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authorJason A. Donenfeld <Jason@zx2c4.com>2021-05-06 10:45:43 +0200
committerJason A. Donenfeld <Jason@zx2c4.com>2021-05-06 10:50:20 +0200
commitd6a8e9d4dc8d6b5eb5b2e0341ef6e43aeb9c5c49 (patch)
tree87fd11374b09d02395f0e91cfb84a704b16d7ad6
parentversion: bump (diff)
downloadwireguard-android-d6a8e9d4dc8d6b5eb5b2e0341ef6e43aeb9c5c49.tar.xz
wireguard-android-d6a8e9d4dc8d6b5eb5b2e0341ef6e43aeb9c5c49.zip
tunnel: avoid race between shutdown and stats
wgTurnOff can block for a while, in which case, calling getStatistics will use a stale handle and stale tunnel. Not only that, but wgGetConfig might return null, in which case string.split throws. java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String[] java.lang.String.split(java.lang.String)' on a null at com.wireguard.android.backend.GoBackend.getStatistics Reported-by: tomt@adslweb.co.uk Link: https://lists.zx2c4.com/pipermail/wireguard/2021-May/006709.html Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
-rw-r--r--tunnel/src/main/java/com/wireguard/android/backend/GoBackend.java11
1 files changed, 6 insertions, 5 deletions
diff --git a/tunnel/src/main/java/com/wireguard/android/backend/GoBackend.java b/tunnel/src/main/java/com/wireguard/android/backend/GoBackend.java
index c738148..8b9213d 100644
--- a/tunnel/src/main/java/com/wireguard/android/backend/GoBackend.java
+++ b/tunnel/src/main/java/com/wireguard/android/backend/GoBackend.java
@@ -68,7 +68,7 @@ public final class GoBackend implements Backend {
alwaysOnCallback = cb;
}
- private static native String wgGetConfig(int handle);
+ @Nullable private static native String wgGetConfig(int handle);
private static native int wgGetSocketV4(int handle);
@@ -115,10 +115,11 @@ public final class GoBackend implements Backend {
@Override
public Statistics getStatistics(final Tunnel tunnel) {
final Statistics stats = new Statistics();
- if (tunnel != currentTunnel) {
+ if (tunnel != currentTunnel || currentTunnelHandle == -1)
return stats;
- }
final String config = wgGetConfig(currentTunnelHandle);
+ if (config == null)
+ return stats;
Key key = null;
long rx = 0;
long tx = 0;
@@ -294,11 +295,11 @@ public final class GoBackend implements Backend {
Log.w(TAG, "Tunnel already down");
return;
}
-
- wgTurnOff(currentTunnelHandle);
+ int handleToClose = currentTunnelHandle;
currentTunnel = null;
currentTunnelHandle = -1;
currentConfig = null;
+ wgTurnOff(handleToClose);
}
tunnel.onStateChange(state);