detect: null sanity checks for pkthdr

Even when the rules are only applied on traffic with the protocol
the structure for the protocol header can be set to NULL if there
was an error parsing the header

src/detect-icmpv6hdr.c

@@ -32,6 +32,7 @@
 #include "detect-engine-content-inspection.h"
 #include "detect-fast-pattern.h"
 #include "detect-icmpv6hdr.h"
+#include "util-validate.h"
 
 /* prototypes */
 static int DetectICMPv6hdrSetup (DetectEngineCtx *, Signature *, const char *);
@@ -104,6 +105,7 @@ static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
     InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
     if (buffer->inspect == NULL) {
         uint32_t hlen = ICMPV6_HEADER_LEN;
+        DEBUG_VALIDATE_BUG_ON(p->icmpv6h == NULL);
         if (((uint8_t *)p->icmpv6h + (ptrdiff_t)hlen) >
                 ((uint8_t *)GET_PKT_DATA(p) + (ptrdiff_t)GET_PKT_LEN(p)))
         {

src/detect-ipv4hdr.c

@@ -100,6 +100,10 @@ static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
 
     InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
     if (buffer->inspect == NULL) {
+        if (p->ip4h == NULL) {
+            // DETECT_PROTO_IPV4 does not prefilter
+            return NULL;
+        }
         uint32_t hlen = IPV4_GET_HLEN(p);
         if (((uint8_t *)p->ip4h + (ptrdiff_t)hlen) >
                 ((uint8_t *)GET_PKT_DATA(p) + (ptrdiff_t)GET_PKT_LEN(p)))

src/detect-ipv6hdr.c

@@ -100,6 +100,10 @@ static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
 
     InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
     if (buffer->inspect == NULL) {
+        if (p->ip6h == NULL) {
+            // DETECT_PROTO_IPV6 does not prefilter
+            return NULL;
+        }
         uint32_t hlen = IPV6_HEADER_LEN + IPV6_GET_EXTHDRS_LEN(p);
         if (((uint8_t *)p->ip6h + (ptrdiff_t)hlen) >
                 ((uint8_t *)GET_PKT_DATA(p) + (ptrdiff_t)GET_PKT_LEN(p)))

src/detect-tcphdr.c

@@ -101,6 +101,11 @@ static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
 
     InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
     if (buffer->inspect == NULL) {
+        if (p->tcph == NULL) {
+            // may happen when DecodeTCPPacket fails
+            // for instance with invalid header length
+            return NULL;
+        }
         uint32_t hlen = TCP_GET_HLEN(p);
         if (((uint8_t *)p->tcph + (ptrdiff_t)hlen) >
                 ((uint8_t *)GET_PKT_DATA(p) + (ptrdiff_t)GET_PKT_LEN(p)))

src/detect-udphdr.c

@@ -99,6 +99,9 @@ static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
 
     InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
     if (buffer->inspect == NULL) {
+        if (p->udph == NULL) {
+            return NULL;
+        }
         if (((uint8_t *)p->udph + (ptrdiff_t)UDP_HEADER_LEN) >
                 ((uint8_t *)GET_PKT_DATA(p) + (ptrdiff_t)GET_PKT_LEN(p)))
         {