Victor Julien [Wed, 16 Jul 2014 22:23:50 +0000 (00:23 +0200)]
stream: detect and filter out bad window updates
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.
Victor Julien [Tue, 5 Aug 2014 15:28:17 +0000 (17:28 +0200)]
defrag: use 'struct timeval' for timeout tracking
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.
Victor Julien [Thu, 24 Jul 2014 11:39:10 +0000 (13:39 +0200)]
ipv6 defrag: fix unfragmentable exthdr handling
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:
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 [Mon, 16 Jun 2014 12:21:11 +0000 (14:21 +0200)]
defrag: fix timeout setting when config is missing
When the config is missing, DefragPolicyGetHostTimeout will default
to returning -1. This will effectively set no timeout at all, leading
to defrag trackers being freed too early.
Eric Leblond [Tue, 17 Jun 2014 09:19:05 +0000 (11:19 +0200)]
defrag: fix reconstruction
This patch is fixing an issue in defragmentation code. The
insertion of a fragment in the list of fragments is done with
respect to the offset of the fragment. But the code was using
the original offset of the fragment and not the one of the
new reconstructed fragment (which can be different in the
case of overlapping segment where the left part is trimmed).
This case could lead to some evasion techniques by causing
Suricata to analyse a different payload.
Eric Leblond [Fri, 20 Jun 2014 16:11:29 +0000 (18:11 +0200)]
unix socket: fix valgrind issue
This patch fixes the following issue reported by valgrind:
31 errors in context 1 of 1:
Conditional jump or move depends on uninitialised value(s)
at 0x8AB2F8: UnixSocketPcapFilesCheck (runmode-unix-socket.c:279)
by 0x97725D: UnixCommandBackgroundTasks (unix-manager.c:368)
by 0x97BC52: UnixManagerThread (unix-manager.c:884)
by 0x6155F6D: start_thread (pthread_create.c:311)
by 0x6E3A9CC: clone (clone.S:113)
The running field in PcapCommand was not initialized.
Eric Leblond [Fri, 20 Jun 2014 15:46:47 +0000 (17:46 +0200)]
unix-manager: fix crash when client disconnect
This patch fixes an issue in unix socket handling. It is possible
that a socket did disconnect when analysing a command and because
the data treatment is done in a loop on clients this was leading
to a update of the list of clients during the loop. So we need
in fact to use TAILQ_FOREACH_SAFE instead of TAILQ_FOREACH.
Reported-by: Luigi Sandon <luigi.sandon@gmail.com> Fix-suggested-by: Luigi Sandon <luigi.sandon@gmail.com>
Alessandro Guido [Fri, 20 Jun 2014 12:01:11 +0000 (14:01 +0200)]
Fix issue #1214
When applying wildcard thresholds (with sid = 0 and/or gid = 0) it's wrong
to exit on the first signature already having an event filter. Indeed,
doing so results in the theshold not being applied to all subsequent
signatures. Change the code in order to skip signatures with event
filters instead of breaking out of the loop.
*** CID 1220099: Dereference before null check (REVERSE_INULL)
/src/log-droplog.c: 199 in LogDropLogNetFilter()
193 if (SCConfLogReopen(dlt->file_ctx) != 0) {
194 /* Rotation failed, error already logged. */
195 return TM_ECODE_FAILED;
196 }
197 }
198
>>> CID 1220099: Dereference before null check (REVERSE_INULL)
>>> Null-checking "dlt->file_ctx" suggests that it may be null, but it has already been dereferenced on all paths leading to the check.
199 if (dlt->file_ctx == NULL) {
200 return TM_ECODE_FAILED;
201 }
202
203 char srcip[46] = "";
204 char dstip[46] = "";
Victor Julien [Fri, 2 May 2014 15:11:10 +0000 (17:11 +0200)]
http-json: fix coverity warning
*** CID 1211009: Bad bit shift operation (BAD_SHIFT)
/src/output-json-http.c: 265 in JsonHttpLogJSON()
259 /* log custom fields if configured */
260 if (http_ctx->fields != 0)
261 {
262 HttpField f;
263 for (f = HTTP_FIELD_ACCEPT; f < HTTP_FIELD_SIZE; f++)
264 {
>>> CID 1211009: Bad bit shift operation (BAD_SHIFT)
>>> In expression "1 << f", left shifting by more than 31 bits has undefined behavior. The shift amount, "f", is as much as 46.
265 if ((http_ctx->fields & (1<<f)) != 0)
266 {
267 /* prevent logging a field twice if extended logging is
268 enabled */
269 if (((http_ctx->flags & LOG_HTTP_EXTENDED) == 0) ||
270 ((http_ctx->flags & LOG_HTTP_EXTENDED) !=
________________________________________________________________________________________________________
*** CID 1211010: Bad bit shift operation (BAD_SHIFT)
/src/output-json-http.c: 492 in OutputHttpLogInitSub()
486 {
487 if ((strcmp(http_fields[f].config_field,
488 field->val) == 0) ||
489 (strcasecmp(http_fields[f].htp_field,
490 field->val) == 0))
491 {
>>> CID 1211010: Bad bit shift operation (BAD_SHIFT)
>>> In expression "1 << f", left shifting by more than 31 bits has undefined behavior. The shift amount, "f", is as much as 46.
492 http_ctx->fields |= (1<<f);
493 break;
494 }
495 }
496 }
497 }
Victor Julien [Thu, 24 Apr 2014 15:31:08 +0000 (17:31 +0200)]
stream: cleanup
StreamTcpSetDisableRawReassemblyFlag() has the same effect as
AppLayerParserTriggerRawStreamReassembly in that it will force the
raw reassembly to flush out asap. So it is redundant to call both.
Victor Julien [Thu, 24 Apr 2014 08:48:37 +0000 (10:48 +0200)]
stream: implement raw reassembly stop api
Implement StreamTcpSetDisableRawReassemblyFlag() which stops raw
reassembly for _NEW_ segments in a stream direction.
It is used only by TLS/SSL now, to flag the streams as encrypted.
Existing segments will still be reassembled and inspected, while
new segments won't be. This allows for pattern based inspection
of the TLS handshake.
Like is the case with completely disabled 'raw' reassembly, the
logic is that the segments are flagged as completed for 'raw' right
away. So they are not considered in raw reassembly anymore.
As no new segments will be considered, the chunk limit check will
return true on the next call.
Victor Julien [Fri, 2 May 2014 09:01:18 +0000 (11:01 +0200)]
http-json: init 'fields' to 0 before setting it
httplog_ctx->fields would not be initialized before setting flags in
it:
Scanbuild:
output-json-http.c:491:46: warning: The left expression of the compound assignment is an uninitialized value. The computed value will also be garbage
http_ctx->fields |= (1<<f);
~~~~~~~~~~~~~~~~ ^
1 warning generated.
Victor Julien [Wed, 23 Apr 2014 09:00:02 +0000 (11:00 +0200)]
rohash: fix potential bad shift
Fix issue detected byCoverity:
*** CID 1197756: Bad bit shift operation (BAD_SHIFT)
/src/util-rohash.c: 74 in ROHashInit()
68 }
69 if (hash_bits < 4 || hash_bits > 32) {
70 SCLogError(SC_ERR_HASH_TABLE_INIT, "invalid hash_bits setting, valid range is 4-32");
71 return NULL;
72 }
73
>>> CID 1197756: Bad bit shift operation (BAD_SHIFT)
>>> In expression "1U << hash_bits", left shifting by more than 31 bits has undefined behavior. The shift amount, "hash_bits", is as much as 32.
74 uint32_t size = hashsize(hash_bits) * sizeof(ROHashTableOffsets);
75
76 ROHashTable *table = SCMalloc(sizeof(ROHashTable) + size);
77 if (unlikely(table == NULL)) {
78 SCLogError(SC_ERR_HASH_TABLE_INIT, "failed to alloc memory");
79 return NULL;
This was only a potential issue as ROHashInit was only called with
hash_bits 16 in the code.
Eric Leblond [Wed, 23 Apr 2014 09:21:11 +0000 (11:21 +0200)]
af-packet: exit in case of a fatal error
During socket creation all error cases were leading to suricata to
retry the opening of capture. This patch updates this behavior to
have fatal and recoverable error case. In case of a fatal error,
suricata is leaving cleanly.
Victor Julien [Wed, 16 Apr 2014 16:10:22 +0000 (18:10 +0200)]
stream: update GAP detection
Change GAP detection logic. If we encounter missing data before
last_ack, we know we have missed data. The receiving host has ack'd
it already, so a retransmission of the missing data is highly
unlikely.