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sphinx/CVE-2020-29050.patch
houyingchao 4704c04426 Fix CVE-2020-29050 
(cherry picked from commit e5ea9be1bdd5a2cd31b9b3354fb021affabe3fdf)
2022-01-18 14:09:11 +08:00

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From 17245f7dd75d47c7365797b3d5feba8976367c6e Mon Sep 17 00:00:00 2001
From: klirichek <alexey@manticoresearch.com>
Date: Tue, 2 Jul 2019 19:06:09 +0700
Subject: [PATCH] Fix random file reading by scattered snippets
Issue was that load_files_scattered option just concatenated prefix with
given name and then opened the file. So, if you provide something like
'/etc/password' as file, or '../../../etc/passwd' even with non-zero
prefix, it will unfortunately work. After this commit such behavior
possible ONLY if user explicitly set `snippets_file_prefix` to empty
string or '/'; another cases will not cause uncontroled reading.
That fixes #866.
[basilgello: Back-port to 2.2.11:
- Refactor sphNormalizePath to use only available classes.
- Do not use 'g_sSnippetsFilePrefix' in src/sphinxexcerpt.h,
use 'tOptions.m_sFilePrefix' instead, as for 2.2.11, all
two instances are assigned to 'g_sSnippetsFilePrefix'.
- Adjust context. ]
The following test passes, adapted from commit
66b5761ad258c60b1866a8e1333f86e74f48035 at
https://github.com/manticoresoftware/manticoresearch :
====
/*
cd test &&
g++ -o test test.cpp -I../src -I../config -I/usr/include/postgresql \
-I/usr/include/mariadb -DHAVE_CONFIG_H -L../src -lsphinx -pthread \
-lm -ldl -lstemmer -lmariadb -lpq -lexpat -lz
*/
void ASSERT_STREQ(const char *src, const char *dst)
{
auto normalized = sphNormalizePath(src);
if (!strcmp(dst, normalized.scstr())) {
auto _src = src;
auto _dst = dst;
if (src == nullptr) _src = "nullptr";
if (dst == nullptr) _dst = "nullptr";
std::cout << "OK : '" << _src << "' = '" << _dst <<
"'" << std::endl;
} else {
auto _src = src;
auto _dst = dst;
if (src == nullptr) _src = "nullptr";
if (dst == nullptr) _dst = "nullptr";
std::cout << "FAIL: '" << _src << "' != '" << _dst << "' ( = '" <<
normalized.scstr() << "')" << std::endl;
}
}
int main()
{
ASSERT_STREQ ( "/", "/" );
ASSERT_STREQ ( "/..//bbb", "/bbb" );
ASSERT_STREQ ( "/quite/long/path/../../../etc/passwd", "/etc/passwd" );
ASSERT_STREQ ( "/aaa/bbb/ccc/ddd/../../../../../../../", "/" );
ASSERT_STREQ ( "", "" );
ASSERT_STREQ ( nullptr, "" );
ASSERT_STREQ ( "aaa/", "aaa" );
ASSERT_STREQ ( "aaa/.", "aaa" );
ASSERT_STREQ ( "aaa/././././////././", "aaa" );
ASSERT_STREQ ( "aaa/////", "aaa" );
ASSERT_STREQ ( "aaa/bbb/ccc", "aaa/bbb/ccc" );
ASSERT_STREQ ( "aaa/bbb/ccc/ddd/..", "aaa/bbb/ccc" );
ASSERT_STREQ ( "aaa/bbb/ccc/ddd/../../..", "aaa" );
ASSERT_STREQ ( "aaa/bbb/ccc/ddd/../../../xxx", "aaa/xxx" );
ASSERT_STREQ ( "aaa/bbb/ccc/ddd/../../../..", "" );
ASSERT_STREQ ( "aaa/bbb/ccc/ddd/../../../../", "" );
ASSERT_STREQ ( "aaa/bbb/ccc/ddd/../../../../../../../", "../../.." );
ASSERT_STREQ ( "..//bbb", "../bbb" );
return 0;
}
====
Fixes CVE-2020-29050.
Signed-off-by: Vasyl Gello <vasek.gello@gmail.com>
---
doc/sphinx.html | 19 ++++++++++-
doc/sphinx.txt | 19 ++++++++++-
sphinx.conf.in | 4 +--
src/searchd.cpp | 8 ++++-
src/sphinx.cpp | 71 ++++++++++++++++++++++++++++++++++++++++++
src/sphinxexcerpt.cpp | 14 +++++++++
src/sphinxexcerpt.h | 3 ++
src/sphinxstd.h | 3 ++
test/test_130/test.xml | 7 +++--
9 files changed, 140 insertions(+), 8 deletions(-)
diff --git a/doc/sphinx.html b/doc/sphinx.html
index b56e445..8ad44dd 100644
--- a/doc/sphinx.html
+++ b/doc/sphinx.html
@@ -11652,7 +11652,7 @@ binlog_max_log_size = 16M
<div class="sect2" title="12.4.28.&nbsp;snippets_file_prefix"><div class="titlepage"><div><div><h3 class="title"><a name="conf-snippets-file-prefix"></a>12.4.28.&nbsp;snippets_file_prefix</h3></div></div></div>
<p>
A prefix to prepend to the local file names when generating snippets.
-Optional, default is empty.
+Optional, default is current working folder.
Introduced in version 2.1.1-beta.
</p><p>
This prefix can be used in distributed snippets generation along with
@@ -11663,6 +11663,19 @@ is set to "server1" and the request refers to "file23", <code class="filename">s
will attempt to open "server1file23" (all of that without quotes). So if you
need it to be a path, you have to mention the trailing slash.
</p><p>
+After constructing final file path, daemon unwinds all relative dirs and
+compares final result with the value of ``snippet_file_prefix``. If result
+is not begin with the prefix, such file will be rejected with error message.
+
+So, if you set it to '/mnt/data' and somebody calls snippet generation with file
+'../../../etc/passwd', as the source, it will get error message
+`File '/mnt/data/../../../etc/passwd' escapes '/mnt/data/' scope`
+instead of content of the file.
+
+Also, with non-set parameter and reading '/etc/passwd' it will actually read
+/daemon/working/folder/etc/passwd since default for param is exactly daemon's
+working folder.
+</p><p>
Note also that this is a local option, it does not affect the agents anyhow.
So you can safely set a prefix on a master server. The requests routed to the
agents will not be affected by the master's setting. They will however be affected
@@ -11673,6 +11686,10 @@ This might be useful, for instance, when the document storage locations
</p><h4><a name="idp33320288"></a>Example:</h4><pre class="programlisting">
snippets_file_prefix = /mnt/common/server1/
</pre></div>
+<p><span class="bold"><strong>WARNING:</strong></span>
+If you still want to access files from the FS root, you have to explicitly set
+'snippets_file_prefix' to empty value (by 'snippets_file_prefix=' line), or to
+root (by 'snippets_file_prefix=/').
<div class="sect2" title="12.4.29.&nbsp;collation_server"><div class="titlepage"><div><div><h3 class="title"><a name="conf-collation-server"></a>12.4.29.&nbsp;collation_server</h3></div></div></div>
<p>
Default server collation.
diff --git a/doc/sphinx.txt b/doc/sphinx.txt
index ed994f9..f750f4e 100644
--- a/doc/sphinx.txt
+++ b/doc/sphinx.txt
@@ -12832,7 +12832,7 @@ Example:
-----------------------------
A prefix to prepend to the local file names when generating snippets.
-Optional, default is empty. Introduced in version 2.1.1-beta.
+Optional, default is current working folder. Introduced in version 2.1.1-beta.
This prefix can be used in distributed snippets generation along with
load_files or load_files_scattered options.
@@ -12842,6 +12842,19 @@ to "server1" and the request refers to "file23", searchd will attempt to
open "server1file23" (all of that without quotes). So if you need it to be
a path, you have to mention the trailing slash.
+After constructing final file path, daemon unwinds all relative dirs and
+compares final result with the value of ``snippet_file_prefix``. If result
+is not begin with the prefix, such file will be rejected with error message.
+
+So, if you set it to '/mnt/data' and somebody calls snippet generation with file
+'../../../etc/passwd', as the source, it will get error message
+`File '/mnt/data/../../../etc/passwd' escapes '/mnt/data/' scope`
+instead of content of the file.
+
+Also, with non-set parameter and reading '/etc/passwd' it will actually read
+/daemon/working/folder/etc/passwd since default for param is exactly daemon's
+working folder.
+
Note also that this is a local option, it does not affect the agents
anyhow. So you can safely set a prefix on a master server. The requests
routed to the agents will not be affected by the master's setting. They
@@ -12855,6 +12868,10 @@ Example:
| snippets_file_prefix = /mnt/common/server1/
+WARNING: If you still want to access files from the FS root, you have to
+explicitly set 'snippets_file_prefix' to empty value (by 'snippets_file_prefix='
+line), or to root (by 'snippets_file_prefix=/').
+
12.4.29. collation_server
-------------------------
diff --git a/sphinx.conf.in b/sphinx.conf.in
index 6ba2dc9..527bbd8 100644
--- a/sphinx.conf.in
+++ b/sphinx.conf.in
@@ -604,7 +604,7 @@ index test1
# snippet document file name prefix
# preprended to file names when generating snippets using load_files option
# WARNING, this is a prefix (not a path), trailing slash matters!
- # optional, default is empty
+ # optional, default is current working directory of a running process
#
# snippets_file_prefix = /mnt/mydocs/server1
@@ -1042,7 +1042,7 @@ searchd
# a prefix to prepend to the local file names when creating snippets
# with load_files and/or load_files_scatter options
- # optional, default is empty
+ # optional, default is current working directory of a running process
#
# snippets_file_prefix = /mnt/common/server1/
}
diff --git a/src/searchd.cpp b/src/searchd.cpp
index 85b1cd6..6462b16 100644
--- a/src/searchd.cpp
+++ b/src/searchd.cpp
@@ -13330,6 +13330,12 @@ bool MakeSnippets ( CSphString sIndex, CSphVector<ExcerptQuery_t> & dQueries, CS
struct stat st;
CSphString sFilename;
sFilename.SetSprintf ( "%s%s", g_sSnippetsFilePrefix.cstr(), dQueries[i].m_sSource.cstr() );
+ if ( !TestEscaping ( g_sSnippetsFilePrefix, sFilename ))
+ {
+ sError.SetSprintf( "File '%s' escapes '%s' scope",
+ sFilename.scstr(), g_sSnippetsFilePrefix.scstr());
+ return false;
+ }
if ( ::stat ( sFilename.cstr(), &st )<0 )
{
if ( !bScattered )
@@ -23719,7 +23725,7 @@ int WINAPI ServiceMain ( int argc, char **argv )
if ( hSearchd.Exists ( "snippets_file_prefix" ) )
g_sSnippetsFilePrefix = hSearchd["snippets_file_prefix"].cstr();
else
- g_sSnippetsFilePrefix = "";
+ g_sSnippetsFilePrefix.SetSprintf("%s/", sphGetCwd().scstr());
const char* sLogFormat = hSearchd.GetStr ( "query_log_format", "plain" );
if ( !strcmp ( sLogFormat, "sphinxql" ) )
diff --git a/src/sphinx.cpp b/src/sphinx.cpp
index d6a7b9d..492c908 100644
--- a/src/sphinx.cpp
+++ b/src/sphinx.cpp
@@ -81,9 +81,11 @@
#include <io.h> // for open()
// workaround Windows quirks
+ #include <direct.h>
#define popen _popen
#define pclose _pclose
#define snprintf _snprintf
+ #define getcwd _getcwd
#define sphSeek _lseeki64
#define stat _stat64
@@ -12420,6 +12422,75 @@ static bool sphTruncate ( int iFD )
#endif
}
+CSphString sphNormalizePath( const CSphString& sOrigPath )
+{
+ CSphVector<CSphString> dChunks;
+ const char* sBegin = sOrigPath.scstr();
+ const char* sEnd = sBegin + sOrigPath.Length();
+ const char* sPath = sBegin;
+ int iLevel = 0;
+
+ while ( sPath<sEnd )
+ {
+ const char* sSlash = ( char* ) memchr( sPath, '/', sEnd - sPath );
+ if ( !sSlash )
+ sSlash = sEnd;
+
+ auto iChunkLen = sSlash - sPath;
+
+ switch ( iChunkLen )
+ {
+ case 0: // empty chunk skipped
+ ++sPath;
+ continue;
+ case 1: // simple dot chunk skipped
+ if ( *sPath=='.' )
+ {
+ sPath += 2;
+ continue;
+ }
+ break;
+ case 2: // double dot abandons chunks, then decrease level
+ if ( sPath[0]=='.' && sPath[1]=='.' )
+ {
+ if ( dChunks.GetLength() <= 0 )
+ --iLevel;
+ else
+ dChunks.Pop();
+ sPath += 3;
+ continue;
+ }
+ default: break;
+ }
+ CSphString temp( "" );
+ temp.SetBinary( sPath, iChunkLen );
+ dChunks.Add( temp );
+ sPath = sSlash + 1;
+ }
+
+ CSphStringBuilder sResult;
+ if ( *sBegin=='/' )
+ sResult += "/";
+ else
+ while ( iLevel++<0 )
+ dChunks.Insert(0, "..");
+
+ int i;
+ for ( i=0; i<dChunks.GetLength(); i++ ) {
+ sResult += dChunks[i].scstr();
+ if (i<dChunks.GetLength()-1)
+ sResult += "/";
+ }
+
+ return sResult.cstr();
+}
+
+CSphString sphGetCwd()
+{
+ CSphVector<char> sBuf (65536);
+ return getcwd( sBuf.Begin(), sBuf.GetLength());
+}
+
class DeleteOnFail : public ISphNoncopyable
{
public:
diff --git a/src/sphinxexcerpt.cpp b/src/sphinxexcerpt.cpp
index b42c6a2..ff593f0 100644
--- a/src/sphinxexcerpt.cpp
+++ b/src/sphinxexcerpt.cpp
@@ -3817,6 +3817,11 @@ void sphBuildExcerpt ( ExcerptQuery_t & tOptions, const CSphIndex * pIndex, cons
{
CSphString sFilename;
sFilename.SetSprintf ( "%s%s", tOptions.m_sFilePrefix.cstr(), tOptions.m_sSource.cstr() );
+ if ( !TestEscaping( tOptions.m_sFilePrefix.scstr(), sFilename ))
+ {
+ sError.SetSprintf( "File '%s' escapes '%s' scope", sFilename.scstr(), tOptions.m_sFilePrefix.scstr());
+ return;
+ }
if ( tFile.Open ( sFilename.cstr(), SPH_O_READ, sError )<0 )
return;
} else if ( tOptions.m_sSource.IsEmpty() )
@@ -3859,6 +3864,15 @@ void sphBuildExcerpt ( ExcerptQuery_t & tOptions, const CSphIndex * pIndex, cons
sWarning, sError, pQueryTokenizer, tOptions.m_dRes );
}
+// check whether filepath from sPath does not escape area of sPrefix
+bool TestEscaping( const CSphString& sPrefix, const CSphString& sPath )
+{
+ if ( sPrefix.IsEmpty() || sPrefix==sPath )
+ return true;
+ auto sNormalized = sphNormalizePath( sPath );
+ return sPrefix==sNormalized.SubString( 0, sPrefix.Length());
+}
+
//
// $Id$
//
diff --git a/src/sphinxexcerpt.h b/src/sphinxexcerpt.h
index cf48b1f..87a55d4 100644
--- a/src/sphinxexcerpt.h
+++ b/src/sphinxexcerpt.h
@@ -81,6 +81,9 @@ struct XQQuery_t;
void sphBuildExcerpt ( ExcerptQuery_t & tOptions, const CSphIndex * pIndex, const CSphHTMLStripper * pStripper, const XQQuery_t & tExtQuery,
DWORD eExtQuerySPZ, CSphString & sWarning, CSphString & sError, CSphDict * pDict, ISphTokenizer * pDocTokenizer, ISphTokenizer * pQueryTokenizer );
+// helper whether filepath from sPath does not escape area of sPrefix
+bool TestEscaping( const CSphString& sPrefix, const CSphString& sPath );
+
#endif // _sphinxexcerpt_
//
diff --git a/src/sphinxstd.h b/src/sphinxstd.h
index 39cc7ee..c1f15c1 100644
--- a/src/sphinxstd.h
+++ b/src/sphinxstd.h
@@ -2294,6 +2294,9 @@ int sphOpenFile ( const char * sFile, CSphString & sError );
/// return size of file descriptor
int64_t sphGetFileSize ( int iFD, CSphString & sError );
+// unwind different tricks like "../../../etc/passwd"
+CSphString sphNormalizePath ( const CSphString& sOrigPath );
+CSphString sphGetCwd();
/// buffer trait that neither own buffer nor clean-up it on destroy
template < typename T >
diff --git a/test/test_130/test.xml b/test/test_130/test.xml
index d8f746c..41e4961 100644
--- a/test/test_130/test.xml
+++ b/test/test_130/test.xml
@@ -7,6 +7,7 @@
searchd
{
<searchd_settings/>
+ snippets_file_prefix=<this_test/>/
}
source test
@@ -30,15 +31,15 @@ index test
$results = array();
-$docs = array( 'test_130/load_file.txt' );
+$docs = array( "load_file.txt" );
$opts = array( 'load_files'=>true, 'limit'=>0 );
$results[] = $client->BuildExcerpts($docs, 'test', 'end point', $opts );
$results[] = $client->BuildExcerpts($docs, 'test', 'not_found', $opts );
-$results[] = $client->BuildExcerpts(array( 'test_130/empty.txt' ), 'test', 'end point', $opts );
+$results[] = $client->BuildExcerpts(array( 'empty.txt' ), 'test', 'end point', $opts );
$results[] = $client->BuildExcerpts(array( '' ), 'test', 'not_found', $opts );
$results[] = $client->GetLastError();
-$results[] = $client->BuildExcerpts ( array ( 'test_130/512k.xml' ), 'test', 'it builds', array ( "limit" => 100, "load_files" => true ) );
+$results[] = $client->BuildExcerpts ( array ( '512k.xml' ), 'test', 'it builds', array ( "limit" => 100, "load_files" => true ) );
]]></custom_test>
--
2.17.1
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