From 18f6aee5c262ada7e46a0c042a0611d7eb66ddb7 Mon Sep 17 00:00:00 2001
From: Wang Xiang W <xiang.w.wang@intel.com>
Date: Tue, 1 Dec 2020 10:50:13 -0500
Subject: [PATCH] chimera: fix return value handling

Fixes github issue #270
---
 chimera/ch_common.h  | 12 +++++++++++-
 chimera/ch_runtime.c | 20 +++++++++++++++++---
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/chimera/ch_common.h b/chimera/ch_common.h
index 8caa4440..bdb0bafa 100644
--- a/chimera/ch_common.h
+++ b/chimera/ch_common.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, Intel Corporation
+ * Copyright (c) 2018-2020, Intel Corporation
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -345,6 +345,16 @@ ch_error_t HS_CDECL ch_set_scratch_allocator(ch_alloc_t alloc_func,
  */
 #define CH_SCRATCH_IN_USE       (-10)
 
+/**
+ * Unexpected internal error from Hyperscan.
+ *
+ * This error indicates that there was unexpected matching behaviors from
+ * Hyperscan. This could be related to invalid usage of scratch space or
+ * invalid memory operations by users.
+ *
+ */
+#define CH_UNKNOWN_HS_ERROR     (-13)
+
 /**
  * Returned when pcre_exec (called for some expressions internally from @ref
  * ch_scan) failed due to a fatal error.
diff --git a/chimera/ch_runtime.c b/chimera/ch_runtime.c
index 212bbc7b..fdb5b992 100644
--- a/chimera/ch_runtime.c
+++ b/chimera/ch_runtime.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, Intel Corporation
+ * Copyright (c) 2018-2020, Intel Corporation
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -419,6 +419,7 @@ int HS_CDECL multiCallback(unsigned int id, unsigned long long from,
             DEBUG_PRINTF("user callback told us to skip this pattern\n");
             pd->scanStart = hyctx->length;
             ret = HS_SUCCESS;
+            hyctx->scratch->ret = ret;
         } else if (ret == CH_FAIL_INTERNAL) {
             return ret;
         }
@@ -590,11 +591,24 @@ ch_error_t ch_scan_i(const ch_database_t *hydb,
 
     if (!(db->flags & CHIMERA_FLAG_NO_MULTIMATCH)) {
         ret = scanHyperscan(&hyctx, data, length);
-        if (ret != HS_SUCCESS && scratch->ret != CH_SUCCESS) {
-            DEBUG_PRINTF("Hyperscan returned error %d\n", scratch->ret);
+        // Errors from pcre scan.
+        if (scratch->ret == CH_CALLBACK_TERMINATE) {
+            DEBUG_PRINTF("Pcre terminates scan\n");
+            unmarkScratchInUse(scratch);
+            return CH_SCAN_TERMINATED;
+        } else if (scratch->ret != CH_SUCCESS) {
+            DEBUG_PRINTF("Pcre internal error\n");
             unmarkScratchInUse(scratch);
             return scratch->ret;
         }
+        // Errors from Hyperscan scan. Note Chimera could terminate
+        // Hyperscan callback on purpose so this is not counted as an error.
+        if (ret != HS_SUCCESS && ret != HS_SCAN_TERMINATED) {
+            assert(scratch->ret == CH_SUCCESS);
+            DEBUG_PRINTF("Hyperscan returned error %d\n", ret);
+            unmarkScratchInUse(scratch);
+            return ret;
+        }
     }
 
     DEBUG_PRINTF("Flush priority queue\n");