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Try to prevent (as much as possible) transfering and, more important, storing, any other files than avatars as png, gif and jpg. The headers of the files are checked whether they are valid for the corresponding format. Files without gif/png/jpg header are never stored on the server, and thus cannot be requested by any client.

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This commit is contained in:
lotodore
2007-10-18 23:00:55 +00:00
parent 8cd93ced8c
commit 6a297effc1
3 changed files with 70 additions and 11 deletions
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src/core/common/avatarmanager.cpp
+66 -10
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@@ -27,6 +27,15 @@
#include <fstream>
#include <cstring>
#define PNG_HEADER "\x89\x50\x4e\x47\x0d\x0a\x1a\x0a"
#define PNG_HEADER_SIZE (sizeof(PNG_HEADER) - 1)
#define JPG_HEADER "\xff\xd8"
#define JPG_HEADER_SIZE (sizeof(JPG_HEADER) - 1)
#define GIF_HEADER_1 "GIF87a"
#define GIF_HEADER_2 "GIF89a"
#define GIF_HEADER_SIZE (sizeof(GIF_HEADER_1) - 1)
#define MAX_HEADER_SIZE PNG_HEADER_SIZE
// Not using boost::algorithm here because of STL issues.
#ifdef _MSC_VER
#define STRCASECMP _stricmp
@@ -103,8 +112,16 @@ AvatarManager::OpenAvatarFileForChunkRead(const std::string &fileName, unsigned
fileState->inputStream.seekg(0, ios_base::beg);
std::streamoff posDiff(endPos - startPos);
outFileSize = (unsigned)posDiff;
if (outFileSize <= MAX_AVATAR_FILE_SIZE)
retVal = fileState;
if (outFileSize >= MIN_AVATAR_FILE_SIZE && outFileSize <= MAX_AVATAR_FILE_SIZE)
{
// Validate type of file by verifying image header.
unsigned char fileHeader[MAX_HEADER_SIZE];
fileState->inputStream.read((char *)fileHeader, sizeof(fileHeader));
fileState->inputStream.seekg(0, ios_base::beg);
if (IsValidAvatarFileType(outFileType, fileHeader, sizeof(fileHeader)))
retVal = fileState;
}
}
} catch (...)
{
@@ -288,16 +305,20 @@ AvatarManager::StoreAvatarInCache(const MD5Buf &md5buf, AvatarFileType avatarFil
}
if (!ext.empty())
{
path tmpPath(m_cacheDir);
tmpPath /= (md5buf.ToString() + ext);
string fileName(tmpPath.file_string());
ofstream o(fileName.c_str(), ios_base::out | ios_base::binary);
o.write((const char *)data, size);
// Check header before storing file.
if (IsValidAvatarFileType(avatarFileType, data, size))
{
boost::mutex::scoped_lock lock(m_cachedAvatarsMutex);
m_cachedAvatars.insert(AvatarMap::value_type(md5buf, fileName));
path tmpPath(m_cacheDir);
tmpPath /= (md5buf.ToString() + ext);
string fileName(tmpPath.file_string());
ofstream o(fileName.c_str(), ios_base::out | ios_base::binary);
o.write((const char *)data, size);
{
boost::mutex::scoped_lock lock(m_cachedAvatarsMutex);
m_cachedAvatars.insert(AvatarMap::value_type(md5buf, fileName));
}
retVal = true;
}
retVal = true;
}
} catch (...)
{
@@ -305,6 +326,41 @@ AvatarManager::StoreAvatarInCache(const MD5Buf &md5buf, AvatarFileType avatarFil
return retVal;
}
bool
AvatarManager::IsValidAvatarFileType(AvatarFileType avatarFileType, const unsigned char *fileHeader, unsigned fileHeaderSize)
{
bool validType = false;
switch (avatarFileType)
{
case AVATAR_FILE_TYPE_PNG:
if (fileHeaderSize >= PNG_HEADER_SIZE
&& memcmp(fileHeader, PNG_HEADER, PNG_HEADER_SIZE) == 0)
{
validType = true;
}
break;
case AVATAR_FILE_TYPE_JPG:
if (fileHeaderSize >= JPG_HEADER_SIZE
&& memcmp(fileHeader, JPG_HEADER, JPG_HEADER_SIZE) == 0)
{
validType = true;
}
break;
case AVATAR_FILE_TYPE_GIF:
if (fileHeaderSize >= GIF_HEADER_SIZE
&& (memcmp(fileHeader, GIF_HEADER_1, GIF_HEADER_SIZE) == 0
|| memcmp(fileHeader, GIF_HEADER_2, GIF_HEADER_SIZE) == 0))
{
validType = true;
}
break;
case AVATAR_FILE_TYPE_UNKNOWN:
break;
}
return validType;
}
bool
AvatarManager::InternalReadDirectory(const std::string &dir, AvatarMap &avatars)
{