Skip to content

Fix JNI string lifetime/null-safety, Windows cancel-drain race, and UWP version parse #1494

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
bmehta001 wants to merge 9 commits into
base: main
Choose a base branch
from
Open

Fix JNI string lifetime/null-safety, Windows cancel-drain race, and UWP version parse #1494

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
9 commits
Select commit Hold shift + click to select a range
cd2f1a9
Fix four latent safety bugs (JNI lifetime/null-safety, cancel race, U…
bmehta001 Jun 22, 2026
4c176db
Address review comments: harden two JNI string reads
bmehta001 Jun 22, 2026
dca30a7
Guard all remaining GetStringUTFChars reads against null
bmehta001 Jun 24, 2026
778a2e5
Merge branch 'main' into bhamehta/fix-jni-windows-uwp-safety
bmehta001 Jun 24, 2026
772ce61
Guard tenant_j for null before GetStringUTFChars in GetRecords (Copil…
bmehta001 Jun 25, 2026
80f865c
Guard remaining jstring inputs before GetStringUTFChars (Copilot review)
bmehta001 Jun 25, 2026
25df775
GetRecords: clear pending JNI exception after tenant-token read (Copi…
bmehta001 Jun 25, 2026
1274680
JStringToStdString: clear pending JNI exception on failed read (Copil…
bmehta001 Jun 25, 2026
76d75ed
UWP: include <exception> directly for std::exception catch (Copilot r…
bmehta001 Jun 25, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
14 changes: 12 additions & 2 deletions lib/http/HttpClient_WinInet.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -534,11 +534,21 @@ void HttpClient_WinInet::CancelAllRequests()
for (const auto &id : ids)
CancelRequestAsync(id);

// wait for all destructors to run
while (!m_requests.empty())
// wait for all destructors to run. Read m_requests under the lock each
// iteration; erase() runs on the WinInet callback thread under the same lock.
bool done;
{
LOCKGUARD(m_requestsMutex);
done = m_requests.empty();
}
while (!done)
{
PAL::sleep(100);
std::this_thread::yield();
{
LOCKGUARD(m_requestsMutex);
done = m_requests.empty();
}
}
}

Expand Down
14 changes: 12 additions & 2 deletions lib/http/HttpClient_WinRt.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -351,11 +351,21 @@ namespace MAT_NS_BEGIN {
for (const auto &id : ids)
CancelRequestAsync(id);

// wait for all destructors to run
while (!m_requests.empty())
// wait for all destructors to run. Read m_requests under the lock each
// iteration; erase() runs on the PPL continuation thread under the same lock.
bool done;
{
std::lock_guard<std::mutex> lock(m_requestsMutex);
done = m_requests.empty();
}
while (!done)
{
PAL::sleep(100);
std::this_thread::yield();
{
std::lock_guard<std::mutex> lock(m_requestsMutex);
done = m_requests.empty();
}
}
};

Expand Down
7 changes: 7 additions & 0 deletions lib/jni/JniConvertors.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,13 @@ std::string JStringToStdString(JNIEnv* env, const jstring& jstr) {

size_t jstr_length = env->GetStringUTFLength(jstr);
auto jstr_utf = env->GetStringUTFChars(jstr, nullptr);
if (jstr_utf == nullptr) {
// GetStringUTFChars failed (e.g. OOM) and left a pending exception. Clear
// it so callers do not keep issuing JNI calls with an exception in flight.
if (env->ExceptionCheck() == JNI_TRUE)
env->ExceptionClear();
return "";
Comment on lines 14 to +21

@bmehta001 bmehta001 Jun 25, 2026

Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Addressed in 1274680 by clearing the pending exception before returning, so callers no longer continue with an exception in flight (the actual hazard you describe). I kept the std::string return contract rather than switching JStringToStdString to std::optional/out-param: it's called from many sites, an OOM mid-conversion is the only failure mode here, and the empty-string-on-failure behavior is the established convention. Reworking the signature and every call site is a broader refactor that's out of scope for this null-safety hardening PR.

}
std::string str(jstr_utf, jstr_utf + jstr_length);
env->ReleaseStringUTFChars(jstr, jstr_utf);
return str;
Expand Down
25 changes: 20 additions & 5 deletions lib/jni/Signals_jni.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -25,11 +25,19 @@ Java_com_microsoft_applications_events_Signals_sendSignal(JNIEnv *env,
jlong nativeLoggerPtr,
jstring signal_item_json) {
jboolean isCopy = true;
if (signal_item_json == nullptr) {
return false;
}
const char *signalItemJson = (env)->GetStringUTFChars(signal_item_json, &isCopy);
env->ReleaseStringUTFChars(signal_item_json, signalItemJson);
if (signalItemJson == nullptr) {
// GetStringUTFChars returned null (e.g. OOM, with a pending exception);
// there is nothing valid to log.
return false;
}
Comment on lines +28 to +36

@bmehta001 bmehta001 Jun 25, 2026

Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This early-return is intentional and is the fix, not a regression. sendSignal returns jboolean success, so a null signal_item_json now yields a clean false (failure) instead of calling GetStringUTFChars(nullptr, …), which is undefined per the JNI spec and would raise a Java NullPointerException back through the host app's logging call. A telemetry SDK should not crash/propagate an NPE into the caller over a null event payload — returning false is the correct, observable failure contract, and the Java wrapper already treats the boolean result as success/failure. The behavior change (NPE -> graceful false) is the intended hardening of this PR.


auto logger = reinterpret_cast<ILogger*>(nativeLoggerPtr);
EventProperties eventProperties = Signals::CreateEventProperties(signalItemJson);
Comment thread
bmehta001 marked this conversation as resolved.
env->ReleaseStringUTFChars(signal_item_json, signalItemJson);
logger->LogEvent(eventProperties);
return true;
}
Expand All @@ -54,11 +62,18 @@ Java_com_microsoft_applications_events_Signals_nativeInitialize(JNIEnv *env, jcl
SubstrateSignalsConfiguration config;

jboolean isCopy = true;
const char *convertedValue = (env)->GetStringUTFChars(base_url, &isCopy);
if (strlen(convertedValue) > 0) {
config.ServiceRequestConfig.BaseUrl = convertedValue;
if (base_url != nullptr) {
const char *convertedValue = (env)->GetStringUTFChars(base_url, &isCopy);
if (convertedValue == nullptr) {
// GetStringUTFChars failed (e.g. OOM) and left a pending exception;
// do not continue making JNI calls with an exception in flight.
return false;
}
if (strlen(convertedValue) > 0) {
config.ServiceRequestConfig.BaseUrl = convertedValue;
}
env->ReleaseStringUTFChars(base_url, convertedValue);
Comment on lines 64 to +75
}
env->ReleaseStringUTFChars(base_url, convertedValue);

config.ServiceRequestConfig.TimeoutMs = reinterpret_cast<int>(timeout_ms);
config.ServiceRequestConfig.RetryTimes = reinterpret_cast<int>(retry_times);
Expand Down
48 changes: 36 additions & 12 deletions lib/offline/OfflineStorage_Room.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -495,7 +495,9 @@ namespace MAT_NS_BEGIN
auto tenantToken_java = static_cast<jstring>(env->GetObjectField(record,
tenantToken_id));
ThrowRuntime(env, "get tenant");
auto token_utf = env->GetStringUTFChars(tenantToken_java, nullptr);
auto token_utf = (tenantToken_java != nullptr)
? env->GetStringUTFChars(tenantToken_java, nullptr)
: nullptr;
ThrowRuntime(env, "string tenant");
auto latency = static_cast<EventLatency>(std::max(latency_lb,
std::min<int>(
Expand Down Expand Up @@ -529,14 +531,17 @@ namespace MAT_NS_BEGIN
uint8_t* end = start + env->GetArrayLength(blob_java);
StorageRecord dest(
std::to_string(id_java),
token_utf,
token_utf != nullptr ? token_utf : "",
latency,
persistence,
timestamp,
StorageBlob(start, end),
retryCount,
reservedUntil);
env->ReleaseStringUTFChars(tenantToken_java, token_utf);
if (token_utf != nullptr)
{
env->ReleaseStringUTFChars(tenantToken_java, token_utf);
}
env->ReleaseByteArrayElements(blob_java,
reinterpret_cast<jbyte*>(start), 0);
env.popLocalFrame();
Expand Down Expand Up @@ -769,10 +774,17 @@ namespace MAT_NS_BEGIN
ThrowLogic(env, "Exception fetching token");
auto count = env->GetLongField(byTenant, count_id);
ThrowLogic(env, "Exception fetching count");
auto utf = env->GetStringUTFChars(token, nullptr);
std::string key(utf);
env->ReleaseStringUTFChars(token, utf);
dropped[key] = static_cast<size_t>(count);
auto utf = (token != nullptr) ? env->GetStringUTFChars(token, nullptr)
: nullptr;
ThrowRuntime(env, "Exception fetching token string");
// Skip rather than misattribute dropped records to an empty
// tenant token when the string read fails.
if (utf != nullptr)
{
std::string key(utf);
env->ReleaseStringUTFChars(token, utf);
dropped[key] = static_cast<size_t>(count);
}
env.popLocalFrame();
}
m_observer->OnStorageRecordsDropped(dropped);
Expand Down Expand Up @@ -1098,8 +1110,11 @@ namespace MAT_NS_BEGIN
{
auto utf = env->GetStringUTFChars(java_value, nullptr);
ThrowRuntime(env, "copy setting value");
result = utf;
env->ReleaseStringUTFChars(java_value, utf);
if (utf != nullptr)
{
result = utf;
env->ReleaseStringUTFChars(java_value, utf);
}
}
return result;
}
Expand Down Expand Up @@ -1343,7 +1358,13 @@ namespace MAT_NS_BEGIN
auto id_j = env->GetLongField(record, id_id);
auto tenant_j = static_cast<jstring>(env->GetObjectField(record,
tenantToken_id));
auto tenant_utf = env->GetStringUTFChars(tenant_j, nullptr);
const char* tenant_utf = (tenant_j != nullptr)
? env->GetStringUTFChars(tenant_j, nullptr)
: nullptr;
// Clear/handle any pending exception from a failed string read
// (e.g. OOM) before making further JNI calls, consistent with the
// other read paths in this file.
ThrowRuntime(env, "string tenant");
auto latency = static_cast<EventLatency>(env->GetIntField(record,
latency_id));
auto persistence = static_cast<EventPersistence>(env->GetIntField(record,
Expand All @@ -1359,14 +1380,17 @@ namespace MAT_NS_BEGIN
auto blob_end = blob_store + blob_length;
records.emplace_back(
std::to_string(id_j),
tenant_utf,
tenant_utf != nullptr ? tenant_utf : "",
latency,
persistence,
Comment on lines 1381 to 1385
timestamp,
StorageBlob(blob_store, blob_end),
retryCount,
reservedUntil);
env->ReleaseStringUTFChars(tenant_j, tenant_utf);
if (tenant_utf != nullptr)
{
env->ReleaseStringUTFChars(tenant_j, tenant_utf);
}
env->ReleaseByteArrayElements(blob_j, elements, 0);
env.popLocalFrame();
}
Expand Down
11 changes: 10 additions & 1 deletion lib/pal/universal/WindowsRuntimeSystemInformationImpl.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@
#include "pal/PAL.hpp"

#include <collection.h>
#include <exception>

#include "ISystemInformation.hpp"
#include "pal/SystemInformationImpl.hpp"
Expand Down Expand Up @@ -80,7 +81,15 @@ namespace PAL_NS_BEGIN {

// The DeviceFamilyVersion is a decimalized form of the ULONGLONG hex form. For example:
// 2814750430068736 = 000A000027840000 = 10.0.10116.0
auto versionDec = std::stoull(AnalyticsInfo::VersionInfo->DeviceFamilyVersion->Data());
unsigned long long versionDec = 0ull;
try
{
versionDec = std::stoull(AnalyticsInfo::VersionInfo->DeviceFamilyVersion->Data());
}
catch (const std::exception&)
{
versionDec = 0ull;
}
if (versionDec != 0ull)
{
m_os_major_version = std::to_string(versionDec >> 16 * 3) + "." + std::to_string(versionDec >> 16 * 2 & 0xFFFF);
Expand Down
Loading