added new filter to remove xml bombs. To be continued

git-svn-id: http://svn.code.sf.net/p/retroshare/code/trunk@6748 b45a01b8-16f6-495d-af2f-9b41ad6348cc
This commit is contained in:
csoler 2013-09-18 19:32:04 +00:00
parent 235a189774
commit 37f00e90a0

View File

@ -38,7 +38,7 @@ inline void* right_shift_void_pointer(void* p, uint32_t len) {
}
//*********************
#define TLV_BASE_DEBUG 1
//#define TLV_BASE_DEBUG 1
/**** Basic TLV Functions ****/
uint32_t GetTlvSize(void *data) {
@ -564,14 +564,35 @@ bool GetTlvWideString(void *data, uint32_t size, uint32_t *offset,
// Check for message content. We want to avoid possible lol bombs as soon as possible.
wchar_t tmp[10];
mbstowcs(tmp, "<!", 9);
static const int number_of_suspiscious_strings = 4 ;
static const std::wstring err_in = L"**** String removed (SVG bomb?) ****" ;
static std::wstring suspiscious_strings[number_of_suspiscious_strings] = { L"<!e", // base ingredient of xml bombs
L"<!E",
L"PD94bWwg", // this is the base64 encoding of <?xml
L"PHN2Zy" // this is the base64 encoding of <svg
} ;
#ifdef TLV_BASE_DEBUG
std::wcerr << L"Checking wide string \"" << in << std::endl;
#endif
// Drop any string with "<!" or "<!"...
// TODO: check what happens with partial messages
//
if (in.find(tmp) != std::string::npos)
in = L"**** This string has been removed because it contains \"<!\" (forbidden for security reasons).****" ;
for(int i=0;i<number_of_suspiscious_strings;++i)
if (in.find(suspiscious_strings[i]) != std::string::npos)
{
std::wcerr << L"**** suspiscious wstring contains \"" << suspiscious_strings[i] << L"\" (SVG bomb suspected). " ;
std::cerr << "========== Original string =========" << std::endl;
std::wcerr << in << std::endl;
std::cerr << "=============== END ================" << std::endl;
for(uint32_t k=0;k<in.length();++k)
if(k < err_in.length())
in[k] = err_in[k] ; // It's important to keep the same size for in than the size it should have,
else
in[k] = L' '; // otherwise the deserialization of derived items that use it might fail
break ;
}
return ok;
}