fs_mgr: Ignore invalid DT device nodes

With treble, the vendor kernel and ramdisk are supposed to be used.
But vendors always find new and interesting ways to break things:

$ cat /proc/device-tree/firmware/android/fstab/system/dev; echo
/by-name/system_a
$

Change-Id: I826a96ebd625b52563d3cc970bf99d9b26dc093e

1 files changed, 6 insertions, 0 deletions

diff --git a/fs_mgr/fs_mgr_fstab.cpp b/fs_mgr/fs_mgr_fstab.cpp
index 9b7405a3d..72a65d264 100644
--- a/fs_mgr/fs_mgr_fstab.cpp
+++ b/fs_mgr/fs_mgr_fstab.cpp
@@ -33,6 +33,8 @@
 
 #include "fs_mgr_priv.h"
 
+using android::base::StartsWith;
+
 const std::string kDefaultAndroidDtDir("/proc/device-tree/firmware/android");
 
 struct fs_mgr_flag_values {
@@ -439,6 +441,10 @@ static std::string read_fstab_from_dt() {
             LERROR << "dt_fstab: Failed to find device for partition " << dp->d_name;
             return {};
         }
+        if (!StartsWith(value, "/dev")) {
+            LERROR << "dt_fstab: Invalid device node for partition " << dp->d_name;
+            return {};
+        }
         fstab_entry.push_back(value);
 
         std::string mount_point;