From 802eaea7696e2e1aa8d6d76d1fee39fbe1c7794b Mon Sep 17 00:00:00 2001
From: Ryan Harrison <rharrison@chromium.org>
Date: Tue, 30 Jan 2018 20:24:50 +0000
Subject: Clean up CSS Data Table entries and access

This cleans up the entries in the table to no longer have a marker for
size, and also removes a hand rolled search. This prevents an out of
bounds issue that had been reported and addresses another potential
out of bounds issue.

BUG=chromium:807214

Change-Id: I3d3ab5a3a174dd4dcec56fa7ee7a0e6c2805bfaa
Reviewed-on: https://pdfium-review.googlesource.com/24690
Reviewed-by: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: dsinclair <dsinclair@chromium.org>
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
---
 core/fxcrt/css/cfx_css.h            |  3 ++-
 core/fxcrt/css/cfx_cssdatatable.cpp | 40 +++++++++++++++----------------------
 core/fxcrt/css/cfx_cssdatatable.h   |  3 +--
 3 files changed, 19 insertions(+), 27 deletions(-)

(limited to 'core')

diff --git a/core/fxcrt/css/cfx_css.h b/core/fxcrt/css/cfx_css.h
index 7b1d7d3f99..3703394d4f 100644
--- a/core/fxcrt/css/cfx_css.h
+++ b/core/fxcrt/css/cfx_css.h
@@ -79,6 +79,8 @@ enum class CFX_CSSPropertyValue : uint8_t {
   LAST_MARKER
 };
 
+// Any entries added/removed here, will need to be mirrored in
+// g_CFX_CSSProperties.
 enum class CFX_CSSProperty : uint8_t {
   BorderLeft = 0,
   Top,
@@ -120,7 +122,6 @@ enum class CFX_CSSProperty : uint8_t {
   Padding,
   MarginBottom,
   MarginTop,
-  LAST_MARKER
 };
 
 enum class CFX_CSSSelectorType : uint8_t { Element = 0, Descendant };
diff --git a/core/fxcrt/css/cfx_cssdatatable.cpp b/core/fxcrt/css/cfx_cssdatatable.cpp
index 53617b6a48..8b2100aaa2 100644
--- a/core/fxcrt/css/cfx_cssdatatable.cpp
+++ b/core/fxcrt/css/cfx_cssdatatable.cpp
@@ -6,6 +6,7 @@
 
 #include "core/fxcrt/css/cfx_cssdatatable.h"
 
+#include <algorithm>
 #include <utility>
 
 #include "core/fxcrt/css/cfx_cssstyleselector.h"
@@ -115,33 +116,24 @@ static const CFX_CSSPropertyTable g_CFX_CSSProperties[] = {
      CFX_CSSVALUETYPE_Primitive | CFX_CSSVALUETYPE_MaybeNumber |
          CFX_CSSVALUETYPE_MaybeEnum},
 };
-const int32_t g_iCSSPropertyCount =
-    sizeof(g_CFX_CSSProperties) / sizeof(CFX_CSSPropertyTable);
-static_assert(g_iCSSPropertyCount ==
-                  static_cast<int32_t>(CFX_CSSProperty::LAST_MARKER),
-              "Property table differs in size from property enum");
 
-const CFX_CSSPropertyTable* CFX_GetCSSPropertyByName(
-    const WideStringView& wsName) {
-  ASSERT(!wsName.IsEmpty());
-  uint32_t dwHash = FX_HashCode_GetW(wsName, true);
-  int32_t iEnd = g_iCSSPropertyCount;
-  int32_t iMid, iStart = 0;
-  uint32_t dwMid;
-  do {
-    iMid = (iStart + iEnd) / 2;
-    dwMid = g_CFX_CSSProperties[iMid].dwHash;
-    if (dwHash == dwMid) {
-      return g_CFX_CSSProperties + iMid;
-    } else if (dwHash > dwMid) {
-      iStart = iMid + 1;
-    } else {
-      iEnd = iMid - 1;
-    }
-  } while (iStart <= iEnd);
+const CFX_CSSPropertyTable* CFX_GetCSSPropertyByName(WideStringView name) {
+  if (name.IsEmpty())
+    return nullptr;
+
+  uint32_t hash = FX_HashCode_GetW(name, true);
+
+  auto cmpFunc = [](const CFX_CSSPropertyTable& iter, const uint32_t& hash) {
+    return iter.dwHash < hash;
+  };
+
+  auto* result = std::lower_bound(std::begin(g_CFX_CSSProperties),
+                                  std::end(g_CFX_CSSProperties), hash, cmpFunc);
+  if (result != std::end(g_CFX_CSSProperties) && result->dwHash == hash)
+    return result;
   return nullptr;
 }
 
 const CFX_CSSPropertyTable* CFX_GetCSSPropertyByEnum(CFX_CSSProperty eName) {
-  return g_CFX_CSSProperties + static_cast<int>(eName);
+  return &g_CFX_CSSProperties[static_cast<uint8_t>(eName)];
 }
diff --git a/core/fxcrt/css/cfx_cssdatatable.h b/core/fxcrt/css/cfx_cssdatatable.h
index 63c303488e..b8476175f6 100644
--- a/core/fxcrt/css/cfx_cssdatatable.h
+++ b/core/fxcrt/css/cfx_cssdatatable.h
@@ -22,8 +22,7 @@ struct CFX_CSSPropertyTable {
   uint32_t dwType;
 };
 
-const CFX_CSSPropertyTable* CFX_GetCSSPropertyByName(
-    const WideStringView& wsName);
+const CFX_CSSPropertyTable* CFX_GetCSSPropertyByName(WideStringView wsName);
 const CFX_CSSPropertyTable* CFX_GetCSSPropertyByEnum(CFX_CSSProperty eName);
 
 #endif  // CORE_FXCRT_CSS_CFX_CSSDATATABLE_H_
-- 
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