Widen allowed UID range for webview zygote.

The webview zygote is shared for all users on the system, and so unlike
the app zygote, it can't use a single whitelisted UID range. For now,
clamp to the upper bound of the UID range, until we have a better idea.

This is still an improvement from the previous status quo, because it
will prevent setuid/setgid into system users.

Bug: 123597434
Test: builds, webview_zygote running
Change-Id: Ia975826ed5b1f20cabb46f60f5951723b1ba80c9

diff --git a/core/java/android/webkit/WebViewZygote.java b/core/java/android/webkit/WebViewZygote.java
index de1f3df..09aa066 100644 (file)
--- a/core/java/android/webkit/WebViewZygote.java
+++ b/core/java/android/webkit/WebViewZygote.java
@@ -163,7 +163,7 @@ public class WebViewZygote {
                     TextUtils.join(",", Build.SUPPORTED_ABIS),
                     null, // instructionSet
                     Process.FIRST_ISOLATED_UID,
-                    Process.LAST_ISOLATED_UID);
+                    Integer.MAX_VALUE); // TODO(b/123615476) deal with user-id ranges properly
             ZygoteProcess.waitForConnectionToZygote(sZygote.getPrimarySocketAddress());
 
             if (sPackageOriginalAppInfo.sourceDir.equals(sPackage.applicationInfo.sourceDir)) {

diff --git a/core/java/com/android/internal/os/ChildZygoteInit.java b/core/java/com/android/internal/os/ChildZygoteInit.java
index a052a3b..cc74863 100644 (file)
--- a/core/java/com/android/internal/os/ChildZygoteInit.java
+++ b/core/java/com/android/internal/os/ChildZygoteInit.java
@@ -98,9 +98,11 @@ public class ChildZygoteInit {
             throw new RuntimeException("Passed in UID range is invalid, min > max.");
         }
 
-        // Verify the UIDs are in the isolated UID range, as that's the only thing that we should
-        // be forking right now
-        if (!Process.isIsolated(uidGidMin) || !Process.isIsolated(uidGidMax)) {
+        // Verify the UIDs at least do not include system UIDs; we can't easily verify there
+        // are just isolated UIDs in the range, because for the webview zygote, there is no
+        // single range that captures all possible isolated UIDs.
+        // TODO(b/123615476) narrow this down
+        if (uidGidMin < Process.FIRST_ISOLATED_UID) {
             throw new RuntimeException("Passed in UID range does not map to isolated processes.");
         }