Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Flow bytes pkts either support/v4 #11897

Closed
wants to merge 2 commits into from
Closed
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
44 changes: 44 additions & 0 deletions doc/userguide/rules/flow-keywords.rst
Original file line number Diff line number Diff line change
Expand Up @@ -340,6 +340,28 @@ Signature example::

alert ip any any -> any any (msg:"Flow has 20 packets"; flow.pkts_toclient:20; sid:1;)

flow.pkts_either
------------------

Flow number of packets in either direction (integer)
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

nit:

Suggested change
Flow number of packets in either direction (integer)
Flow number of packets in either direction (integer).

Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I wonder if it is needed to add that it is either, but not the some of both - or if it is clear enough.

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I think mathematically either is different than both or/and sum. But, if it seems like it can confuse new people, sure. Do you have suggestions on incorporating it in the sentence?

This keyword does not wait for the end of the flow, but will be checked at each packet.

flow.pkts_either uses an :ref:`unsigned 32-bit integer <rules-integer-keywords>`.

Syntax::

flow.pkts_either: [op]<number>

The number of packets can be matched exactly, or compared using the _op_ setting::

flow.pkts_either:3 # exactly 3
flow.pkts_either:<3 # smaller than 3
flow.pkts_either:>=2 # greater than or equal to 2
Comment on lines +357 to +359
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Is this list non-exhaustive? Should we somehow indicate the other possible operations (even if by just adding a "for example", at the end of the sentence?

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Well, we do link to all the possible ops in the ref tag above. It leads to this elaborate doc: https://docs.suricata.io/en/latest/rules/integer-keywords.html#rules-integer-keywords.
Lmk if this does not seem enough


Signature example::

alert ip any any -> any any (msg:"Flow has 20 packets in either dir"; flow.pkts_either:20; sid:1;)

flow.pkts_toserver
------------------

Expand Down Expand Up @@ -405,3 +427,25 @@ The number of packets can be matched exactly, or compared using the _op_ setting
Signature example::

alert ip any any -> any any (msg:"Flow has less than 2000 bytes"; flow.bytes_toserver:<2000; sid:1;)

flow.bytes_either
-------------------

Flow number of bytes in either direction (integer)
This keyword does not wait for the end of the flow, but will be checked at each packet.

flow.bytes_either uses an :ref:`unsigned 64-bit integer <rules-integer-keywords>`.

Syntax::

flow.bytes_either: [op]<number>

The number of packets can be matched exactly, or compared using the _op_ setting::

flow.bytes_either:3 # exactly 3
flow.bytes_either:<3 # smaller than 3
flow.bytes_either:>=2 # greater than or equal to 2

Signature example::

alert ip any any -> any any (msg:"Flow has greater than 3000 bytes in either dir"; flow.bytes_either:>3000; sid:1;)
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

nit:

Suggested change
alert ip any any -> any any (msg:"Flow has greater than 3000 bytes in either dir"; flow.bytes_either:>3000; sid:1;)
alert ip any any -> any any (msg:"Flow is greater than 3000 bytes in either dir"; flow.bytes_either:>3000; sid:1;)

2 changes: 2 additions & 0 deletions src/detect-engine-register.c
Original file line number Diff line number Diff line change
Expand Up @@ -571,8 +571,10 @@ void SigTableSetup(void)
DetectFlowAgeRegister();
DetectFlowPktsToClientRegister();
DetectFlowPktsToServerRegister();
DetectFlowPktsEitherRegister();
DetectFlowBytesToClientRegister();
DetectFlowBytesToServerRegister();
DetectFlowBytesEitherRegister();
DetectRequiresRegister();
DetectWindowRegister();
DetectRpcRegister();
Expand Down
2 changes: 2 additions & 0 deletions src/detect-engine-register.h
Original file line number Diff line number Diff line change
Expand Up @@ -126,8 +126,10 @@ enum DetectKeywordId {
DETECT_FLOW_AGE,
DETECT_FLOW_PKTS_TO_CLIENT,
DETECT_FLOW_PKTS_TO_SERVER,
DETECT_FLOW_PKTS_EITHER,
DETECT_FLOW_BYTES_TO_CLIENT,
DETECT_FLOW_BYTES_TO_SERVER,
DETECT_FLOW_BYTES_EITHER,

DETECT_REQUIRES,

Expand Down
138 changes: 137 additions & 1 deletion src/detect-flow-pkts.c
Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
/* Copyright (C) 2023 Open Information Security Foundation
/* Copyright (C) 2023-2024 Open Information Security Foundation
*
* You can copy, redistribute or modify this Program under the terms of
* the GNU General Public License version 2 as published by the Free
Expand All @@ -23,6 +23,89 @@
#include "detect-engine-uint.h"
#include "detect-parse.h"

static int DetectFlowPktsEitherMatch(
DetectEngineThreadCtx *det_ctx, Packet *p, const Signature *s, const SigMatchCtx *ctx)
{
if (p->flow == NULL) {
return 0;
}
uint32_t nb = p->flow->tosrcpktcnt;

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

can avoid using nb and just use p->flow->tosrcpkt_cnt directly?

const DetectU32Data *du32 = (const DetectU32Data *)ctx;
int ret1 = DetectU32Match(nb, du32);
if (ret1 == 1)
return 1;

nb = p->flow->todstpktcnt;
int ret2 = DetectU32Match(nb, du32);
if (ret2 == 1)
return 1;

return 0;
}

static void DetectFlowPktsEitherFree(DetectEngineCtx *de_ctx, void *ptr)
{
rs_detect_u32_free(ptr);
}

static int DetectFlowPktsEitherSetup(DetectEngineCtx *de_ctx, Signature *s, const char *rawstr)
{
DetectU32Data *du32 = DetectU32Parse(rawstr);
if (du32 == NULL)
return -1;

if (SigMatchAppendSMToList(de_ctx, s, DETECT_FLOW_PKTS_EITHER, (SigMatchCtx *)du32,
DETECT_SM_LIST_MATCH) == NULL) {
DetectFlowPktsEitherFree(de_ctx, du32);
return -1;
}
s->flags |= SIG_FLAG_REQUIRE_PACKET;

return 0;
}

static void PrefilterPacketFlowPktsEitherMatch(
DetectEngineThreadCtx *det_ctx, Packet *p, const void *pectx)
{
const PrefilterPacketHeaderCtx *ctx = pectx;
if (!PrefilterPacketHeaderExtraMatch(ctx, p))
return;

DetectU32Data du32;
du32.mode = ctx->v1.u8[0];
du32.arg1 = ctx->v1.u32[1];
du32.arg2 = ctx->v1.u32[2];
if (DetectFlowPktsEitherMatch(det_ctx, p, NULL, (const SigMatchCtx *)&du32)) {
PrefilterAddSids(&det_ctx->pmq, ctx->sigs_array, ctx->sigs_cnt);
}
}

static int PrefilterSetupFlowPktsEither(DetectEngineCtx *de_ctx, SigGroupHead *sgh)
{
return PrefilterSetupPacketHeader(de_ctx, sgh, DETECT_FLOW_PKTS_EITHER, SIG_MASK_REQUIRE_FLOW,
PrefilterPacketU32Set, PrefilterPacketU32Compare, PrefilterPacketFlowPktsEitherMatch);
}

static bool PrefilterFlowPktsEitherIsPrefilterable(const Signature *s)
{
return PrefilterIsPrefilterableById(s, DETECT_FLOW_PKTS_EITHER);
}

void DetectFlowPktsEitherRegister(void)
{
sigmatch_table[DETECT_FLOW_PKTS_EITHER].name = "flow.pkts_either";
sigmatch_table[DETECT_FLOW_PKTS_EITHER].desc =
"match flow number of packets in either direction";
sigmatch_table[DETECT_FLOW_PKTS_EITHER].url = "/rules/flow-keywords.html#flow-pkts_either";
sigmatch_table[DETECT_FLOW_PKTS_EITHER].Match = DetectFlowPktsEitherMatch;
sigmatch_table[DETECT_FLOW_PKTS_EITHER].Setup = DetectFlowPktsEitherSetup;
sigmatch_table[DETECT_FLOW_PKTS_EITHER].Free = DetectFlowPktsEitherFree;
sigmatch_table[DETECT_FLOW_PKTS_EITHER].SupportsPrefilter =
PrefilterFlowPktsEitherIsPrefilterable;
sigmatch_table[DETECT_FLOW_PKTS_EITHER].SetupPrefilter = PrefilterSetupFlowPktsEither;
}

static int DetectFlowPktsToClientMatch(
DetectEngineThreadCtx *det_ctx, Packet *p, const Signature *s, const SigMatchCtx *ctx)
{
Expand Down Expand Up @@ -171,6 +254,59 @@ void DetectFlowPktsToServerRegister(void)
sigmatch_table[DETECT_FLOW_PKTS_TO_SERVER].SetupPrefilter = PrefilterSetupFlowPktsToServer;
}

static int DetectFlowBytesEitherMatch(
DetectEngineThreadCtx *det_ctx, Packet *p, const Signature *s, const SigMatchCtx *ctx)
{
if (p->flow == NULL) {
return 0;
}
uint64_t nb = p->flow->tosrcbytecnt;

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

same as with pkts

const DetectU64Data *du64 = (const DetectU64Data *)ctx;
int ret1 = DetectU64Match(nb, du64);
if (ret1 == 1)
return 1;

nb = p->flow->todstbytecnt;
int ret2 = DetectU64Match(nb, du64);
if (ret2 == 1)
return 1;

return 0;
}

static void DetectFlowBytesEitherFree(DetectEngineCtx *de_ctx, void *ptr)
{
rs_detect_u64_free(ptr);
}

static int DetectFlowBytesEitherSetup(DetectEngineCtx *de_ctx, Signature *s, const char *rawstr)
{
DetectU64Data *du64 = DetectU64Parse(rawstr);
if (du64 == NULL)
return -1;

if (SigMatchAppendSMToList(de_ctx, s, DETECT_FLOW_BYTES_EITHER, (SigMatchCtx *)du64,
DETECT_SM_LIST_MATCH) == NULL) {
DetectFlowBytesEitherFree(de_ctx, du64);
return -1;
}
s->flags |= SIG_FLAG_REQUIRE_PACKET;

return 0;
}

void DetectFlowBytesEitherRegister(void)
{
sigmatch_table[DETECT_FLOW_BYTES_EITHER].name = "flow.bytes_either";
sigmatch_table[DETECT_FLOW_BYTES_EITHER].desc =
"match flow number of bytes in either direction";
sigmatch_table[DETECT_FLOW_BYTES_EITHER].url = "/rules/flow-keywords.html#flow-bytes_either";
sigmatch_table[DETECT_FLOW_BYTES_EITHER].Match = DetectFlowBytesEitherMatch;
sigmatch_table[DETECT_FLOW_BYTES_EITHER].Setup = DetectFlowBytesEitherSetup;
sigmatch_table[DETECT_FLOW_BYTES_EITHER].Free = DetectFlowBytesEitherFree;
}

static int DetectFlowBytesToClientMatch(
DetectEngineThreadCtx *det_ctx, Packet *p, const Signature *s, const SigMatchCtx *ctx)
{
Expand Down
2 changes: 2 additions & 0 deletions src/detect-flow-pkts.h
Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,9 @@

void DetectFlowPktsToClientRegister(void);
void DetectFlowPktsToServerRegister(void);
void DetectFlowPktsEitherRegister(void);
void DetectFlowBytesToClientRegister(void);
void DetectFlowBytesToServerRegister(void);
void DetectFlowBytesEitherRegister(void);

#endif /* SURICATA_DETECT_FLOW_PKTS_H */
Loading