Fix use-after-free in DatabaseConnection._run

SOBotics · Nov 2, 2017 · a7fc3ad · a7fc3ad
1 parent 119bfc0
commit a7fc3ad
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Showing 2 changed files with 16 additions and 14 deletions.
diff --git a/Sources/SwiftChatSE/DatabaseConnection.swift b/Sources/SwiftChatSE/DatabaseConnection.swift
@@ -249,22 +249,23 @@ open class DatabaseConnection {
             //cache miss; compile the query
             var tail: UnsafePointer<Int8>?
             var stmt: OpaquePointer?
-            let result = query.utf8CString.withUnsafeBufferPointer {
-                sqlite3_prepare_v2(
+            try query.utf8CString.withUnsafeBufferPointer {
+                let result = sqlite3_prepare_v2(
                     db,
                     $0.baseAddress,
                     Int32($0.count),
                     &stmt,
                     &tail
                 )
-            }
-
-            guard result == SQLITE_OK, stmt != nil else {
-                try throwSQLiteError(code: result, db: db)
-            }
-            if tail != nil && tail!.pointee != 0 {
-                //programmer error, so crash instead of throwing
-                fatalError("\(#function) does not accept multiple statements: '\(query)' (tail: \(String(cString: tail!)))")
+
+
+                guard result == SQLITE_OK, stmt != nil else {
+                    try throwSQLiteError(code: result, db: db)
+                }
+                if tail != nil && tail!.pointee != 0 {
+                    //programmer error, so crash instead of throwing
+                    fatalError("\(#function) does not accept multiple statements: '\(query)' (tail: \(String(cString: tail!)))")
+                }
             }
 
             statement = stmt!

diff --git a/Tests/SwiftChatSETests/DatabaseTests.swift b/Tests/SwiftChatSETests/DatabaseTests.swift
@@ -34,17 +34,18 @@ class DatabaseTests: XCTestCase {
 
     func testRepeatedAsynchronousQuery() throws {
         let iterations = 1000
-        let expectation = self.expectation(description: "Finished iterations")
+        let sema = DispatchSemaphore(value: 0)
 
-        expectation.expectedFulfillmentCount = iterations
         for _ in 0..<iterations {
             DispatchQueue.global().async {
                 _ = try! self.db.run("SELECT 1", cache: false)
-                expectation.fulfill()
+                sema.signal()
             }
         }
 
-        waitForExpectations(timeout: 10)
+        for _ in 0..<iterations {
+            sema.wait()
+        }
     }
 
     func testOnDiskDatabase() {