(const ENCODING *enc, const char *ptr, const char *end,
- {
-   ptr += MINBPC(enc);
-   end -= MINBPC(enc);
--  for (; ptr != end; ptr += MINBPC(enc)) {
-+  for (; ptr < end; ptr += MINBPC(enc)) {
-     switch (BYTE_TYPE(enc, ptr)) {
-     case BT_DIGIT:
-     case BT_HEX:
-@@ -1760,7 +1760,7 @@ PREFIX(updatePosition)(const ENCODING *enc,
-     case BT_CR:
-       pos->lineNumber++;
-       ptr += MINBPC(enc);
--      if (ptr != end && BYTE_TYPE(enc, ptr) == BT_LF)
-+      if (ptr < end && BYTE_TYPE(enc, ptr) == BT_LF)
-         ptr += MINBPC(enc);
-       pos->columnNumber = (XML_Size)-1;
-       break;
--- 
-2.8.2
-
diff --git a/gnu/packages/xml.scm b/gnu/packages/xml.scm
index a478599..bafbf42 100644
--- a/gnu/packages/xml.scm
+++ b/gnu/packages/xml.scm
@@ -49,17 +49,16 @@ 
 (define-public expat
   (package
     (name "expat")
-    (version "2.1.1")
+    (version "2.2.0")
     (source (origin
              (method url-fetch)
              (uri (string-append "mirror://sourceforge/expat/expat/"
                                  version "/expat-" version ".tar.bz2"))
-             (patches (search-patches "expat-CVE-2012-6702-and-CVE-2016-5300.patch"
-                                      "expat-CVE-2015-1283-refix.patch"
-                                      "expat-CVE-2016-0718.patch"))
+             (patches
+               (search-patches "expat-CVE-2016-0718-fix-regression.patch"))
              (sha256
               (base32
-               "0ryyjgvy7jq0qb7a9mhc1giy3bzn56aiwrs8dpydqngplbjq9xdg"))))
+               "1zq4lnwjlw8s9mmachwfvfjf2x3lk24jm41746ykhdcvs7r0zrfr"))))
     (build-system gnu-build-system)
     (home-page "http://www.libexpat.org/")
     (synopsis "Stream-oriented XML parser library written in C")