Add file logger support. The script uses:
function init (args)
local needs = {}
needs['type'] = 'file'
return needs
end
The type is set to file to make it a file logger.
Add utility functions for placing things on the stack for use
by the scripts. Functions for numbers, strings and byte arrays.
Add callback for returing IP header info: ip version, src ip,
dst ip, proto, sp, dp (or type and code for icmp and icmpv6):
SCPacketTuple
Through 'needs' the script init function can indicate it wants to
see packets and select a condition function. Currently only alerts
is an option:
function init (args)
local needs = {}
needs["type"] = "packet"
needs["filter"] = "alerts"
return needs
end
Add an argument to the registration to indicate which iterator
needs to be used: Stream or HttpBody
Add HttpBody Iterator, calling the logger(s) for each Http body chunk.
StreamIterator implementation for iterating over ACKed segments.
Flag each segment as logged when the log function has been called for it.
Set a 'OPEN' flag for the first segment in both directions.
Set a 'CLOSE' flag when the stream ends. If the last segment was already
logged, a empty CLOSE call is performed with NULL data.
This patch adds a new Log API for streaming data such as TCP reassembled
data and HTTP body data. It could also replace Filedata API.
Each time a new chunk of data is available, the callback will be called.
- Removed unnecessary assignment of the data field
- Removed else condition (same function called for IPv4 and IPV6)
- Fixed constants to be a power of two (used in bitwise operations)
The field ext_pkt was cleaned before calling the release function.
The result was that IPS mode such as the one of AF_PACKET were not
working anymore because they were not able to send the data which
were initially pointed by ext_pkt.
This patch moves the ext_pkt cleaning to the cleaning macro. This
ensures that the cleaning is done for allocated and pool packets.
Call PACKET_RELEASE_REFS from PacketPoolGetPacket() so that
we only access the large packet structure just before actually
using it. Should give better cache behaviour.
The Source Routing Header had routing defined as a char* for a field
of variable size. Since that field was not being used in the code, I
removed the pointer and added a comment.
Structures that are used to cast packet data into fields need to be packed
so that the compiler doesn't add any padding to these fields. This also helps
Tile-Gx to avoid unaligned loads because the compiler will insert code to
handle the possible unaligned load.
The base 'lua' library has different names on different OS' and even
Linux distro's. Instead of selecting the proper one, we now just try
all. This way no OS/distro specific knowledge about the name is needed.
Reported in bug 1238 is an issue where stream reassembly can be
disrupted.
A packet that was in-window, but otherwise unexpected set the
window to a really low value, causing the next *expected* packet
to be considered out of window. This lead to missing data in the
stream reassembly.
The packet was unexpected in various ways:
- it would ack unseen traffic
- it's sequence number would not match the expected next_seq
- set a really low window, while not being a proper window update
Detection however, it greatly hampered by the fact that in case of
packet loss, quite similar packets come in. Alerting in this case
is unwanted. Ignoring/skipping packets in this case as well.
The logic used in this patch is as follows. If:
- the packet is not a window update AND
- packet seq > next_seq AND
- packet acq > next_seq (packet acks unseen data) AND
- packet shrinks window more than it's own data size
THEN set event and skip the packet in the stream engine.
So in case of a segment with no data, any window shrinking is rejected.
Bug #1238.
Until now the time out handling in defrag was done using a single
uint32_t that tracked seconds. This lead to corner cases, where
defrag trackers could be timed out a little too early.
If a next header / protocol is encountered that we can't handle (yet)
set an event. Disabled the rule by default.
decode-event:ipv6.unknown_next_header;
Fix or rather implement handling of unfragmentable exthdrs in ipv6.
The exthdr(s) appearing before the frag header were copied into the
reassembled packet correctly, however the stripping of the frag header
did not work correctly.
Example:
The common case is a frag header directly after the ipv6 header:
[ipv6 header]->[frag header]->[icmpv6 (part1)]
[ipv6 header]->[frag header]->[icmpv6 (part2)]
This would result in:
[ipv6 header]->[icmpv6]
The ipv6 headers 'next header' setting would be updated to point to
whatever the frag header was pointing to.
This would also happen when is this case:
[ipv6 header]->[hop header]->[frag header]->[icmpv6 (part1)]
[ipv6 header]->[hop header]->[frag header]->[icmpv6 (part2)]
The result would be:
[ipv6 header]->[hop header]->[icmpv6]
However, here too the ipv6 header would have been updated to point
to what the frag header pointed at. So it would consider the hop header
as if it was an ICMPv6 header, or whatever the frag header pointed at.
The result is that packets would not be correctly parsed, and thus this
issue can lead to evasion.
This patch implements handling of the unfragmentable part. In the first
segment that is stored in the list for reassembly, this patch detects
unfragmentable headers and updates it to have the last unfragmentable
header point to the layer after the frag header.
Also, the ipv6 headers 'next hdr' is only updated if no unfragmentable
headers are used. If they are used, the original value is correct.
Reported-By: Rafael Schaefer <rschaefer@ernw.de>
Bug #1244.
Victor Julien
Ken Steele
Duarte Silva
Eric Leblond
Giuseppe Longo