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Revert "expat: fix CVE-2023-52425"

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This reverts commit 1bdcd10930a2998f6bbe56b3ba4c9b6c91203b39.

Causes ptest failures:

{'expat': ['test_accounting_precision',
           'test_return_ns_triplet',
           'test_column_number_after_parse',
           'test_default_current',
           'test_external_entity_values']}

(From OE-Core rev: 46fb46c0fff83da85f37a1ea705170a6d2039eff)

Signed-off-by: Steve Sakoman <steve@sakoman.com>
This commit is contained in:
Steve Sakoman
2024-04-10 06:00:20 -07:00
parent 71267466e9
commit ca3bb1f53e
13 changed files with 0 additions and 1132 deletions
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meta/recipes-core/expat/expat/CVE-2023-52425-0001.patch
-40
View File
@@ -1,40 +0,0 @@
From d5b02e96ab95d2a7ae0aea72d00054b9d036d76d Mon Sep 17 00:00:00 2001
From: Sebastian Pipping <sebastian@pipping.org>
Date: Thu, 9 Nov 2023 19:28:05 +0100
Subject: [PATCH] xmlwf: Document argument "-q"
Rebased-and-adapted-by: Snild Dolkow <snild@sony.com>
CVE: CVE-2023-52425
Upstream-Status: Backport [https://github.com/libexpat/libexpat/commit/d5b02e96ab95d2a7ae0aea72d00054b9d036d76d]
Signed-off-by: Meenali Gupta <meenali.gupta@windriver.com>
---
doc/xmlwf.xml | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/doc/xmlwf.xml b/doc/xmlwf.xml
index 9603abf..3d35393 100644
--- a/doc/xmlwf.xml
+++ b/doc/xmlwf.xml
@@ -313,6 +313,16 @@ supports both.
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><option>-q</option></term>
+ <listitem>
+ <para>
+ Disable reparse deferral, and allow quadratic parse runtime
+ on large tokens (default: reparse deferral enabled).
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry>
<term><option>-r</option></term>
<listitem>
--
2.40.0
meta/recipes-core/expat/expat/CVE-2023-52425-0002.patch
-87
View File
@@ -1,87 +0,0 @@
From 09fdf998e7cf3f8f9327e6602077791095aedd4d Mon Sep 17 00:00:00 2001
From: Sebastian Pipping <sebastian@pipping.org>
Date: Thu, 9 Nov 2023 19:14:14 +0100
Subject: [PATCH] xmlwf: Support disabling reparse deferral
Rebased-and-adapted-by: Snild Dolkow <snild@sony.com>
CVE: CVE-2023-52425
Upstream-Status: Backport [https://github.com/libexpat/libexpat/commit/09fdf998e7cf3f8f9327e6602077791095aedd4d]
Signed-off-by: Meenali Gupta <meenali.gupta@windriver.com>
---
xmlwf/xmlwf.c | 20 ++++++++++++++++++++
xmlwf/xmlwf_helpgen.py | 4 ++++
2 files changed, 24 insertions(+)
diff --git a/xmlwf/xmlwf.c b/xmlwf/xmlwf.c
index dd023a9..9a5441c 100644
--- a/xmlwf/xmlwf.c
+++ b/xmlwf/xmlwf.c
@@ -911,6 +911,9 @@ usage(const XML_Char *prog, int rc) {
T("billion laughs attack protection:\n")
T(" NOTE: If you ever need to increase these values for non-attack payload, please file a bug report.\n")
T("\n")
+ T("reparse deferral:\n")
+ T(" -q disable reparse deferral, and allow [q]uadratic parse runtime with large tokens\n")
+ T("\n")
T(" -a FACTOR set maximum tolerated [a]mplification factor (default: 100.0)\n")
T(" -b BYTES set number of output [b]ytes needed to activate (default: 8 MiB)\n")
T("\n")
@@ -967,6 +970,8 @@ tmain(int argc, XML_Char **argv) {
unsigned long long attackThresholdBytes;
XML_Bool attackThresholdGiven = XML_FALSE;
+ XML_Bool disableDeferral = XML_FALSE;
+
int exitCode = XMLWF_EXIT_SUCCESS;
enum XML_ParamEntityParsing paramEntityParsing
= XML_PARAM_ENTITY_PARSING_NEVER;
@@ -1091,6 +1096,11 @@ tmain(int argc, XML_Char **argv) {
#endif
break;
}
+ case T('q'): {
+ disableDeferral = XML_TRUE;
+ j++;
+ break;
+ }
case T('\0'):
if (j > 1) {
i++;
@@ -1136,6 +1146,16 @@ tmain(int argc, XML_Char **argv) {
#endif
}
+ if (disableDeferral) {
+ const XML_Bool success = XML_SetReparseDeferralEnabled(parser, XML_FALSE);
+ if (! success) {
+ // This prevents tperror(..) from reporting misleading "[..]: Success"
+ errno = EINVAL;
+ tperror(T("Failed to disable reparse deferral"));
+ exit(XMLWF_EXIT_INTERNAL_ERROR);
+ }
+ }
+
if (requireStandalone)
XML_SetNotStandaloneHandler(parser, notStandalone);
XML_SetParamEntityParsing(parser, paramEntityParsing);
diff --git a/xmlwf/xmlwf_helpgen.py b/xmlwf/xmlwf_helpgen.py
index c2a527f..1bd0a0a 100755
--- a/xmlwf/xmlwf_helpgen.py
+++ b/xmlwf/xmlwf_helpgen.py
@@ -81,6 +81,10 @@ billion_laughs.add_argument('-a', metavar='FACTOR',
help='set maximum tolerated [a]mplification factor (default: 100.0)')
billion_laughs.add_argument('-b', metavar='BYTES', help='set number of output [b]ytes needed to activate (default: 8 MiB)')
+reparse_deferral = parser.add_argument_group('reparse deferral')
+reparse_deferral.add_argument('-q', metavar='FACTOR',
+ help='disable reparse deferral, and allow [q]uadratic parse runtime with large tokens')
+
parser.add_argument('files', metavar='FILE', nargs='*', help='file to process (default: STDIN)')
info = parser.add_argument_group('info arguments')
--
2.40.0
meta/recipes-core/expat/expat/CVE-2023-52425-0003.patch
-222
View File
@@ -1,222 +0,0 @@
From 9cdf9b8d77d5c2c2a27d15fb68dd3f83cafb45a1 Mon Sep 17 00:00:00 2001
From: Snild Dolkow <snild@sony.com>
Date: Thu, 17 Aug 2023 16:25:26 +0200
Subject: [PATCH] Skip parsing after repeated partials on the same token When
the parse buffer contains the starting bytes of a token but not all of them,
we cannot parse the token to completion. We call this a partial token. When
this happens, the parse position is reset to the start of the token, and the
parse() call returns. The client is then expected to provide more data and
call parse() again.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
In extreme cases, this means that the bytes of a token may be parsed
many times: once for every buffer refill required before the full token
is present in the buffer.
Math:
Assume there's a token of T bytes
Assume the client fills the buffer in chunks of X bytes
We'll try to parse X, 2X, 3X, 4X ... until mX == T (technically >=)
That's (m²+m)X/2 = (T²/X+T)/2 bytes parsed (arithmetic progression)
While it is alleviated by larger refills, this amounts to O(T²)
Expat grows its internal buffer by doubling it when necessary, but has
no way to inform the client about how much space is available. Instead,
we add a heuristic that skips parsing when we've repeatedly stopped on
an incomplete token. Specifically:
* Only try to parse if we have a certain amount of data buffered
* Every time we stop on an incomplete token, double the threshold
* As soon as any token completes, the threshold is reset
This means that when we get stuck on an incomplete token, the threshold
grows exponentially, effectively making the client perform larger buffer
fills, limiting how many times we can end up re-parsing the same bytes.
Math:
Assume there's a token of T bytes
Assume the client fills the buffer in chunks of X bytes
We'll try to parse X, 2X, 4X, 8X ... until (2^k)X == T (or larger)
That's (2^(k+1)-1)X bytes parsed -- e.g. 15X if T = 8X
This is equal to 2T-X, which amounts to O(T)
We could've chosen a faster growth rate, e.g. 4 or 8. Those seem to
increase performance further, at the cost of further increasing the
risk of growing the buffer more than necessary. This can easily be
adjusted in the future, if desired.
This is all completely transparent to the client, except for:
1. possible delay of some callbacks (when our heuristic overshoots)
2. apps that never do isFinal=XML_TRUE could miss data at the end
For the affected testdata, this change shows a 100-400x speedup.
The recset.xml benchmark shows no clear change either way.
Before:
benchmark -n ../testdata/largefiles/recset.xml 65535 3
3 loops, with buffer size 65535. Average time per loop: 0.270223
benchmark -n ../testdata/largefiles/aaaaaa_attr.xml 4096 3
3 loops, with buffer size 4096. Average time per loop: 15.033048
benchmark -n ../testdata/largefiles/aaaaaa_cdata.xml 4096 3
3 loops, with buffer size 4096. Average time per loop: 0.018027
benchmark -n ../testdata/largefiles/aaaaaa_comment.xml 4096 3
3 loops, with buffer size 4096. Average time per loop: 11.775362
benchmark -n ../testdata/largefiles/aaaaaa_tag.xml 4096 3
3 loops, with buffer size 4096. Average time per loop: 11.711414
benchmark -n ../testdata/largefiles/aaaaaa_text.xml 4096 3
3 loops, with buffer size 4096. Average time per loop: 0.019362
After:
./run.sh benchmark -n ../testdata/largefiles/recset.xml 65535 3
3 loops, with buffer size 65535. Average time per loop: 0.269030
./run.sh benchmark -n ../testdata/largefiles/aaaaaa_attr.xml 4096 3
3 loops, with buffer size 4096. Average time per loop: 0.044794
./run.sh benchmark -n ../testdata/largefiles/aaaaaa_cdata.xml 4096 3
3 loops, with buffer size 4096. Average time per loop: 0.016377
./run.sh benchmark -n ../testdata/largefiles/aaaaaa_comment.xml 4096 3
3 loops, with buffer size 4096. Average time per loop: 0.027022
./run.sh benchmark -n ../testdata/largefiles/aaaaaa_tag.xml 4096 3
3 loops, with buffer size 4096. Average time per loop: 0.099360
./run.sh benchmark -n ../testdata/largefiles/aaaaaa_text.xml 4096 3
3 loops, with buffer size 4096. Average time per loop: 0.017956
CVE: CVE-2023-52425
Upstream-Status: Backport [https://github.com/libexpat/libexpat/commit/9cdf9b8d77d5c2c2a27d15fb68dd3f83cafb45a1]
Signed-off-by: Meenali Gupta <meenali.gupta@windriver.com>
---
lib/xmlparse.c | 58 +++++++++++++++++++++++++++++++++-----------------
1 file changed, 39 insertions(+), 19 deletions(-)
diff --git a/lib/xmlparse.c b/lib/xmlparse.c
index bbffcaa..5695417 100644
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -81,6 +81,7 @@
# endif
#endif
+#include <stdbool.h>
#include <stddef.h>
#include <string.h> /* memset(), memcpy() */
#include <assert.h>
@@ -629,6 +630,7 @@ struct XML_ParserStruct {
const char *m_bufferLim;
XML_Index m_parseEndByteIndex;
const char *m_parseEndPtr;
+ size_t m_partialTokenBytesBefore; /* used in heuristic to avoid O(n^2) */
XML_Char *m_dataBuf;
XML_Char *m_dataBufEnd;
XML_StartElementHandler m_startElementHandler;
@@ -960,6 +962,32 @@ get_hash_secret_salt(XML_Parser parser) {
return parser->m_hash_secret_salt;
}
+static enum XML_Error
+callProcessor(XML_Parser parser, const char *start, const char *end,
+ const char **endPtr) {
+ const size_t have_now = EXPAT_SAFE_PTR_DIFF(end, start);
+
+ if (! parser->m_parsingStatus.finalBuffer) {
+ // Heuristic: don't try to parse a partial token again until the amount of
+ // available data has increased significantly.
+ const size_t had_before = parser->m_partialTokenBytesBefore;
+ const bool enough = (have_now >= 2 * had_before);
+
+ if (! enough) {
+ *endPtr = start; // callers may expect this to be set
+ return XML_ERROR_NONE;
+ }
+ }
+ const enum XML_Error ret = parser->m_processor(parser, start, end, endPtr);
+ // if we consumed nothing, remember what we had on this parse attempt.
+ if (*endPtr == start) {
+ parser->m_partialTokenBytesBefore = have_now;
+ } else {
+ parser->m_partialTokenBytesBefore = 0;
+ }
+ return ret;
+}
+
static XML_Bool /* only valid for root parser */
startParsing(XML_Parser parser) {
/* hash functions must be initialized before setContext() is called */
@@ -1141,6 +1169,7 @@ parserInit(XML_Parser parser, const XML_Char *encodingName) {
parser->m_bufferEnd = parser->m_buffer;
parser->m_parseEndByteIndex = 0;
parser->m_parseEndPtr = NULL;
+ parser->m_partialTokenBytesBefore = 0;
parser->m_declElementType = NULL;
parser->m_declAttributeId = NULL;
parser->m_declEntity = NULL;
@@ -1872,29 +1901,20 @@ XML_Parse(XML_Parser parser, const char *s, int len, int isFinal) {
to detect errors based on that fact.
*/
parser->m_errorCode
- = parser->m_processor(parser, parser->m_bufferPtr,
- parser->m_parseEndPtr, &parser->m_bufferPtr);
+ = callProcessor(parser, parser->m_bufferPtr, parser->m_parseEndPtr,
+ &parser->m_bufferPtr);
if (parser->m_errorCode == XML_ERROR_NONE) {
switch (parser->m_parsingStatus.parsing) {
case XML_SUSPENDED:
- /* It is hard to be certain, but it seems that this case
- * cannot occur. This code is cleaning up a previous parse
- * with no new data (since len == 0). Changing the parsing
- * state requires getting to execute a handler function, and
- * there doesn't seem to be an opportunity for that while in
- * this circumstance.
- *
- * Given the uncertainty, we retain the code but exclude it
- * from coverage tests.
- *
- * LCOV_EXCL_START
- */
+ /* While we added no new data, the finalBuffer flag may have caused
+ * us to parse previously-unparsed data in the internal buffer.
+ * If that triggered a callback to the application, it would have
+ * had an opportunity to suspend parsing. */
XmlUpdatePosition(parser->m_encoding, parser->m_positionPtr,
parser->m_bufferPtr, &parser->m_position);
parser->m_positionPtr = parser->m_bufferPtr;
return XML_STATUS_SUSPENDED;
- /* LCOV_EXCL_STOP */
case XML_INITIALIZED:
case XML_PARSING:
parser->m_parsingStatus.parsing = XML_FINISHED;
@@ -1924,7 +1944,7 @@ XML_Parse(XML_Parser parser, const char *s, int len, int isFinal) {
parser->m_parsingStatus.finalBuffer = (XML_Bool)isFinal;
parser->m_errorCode
- = parser->m_processor(parser, s, parser->m_parseEndPtr = s + len, &end);
+ = callProcessor(parser, s, parser->m_parseEndPtr = s + len, &end);
if (parser->m_errorCode != XML_ERROR_NONE) {
parser->m_eventEndPtr = parser->m_eventPtr;
@@ -2027,8 +2047,8 @@ XML_ParseBuffer(XML_Parser parser, int len, int isFinal) {
parser->m_parseEndByteIndex += len;
parser->m_parsingStatus.finalBuffer = (XML_Bool)isFinal;
- parser->m_errorCode = parser->m_processor(
- parser, start, parser->m_parseEndPtr, &parser->m_bufferPtr);
+ parser->m_errorCode = callProcessor(parser, start, parser->m_parseEndPtr,
+ &parser->m_bufferPtr);
if (parser->m_errorCode != XML_ERROR_NONE) {
parser->m_eventEndPtr = parser->m_eventPtr;
@@ -2220,7 +2240,7 @@ XML_ResumeParser(XML_Parser parser) {
}
parser->m_parsingStatus.parsing = XML_PARSING;
- parser->m_errorCode = parser->m_processor(
+ parser->m_errorCode = callProcessor(
parser, parser->m_bufferPtr, parser->m_parseEndPtr, &parser->m_bufferPtr);
if (parser->m_errorCode != XML_ERROR_NONE) {
--
2.40.0
meta/recipes-core/expat/expat/CVE-2023-52425-0004.patch
-42
View File
@@ -1,42 +0,0 @@
From 1b9d398517befeb944cbbadadf10992b07e96fa2 Mon Sep 17 00:00:00 2001
From: Snild Dolkow <snild@sony.com>
Date: Mon, 4 Sep 2023 17:21:14 +0200
Subject: [PATCH] [PATCH] Don't update partial token heuristic on error
Suggested-by: Sebastian Pipping <sebastian@pipping.org>
CVE: CVE-2023-52425
Upstream-Status: Backport [https://github.com/libexpat/libexpat/commit/1b9d398517befeb944cbbadadf10992b07e96fa2]
Signed-off-by: Meenali Gupta <meenali.gupta@windriver.com>
---
lib/xmlparse.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/lib/xmlparse.c b/lib/xmlparse.c
index 5695417..5c66f54 100644
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -979,11 +979,13 @@ callProcessor(XML_Parser parser, const char *start, const char *end,
}
}
const enum XML_Error ret = parser->m_processor(parser, start, end, endPtr);
- // if we consumed nothing, remember what we had on this parse attempt.
- if (*endPtr == start) {
- parser->m_partialTokenBytesBefore = have_now;
- } else {
- parser->m_partialTokenBytesBefore = 0;
+ if (ret == XML_ERROR_NONE) {
+ // if we consumed nothing, remember what we had on this parse attempt.
+ if (*endPtr == start) {
+ parser->m_partialTokenBytesBefore = have_now;
+ } else {
+ parser->m_partialTokenBytesBefore = 0;
+ }
}
return ret;
}
--
2.40.0
meta/recipes-core/expat/expat/CVE-2023-52425-0005.patch
-69
View File
@@ -1,69 +0,0 @@
From 09957b8ced725b96a95acff150facda93f03afe1 Mon Sep 17 00:00:00 2001
From: Snild Dolkow <snild@sony.com>
Date: Thu, 26 Oct 2023 10:41:00 +0200
Subject: [PATCH] Allow XML_GetBuffer() with len=0 on a fresh parser
len=0 was previously OK if there had previously been a non-zero call.
It makes sense to allow an application to work the same way on a
newly-created parser, and not have to care if its incoming buffer
happens to be 0.
CVE: CVE-2023-52425
Upstream-Status: Backport [https://github.com/libexpat/libexpat/commit/09957b8ced725b96a95acff150facda93f03afe1]
Signed-off-by: Meenali Gupta <meenali.gupta@windriver.com>
---
lib/xmlparse.c | 22 +++++++++++-----------
1 file changed, 11 insertions(+), 11 deletions(-)
diff --git a/lib/xmlparse.c b/lib/xmlparse.c
index 5c66f54..5b112c6 100644
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -2095,7 +2095,8 @@ XML_GetBuffer(XML_Parser parser, int len) {
default:;
}
- if (len > EXPAT_SAFE_PTR_DIFF(parser->m_bufferLim, parser->m_bufferEnd)) {
+ if (len > EXPAT_SAFE_PTR_DIFF(parser->m_bufferLim, parser->m_bufferEnd)
+ || parser->m_buffer == NULL) {
#ifdef XML_CONTEXT_BYTES
int keep;
#endif /* defined XML_CONTEXT_BYTES */
@@ -2118,8 +2119,9 @@ XML_GetBuffer(XML_Parser parser, int len) {
}
neededSize += keep;
#endif /* defined XML_CONTEXT_BYTES */
- if (neededSize
- <= EXPAT_SAFE_PTR_DIFF(parser->m_bufferLim, parser->m_buffer)) {
+ if (parser->m_buffer && parser->m_bufferPtr
+ && neededSize
+ <= EXPAT_SAFE_PTR_DIFF(parser->m_bufferLim, parser->m_buffer)) {
#ifdef XML_CONTEXT_BYTES
if (keep < EXPAT_SAFE_PTR_DIFF(parser->m_bufferPtr, parser->m_buffer)) {
int offset
@@ -2133,14 +2135,12 @@ XML_GetBuffer(XML_Parser parser, int len) {
parser->m_bufferPtr -= offset;
}
#else
- if (parser->m_buffer && parser->m_bufferPtr) {
- memmove(parser->m_buffer, parser->m_bufferPtr,
- EXPAT_SAFE_PTR_DIFF(parser->m_bufferEnd, parser->m_bufferPtr));
- parser->m_bufferEnd
- = parser->m_buffer
- + EXPAT_SAFE_PTR_DIFF(parser->m_bufferEnd, parser->m_bufferPtr);
- parser->m_bufferPtr = parser->m_buffer;
- }
+ memmove(parser->m_buffer, parser->m_bufferPtr,
+ EXPAT_SAFE_PTR_DIFF(parser->m_bufferEnd, parser->m_bufferPtr));
+ parser->m_bufferEnd
+ = parser->m_buffer
+ + EXPAT_SAFE_PTR_DIFF(parser->m_bufferEnd, parser->m_bufferPtr);
+ parser->m_bufferPtr = parser->m_buffer;
#endif /* not defined XML_CONTEXT_BYTES */
} else {
char *newBuf;
--
2.40.0
meta/recipes-core/expat/expat/CVE-2023-52425-0006.patch
-67
View File
@@ -1,67 +0,0 @@
From 9fe3672459c1bf10926b85f013aa1b623d855545 Mon Sep 17 00:00:00 2001
From: Snild Dolkow <snild@sony.com>
Date: Mon, 18 Sep 2023 20:32:55 +0200
Subject: [PATCH] tests: Run both with and without partial token heuristic
If we always run with the heuristic enabled, it may hide some bugs by
grouping up input into bigger parse attempts.
CI-fighting-assistance-by: Sebastian Pipping <sebastian@pipping.org>
CVE: CVE-2023-52425
Upstream-Status: Backport [https://github.com/libexpat/libexpat/commit/9fe3672459c1bf10926b85f013aa1b623d855545]
Signed-off-by: Meenali Gupta <meenali.gupta@windriver.com>
---
lib/internal.h | 3 +++
lib/xmlparse.c | 5 ++++-
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/lib/internal.h b/lib/internal.h
index 03c8fde..1df417f 100644
--- a/lib/internal.h
+++ b/lib/internal.h
@@ -31,6 +31,7 @@
Copyright (c) 2016-2022 Sebastian Pipping <sebastian@pipping.org>
Copyright (c) 2018 Yury Gribov <tetra2005@gmail.com>
Copyright (c) 2019 David Loffredo <loffredo@steptools.com>
+ Copyright (c) 2023 Sony Corporation / Snild Dolkow <snild@sony.com>
Licensed under the MIT license:
Permission is hereby granted, free of charge, to any person obtaining
@@ -160,6 +161,8 @@ unsigned long long testingAccountingGetCountBytesIndirect(XML_Parser parser);
const char *unsignedCharToPrintable(unsigned char c);
#endif
+extern XML_Bool g_reparseDeferralEnabledDefault; // written ONLY in runtests.c
+ //
#ifdef __cplusplus
}
#endif
diff --git a/lib/xmlparse.c b/lib/xmlparse.c
index 5b112c6..be6dd92 100644
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -615,6 +615,8 @@ static unsigned long getDebugLevel(const char *variableName,
? 0 \
: ((*((pool)->ptr)++ = c), 1))
+XML_Bool g_reparseDeferralEnabledDefault = XML_TRUE; // write ONLY in runtests.c
+ //
struct XML_ParserStruct {
/* The first member must be m_userData so that the XML_GetUserData
macro works. */
@@ -967,7 +969,8 @@ callProcessor(XML_Parser parser, const char *start, const char *end,
const char **endPtr) {
const size_t have_now = EXPAT_SAFE_PTR_DIFF(end, start);
- if (! parser->m_parsingStatus.finalBuffer) {
+ if (g_reparseDeferralEnabledDefault
+ && ! parser->m_parsingStatus.finalBuffer) {
// Heuristic: don't try to parse a partial token again until the amount of
// available data has increased significantly.
const size_t had_before = parser->m_partialTokenBytesBefore;
--
2.40.0
meta/recipes-core/expat/expat/CVE-2023-52425-0007.patch
-159
View File
@@ -1,159 +0,0 @@
From 1d3162da8a85a398ab451aadd6c2ad19587e5a68 Mon Sep 17 00:00:00 2001
From: Snild Dolkow <snild@sony.com>
Date: Mon, 11 Sep 2023 15:31:24 +0200
Subject: [PATCH] Add app setting for enabling/disabling reparse heuristic
Suggested-by: Sebastian Pipping <sebastian@pipping.org>
CI-fighting-assistance-by: Sebastian Pipping <sebastian@pipping.org>
CVE: CVE-2023-52425
Upstream-Status: Backport [https://github.com/libexpat/libexpat/commit/1d3162da8a85a398ab451aadd6c2ad19587e5a68]
Signed-off-by: Meenali Gupta <meenali.gupta@windriver.com>
---
doc/reference.html | 30 ++++++++++++++++++++++++------
lib/expat.h | 5 +++++
lib/libexpat.def.cmake | 2 ++
lib/xmlparse.c | 13 ++++++++++++-
4 files changed, 43 insertions(+), 7 deletions(-)
diff --git a/doc/reference.html b/doc/reference.html
index 9953aa7..7dd9370 100644
--- a/doc/reference.html
+++ b/doc/reference.html
@@ -151,10 +151,11 @@ interface.</p>
</ul>
</li>
<li>
- <a href="#billion-laughs">Billion Laughs Attack Protection</a>
+ <a href="#attack-protection">Attack Protection</a>
<ul>
<li><a href="#XML_SetBillionLaughsAttackProtectionMaximumAmplification">XML_SetBillionLaughsAttackProtectionMaximumAmplification</a></li>
<li><a href="#XML_SetBillionLaughsAttackProtectionActivationThreshold">XML_SetBillionLaughsAttackProtectionActivationThreshold</a></li>
+ <li><a href="#XML_SetReparseDeferralEnabled">XML_SetReparseDeferralEnabled</a></li>
</ul>
</li>
<li><a href="#miscellaneous">Miscellaneous Functions</a>
@@ -2123,11 +2124,7 @@ parse position may be before the beginning of the buffer.</p>
return NULL.</p>
</div>
-<h3><a name="billion-laughs">Billion Laughs Attack Protection</a></h3>
-
-<p>The functions in this section configure the built-in
- protection against various forms of
- <a href="https://en.wikipedia.org/wiki/Billion_laughs_attack">billion laughs attacks</a>.</p>
+<h3><a name="attack-protection">Attack Protection</a><a name="billion-laughs"></a></h3>
<h4 id="XML_SetBillionLaughsAttackProtectionMaximumAmplification">XML_SetBillionLaughsAttackProtectionMaximumAmplification</h4>
<pre class="fcndec">
@@ -2215,6 +2212,27 @@ XML_SetBillionLaughsAttackProtectionActivationThreshold(XML_Parser p,
</p>
</div>
+<h4 id="XML_SetReparseDeferralEnabled">XML_SetReparseDeferralEnabled</h4>
+<pre class="fcndec">
+/* Added in Expat 2.6.0. */
+XML_Bool XMLCALL
+XML_SetReparseDeferralEnabled(XML_Parser parser, XML_Bool enabled);
+</pre>
+<div class="fcndef">
+ <p>
+ Large tokens may require many parse calls before enough data is available for Expat to parse it in full.
+ If Expat retried parsing the token on every parse call, parsing could take quadratic time.
+ To avoid this, Expat only retries once a significant amount of new data is available.
+ This function allows disabling this behavior.
+ </p>
+ <p>
+ The <code>enabled</code> argument should be <code>XML_TRUE</code> or <code>XML_FALSE</code>.
+ </p>
+ <p>
+ Returns <code>XML_TRUE</code> on success, and <code>XML_FALSE</code> on error.
+ </p>
+</div>
+
<h3><a name="miscellaneous">Miscellaneous functions</a></h3>
<p>The functions in this section either obtain state information from
diff --git a/lib/expat.h b/lib/expat.h
index 9e64174..73dda6d 100644
--- a/lib/expat.h
+++ b/lib/expat.h
@@ -16,6 +16,7 @@
Copyright (c) 2016 Thomas Beutlich <tc@tbeu.de>
Copyright (c) 2017 Rhodri James <rhodri@wildebeest.org.uk>
Copyright (c) 2022 Thijs Schreijer <thijs@thijsschreijer.nl>
+ Copyright (c) 2023 Sony Corporation / Snild Dolkow <snild@sony.com>
Licensed under the MIT license:
Permission is hereby granted, free of charge, to any person obtaining
@@ -1054,6 +1055,10 @@ XML_SetBillionLaughsAttackProtectionActivationThreshold(
XML_Parser parser, unsigned long long activationThresholdBytes);
#endif
+/* Added in Expat 2.6.0. */
+XMLPARSEAPI(XML_Bool)
+XML_SetReparseDeferralEnabled(XML_Parser parser, XML_Bool enabled);
+
/* Expat follows the semantic versioning convention.
See http://semver.org.
*/
diff --git a/lib/libexpat.def.cmake b/lib/libexpat.def.cmake
index 61a4f00..10ee9cd 100644
--- a/lib/libexpat.def.cmake
+++ b/lib/libexpat.def.cmake
@@ -77,3 +77,5 @@ EXPORTS
; added with version 2.4.0
@_EXPAT_COMMENT_DTD_OR_GE@ XML_SetBillionLaughsAttackProtectionActivationThreshold @69
@_EXPAT_COMMENT_DTD_OR_GE@ XML_SetBillionLaughsAttackProtectionMaximumAmplification @70
+; added with version 2.6.0
+ XML_SetReparseDeferralEnabled @71
diff --git a/lib/xmlparse.c b/lib/xmlparse.c
index be6dd92..8cf32e0 100644
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -633,6 +633,7 @@ struct XML_ParserStruct {
XML_Index m_parseEndByteIndex;
const char *m_parseEndPtr;
size_t m_partialTokenBytesBefore; /* used in heuristic to avoid O(n^2) */
+ XML_Bool m_reparseDeferralEnabled;
XML_Char *m_dataBuf;
XML_Char *m_dataBufEnd;
XML_StartElementHandler m_startElementHandler;
@@ -969,7 +970,7 @@ callProcessor(XML_Parser parser, const char *start, const char *end,
const char **endPtr) {
const size_t have_now = EXPAT_SAFE_PTR_DIFF(end, start);
- if (g_reparseDeferralEnabledDefault
+ if (parser->m_reparseDeferralEnabled
&& ! parser->m_parsingStatus.finalBuffer) {
// Heuristic: don't try to parse a partial token again until the amount of
// available data has increased significantly.
@@ -1175,6 +1176,7 @@ parserInit(XML_Parser parser, const XML_Char *encodingName) {
parser->m_parseEndByteIndex = 0;
parser->m_parseEndPtr = NULL;
parser->m_partialTokenBytesBefore = 0;
+ parser->m_reparseDeferralEnabled = g_reparseDeferralEnabledDefault;
parser->m_declElementType = NULL;
parser->m_declAttributeId = NULL;
parser->m_declEntity = NULL;
@@ -2601,6 +2603,15 @@ XML_SetBillionLaughsAttackProtectionActivationThreshold(
}
#endif /* XML_GE == 1 */
+XML_Bool XMLCALL
+XML_SetReparseDeferralEnabled(XML_Parser parser, XML_Bool enabled) {
+ if (parser != NULL && (enabled == XML_TRUE || enabled == XML_FALSE)) {
+ parser->m_reparseDeferralEnabled = enabled;
+ return XML_TRUE;
+ }
+ return XML_FALSE;
+}
+
/* Initially tag->rawName always points into the parse buffer;
for those TAG instances opened while the current parse buffer was
processed, and not yet closed, we need to store tag->rawName in a more
--
2.40.0
meta/recipes-core/expat/expat/CVE-2023-52425-0008.patch
-95
View File
@@ -1,95 +0,0 @@
From 8ddd8e86aa446d02eb8d398972d3b10d4cad908a Mon Sep 17 00:00:00 2001
From: Snild Dolkow <snild@sony.com>
Date: Fri, 29 Sep 2023 10:14:59 +0200
Subject: [PATCH] Try to parse even when incoming len is zero
If the reparse deferral setting has changed, it may be possible to
finish a token.
CVE: CVE-2023-52425
Upstream-Status: Backport [https://github.com/libexpat/libexpat/commit/8ddd8e86aa446d02eb8d398972d3b10d4cad908a]
Signed-off-by: Meenali Gupta <meenali.gupta@windriver.com>
---
lib/xmlparse.c | 55 ++++++++------------------------------------------
1 file changed, 8 insertions(+), 47 deletions(-)
diff --git a/lib/xmlparse.c b/lib/xmlparse.c
index 8cf32e0..f4ff66e 100644
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -1896,46 +1896,8 @@ XML_Parse(XML_Parser parser, const char *s, int len, int isFinal) {
parser->m_parsingStatus.parsing = XML_PARSING;
}
- if (len == 0) {
- parser->m_parsingStatus.finalBuffer = (XML_Bool)isFinal;
- if (! isFinal)
- return XML_STATUS_OK;
- parser->m_positionPtr = parser->m_bufferPtr;
- parser->m_parseEndPtr = parser->m_bufferEnd;
-
- /* If data are left over from last buffer, and we now know that these
- data are the final chunk of input, then we have to check them again
- to detect errors based on that fact.
- */
- parser->m_errorCode
- = callProcessor(parser, parser->m_bufferPtr, parser->m_parseEndPtr,
- &parser->m_bufferPtr);
-
- if (parser->m_errorCode == XML_ERROR_NONE) {
- switch (parser->m_parsingStatus.parsing) {
- case XML_SUSPENDED:
- /* While we added no new data, the finalBuffer flag may have caused
- * us to parse previously-unparsed data in the internal buffer.
- * If that triggered a callback to the application, it would have
- * had an opportunity to suspend parsing. */
- XmlUpdatePosition(parser->m_encoding, parser->m_positionPtr,
- parser->m_bufferPtr, &parser->m_position);
- parser->m_positionPtr = parser->m_bufferPtr;
- return XML_STATUS_SUSPENDED;
- case XML_INITIALIZED:
- case XML_PARSING:
- parser->m_parsingStatus.parsing = XML_FINISHED;
- /* fall through */
- default:
- return XML_STATUS_OK;
- }
- }
- parser->m_eventEndPtr = parser->m_eventPtr;
- parser->m_processor = errorProcessor;
- return XML_STATUS_ERROR;
- }
#ifndef XML_CONTEXT_BYTES
- else if (parser->m_bufferPtr == parser->m_bufferEnd) {
+ if (parser->m_bufferPtr == parser->m_bufferEnd) {
const char *end;
int nLeftOver;
enum XML_Status result;
@@ -2006,15 +1968,14 @@ XML_Parse(XML_Parser parser, const char *s, int len, int isFinal) {
return result;
}
#endif /* not defined XML_CONTEXT_BYTES */
- else {
- void *buff = XML_GetBuffer(parser, len);
- if (buff == NULL)
- return XML_STATUS_ERROR;
- else {
- memcpy(buff, s, len);
- return XML_ParseBuffer(parser, len, isFinal);
- }
+ void *buff = XML_GetBuffer(parser, len);
+ if (buff == NULL)
+ return XML_STATUS_ERROR;
+ if (len > 0) {
+ assert(s != NULL); // make sure s==NULL && len!=0 was rejected above
+ memcpy(buff, s, len);
}
+ return XML_ParseBuffer(parser, len, isFinal);
}
enum XML_Status XMLCALL
--
2.40.0
meta/recipes-core/expat/expat/CVE-2023-52425-0009.patch
-52
View File
@@ -1,52 +0,0 @@
From ad9c01be8ee5d3d5cac2bfd3949ad764541d35e7 Mon Sep 17 00:00:00 2001
From: Snild Dolkow <snild@sony.com>
Date: Thu, 26 Oct 2023 13:55:02 +0200
Subject: [PATCH] Make external entity parser inherit partial token heuristic
setting
The test is essentially a copy of the existing test for the setter,
adapted to run on the external parser instead of the original one.
Suggested-by: Sebastian Pipping <sebastian@pipping.org>
CI-fighting-assistance-by: Sebastian Pipping <sebastian@pipping.org>
CVE: CVE-2023-52425
Upstream-Status: Backport [https://github.com/libexpat/libexpat/commit/ad9c01be8ee5d3d5cac2bfd3949ad764541d35e7]
Signed-off-by: Meenali Gupta <meenali.gupta@windriver.com>
---
lib/xmlparse.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/lib/xmlparse.c b/lib/xmlparse.c
index f4ff66e..6746d70 100644
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -1346,6 +1346,7 @@ XML_ExternalEntityParserCreate(XML_Parser oldParser, const XML_Char *context,
to worry which hash secrets each table has.
*/
unsigned long oldhash_secret_salt;
+ XML_Bool oldReparseDeferralEnabled;
/* Validate the oldParser parameter before we pull everything out of it */
if (oldParser == NULL)
@@ -1390,6 +1391,7 @@ XML_ExternalEntityParserCreate(XML_Parser oldParser, const XML_Char *context,
to worry which hash secrets each table has.
*/
oldhash_secret_salt = parser->m_hash_secret_salt;
+ oldReparseDeferralEnabled = parser->m_reparseDeferralEnabled;
#ifdef XML_DTD
if (! context)
@@ -1442,6 +1444,7 @@ XML_ExternalEntityParserCreate(XML_Parser oldParser, const XML_Char *context,
parser->m_defaultExpandInternalEntities = oldDefaultExpandInternalEntities;
parser->m_ns_triplets = oldns_triplets;
parser->m_hash_secret_salt = oldhash_secret_salt;
+ parser->m_reparseDeferralEnabled = oldReparseDeferralEnabled;
parser->m_parentParser = oldParser;
#ifdef XML_DTD
parser->m_paramEntityParsing = oldParamEntityParsing;
--
2.40.0
meta/recipes-core/expat/expat/CVE-2023-52425-0010.patch
-111
View File
@@ -1,111 +0,0 @@
From 60b74209899a67d426d208662674b55a5eed918c Mon Sep 17 00:00:00 2001
From: Snild Dolkow <snild@sony.com>
Date: Wed, 4 Oct 2023 16:00:14 +0200
Subject: [PATCH] Bypass partial token heuristic when close to maximum buffer
size
For huge tokens, we may end up in a situation where the partial token
parse deferral heuristic demands more bytes than Expat's maximum buffer
size (currently ~half of INT_MAX) could fit.
INT_MAX/2 is 1024 MiB on most systems. Clearly, a token of 950 MiB could
fit in that buffer, but the reparse threshold might be such that
callProcessor() will defer it, allowing the app to keep filling the
buffer until XML_GetBuffer() eventually returns a memory error.
By bypassing the heuristic when we're getting close to the maximum
buffer size, it will once again be possible to parse tokens in the size
range INT_MAX/2/ratio < size < INT_MAX/2 reliably.
We subtract the last buffer fill size as a way to detect that the next
XML_GetBuffer() call has a risk of returning a memory error -- assuming
that the application is likely to keep using the same (or smaller) fill.
We subtract XML_CONTEXT_BYTES because that's the maximum amount of bytes
that could remain at the start of the buffer, preceding the partial
token. Technically, it could be fewer bytes, but XML_CONTEXT_BYTES is
normally small relative to INT_MAX, and is much simpler to use.
Co-authored-by: Sebastian Pipping <sebastian@pipping.org>
CVE: CVE-2023-52425
Upstream-Status: Backport [https://github.com/libexpat/libexpat/commit/60b74209899a67d426d208662674b55a5eed918c]
Signed-off-by: Meenali Gupta <meenali.gupta@windriver.com>
---
lib/xmlparse.c | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/lib/xmlparse.c b/lib/xmlparse.c
index 6746d70..32c57f6 100644
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -205,6 +205,8 @@ typedef char ICHAR;
/* Do safe (NULL-aware) pointer arithmetic */
#define EXPAT_SAFE_PTR_DIFF(p, q) (((p) && (q)) ? ((p) - (q)) : 0)
+#define EXPAT_MIN(a, b) (((a) < (b)) ? (a) : (b))
+
#include "internal.h"
#include "xmltok.h"
#include "xmlrole.h"
@@ -634,6 +636,7 @@ struct XML_ParserStruct {
const char *m_parseEndPtr;
size_t m_partialTokenBytesBefore; /* used in heuristic to avoid O(n^2) */
XML_Bool m_reparseDeferralEnabled;
+ int m_lastBufferRequestSize;
XML_Char *m_dataBuf;
XML_Char *m_dataBufEnd;
XML_StartElementHandler m_startElementHandler;
@@ -975,7 +978,18 @@ callProcessor(XML_Parser parser, const char *start, const char *end,
// Heuristic: don't try to parse a partial token again until the amount of
// available data has increased significantly.
const size_t had_before = parser->m_partialTokenBytesBefore;
- const bool enough = (have_now >= 2 * had_before);
+ // ...but *do* try anyway if we're close to reaching the max buffer size.
+ size_t close_to_maxbuf = INT_MAX / 2 + (INT_MAX & 1); // round up
+#if XML_CONTEXT_BYTES > 0
+ // subtract XML_CONTEXT_BYTES, but don't go below zero
+ close_to_maxbuf -= EXPAT_MIN(close_to_maxbuf, XML_CONTEXT_BYTES);
+#endif
+ // subtract the last buffer fill size, but don't go below zero
+ // m_lastBufferRequestSize is never assigned a value < 0, so the cast is ok
+ close_to_maxbuf
+ -= EXPAT_MIN(close_to_maxbuf, (size_t)parser->m_lastBufferRequestSize);
+ const bool enough
+ = (have_now >= 2 * had_before) || (have_now > close_to_maxbuf);
if (! enough) {
*endPtr = start; // callers may expect this to be set
@@ -1177,6 +1191,7 @@ parserInit(XML_Parser parser, const XML_Char *encodingName) {
parser->m_parseEndPtr = NULL;
parser->m_partialTokenBytesBefore = 0;
parser->m_reparseDeferralEnabled = g_reparseDeferralEnabledDefault;
+ parser->m_lastBufferRequestSize = 0;
parser->m_declElementType = NULL;
parser->m_declAttributeId = NULL;
parser->m_declEntity = NULL;
@@ -1911,6 +1926,9 @@ XML_Parse(XML_Parser parser, const char *s, int len, int isFinal) {
parser->m_processor = errorProcessor;
return XML_STATUS_ERROR;
}
+ // though this isn't a buffer request, we assume that `len` is the app's
+ // preferred buffer fill size, and therefore save it here.
+ parser->m_lastBufferRequestSize = len;
parser->m_parseEndByteIndex += len;
parser->m_positionPtr = s;
parser->m_parsingStatus.finalBuffer = (XML_Bool)isFinal;
@@ -2064,6 +2082,9 @@ XML_GetBuffer(XML_Parser parser, int len) {
default:;
}
+ // whether or not the request succeeds, `len` seems to be the app's preferred
+ // buffer fill size; remember it.
+ parser->m_lastBufferRequestSize = len;
if (len > EXPAT_SAFE_PTR_DIFF(parser->m_bufferLim, parser->m_bufferEnd)
|| parser->m_buffer == NULL) {
#ifdef XML_CONTEXT_BYTES
--
2.40.0
meta/recipes-core/expat/expat/CVE-2023-52425-0011.patch
-89
View File
@@ -1,89 +0,0 @@
From 3d8141d26a3b01ff948e00956cb0723a89dadf7f Mon Sep 17 00:00:00 2001
From: Snild Dolkow <snild@sony.com>
Date: Mon, 20 Nov 2023 16:11:24 +0100
Subject: [PATCH] Bypass partial token heuristic when nearing full buffer
...instead of only when approaching the maximum buffer size INT/2+1.
We'd like to give applications a chance to finish parsing a large token
before buffer reallocation, in case the reallocation fails.
By bypassing the reparse deferral heuristic when getting close to the
filling the buffer, we give them this chance -- if the whole token is
present in the buffer, it will be parsed at that time.
This may come at the cost of some extra reparse attempts. For a token
of n bytes, these extra parses cause us to scan over a maximum of
2n bytes (... + n/8 + n/4 + n/2 + n). Therefore, parsing of big tokens
remains O(n) in regard how many bytes we scan in attempts to parse. The
cost in reality is lower than that, since the reparses that happen due
to the bypass will affect m_partialTokenBytesBefore, delaying the next
ratio-based reparse. Furthermore, only the first token that "breaks
through" a buffer ceiling takes that extra reparse attempt; subsequent
large tokens will only bypass the heuristic if they manage to hit the
new buffer ceiling.
Note that this cost analysis depends on the assumption that Expat grows
its buffer by doubling it (or, more generally, grows it exponentially).
If this changes, the cost of this bypass may increase. Hopefully, this
would be caught by test_big_tokens_take_linear_time or the new test.
The bypass logic assumes that the application uses a consistent fill.
If the app increases its fill size, it may miss the bypass (and the
normal heuristic will apply). If the app decreases its fill size, the
bypass may be hit multiple times for the same buffer size. The very
worst case would be to always fill half of the remaining buffer space,
in which case parsing of a large n-byte token becomes O(n log n).
As an added bonus, the new test case should be faster than the old one,
since it doesn't have to go all the way to 1GiB to check the behavior.
Finally, this change necessitated a small modification to two existing
tests related to reparse deferral. These tests are testing the deferral
enabled setting, and assume that reparsing will not happen for any other
reason. By pre-growing the buffer, we make sure that this new deferral
does not affect those test cases.
CVE: CVE-2023-52425
Upstream-Status: Backport [https://github.com/libexpat/libexpat/commit/3d8141d26a3b01ff948e00956cb0723a89dadf7f]
Signed-off-by: Meenali Gupta <meenali.gupta@windriver.com>
---
lib/xmlparse.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/lib/xmlparse.c b/lib/xmlparse.c
index 32c57f6..2830c1e 100644
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -978,18 +978,18 @@ callProcessor(XML_Parser parser, const char *start, const char *end,
// Heuristic: don't try to parse a partial token again until the amount of
// available data has increased significantly.
const size_t had_before = parser->m_partialTokenBytesBefore;
- // ...but *do* try anyway if we're close to reaching the max buffer size.
- size_t close_to_maxbuf = INT_MAX / 2 + (INT_MAX & 1); // round up
+ // ...but *do* try anyway if we're close to causing a reallocation.
+ size_t available_buffer
+ = EXPAT_SAFE_PTR_DIFF(parser->m_bufferPtr, parser->m_buffer);
#if XML_CONTEXT_BYTES > 0
- // subtract XML_CONTEXT_BYTES, but don't go below zero
- close_to_maxbuf -= EXPAT_MIN(close_to_maxbuf, XML_CONTEXT_BYTES);
+ available_buffer -= EXPAT_MIN(available_buffer, XML_CONTEXT_BYTES);
#endif
- // subtract the last buffer fill size, but don't go below zero
+ available_buffer
+ += EXPAT_SAFE_PTR_DIFF(parser->m_bufferLim, parser->m_bufferEnd);
// m_lastBufferRequestSize is never assigned a value < 0, so the cast is ok
- close_to_maxbuf
- -= EXPAT_MIN(close_to_maxbuf, (size_t)parser->m_lastBufferRequestSize);
const bool enough
- = (have_now >= 2 * had_before) || (have_now > close_to_maxbuf);
+ = (have_now >= 2 * had_before)
+ || ((size_t)parser->m_lastBufferRequestSize > available_buffer);
if (! enough) {
*endPtr = start; // callers may expect this to be set
--
2.40.0
meta/recipes-core/expat/expat/CVE-2023-52425-0012.patch
-87
View File
@@ -1,87 +0,0 @@
From 119ae277abaabd4d17b2e64300fec712ef403b28 Mon Sep 17 00:00:00 2001
From: Snild Dolkow <snild@sony.com>
Date: Thu, 28 Sep 2023 18:26:19 +0200
Subject: [PATCH] Grow buffer based on current size Until now, the buffer size
to grow to has been calculated based on the distance from the current parse
position to the end of the buffer. This means that the size of any
already-parsed data was not considered, leading to inconsistent buffer
growth.
There was also a special case in XML_Parse() when XML_CONTEXT_BYTES was
zero, where the buffer size would be set to twice the incoming string
length. This patch replaces this with an XML_GetBuffer() call.
Growing the buffer based on its total size makes its growth consistent.
The commit includes a test that checks that we can reach the max buffer
size (usually INT_MAX/2 + 1) regardless of previously parsed content.
GitHub CI couldn't allocate the full 1GiB with MinGW/wine32, though it
works locally with the same compiler and wine version. As a workaround,
the test tries to malloc 1GiB, and reduces `maxbuf` to 512MiB in case
of failure.
CVE: CVE-2023-52425
Upstream-Status: Backport [https://github.com/libexpat/libexpat/commit/119ae277abaabd4d17b2e64300fec712ef403b28]
Signed-off-by: Meenali Gupta <meenali.gupta@windriver.com>
---
lib/xmlparse.c | 33 ++++++++++++++++-----------------
1 file changed, 16 insertions(+), 17 deletions(-)
diff --git a/lib/xmlparse.c b/lib/xmlparse.c
index 2830c1e..81f9bb3 100644
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -1961,23 +1961,22 @@ XML_Parse(XML_Parser parser, const char *s, int len, int isFinal) {
&parser->m_position);
nLeftOver = s + len - end;
if (nLeftOver) {
- if (parser->m_buffer == NULL
- || nLeftOver > parser->m_bufferLim - parser->m_buffer) {
- /* avoid _signed_ integer overflow */
- char *temp = NULL;
- const int bytesToAllocate = (int)((unsigned)len * 2U);
- if (bytesToAllocate > 0) {
- temp = (char *)REALLOC(parser, parser->m_buffer, bytesToAllocate);
- }
- if (temp == NULL) {
- parser->m_errorCode = XML_ERROR_NO_MEMORY;
- parser->m_eventPtr = parser->m_eventEndPtr = NULL;
- parser->m_processor = errorProcessor;
- return XML_STATUS_ERROR;
- }
- parser->m_buffer = temp;
- parser->m_bufferLim = parser->m_buffer + bytesToAllocate;
+ // Back up and restore the parsing status to avoid XML_ERROR_SUSPENDED
+ // (and XML_ERROR_FINISHED) from XML_GetBuffer.
+ const enum XML_Parsing originalStatus = parser->m_parsingStatus.parsing;
+ parser->m_parsingStatus.parsing = XML_PARSING;
+ void *const temp = XML_GetBuffer(parser, nLeftOver);
+ parser->m_parsingStatus.parsing = originalStatus;
+ if (temp == NULL) {
+ // NOTE: parser->m_errorCode has already been set by XML_GetBuffer().
+ parser->m_eventPtr = parser->m_eventEndPtr = NULL;
+ parser->m_processor = errorProcessor;
+ return XML_STATUS_ERROR;
}
+ // Since we know that the buffer was empty and XML_CONTEXT_BYTES is 0, we
+ // don't have any data to preserve, and can copy straight into the start
+ // of the buffer rather than the GetBuffer return pointer (which may be
+ // pointing further into the allocated buffer).
memcpy(parser->m_buffer, end, nLeftOver);
}
parser->m_bufferPtr = parser->m_buffer;
@@ -2135,7 +2134,7 @@ XML_GetBuffer(XML_Parser parser, int len) {
} else {
char *newBuf;
int bufferSize
- = (int)EXPAT_SAFE_PTR_DIFF(parser->m_bufferLim, parser->m_bufferPtr);
+ = (int)EXPAT_SAFE_PTR_DIFF(parser->m_bufferLim, parser->m_buffer);
if (bufferSize == 0)
bufferSize = INIT_BUFFER_SIZE;
do {
--
2.40.0
meta/recipes-core/expat/expat_2.5.0.bb
-12
View File
@@ -22,18 +22,6 @@ SRC_URI = "https://github.com/libexpat/libexpat/releases/download/R_${VERSION_TA
file://CVE-2023-52426-009.patch \ file://CVE-2023-52426-009.patch \
file://CVE-2023-52426-010.patch \ file://CVE-2023-52426-010.patch \
file://CVE-2023-52426-011.patch \ file://CVE-2023-52426-011.patch \
file://CVE-2023-52425-0001.patch \
file://CVE-2023-52425-0002.patch \
file://CVE-2023-52425-0003.patch \
file://CVE-2023-52425-0004.patch \
file://CVE-2023-52425-0005.patch \
file://CVE-2023-52425-0006.patch \
file://CVE-2023-52425-0007.patch \
file://CVE-2023-52425-0008.patch \
file://CVE-2023-52425-0009.patch \
file://CVE-2023-52425-0010.patch \
file://CVE-2023-52425-0011.patch \
file://CVE-2023-52425-0012.patch \
" "
UPSTREAM_CHECK_URI = "https://github.com/libexpat/libexpat/releases/" UPSTREAM_CHECK_URI = "https://github.com/libexpat/libexpat/releases/"