From 070a24e7f53bd44ee96f69a19241312bce153d47 Mon Sep 17 00:00:00 2001
From: Victor Julien <vjulien@oisf.net>
Date: Mon, 25 Sep 2023 20:14:29 +0200
Subject: [PATCH] detect/asn1: handle in PMATCH

Since the asn1 keyword is processing payload data, move the handling of
the keyword into the PMATCH with content inspection.
---
 src/detect-asn1.c                      | 41 +++++---------------------
 src/detect-asn1.h                      |  3 ++
 src/detect-engine-content-inspection.c |  8 +++++
 3 files changed, 19 insertions(+), 33 deletions(-)

diff --git a/src/detect-asn1.c b/src/detect-asn1.c
index 5b3a3a2229b2..c70bf8921fd3 100644
--- a/src/detect-asn1.c
+++ b/src/detect-asn1.c
@@ -36,8 +36,6 @@
 #include "util-byte.h"
 #include "util-debug.h"
 
-static int DetectAsn1Match(DetectEngineThreadCtx *, Packet *,
-                     const Signature *, const SigMatchCtx *);
 static int DetectAsn1Setup (DetectEngineCtx *, Signature *, const char *);
 #ifdef UNITTESTS
 static void DetectAsn1RegisterTests(void);
@@ -50,7 +48,6 @@ static void DetectAsn1Free(DetectEngineCtx *, void *);
 void DetectAsn1Register(void)
 {
     sigmatch_table[DETECT_ASN1].name = "asn1";
-    sigmatch_table[DETECT_ASN1].Match = DetectAsn1Match;
     sigmatch_table[DETECT_ASN1].Setup = DetectAsn1Setup;
     sigmatch_table[DETECT_ASN1].Free  = DetectAsn1Free;
 #ifdef UNITTESTS
@@ -58,37 +55,14 @@ void DetectAsn1Register(void)
 #endif
 }
 
-/**
- * \brief This function will decode the asn1 data and inspect the resulting
- *        nodes to detect if any of the specified checks match this data
- *
- * \param det_ctx pointer to the detect engine thread context
- * \param p pointer to the current packet
- * \param s pointer to the signature
- * \param ctx pointer to the sigmatch that we will cast into `DetectAsn1Data`
- *
- * \retval 1 match
- * \retval 0 no match
- */
-static int DetectAsn1Match(DetectEngineThreadCtx *det_ctx, Packet *p,
-                    const Signature *s, const SigMatchCtx *ctx)
+bool DetectAsn1Match(const SigMatchData *smd, const uint8_t *buffer, const uint32_t buffer_len,
+        const uint32_t offset)
 {
-    uint8_t ret = 0;
-
-    if (p->payload_len == 0) {
-        /* No error, parser done, no data in bounds to decode */
-        return 0;
-    }
-
-    const DetectAsn1Data *ad = (const DetectAsn1Data *)ctx;
-
-    Asn1 *asn1 = rs_asn1_decode(p->payload, p->payload_len, det_ctx->buffer_offset, ad);
-
-    ret = rs_asn1_checks(asn1, ad);
-
+    const DetectAsn1Data *ad = (const DetectAsn1Data *)smd->ctx;
+    Asn1 *asn1 = rs_asn1_decode(buffer, buffer_len, offset, ad);
+    uint8_t ret = rs_asn1_checks(asn1, ad);
     rs_asn1_free(asn1);
-
-    return ret;
+    return ret == 1;
 }
 
 /**
@@ -127,12 +101,13 @@ static int DetectAsn1Setup(DetectEngineCtx *de_ctx, Signature *s, const char *as
     if (ad == NULL)
         return -1;
 
-    if (SigMatchAppendSMToList(de_ctx, s, DETECT_ASN1, (SigMatchCtx *)ad, DETECT_SM_LIST_MATCH) ==
+    if (SigMatchAppendSMToList(de_ctx, s, DETECT_ASN1, (SigMatchCtx *)ad, DETECT_SM_LIST_PMATCH) ==
             NULL) {
         DetectAsn1Free(de_ctx, ad);
         return -1;
     }
 
+    s->flags |= SIG_FLAG_REQUIRE_PACKET;
     return 0;
 }
 
diff --git a/src/detect-asn1.h b/src/detect-asn1.h
index a7b67340aa27..8c81ddcb305b 100644
--- a/src/detect-asn1.h
+++ b/src/detect-asn1.h
@@ -26,4 +26,7 @@
 /* prototypes */
 void DetectAsn1Register (void);
 
+bool DetectAsn1Match(const SigMatchData *smd, const uint8_t *buffer, const uint32_t buffer_len,
+        const uint32_t offset);
+
 #endif /* __DETECT_ASN1_H__ */
diff --git a/src/detect-engine-content-inspection.c b/src/detect-engine-content-inspection.c
index 8c5feb61a226..d6dc980bf1d0 100644
--- a/src/detect-engine-content-inspection.c
+++ b/src/detect-engine-content-inspection.c
@@ -31,6 +31,7 @@
 #include "detect.h"
 #include "detect-engine.h"
 #include "detect-parse.h"
+#include "detect-asn1.h"
 #include "detect-content.h"
 #include "detect-pcre.h"
 #include "detect-isdataat.h"
@@ -683,6 +684,13 @@ uint8_t DetectEngineContentInspection(DetectEngineCtx *de_ctx, DetectEngineThrea
                 }
             }
         }
+    } else if (smd->type == DETECT_ASN1) {
+        if (!DetectAsn1Match(smd, buffer, buffer_len, det_ctx->buffer_offset)) {
+            SCLogDebug("asn1 no_match");
+            goto no_match;
+        }
+        SCLogDebug("asn1 match");
+        goto match;
     } else {
         SCLogDebug("sm->type %u", smd->type);
 #ifdef DEBUG