From 6899cab37038f2493de147a264845f559ca93736 Mon Sep 17 00:00:00 2001
From: Justin Viiret <justin.viiret@intel.com>
Date: Mon, 9 May 2016 13:51:50 +1000
Subject: [PATCH] unit-internal: fix FDR issues reported by ASan

FDR's streaming mode now assumes that it is safe to read 16 bytes before
the end of the history buffer, and this was not reflected in the unit
tests.
---
 unit/internal/fdr.cpp | 57 ++++++++++++++++++++++++++++---------------
 1 file changed, 37 insertions(+), 20 deletions(-)

diff --git a/unit/internal/fdr.cpp b/unit/internal/fdr.cpp
index ddfa8bb1..c66ab4c5 100644
--- a/unit/internal/fdr.cpp
+++ b/unit/internal/fdr.cpp
@@ -330,14 +330,32 @@ TEST_P(FDRp, NoRepeat3) {
     EXPECT_EQ(match(31, 32, 0), matches[0]);
 }
 
+/**
+ * \brief Helper function wrapping the FDR streaming call that ensures it is
+ * always safe to read 16 bytes before the end of the history buffer.
+ */
+static
+hwlm_error_t safeExecStreaming(const FDR *fdr, const u8 *hbuf, size_t hlen,
+                               const u8 *buf, size_t len, size_t start,
+                               HWLMCallback cb, void *ctxt, hwlm_group_t groups,
+                               u8 *stream_state) {
+    array<u8, 16> wrapped_history = {{'0', '1', '2', '3', '4', '5', '6', '7',
+                                      '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'}};
+    if (hlen < 16) {
+        u8 *new_hbuf = wrapped_history.data() + 16 - hlen;
+        memcpy(new_hbuf, hbuf, hlen);
+        hbuf = new_hbuf;
+    }
+    return fdrExecStreaming(fdr, hbuf, hlen, buf, len, start, cb, ctxt, groups,
+                            stream_state);
+}
 
 TEST_P(FDRp, SmallStreaming) {
     const u32 hint = GetParam();
     SCOPED_TRACE(hint);
-    vector<hwlmLiteral> lits;
 
-    lits.push_back(hwlmLiteral("a", 1, 1));
-    lits.push_back(hwlmLiteral("aardvark", 0, 10));
+    vector<hwlmLiteral> lits = {hwlmLiteral("a", 1, 1),
+                                hwlmLiteral("aardvark", 0, 10)};
 
     auto fdr = fdrBuildTableHinted(lits, false, hint, get_current_target(), Grey());
     CHECK_WITH_TEDDY_OK_TO_FAIL(fdr, hint);
@@ -347,8 +365,8 @@ TEST_P(FDRp, SmallStreaming) {
     expected.push_back(match(1, 1, 1));
     expected.push_back(match(2, 2, 1));
 
-    fdrExecStreaming(fdr.get(), (const u8 *)"", 0, (const u8 *)"aaar", 4, 0,
-                     decentCallback, &matches, HWLM_ALL_GROUPS, nullptr);
+    safeExecStreaming(fdr.get(), (const u8 *)"", 0, (const u8 *)"aaar", 4, 0,
+                      decentCallback, &matches, HWLM_ALL_GROUPS, nullptr);
     for (u32 i = 0; i < MIN(expected.size(), matches.size()); i++) {
         EXPECT_EQ(expected[i], matches[i]);
     }
@@ -359,8 +377,8 @@ TEST_P(FDRp, SmallStreaming) {
     expected.push_back(match(6, 6, 1));
     expected.push_back(match(1, 8, 10));
 
-    fdrExecStreaming(fdr.get(), (const u8 *)"aaar", 4, (const u8 *)"dvark", 5,
-                     0, decentCallback, &matches, HWLM_ALL_GROUPS, nullptr);
+    safeExecStreaming(fdr.get(), (const u8 *)"aaar", 4, (const u8 *)"dvark", 5,
+                      0, decentCallback, &matches, HWLM_ALL_GROUPS, nullptr);
 
     for (u32 i = 0; i < MIN(expected.size(), matches.size()); i++) {
         EXPECT_EQ(expected[i], matches[i] + 4);
@@ -371,11 +389,10 @@ TEST_P(FDRp, SmallStreaming) {
 TEST_P(FDRp, SmallStreaming2) {
     const u32 hint = GetParam();
     SCOPED_TRACE(hint);
-    vector<hwlmLiteral> lits;
 
-    lits.push_back(hwlmLiteral("a",1,1));
-    lits.push_back(hwlmLiteral("kk",1,2));
-    lits.push_back(hwlmLiteral("aardvark", 0,10));
+    vector<hwlmLiteral> lits = {hwlmLiteral("a", 1, 1),
+                                hwlmLiteral("kk", 1, 2),
+                                hwlmLiteral("aardvark", 0, 10)};
 
     auto fdr = fdrBuildTableHinted(lits, false, hint, get_current_target(), Grey());
     CHECK_WITH_TEDDY_OK_TO_FAIL(fdr, hint);
@@ -388,9 +405,9 @@ TEST_P(FDRp, SmallStreaming2) {
     expected.push_back(match(13,14,2));
     expected.push_back(match(14,15,2));
 
-    fdrExecStreaming(fdr.get(), (const u8 *)"foobar", 6,
-                     (const u8 *)"aardvarkkk", 10, 0, decentCallback, &matches,
-                     HWLM_ALL_GROUPS, nullptr);
+    safeExecStreaming(fdr.get(), (const u8 *)"foobar", 6,
+                      (const u8 *)"aardvarkkk", 10, 0, decentCallback, &matches,
+                      HWLM_ALL_GROUPS, nullptr);
 
     for (u32 i = 0; i < MIN(expected.size(), matches.size()); i++) {
         EXPECT_EQ(expected[i], matches[i] + 6);
@@ -521,9 +538,9 @@ TEST_P(FDRp, Stream1) {
     // check matches
     vector<match> matches;
 
-    fdrStatus = fdrExecStreaming(fdr.get(), (const u8 *)data1, data_len1,
-                                 (const u8 *)data2, data_len2, 0,
-                                 decentCallback, &matches, HWLM_ALL_GROUPS, nullptr);
+    fdrStatus = safeExecStreaming(
+        fdr.get(), (const u8 *)data1, data_len1, (const u8 *)data2, data_len2,
+        0, decentCallback, &matches, HWLM_ALL_GROUPS, nullptr);
     ASSERT_EQ(0, fdrStatus);
 
     ASSERT_EQ(4U, matches.size());
@@ -766,9 +783,9 @@ TEST(FDR, FDRTermS) {
     // check matches
     vector<match> matches;
 
-    fdrStatus = fdrExecStreaming(fdr.get(), (const u8 *)data1, data_len1,
-                                 (const u8 *)data2, data_len2, 0,
-                                 decentCallbackT, &matches, HWLM_ALL_GROUPS, nullptr);
+    fdrStatus = safeExecStreaming(
+        fdr.get(), (const u8 *)data1, data_len1, (const u8 *)data2, data_len2,
+        0, decentCallbackT, &matches, HWLM_ALL_GROUPS, nullptr);
     ASSERT_EQ(HWLM_TERMINATED, fdrStatus);
 
     ASSERT_EQ(1U, matches.size());