From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Fri, 12 Nov 2021 16:11:56 +0000 (+0100)
Subject: 4.4-stable patches
X-Git-Tag: v5.4.160~182
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=fdbcfd8128a6b0d04bfc61e9d77c3aa18d8e1caf;p=thirdparty%2Fkernel%2Fstable-queue.git

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
index 00000000000..390e1d0a3f1
--- /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
index 00000000000..234c6f5bb48
--- /dev/null
+++ b/queue-4.4/series
@@ -0,0 +1 @@
+binder-use-euid-from-cred-instead-of-using-task.patch