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Unified Diff: courgette/rel32_finder_x86.cc

Issue 2008253004: Refactor rel32 searching process for x64 to make it more similar to x86. (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@master
Patch Set: Improve rel32_finder doc Created 4 years, 7 months ago
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Index: courgette/rel32_finder_x86.cc
diff --git a/courgette/rel32_finder_win32_x86.cc b/courgette/rel32_finder_x86.cc
similarity index 60%
rename from courgette/rel32_finder_win32_x86.cc
rename to courgette/rel32_finder_x86.cc
index 61ff9696d5ac19174d514c8930111e64c326342e..13ce7c365381e646fe6bf39c07e383a4d4359214 100644
--- a/courgette/rel32_finder_win32_x86.cc
+++ b/courgette/rel32_finder_x86.cc
@@ -2,45 +2,25 @@
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
-#include <stdint.h>
-
-#include "courgette/rel32_finder_win32_x86.h"
+#include "courgette/rel32_finder_x86.h"
namespace courgette {
-Rel32FinderWin32X86::Rel32FinderWin32X86(RVA relocs_start_rva,
- RVA relocs_end_rva)
- : relocs_start_rva_(relocs_start_rva), relocs_end_rva_(relocs_end_rva) {
-}
-
-Rel32FinderWin32X86::~Rel32FinderWin32X86() {
-}
-
-void Rel32FinderWin32X86::SwapRel32Locations(std::vector<RVA>* dest) {
- dest->swap(rel32_locations_);
-}
-
-#if COURGETTE_HISTOGRAM_TARGETS
-void Rel32FinderWin32X86::SwapRel32TargetRVAs(std::map<RVA, int>* dest) {
- dest->swap(rel32_target_rvas_);
-}
-#endif
-
-Rel32FinderWin32X86_Basic::Rel32FinderWin32X86_Basic(RVA relocs_start_rva,
- RVA relocs_end_rva)
- : Rel32FinderWin32X86(relocs_start_rva, relocs_end_rva) {
-}
-
-Rel32FinderWin32X86_Basic::~Rel32FinderWin32X86_Basic() {
-}
-
-void Rel32FinderWin32X86_Basic::Find(const uint8_t* start_pointer,
- const uint8_t* end_pointer,
- RVA start_rva,
- RVA end_rva,
- const std::vector<RVA>& abs32_locations) {
+Rel32FinderX86::Rel32FinderX86(RVA relocs_start_rva, RVA relocs_end_rva)
+ : Rel32Finder(relocs_start_rva, relocs_end_rva) {}
+
+// Scan for opcodes matching the following instructions :
+// rel32 JMP/CALL
+// Jcc (excluding JPO/JPE)
+// Falsely detected rel32 that collide with known abs32 or that point outside
+// valid regions are discarded.
+void Rel32FinderX86::Find(const uint8_t* start_pointer,
+ const uint8_t* end_pointer,
+ RVA start_rva,
+ RVA end_rva,
+ const std::vector<RVA>& abs32_locations) {
// Quick way to convert from Pointer to RVA within a single Section is to
- // subtract 'pointer_to_rva'.
+ // subtract 'adjust_pointer_to_rva'.
huangs 2016/05/30 05:48:35 NIT: |adjust_pointer_to_rva|.
etiennep 2016/05/30 17:07:30 Done.
const uint8_t* const adjust_pointer_to_rva = start_pointer - start_rva;
std::vector<RVA>::const_iterator abs32_pos = abs32_locations.begin();
@@ -53,11 +33,9 @@ void Rel32FinderWin32X86_Basic::Find(const uint8_t* start_pointer,
// Skip the base reloation table if we encounter it.
// Note: We're not bothering to handle the edge case where a Rel32 pointer
// collides with |relocs_start_rva_| by being {1, 2, 3}-bytes before it.
- if (current_rva == relocs_start_rva_) {
- if (relocs_start_rva_ < relocs_end_rva_) {
- p += relocs_end_rva_ - relocs_start_rva_;
- continue;
- }
+ if (current_rva >= relocs_start_rva_ && current_rva < relocs_end_rva_) {
+ p += relocs_end_rva_ - current_rva;
+ continue;
}
// Heuristic discovery of rel32 locations in instruction stream: are the
@@ -66,13 +44,13 @@ void Rel32FinderWin32X86_Basic::Find(const uint8_t* start_pointer,
const uint8_t* rel32 = nullptr;
if (p + 5 <= end_pointer) {
- if (*p == 0xE8 || *p == 0xE9) { // jmp rel32 and call rel32
+ if (p[0] == 0xE8 || p[0] == 0xE9) { // jmp rel32 and call rel32
rel32 = p + 1;
}
}
if (p + 6 <= end_pointer) {
- if (*p == 0x0F && (*(p+1) & 0xF0) == 0x80) { // Jcc long form
- if (p[1] != 0x8A && p[1] != 0x8B) // JPE/JPO unlikely
+ if (p[0] == 0x0F && (p[1] & 0xF0) == 0x80) { // Jcc long form
+ if (p[1] != 0x8A && p[1] != 0x8B) // JPE/JPO unlikely
rel32 = p + 2;
}
}

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