Merge pull request #2740 from DataDog/simaoseica/RUM-15005/c-string-conversion

RUM-15005: Fix context C-string conversion in KSCrash injection

Author: simaoseica-dd

CHANGELOG.md

@@ -3,6 +3,7 @@
 - [FEATURE] Add OOB scroll and swipe action tracking. See [#2717][]
 - [IMPROVEMENT] Rename `DDRUMErrorEventErrorMeta` to `DDRUMErrorEventErrorMetaInfo`, add support of custom Objective-C runtime names for generated RUM models. See [#2705][]
 - [FEATURE] Add `trackResourceHeaders` configuration to capture HTTP request and response headers in RUM Resource events. See [#2721][]
+- [FIX] Fix crash context C-string conversion in KSCrash injection. See [#2740][]
 
 # 3.7.0 / 18-02-2026
 
@@ -1064,6 +1065,7 @@ Release `2.0` introduces breaking changes. Follow the [Migration Guide](MIGRATIO
 [#2705]: https://github.com/DataDog/dd-sdk-ios/pull/2705
 [#2721]: https://github.com/DataDog/dd-sdk-ios/pull/2721
 [#2717]: https://github.com/DataDog/dd-sdk-ios/pull/2717
+[#2740]: https://github.com/DataDog/dd-sdk-ios/pull/2740
 
 [@00fa9a]: https://github.com/00FA9A
 [@britton-earnin]: https://github.com/Britton-Earnin

DatadogCrashReporting/Sources/KSCrashIntegration/KSCrashBacktrace.swift

@@ -116,8 +116,7 @@ internal struct KSCrashBacktrace: BacktraceReporting {
     private func getThreadName(pthread: pthread_t) -> String? {
         var buffer = [CChar](repeating: 0, count: 256)
         guard pthread_getname_np(pthread, &buffer, buffer.count) == KERN_SUCCESS, buffer[0] != 0 else {
-            telemetry.error("Failed to get pthread name")
-            return nil // fails or empty
+            return nil // Failed to get pthread name
         }
         return String(cString: buffer)
     }

DatadogCrashReporting/Sources/KSCrashIntegration/KSCrashPlugin.swift

@@ -85,9 +85,9 @@ internal class KSCrashPlugin: NSObject, CrashReportingPlugin {
     }
 
     func inject(context: Data) {
-        context.withUnsafeBytes {
-            let c_char = $0.bindMemory(to: CChar.self).baseAddress
-            kscrash_setUserInfoJSON(c_char)
+        let contextString = String(decoding: context, as: UTF8.self)
+        contextString.withCString {
+            kscrash_setUserInfoJSON($0)
         }
     }
 

DatadogCrashReporting/Tests/KSCrashIntegration/KSCrashPluginTests.swift

@@ -8,7 +8,7 @@ import XCTest
 @testable import DatadogCrashReporting
 import KSCrashRecording
 
-class KSCrashPluginTests: XCTestCase {
+final class KSCrashPluginTests: XCTestCase {
     // MARK: - Configuration Tests
 
     func testConfiguration() throws {
@@ -20,4 +20,33 @@ class KSCrashPluginTests: XCTestCase {
         XCTAssertEqual(config.reportStoreConfiguration.maxReportCount, 1)
         XCTAssertEqual(config.reportStoreConfiguration.reportCleanupPolicy, .never)
     }
+
+    func testCStringFromContextAppendsTrailingNullTerminator() {
+        // Given
+        let context = Data("{\"context\":\"value\"}".utf8)
+
+        // When
+        let cString = cStringBytesFrom(context: context)
+
+        // Then
+        XCTAssertEqual(cString.dropLast(), context[...])
+        XCTAssertEqual(cString.last, 0)
+    }
+
+    func testCStringFromContextPreservesExplicitTrailingNullCharacter() {
+        // Given
+        let context = Data([123, 125, 0])
+
+        // When
+        let cString = cStringBytesFrom(context: context)
+
+        // Then
+        XCTAssertEqual(cString, Data([123, 125, 0, 0]))
+    }
+
+    /// Rebuilds the exact C-string bytes (`utf8` payload + trailing `\0`) used by `inject(context:)`.
+    private func cStringBytesFrom(context: Data) -> Data {
+        let contextString = String(decoding: context, as: UTF8.self)
+        return Data(contextString.utf8CString.map(UInt8.init(bitPattern:)))
+    }
 }