4.4-stable patches

added patches:
	binder-use-euid-from-cred-instead-of-using-task.patch

diff --git a/queue-4.4/binder-use-euid-from-cred-instead-of-using-task.patch b/queue-4.4/binder-use-euid-from-cred-instead-of-using-task.patch
new file mode 100644 (file)
index 0000000..390e1d0
--- /dev/null
+++ b/queue-4.4/binder-use-euid-from-cred-instead-of-using-task.patch
@@ -0,0 +1,68 @@
+From 29bc22ac5e5bc63275e850f0c8fc549e3d0e306b Mon Sep 17 00:00:00 2001
+From: Todd Kjos <tkjos@google.com>
+Date: Tue, 12 Oct 2021 09:56:12 -0700
+Subject: binder: use euid from cred instead of using task
+
+From: Todd Kjos <tkjos@google.com>
+
+commit 29bc22ac5e5bc63275e850f0c8fc549e3d0e306b upstream.
+
+Save the 'struct cred' associated with a binder process
+at initial open to avoid potential race conditions
+when converting to an euid.
+
+Set a transaction's sender_euid from the 'struct cred'
+saved at binder_open() instead of looking up the euid
+from the binder proc's 'struct task'. This ensures
+the euid is associated with the security context that
+of the task that opened binder.
+
+Cc: stable@vger.kernel.org # 4.4+
+Fixes: 457b9a6f09f0 ("Staging: android: add binder driver")
+Signed-off-by: Todd Kjos <tkjos@google.com>
+Suggested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
+Suggested-by: Jann Horn <jannh@google.com>
+Acked-by: Casey Schaufler <casey@schaufler-ca.com>
+Signed-off-by: Paul Moore <paul@paul-moore.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+
+---
+ drivers/android/binder.c |    5 ++++-
+ 1 file changed, 4 insertions(+), 1 deletion(-)
+
+--- a/drivers/android/binder.c
++++ b/drivers/android/binder.c
+@@ -303,6 +303,7 @@ struct binder_proc {
+       struct mm_struct *vma_vm_mm;
+       struct task_struct *tsk;
+       struct files_struct *files;
++      const struct cred *cred;
+       struct hlist_node deferred_work_node;
+       int deferred_work;
+       void *buffer;
+@@ -1493,7 +1494,7 @@ static void binder_transaction(struct bi
+               t->from = thread;
+       else
+               t->from = NULL;
+-      t->sender_euid = task_euid(proc->tsk);
++      t->sender_euid = proc->cred->euid;
+       t->to_proc = target_proc;
+       t->to_thread = target_thread;
+       t->code = tr->code;
+@@ -3015,6 +3016,7 @@ static int binder_open(struct inode *nod
+               return -ENOMEM;
+       get_task_struct(current->group_leader);
+       proc->tsk = current->group_leader;
++      proc->cred = get_cred(filp->f_cred);
+       INIT_LIST_HEAD(&proc->todo);
+       init_waitqueue_head(&proc->wait);
+       proc->default_priority = task_nice(current);
+@@ -3220,6 +3222,7 @@ static void binder_deferred_release(stru
+       }
+ 
+       put_task_struct(proc->tsk);
++      put_cred(proc->cred);
+ 
+       binder_debug(BINDER_DEBUG_OPEN_CLOSE,
+                    "%s: %d threads %d, nodes %d (ref %d), refs %d, active transactions %d, buffers %d, pages %d\n",

diff --git a/queue-4.4/series b/queue-4.4/series
new file mode 100644 (file)
index 0000000..234c6f5
--- /dev/null
+++ b/queue-4.4/series
@@ -0,0 +1 @@
+binder-use-euid-from-cred-instead-of-using-task.patch