[compiler-rt] r322941 - [XRay] [compiler-rt] fix heap overflow by computing record pointers correctly
Martin Pelikan via llvm-commits
llvm-commits at lists.llvm.org
Fri Jan 19 05:18:40 PST 2018
Author: pelikan
Date: Fri Jan 19 05:18:40 2018
New Revision: 322941
URL: http://llvm.org/viewvc/llvm-project?rev=322941&view=rev
Log:
[XRay] [compiler-rt] fix heap overflow by computing record pointers correctly
Summary:
While there, unify InMemoryRawLog and InMemoryRawLogWithArg's coding style:
- swap libc's memcpy(3) for sanitizer's internal memcpy
- use basic pointer arithmetics to compute offsets from the first record
entry in the pre-allocated buffer, which is always the appropriate type
for the given function
- lose the local variable references as the TLD.* names fit just as well
Reviewers: eizan, kpw, dberris, dblaikie
Subscribers: #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D42289
Modified:
compiler-rt/trunk/lib/xray/xray_inmemory_log.cc
Modified: compiler-rt/trunk/lib/xray/xray_inmemory_log.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/xray/xray_inmemory_log.cc?rev=322941&r1=322940&r2=322941&view=diff
==============================================================================
--- compiler-rt/trunk/lib/xray/xray_inmemory_log.cc (original)
+++ compiler-rt/trunk/lib/xray/xray_inmemory_log.cc Fri Jan 19 05:18:40 2018
@@ -157,7 +157,6 @@ template <class RDTSC>
void InMemoryRawLog(int32_t FuncId, XRayEntryType Type,
RDTSC ReadTSC) XRAY_NEVER_INSTRUMENT {
auto &TLD = getThreadLocalData();
- auto &InMemoryBuffer = TLD.InMemoryBuffer;
int Fd = getGlobalFd();
if (Fd == -1)
return;
@@ -240,14 +239,12 @@ void InMemoryRawLog(int32_t FuncId, XRay
R.TId = TLD.TID;
R.Type = Type;
R.FuncId = FuncId;
- auto EntryPtr = static_cast<char *>(InMemoryBuffer) +
- (sizeof(__xray::XRayRecord) * TLD.BufferOffset);
- __sanitizer::internal_memcpy(EntryPtr, &R, sizeof(R));
+ auto FirstEntry = reinterpret_cast<__xray::XRayRecord *>(TLD.InMemoryBuffer);
+ __sanitizer::internal_memcpy(FirstEntry + TLD.BufferOffset, &R, sizeof(R));
if (++TLD.BufferOffset == TLD.BufferSize) {
__sanitizer::SpinMutexLock L(&LogMutex);
- auto RecordBuffer = reinterpret_cast<__xray::XRayRecord *>(InMemoryBuffer);
- retryingWriteAll(Fd, reinterpret_cast<char *>(RecordBuffer),
- reinterpret_cast<char *>(RecordBuffer + TLD.BufferOffset));
+ retryingWriteAll(Fd, reinterpret_cast<char *>(FirstEntry),
+ reinterpret_cast<char *>(FirstEntry + TLD.BufferOffset));
TLD.BufferOffset = 0;
TLD.StackEntries = 0;
}
@@ -257,8 +254,8 @@ template <class RDTSC>
void InMemoryRawLogWithArg(int32_t FuncId, XRayEntryType Type, uint64_t Arg1,
RDTSC ReadTSC) XRAY_NEVER_INSTRUMENT {
auto &TLD = getThreadLocalData();
- auto &InMemoryBuffer = TLD.InMemoryBuffer;
- auto &Offset = TLD.BufferOffset;
+ auto FirstEntry =
+ reinterpret_cast<__xray::XRayArgPayload *>(TLD.InMemoryBuffer);
const auto &BuffLen = TLD.BufferSize;
int Fd = getGlobalFd();
if (Fd == -1)
@@ -267,12 +264,11 @@ void InMemoryRawLogWithArg(int32_t FuncI
// First we check whether there's enough space to write the data consecutively
// in the thread-local buffer. If not, we first flush the buffer before
// attempting to write the two records that must be consecutive.
- if (Offset + 2 > BuffLen) {
+ if (TLD.BufferOffset + 2 > BuffLen) {
__sanitizer::SpinMutexLock L(&LogMutex);
- auto RecordBuffer = reinterpret_cast<__xray::XRayRecord *>(InMemoryBuffer);
- retryingWriteAll(Fd, reinterpret_cast<char *>(RecordBuffer),
- reinterpret_cast<char *>(RecordBuffer + Offset));
- Offset = 0;
+ retryingWriteAll(Fd, reinterpret_cast<char *>(FirstEntry),
+ reinterpret_cast<char *>(FirstEntry + TLD.BufferOffset));
+ TLD.BufferOffset = 0;
TLD.StackEntries = 0;
}
@@ -290,15 +286,12 @@ void InMemoryRawLogWithArg(int32_t FuncI
R.FuncId = FuncId;
R.TId = TLD.TID;
R.Arg = Arg1;
- auto EntryPtr =
- &reinterpret_cast<__xray::XRayArgPayload *>(&InMemoryBuffer)[Offset];
- std::memcpy(EntryPtr, &R, sizeof(R));
- if (++Offset == BuffLen) {
+ __sanitizer::internal_memcpy(FirstEntry + TLD.BufferOffset, &R, sizeof(R));
+ if (++TLD.BufferOffset == BuffLen) {
__sanitizer::SpinMutexLock L(&LogMutex);
- auto RecordBuffer = reinterpret_cast<__xray::XRayRecord *>(InMemoryBuffer);
- retryingWriteAll(Fd, reinterpret_cast<char *>(RecordBuffer),
- reinterpret_cast<char *>(RecordBuffer + Offset));
- Offset = 0;
+ retryingWriteAll(Fd, reinterpret_cast<char *>(FirstEntry),
+ reinterpret_cast<char *>(FirstEntry + TLD.BufferOffset));
+ TLD.BufferOffset = 0;
TLD.StackEntries = 0;
}
}
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