jlec 15/06/22 07:12:51 Added: p7zip-9.38.1-CVE-2015-1038.patch Log: Fix CVE-2015-1038 in latest version, bug #536012 (Portage version: 2.2.20/cvs/Linux x86_64, signed Manifest commit with key E9402A79B03529A2!)
Revision Changes Path 1.1 app-arch/p7zip/files/p7zip-9.38.1-CVE-2015-1038.patch file : http://sources.gentoo.org/viewvc.cgi/gentoo-x86/app-arch/p7zip/files/p7zip-9.38.1-CVE-2015-1038.patch?rev=1.1&view=markup plain: http://sources.gentoo.org/viewvc.cgi/gentoo-x86/app-arch/p7zip/files/p7zip-9.38.1-CVE-2015-1038.patch?rev=1.1&content-type=text/plain Index: p7zip-9.38.1-CVE-2015-1038.patch =================================================================== Author: Ben Hutchings <b...@decadent.org.uk> Date: Tue, 19 May 2015 02:38:40 +0100 Description: Delay creation of symlinks to prevent arbitrary file writes (CVE-2015-1038) Bug: http://sourceforge.net/p/p7zip/bugs/147/ Bug-Debian: https://bugs.debian.org/774660 Alexander Cherepanov discovered that 7zip is susceptible to a directory traversal vulnerability. While extracting an archive, it will extract symlinks and then follow them if they are referenced in further entries. This can be exploited by a rogue archive to write files outside the current directory. We have to create placeholder files (which we already do) and delay creating symlinks until the end of extraction. Due to the possibility of anti-items (deletions) in the archive, it is possible for placeholders to be deleted and replaced before we create the symlinks. It's not clear that this can be used for mischief, but GNU tar guards against similar problems by checking that the placeholder still exists and is the same inode. XXX It also checks 'birth time' but this isn't portable. We can probably get away with comparing ctime since we don't support hard links. --- a/CPP/7zip/UI/Agent/Agent.cpp +++ b/CPP/7zip/UI/Agent/Agent.cpp @@ -1215,7 +1215,7 @@ STDMETHODIMP CAgentFolder::Extract(const HRESULT result = _agentSpec->GetArchive()->Extract(&realIndices.Front(), realIndices.Size(), testMode, extractCallback); if (result == S_OK) - result = extractCallbackSpec->SetDirsTimes(); + result = extractCallbackSpec->SetFinalAttribs(); return result; COM_TRY_END } --- a/CPP/7zip/UI/Client7z/Client7z.cpp +++ b/CPP/7zip/UI/Client7z/Client7z.cpp @@ -222,8 +222,11 @@ private: COutFileStream *_outFileStreamSpec; CMyComPtr<ISequentialOutStream> _outFileStream; + CObjectVector<NWindows::NFile::NDir::CDelayedSymLink> _delayedSymLinks; + public: void Init(IInArchive *archiveHandler, const FString &directoryPath); + HRESULT SetFinalAttribs(); UInt64 NumErrors; bool PasswordIsDefined; @@ -441,11 +444,23 @@ STDMETHODIMP CArchiveExtractCallback::Se } _outFileStream.Release(); if (_extractMode && _processedFileInfo.AttribDefined) - SetFileAttrib(_diskFilePath, _processedFileInfo.Attrib); + SetFileAttrib(_diskFilePath, _processedFileInfo.Attrib, &_delayedSymLinks); PrintNewLine(); return S_OK; } +HRESULT CArchiveExtractCallback::SetFinalAttribs() +{ + HRESULT result = S_OK; + + for (int i = 0; i != _delayedSymLinks.Size(); ++i) + if (!_delayedSymLinks[i].Create()) + result = E_FAIL; + + _delayedSymLinks.Clear(); + + return result; +} STDMETHODIMP CArchiveExtractCallback::CryptoGetTextPassword(BSTR *password) { @@ -912,6 +927,8 @@ int MY_CDECL main(int numArgs, const cha // extractCallbackSpec->PasswordIsDefined = true; // extractCallbackSpec->Password = L"1"; HRESULT result = archive->Extract(NULL, (UInt32)(Int32)(-1), false, extractCallback); + if (result == S_OK) + result = extractCallbackSpec->SetFinalAttribs(); if (result != S_OK) { PrintError("Extract Error"); --- a/CPP/7zip/UI/Common/ArchiveExtractCallback.cpp +++ b/CPP/7zip/UI/Common/ArchiveExtractCallback.cpp @@ -1083,7 +1083,7 @@ STDMETHODIMP CArchiveExtractCallback::Se NumFiles++; if (_extractMode && _fi.AttribDefined) - SetFileAttrib(_diskFilePath, _fi.Attrib); + SetFileAttrib(_diskFilePath, _fi.Attrib, &_delayedSymLinks); RINOK(_extractCallback2->SetOperationResult(operationResult, _encrypted)); return S_OK; COM_TRY_END @@ -1149,8 +1149,9 @@ static int GetNumSlashes(const FChar *s) } } -HRESULT CArchiveExtractCallback::SetDirsTimes() +HRESULT CArchiveExtractCallback::SetFinalAttribs() { + HRESULT result = S_OK; CRecordVector<CExtrRefSortPair> pairs; pairs.ClearAndSetSize(_extractedFolderPaths.Size()); unsigned i; @@ -1187,5 +1188,12 @@ HRESULT CArchiveExtractCallback::SetDirs (WriteATime && ATimeDefined) ? &ATime : NULL, (WriteMTime && MTimeDefined) ? &MTime : (_arc->MTimeDefined ? &_arc->MTime : NULL)); } - return S_OK; + + for (int i = 0; i != _delayedSymLinks.Size(); ++i) + if (!_delayedSymLinks[i].Create()) + result = E_FAIL; + + _delayedSymLinks.Clear(); + + return result; } --- a/CPP/7zip/UI/Common/ArchiveExtractCallback.h +++ b/CPP/7zip/UI/Common/ArchiveExtractCallback.h @@ -6,6 +6,8 @@ #include "../../../Common/MyCom.h" #include "../../../Common/Wildcard.h" +#include "../../../Windows/FileDir.h" + #include "../../IPassword.h" #include "../../Common/FileStreams.h" @@ -213,6 +215,8 @@ class CArchiveExtractCallback: bool _saclEnabled; #endif + CObjectVector<NWindows::NFile::NDir::CDelayedSymLink> _delayedSymLinks; + void CreateComplexDirectory(const UStringVector &dirPathParts, FString &fullPath); HRESULT GetTime(int index, PROPID propID, FILETIME &filetime, bool &filetimeIsDefined); HRESULT GetUnpackSize(); @@ -293,7 +297,7 @@ public: _baseParentFolder = indexInArc; } - HRESULT SetDirsTimes(); + HRESULT SetFinalAttribs(); }; #endif --- a/CPP/7zip/UI/Common/Extract.cpp +++ b/CPP/7zip/UI/Common/Extract.cpp @@ -170,7 +170,7 @@ static HRESULT DecompressArchive( else result = archive->Extract(&realIndices.Front(), realIndices.Size(), testMode, ecs); if (result == S_OK && !options.StdInMode) - result = ecs->SetDirsTimes(); + result = ecs->SetFinalAttribs(); return callback->ExtractResult(result); } --- a/CPP/Windows/FileDir.cpp +++ b/CPP/Windows/FileDir.cpp @@ -343,7 +343,8 @@ static int convert_to_symlink(const char return -1; } -bool SetFileAttrib(CFSTR fileName, DWORD fileAttributes) +bool SetFileAttrib(CFSTR fileName, DWORD fileAttributes, + CObjectVector<CDelayedSymLink> *delayedSymLinks) { if (!fileName) { SetLastError(ERROR_PATH_NOT_FOUND); @@ -375,7 +376,9 @@ bool SetFileAttrib(CFSTR fileName, DWORD stat_info.st_mode = fileAttributes >> 16; #ifdef ENV_HAVE_LSTAT if (S_ISLNK(stat_info.st_mode)) { - if ( convert_to_symlink(name) != 0) { + if (delayedSymLinks) + delayedSymLinks->Add(CDelayedSymLink(name)); + else if ( convert_to_symlink(name) != 0) { TRACEN((printf("SetFileAttrib(%s,%d) : false-3\n",(const char *)name,fileAttributes))) return false; } @@ -885,6 +888,43 @@ bool CTempDir::Remove() return !_mustBeDeleted; } +#ifdef ENV_UNIX + +CDelayedSymLink::CDelayedSymLink(const char * source) + : _source(source) +{ + struct stat st; + + if (lstat(_source, &st) == 0) { + _dev = st.st_dev; + _ino = st.st_ino; + } else { + _dev = 0; + } +} + +bool CDelayedSymLink::Create() +{ + struct stat st; + + if (_dev == 0) { + errno = EPERM; + return false; + } + if (lstat(_source, &st) != 0) + return false; + if (_dev != st.st_dev || _ino != st.st_ino) { + // Placeholder file has been overwritten or moved by another + // symbolic link creation + errno = EPERM; + return false; + } + + return convert_to_symlink(_source) == 0; +} + +#endif // ENV_UNIX + }}} --- a/CPP/Windows/FileDir.h +++ b/CPP/Windows/FileDir.h @@ -4,6 +4,7 @@ #define __WINDOWS_FILE_DIR_H #include "../Common/MyString.h" +#include "../Common/MyVector.h" #include "FileIO.h" @@ -11,11 +12,14 @@ namespace NWindows { namespace NFile { namespace NDir { +class CDelayedSymLink; + bool GetWindowsDir(FString &path); bool GetSystemDir(FString &path); bool SetDirTime(CFSTR path, const FILETIME *cTime, const FILETIME *aTime, const FILETIME *mTime); -bool SetFileAttrib(CFSTR path, DWORD attrib); +bool SetFileAttrib(CFSTR path, DWORD attrib, + CObjectVector<CDelayedSymLink> *delayedSymLinks = 0); bool MyMoveFile(CFSTR existFileName, CFSTR newFileName); #ifndef UNDER_CE @@ -69,6 +73,31 @@ public: bool Remove(); }; +// Symbolic links must be created last so that they can't be used to +// create or overwrite files above the extraction directory. +class CDelayedSymLink +{ +#ifdef ENV_UNIX + // Where the symlink should be created. The target is specified in + // the placeholder file. + AString _source; + + // Device and inode of the placeholder file. Before creating the + // symlink, we must check that these haven't been changed by creation + // of another symlink. + dev_t _dev; + ino_t _ino; + +public: + explicit CDelayedSymLink(const char * source); + bool Create(); +#else // !ENV_UNIX +public: + CDelayedSymLink(const char * source) {} + bool Create() { return true; } +#endif // ENV_UNIX +}; + #if !defined(UNDER_CE) class CCurrentDirRestorer {
