Chromium Code Reviews
chromiumcodereview-hr@appspot.gserviceaccount.com (chromiumcodereview-hr) | Please choose your nickname with Settings | Help | Chromium Project | Gerrit Changes | Sign out
(100)

Unified Diff: sandbox/win/src/sidestep/preamble_patcher_with_stub.cpp

Issue 1851213002: Remove sandbox on Windows. (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@master
Patch Set: fix nacl compile issues Created 4 years, 9 months ago
Use n/p to move between diff chunks; N/P to move between comments. Draft comments are only viewable by you.
Jump to:
View side-by-side diff with in-line comments
Download patch
« no previous file with comments | « sandbox/win/src/sidestep/preamble_patcher.h ('k') | sandbox/win/src/sidestep_resolver.h » ('j') | no next file with comments »
Expand Comments ('e') | Collapse Comments ('c') | Show Comments Hide Comments ('s')
Index: sandbox/win/src/sidestep/preamble_patcher_with_stub.cpp
diff --git a/sandbox/win/src/sidestep/preamble_patcher_with_stub.cpp b/sandbox/win/src/sidestep/preamble_patcher_with_stub.cpp
deleted file mode 100644
index b5016009d60ac38b256968801497fc168f669def..0000000000000000000000000000000000000000
--- a/sandbox/win/src/sidestep/preamble_patcher_with_stub.cpp
+++ /dev/null
@@ -1,181 +0,0 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// Implementation of PreamblePatcher
-
-#include "sandbox/win/src/sidestep/preamble_patcher.h"
-
-#include <stddef.h>
-
-#include "sandbox/win/src/sandbox_nt_util.h"
-#include "sandbox/win/src/sidestep/mini_disassembler.h"
-
-// Definitions of assembly statements we need
-#define ASM_JMP32REL 0xE9
-#define ASM_INT3 0xCC
-
-namespace {
-
-// Very basic memcpy. We are copying 4 to 12 bytes most of the time, so there
-// is no attempt to optimize this code or have a general purpose function.
-// We don't want to call the crt from this code.
-inline void* RawMemcpy(void* destination, const void* source, size_t bytes) {
- const char* from = reinterpret_cast<const char*>(source);
- char* to = reinterpret_cast<char*>(destination);
-
- for (size_t i = 0; i < bytes ; i++)
- to[i] = from[i];
-
- return destination;
-}
-
-// Very basic memset. We are filling 1 to 7 bytes most of the time, so there
-// is no attempt to optimize this code or have a general purpose function.
-// We don't want to call the crt from this code.
-inline void* RawMemset(void* destination, int value, size_t bytes) {
- char* to = reinterpret_cast<char*>(destination);
-
- for (size_t i = 0; i < bytes ; i++)
- to[i] = static_cast<char>(value);
-
- return destination;
-}
-
-} // namespace
-
-#define ASSERT(a, b) DCHECK_NT(a)
-
-namespace sidestep {
-
-SideStepError PreamblePatcher::RawPatchWithStub(
- void* target_function,
- void* replacement_function,
- unsigned char* preamble_stub,
- size_t stub_size,
- size_t* bytes_needed) {
- if ((NULL == target_function) ||
- (NULL == replacement_function) ||
- (NULL == preamble_stub)) {
- ASSERT(false, (L"Invalid parameters - either pTargetFunction or "
- L"pReplacementFunction or pPreambleStub were NULL."));
- return SIDESTEP_INVALID_PARAMETER;
- }
-
- // TODO(V7:joi) Siggi and I just had a discussion and decided that both
- // patching and unpatching are actually unsafe. We also discussed a
- // method of making it safe, which is to freeze all other threads in the
- // process, check their thread context to see if their eip is currently
- // inside the block of instructions we need to copy to the stub, and if so
- // wait a bit and try again, then unfreeze all threads once we've patched.
- // Not implementing this for now since we're only using SideStep for unit
- // testing, but if we ever use it for production code this is what we
- // should do.
- //
- // NOTE: Stoyan suggests we can write 8 or even 10 bytes atomically using
- // FPU instructions, and on newer processors we could use cmpxchg8b or
- // cmpxchg16b. So it might be possible to do the patching/unpatching
- // atomically and avoid having to freeze other threads. Note though, that
- // doing it atomically does not help if one of the other threads happens
- // to have its eip in the middle of the bytes you change while you change
- // them.
- unsigned char* target = reinterpret_cast<unsigned char*>(target_function);
-
- // Let's disassemble the preamble of the target function to see if we can
- // patch, and to see how much of the preamble we need to take. We need 5
- // bytes for our jmp instruction, so let's find the minimum number of
- // instructions to get 5 bytes.
- MiniDisassembler disassembler;
- unsigned int preamble_bytes = 0;
- while (preamble_bytes < 5) {
- InstructionType instruction_type =
- disassembler.Disassemble(target + preamble_bytes, &preamble_bytes);
- if (IT_JUMP == instruction_type) {
- ASSERT(false, (L"Unable to patch because there is a jump instruction "
- L"in the first 5 bytes."));
- return SIDESTEP_JUMP_INSTRUCTION;
- } else if (IT_RETURN == instruction_type) {
- ASSERT(false, (L"Unable to patch because function is too short"));
- return SIDESTEP_FUNCTION_TOO_SMALL;
- } else if (IT_GENERIC != instruction_type) {
- ASSERT(false, (L"Disassembler encountered unsupported instruction "
- L"(either unused or unknown"));
- return SIDESTEP_UNSUPPORTED_INSTRUCTION;
- }
- }
-
- if (NULL != bytes_needed)
- *bytes_needed = preamble_bytes + 5;
-
- // Inv: preamble_bytes is the number of bytes (at least 5) that we need to
- // take from the preamble to have whole instructions that are 5 bytes or more
- // in size total. The size of the stub required is cbPreamble + size of
- // jmp (5)
- if (preamble_bytes + 5 > stub_size) {
- NOTREACHED_NT();
- return SIDESTEP_INSUFFICIENT_BUFFER;
- }
-
- // First, copy the preamble that we will overwrite.
- RawMemcpy(reinterpret_cast<void*>(preamble_stub),
- reinterpret_cast<void*>(target), preamble_bytes);
-
- // Now, make a jmp instruction to the rest of the target function (minus the
- // preamble bytes we moved into the stub) and copy it into our preamble-stub.
- // find address to jump to, relative to next address after jmp instruction
-#pragma warning(push)
-#pragma warning(disable:4244)
- // This assignment generates a warning because it is 32 bit specific.
- int relative_offset_to_target_rest
- = ((reinterpret_cast<unsigned char*>(target) + preamble_bytes) -
- (preamble_stub + preamble_bytes + 5));
-#pragma warning(pop)
- // jmp (Jump near, relative, displacement relative to next instruction)
- preamble_stub[preamble_bytes] = ASM_JMP32REL;
- // copy the address
- RawMemcpy(reinterpret_cast<void*>(preamble_stub + preamble_bytes + 1),
- reinterpret_cast<void*>(&relative_offset_to_target_rest), 4);
-
- // Inv: preamble_stub points to assembly code that will execute the
- // original function by first executing the first cbPreamble bytes of the
- // preamble, then jumping to the rest of the function.
-
- // Overwrite the first 5 bytes of the target function with a jump to our
- // replacement function.
- // (Jump near, relative, displacement relative to next instruction)
- target[0] = ASM_JMP32REL;
-
- // Find offset from instruction after jmp, to the replacement function.
-#pragma warning(push)
-#pragma warning(disable:4244)
- int offset_to_replacement_function =
- reinterpret_cast<unsigned char*>(replacement_function) -
- reinterpret_cast<unsigned char*>(target) - 5;
-#pragma warning(pop)
- // complete the jmp instruction
- RawMemcpy(reinterpret_cast<void*>(target + 1),
- reinterpret_cast<void*>(&offset_to_replacement_function), 4);
- // Set any remaining bytes that were moved to the preamble-stub to INT3 so
- // as not to cause confusion (otherwise you might see some strange
- // instructions if you look at the disassembly, or even invalid
- // instructions). Also, by doing this, we will break into the debugger if
- // some code calls into this portion of the code. If this happens, it
- // means that this function cannot be patched using this patcher without
- // further thought.
- if (preamble_bytes > 5) {
- RawMemset(reinterpret_cast<void*>(target + 5), ASM_INT3,
- preamble_bytes - 5);
- }
-
- // Inv: The memory pointed to by target_function now points to a relative
- // jump instruction that jumps over to the preamble_stub. The preamble
- // stub contains the first stub_size bytes of the original target
- // function's preamble code, followed by a relative jump back to the next
- // instruction after the first cbPreamble bytes.
-
- return SIDESTEP_SUCCESS;
-}
-
-}; // namespace sidestep
-
-#undef ASSERT
« no previous file with comments | « sandbox/win/src/sidestep/preamble_patcher.h ('k') | sandbox/win/src/sidestep_resolver.h » ('j') | no next file with comments »

Powered by Google App Engine
This is Rietveld 408576698