Backport of Win-specific suppression of potentially rogue construct that can engage

in directory traversal on the host.

Bug:209438553

Ignore-AOSP-First: Resolution for potential security exploit.

Test: Synced just system/core, therefore relying on presubmits for now.
Will followup with a full-fledged sync and manual cursory test.

Signed-off-by: Shaju Mathew <shaju@google.com>
Change-Id: I993a00ce6130478b7becfdbea816c348824f319f
Merged-In: Ie1f82db2fb14e1bdd183bf8d3d93d5e9f974be5d

adb/client/file_sync_client.cpp

@@ -629,6 +629,18 @@ static bool sync_ls(SyncConnection& sc, const char* path,
         if (!ReadFdExactly(sc.fd, buf, len)) return false;
         buf[len] = 0;
 
+        // Address the unlikely scenario wherein a
+        // compromised device/service might be able to
+        // traverse across directories on the host. Let's
+        // shut that door!
+        if (strchr(buf, '/')
+#if defined(_WIN32)
+            || strchr(buf, '\\')
+#endif
+           ) {
+          return false;
+        }
+
         func(msg.dent.mode, msg.dent.size, msg.dent.time, buf);
     }
 }