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[tor-commits] [tor-browser/tor-browser-60.0.1esr-8.0-1] Bug 1461421 Use OffsetOf to calculate the location of param_info_ rather than assuming it's at the end of the parent class r?bobowen
commit a64a7c2de648ad87f392e407a92589515a72b0ef
Author: Tom Ritter <tom@xxxxxxxxxxx>
Date: Thu Jun 7 13:08:27 2018 -0500
Bug 1461421 Use OffsetOf to calculate the location of param_info_ rather than assuming it's at the end of the parent class r?bobowen
MozReview-Commit-ID: D7REZiAIMpN
---
.../chromium/sandbox/win/src/crosscall_params.h | 5 ++
.../chromium/sandbox/win/src/crosscall_server.cc | 56 +++++++++++++++++-----
2 files changed, 48 insertions(+), 13 deletions(-)
diff --git a/security/sandbox/chromium/sandbox/win/src/crosscall_params.h b/security/sandbox/chromium/sandbox/win/src/crosscall_params.h
index eb59c44239e2..baceebd9e285 100644
--- a/security/sandbox/chromium/sandbox/win/src/crosscall_params.h
+++ b/security/sandbox/chromium/sandbox/win/src/crosscall_params.h
@@ -60,6 +60,7 @@ union MultiType {
// - Add another Callback typedef to Dispatcher.
// - Add another case to the switch on SharedMemIPCServer::InvokeCallback.
// - Add another case to the switch in GetActualAndMaxBufferSize
+// - Add another case to the switch in GetOffsetOfFirstMemberOfActualCallParams
const int kMaxIpcParams = 9;
// Contains the information about a parameter in the ipc buffer.
@@ -92,6 +93,8 @@ struct CrossCallReturn {
MultiType extended[kExtendedReturnCount];
};
+uint32_t GetOffsetOfFirstMemberOfActualCallParams(uint32_t param_count);
+
// CrossCallParams base class that models the input params all packed in a
// single compact memory blob. The representation can vary but in general a
// given child of this class is meant to represent all input parameters
@@ -276,6 +279,8 @@ class ActualCallParams : public CrossCallParams {
char parameters_[BLOCK_SIZE - sizeof(CrossCallParams)
- sizeof(ParamInfo) * (NUMBER_PARAMS + 1)];
DISALLOW_COPY_AND_ASSIGN(ActualCallParams);
+
+ friend uint32_t GetOffsetOfFirstMemberOfActualCallParams(uint32_t param_count);
};
static_assert(sizeof(ActualCallParams<1, 1024>) == 1024, "bad size buffer");
diff --git a/security/sandbox/chromium/sandbox/win/src/crosscall_server.cc b/security/sandbox/chromium/sandbox/win/src/crosscall_server.cc
index 9f71f333f02d..6d94b1cb14c2 100644
--- a/security/sandbox/chromium/sandbox/win/src/crosscall_server.cc
+++ b/security/sandbox/chromium/sandbox/win/src/crosscall_server.cc
@@ -27,20 +27,21 @@ const size_t kMaxBufferSize = sandbox::kIPCChannelSize;
namespace sandbox {
+// The template types are used to calculate the maximum expected size.
+typedef ActualCallParams<0, kMaxBufferSize> ActualCP0;
+typedef ActualCallParams<1, kMaxBufferSize> ActualCP1;
+typedef ActualCallParams<2, kMaxBufferSize> ActualCP2;
+typedef ActualCallParams<3, kMaxBufferSize> ActualCP3;
+typedef ActualCallParams<4, kMaxBufferSize> ActualCP4;
+typedef ActualCallParams<5, kMaxBufferSize> ActualCP5;
+typedef ActualCallParams<6, kMaxBufferSize> ActualCP6;
+typedef ActualCallParams<7, kMaxBufferSize> ActualCP7;
+typedef ActualCallParams<8, kMaxBufferSize> ActualCP8;
+typedef ActualCallParams<9, kMaxBufferSize> ActualCP9;
+
// Returns the actual size for the parameters in an IPC buffer. Returns
// zero if the |param_count| is zero or too big.
uint32_t GetActualBufferSize(uint32_t param_count, void* buffer_base) {
- // The template types are used to calculate the maximum expected size.
- typedef ActualCallParams<1, kMaxBufferSize> ActualCP1;
- typedef ActualCallParams<2, kMaxBufferSize> ActualCP2;
- typedef ActualCallParams<3, kMaxBufferSize> ActualCP3;
- typedef ActualCallParams<4, kMaxBufferSize> ActualCP4;
- typedef ActualCallParams<5, kMaxBufferSize> ActualCP5;
- typedef ActualCallParams<6, kMaxBufferSize> ActualCP6;
- typedef ActualCallParams<7, kMaxBufferSize> ActualCP7;
- typedef ActualCallParams<8, kMaxBufferSize> ActualCP8;
- typedef ActualCallParams<9, kMaxBufferSize> ActualCP9;
-
// Retrieve the actual size and the maximum size of the params buffer.
switch (param_count) {
case 0:
@@ -68,6 +69,35 @@ uint32_t GetActualBufferSize(uint32_t param_count, void* buffer_base) {
}
}
+// Returns the actual size for the parameters in an IPC buffer. Returns
+// zero if the |param_count| is zero or too big.
+uint32_t GetOffsetOfFirstMemberOfActualCallParams(uint32_t param_count) {
+ switch (param_count) {
+ case 0:
+ return offsetof(ActualCP0, param_info_);
+ case 1:
+ return offsetof(ActualCP1, param_info_);
+ case 2:
+ return offsetof(ActualCP2, param_info_);
+ case 3:
+ return offsetof(ActualCP3, param_info_);
+ case 4:
+ return offsetof(ActualCP4, param_info_);
+ case 5:
+ return offsetof(ActualCP5, param_info_);
+ case 6:
+ return offsetof(ActualCP6, param_info_);
+ case 7:
+ return offsetof(ActualCP7, param_info_);
+ case 8:
+ return offsetof(ActualCP8, param_info_);
+ case 9:
+ return offsetof(ActualCP9, param_info_);
+ default:
+ return 0;
+ }
+}
+
// Verifies that the declared sizes of an IPC buffer are within range.
bool IsSizeWithinRange(uint32_t buffer_size,
uint32_t min_declared_size,
@@ -137,7 +167,7 @@ CrossCallParamsEx* CrossCallParamsEx::CreateFromBuffer(void* buffer_base,
// Check against the minimum size given the number of stated params
// if too small we bail out.
param_count = call_params->GetParamsCount();
- min_declared_size = sizeof(CrossCallParams) +
+ min_declared_size = GetOffsetOfFirstMemberOfActualCallParams(param_count) +
((param_count + 1) * sizeof(ParamInfo));
// Retrieve the declared size which if it fails returns 0.
@@ -157,7 +187,7 @@ CrossCallParamsEx* CrossCallParamsEx::CreateFromBuffer(void* buffer_base,
// should be actually read.
_ReadWriteBarrier();
- min_declared_size = sizeof(CrossCallParams) +
+ min_declared_size = GetOffsetOfFirstMemberOfActualCallParams(param_count) +
((param_count + 1) * sizeof(ParamInfo));
// Check that the copied buffer is still valid.
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