mirror of
https://github.com/zeek/zeek.git
synced 2025-10-02 14:48:21 +00:00
Fixes to SSL/TLS analyzer
Analyzer can cope with zero length client and server certificates. It does still generate a weird though. Extended cipherspec_size weirds are not thrown anymore, they are incredibly overwhelming and should be handled completely at the scripting in my opinion. Integrated and expanded on patch Rmkml from ticket #209 that fixes problem with not parsing or expecting SSL extensions. SSL extensions still are not extracted and passed to script land, but the analyzer doesn't fail anymore.
This commit is contained in:
Seth Hall
parent
c8076619ce
commit
1ccfca09ac
2 changed files with 92 additions and 98 deletions
|
|
@ -174,7 +174,6 @@ bool SSL_RecordBuilder::addSegment(const u_char* data, int length)
|
|||
if ( ! computeExpectedSize(data, length) )
|
||||
return false;
|
||||
|
||||
// Insert weird here replacing assert.
|
||||
if ( neededSize > expectedSize )
|
||||
{
|
||||
sslEndpoint->Weird("SSL_RecordBuilder::addSegment neededSize > expectedSize");
|
||||
|
|
@ -278,7 +277,6 @@ bool SSL_RecordBuilder::addSegment(const u_char* data, int length)
|
|||
{ // another (middle) segment
|
||||
if ( length <= MIN_FRAGMENT_SIZE )
|
||||
sslEndpoint->Parent()->Weird( "SSLProxy: Excessive small TCP Segment!" );
|
||||
|
||||
addData(data, length);
|
||||
break;
|
||||
}
|
||||
|
|
|
|||
188
src/SSLv3.cc
188
src/SSLv3.cc
|
|
@ -383,84 +383,71 @@ void SSLv3_Interpreter::DeliverSSLv3_Record(SSLv3_HandshakeRecord* rec)
|
|||
|
||||
case SSL3_1_CERTIFICATE:
|
||||
{
|
||||
if ( rec->length >= 3 )
|
||||
const u_char* pData = rec->data;
|
||||
uint32 certListLength =
|
||||
uint32((pData[4] << 16) |
|
||||
pData[5] << 8) | pData[6];
|
||||
|
||||
// Sum of all cert sizes has to match
|
||||
// certListLength.
|
||||
uint tempLength = 0;
|
||||
uint certCount = 0;
|
||||
while ( tempLength < certListLength )
|
||||
{
|
||||
const u_char* pData = rec->data;
|
||||
uint32 certListLength =
|
||||
uint32((pData[4] << 16) |
|
||||
pData[5] << 8) | pData[6];
|
||||
|
||||
// Size consistency checks.
|
||||
if ( certListLength + 3 != uint32(rec->length) )
|
||||
if ( tempLength + 3 <= certListLength )
|
||||
{
|
||||
if ( rec->endp->IsOrig() )
|
||||
Weird("SSLv3x: Corrupt length field in client certificate list!");
|
||||
else
|
||||
Weird("SSLv3x: Corrupt length field in server certificate list!");
|
||||
return;
|
||||
}
|
||||
|
||||
// Sum of all cert sizes has to match
|
||||
// certListLength.
|
||||
uint tempLength = 0;
|
||||
uint certCount = 0;
|
||||
while ( tempLength < certListLength )
|
||||
{
|
||||
if ( tempLength + 3 <= certListLength )
|
||||
{
|
||||
++certCount;
|
||||
uint32 certLength =
|
||||
uint32((pData[tempLength + 7] << 16) | pData[tempLength + 8] << 8) | pData[tempLength + 9];
|
||||
tempLength += certLength + 3;
|
||||
}
|
||||
else
|
||||
{
|
||||
Weird("SSLv3x: Corrupt length field in certificate list!");
|
||||
return;
|
||||
}
|
||||
}
|
||||
|
||||
if ( tempLength > certListLength )
|
||||
{
|
||||
Weird("SSLv3x: sum of size of certificates doesn't match size of certificate chain");
|
||||
return;
|
||||
}
|
||||
|
||||
SSL_InterpreterEndpoint* pEp =
|
||||
(SSL_InterpreterEndpoint*) rec->endp;
|
||||
|
||||
if ( certCount == 0 )
|
||||
{ // we don't have a certificate...
|
||||
if ( rec->endp->IsOrig() )
|
||||
{
|
||||
Weird("SSLv3x: Client certificate is missing!");
|
||||
break;
|
||||
}
|
||||
else
|
||||
{
|
||||
Weird("SSLv3x: Server certificate is missing!");
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
if ( certCount > 1 )
|
||||
{ // we have a chain
|
||||
analyzeCertificate(pEp,
|
||||
rec->data + 7,
|
||||
certListLength, 1, true);
|
||||
++certCount;
|
||||
uint32 certLength =
|
||||
uint32((pData[tempLength + 7] << 16) | pData[tempLength + 8] << 8) | pData[tempLength + 9];
|
||||
tempLength += certLength + 3;
|
||||
}
|
||||
else
|
||||
{
|
||||
// We have a single certificate.
|
||||
// FIXME.
|
||||
analyzeCertificate(pEp,
|
||||
rec->data + 10,
|
||||
certListLength-3, 1, false);
|
||||
Weird("SSLv3x: Corrupt length field in certificate list!");
|
||||
return;
|
||||
}
|
||||
}
|
||||
|
||||
if ( tempLength > certListLength )
|
||||
{
|
||||
Weird("SSLv3x: sum of size of certificates doesn't match size of certificate chain");
|
||||
return;
|
||||
}
|
||||
|
||||
SSL_InterpreterEndpoint* pEp =
|
||||
(SSL_InterpreterEndpoint*) rec->endp;
|
||||
|
||||
if ( certCount == 0 )
|
||||
{
|
||||
// we don't have a certificate, but this is valid
|
||||
// according to RFC2246
|
||||
if ( rec->endp->IsOrig() )
|
||||
{
|
||||
Weird("SSLv3x: Client certificate is missing!");
|
||||
break;
|
||||
}
|
||||
else
|
||||
{
|
||||
Weird("SSLv3x: Server certificate is missing!");
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
if ( certCount > 1 )
|
||||
{ // we have a chain
|
||||
analyzeCertificate(pEp,
|
||||
rec->data + 7,
|
||||
certListLength, 1, true);
|
||||
}
|
||||
else
|
||||
Weird("SSLv3x: Certificate record too small!" );
|
||||
{
|
||||
// We have a single certificate.
|
||||
// FIXME.
|
||||
analyzeCertificate(pEp,
|
||||
rec->data + 10,
|
||||
certListLength-3, 1, false);
|
||||
}
|
||||
|
||||
break;
|
||||
}
|
||||
|
||||
|
|
@ -938,13 +925,15 @@ TableVal* SSLv3_Interpreter::analyzeCiphers(const SSLv3_Endpoint* s, int length,
|
|||
{
|
||||
int is_orig = (SSL_InterpreterEndpoint*) s == orig;
|
||||
|
||||
if ( length > ssl_max_cipherspec_size )
|
||||
{
|
||||
if ( is_orig )
|
||||
Weird("SSLv3: Client has CipherSpecs > ssl_max_cipherspec_size");
|
||||
else
|
||||
Weird("SSLv3: Server has CipherSpecs > ssl_max_cipherspec_size");
|
||||
}
|
||||
// This probably shouldn't be a weird. This data should be passed to
|
||||
// script layer and dealt with there as appropriate.
|
||||
//if ( length > ssl_max_cipherspec_size )
|
||||
// {
|
||||
// if ( is_orig )
|
||||
// Weird("SSLv3: Client has CipherSpecs > ssl_max_cipherspec_size");
|
||||
// else
|
||||
// Weird("SSLv3: Server has CipherSpecs > ssl_max_cipherspec_size");
|
||||
// }
|
||||
|
||||
const u_char* pCipher = data;
|
||||
SSL_CipherSpec* pCipherSuiteTemp = 0;
|
||||
|
|
@ -1236,16 +1225,6 @@ SSLv3_HandshakeRecord::SSLv3_HandshakeRecord(const u_char* data, int len,
|
|||
uint16 version, SSLv3_Endpoint const* e)
|
||||
: SSLv3_Record(data, len, version, e)
|
||||
{
|
||||
// Weird-check for minimum handshake length header.
|
||||
if ( len < 4 )
|
||||
{
|
||||
e->Interpreter()->Weird("SSLv3x: Handshake-header-length too small!");
|
||||
type = 255;
|
||||
length = 0;
|
||||
next = 0;
|
||||
return;
|
||||
}
|
||||
|
||||
// Don't analyze encrypted client handshake messages.
|
||||
if ( e->IsOrig() &&
|
||||
((SSLv3_Interpreter*) e->Interpreter())->change_cipher_client_seen &&
|
||||
|
|
@ -1270,7 +1249,10 @@ SSLv3_HandshakeRecord::SSLv3_HandshakeRecord(const u_char* data, int len,
|
|||
|
||||
type = uint8(*(this->data));
|
||||
length = ExtractInt24(data, len, 1);
|
||||
if ( length + 4 < len )
|
||||
|
||||
if ( length == 0 ) // this is a special case to deal with 0 length certs
|
||||
next = 0;
|
||||
else if ( length + 4 < len )
|
||||
next = new SSLv3_HandshakeRecord(data + length + 4,
|
||||
len - (length + 4), version, e);
|
||||
else if ( length + 4 > len )
|
||||
|
|
@ -1340,7 +1322,6 @@ int SSLv3_HandshakeRecord::checkClientHello()
|
|||
uint16 cipherSuiteLength =
|
||||
uint16(data[offset] << 8) | data[offset+1];
|
||||
offset += (2 + cipherSuiteLength);
|
||||
|
||||
if ( cipherSuiteLength < 2 )
|
||||
endp->Interpreter()->Weird("SSLv3x: CipherSuite length too small!");
|
||||
|
||||
|
|
@ -1352,16 +1333,14 @@ int SSLv3_HandshakeRecord::checkClientHello()
|
|||
|
||||
uint8 compressionMethodLength = uint8(data[offset]);
|
||||
offset += (1 + compressionMethodLength);
|
||||
|
||||
if ( compressionMethodLength < 1 )
|
||||
endp->Interpreter()->Weird("SSLv3x: CompressionMethod length too small!");
|
||||
|
||||
if ( offset != length )
|
||||
if ( offset < length )
|
||||
{
|
||||
uint16 sslExtensionsLength =
|
||||
uint16(data[offset] << 8 ) | data[offset+1];
|
||||
uint16(data[offset] << 8) | data[offset+1];
|
||||
offset += 2;
|
||||
|
||||
if ( sslExtensionsLength < 4 )
|
||||
endp->Interpreter()->Weird("SSLv3x: Extensions length too small!");
|
||||
|
||||
|
|
@ -1391,16 +1370,33 @@ int SSLv3_HandshakeRecord::checkServerHello()
|
|||
version != SSLProxy_Analyzer::SSLv31 )
|
||||
endp->Interpreter()->Weird("SSLv3x: Corrupt version information in Server hello!");
|
||||
|
||||
uint8 sessionIDLength = uint8(data[38]);
|
||||
uint16 offset = 38;
|
||||
uint8 sessionIDLength = uint8(data[offset]);
|
||||
if ( sessionIDLength > 32 )
|
||||
{
|
||||
endp->Interpreter()->Weird("SSLv3x: SessionID too long in Server hello!");
|
||||
return 0;
|
||||
}
|
||||
|
||||
if ( (sessionIDLength + 45) != length )
|
||||
offset += (1 + sessionIDLength);
|
||||
|
||||
offset += 3; // account for cipher and compression method
|
||||
if ( offset < length )
|
||||
{
|
||||
endp->Interpreter()->Weird("SSLv3x: Corrupt length fields in Server hello!");
|
||||
uint16 sslExtensionsLength =
|
||||
uint16(data[offset] << 8) | data[offset+1];
|
||||
offset += 2;
|
||||
if ( sslExtensionsLength < 4 )
|
||||
endp->Interpreter()->Weird("SSLv3x: Extensions length too small!");
|
||||
|
||||
// TODO: extract SSL extensions here
|
||||
offset += sslExtensionsLength;
|
||||
|
||||
if ( offset != length+4 )
|
||||
{
|
||||
endp->Interpreter()->Weird("SSLv3x: Corrupt length fields in Server hello!");
|
||||
return 0;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue