This is a note to let you know that I've just added the patch titled
tee: amdtee: fix race condition in amdtee_open_session
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tee-amdtee-fix-race-condition-in-amdtee_open_session.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From f8502fba45bd30e1a6a354d9d898bc99d1a11e6d Mon Sep 17 00:00:00 2001
From: Rijo Thomas <Rijo-john.Thomas@xxxxxxx>
Date: Tue, 28 Feb 2023 15:11:20 +0530
Subject: tee: amdtee: fix race condition in amdtee_open_session
From: Rijo Thomas <Rijo-john.Thomas@xxxxxxx>
commit f8502fba45bd30e1a6a354d9d898bc99d1a11e6d upstream.
There is a potential race condition in amdtee_open_session that may
lead to use-after-free. For instance, in amdtee_open_session() after
sess->sess_mask is set, and before setting:
sess->session_info[i] = session_info;
if amdtee_close_session() closes this same session, then 'sess' data
structure will be released, causing kernel panic when 'sess' is
accessed within amdtee_open_session().
The solution is to set the bit sess->sess_mask as the last step in
amdtee_open_session().
Fixes: 757cc3e9ff1d ("tee: add AMD-TEE driver")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Rijo Thomas <Rijo-john.Thomas@xxxxxxx>
Acked-by: Sumit Garg <sumit.garg@xxxxxxxxxx>
Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tee/amdtee/core.c | 29 ++++++++++++++---------------
1 file changed, 14 insertions(+), 15 deletions(-)
--- a/drivers/tee/amdtee/core.c
+++ b/drivers/tee/amdtee/core.c
@@ -267,35 +267,34 @@ int amdtee_open_session(struct tee_conte
goto out;
}
+ /* Open session with loaded TA */
+ handle_open_session(arg, &session_info, param);
+ if (arg->ret != TEEC_SUCCESS) {
+ pr_err("open_session failed %d\n", arg->ret);
+ handle_unload_ta(ta_handle);
+ kref_put(&sess->refcount, destroy_session);
+ goto out;
+ }
+
/* Find an empty session index for the given TA */
spin_lock(&sess->lock);
i = find_first_zero_bit(sess->sess_mask, TEE_NUM_SESSIONS);
- if (i < TEE_NUM_SESSIONS)
+ if (i < TEE_NUM_SESSIONS) {
+ sess->session_info[i] = session_info;
+ set_session_id(ta_handle, i, &arg->session);
set_bit(i, sess->sess_mask);
+ }
spin_unlock(&sess->lock);
if (i >= TEE_NUM_SESSIONS) {
pr_err("reached maximum session count %d\n", TEE_NUM_SESSIONS);
+ handle_close_session(ta_handle, session_info);
handle_unload_ta(ta_handle);
kref_put(&sess->refcount, destroy_session);
rc = -ENOMEM;
goto out;
}
- /* Open session with loaded TA */
- handle_open_session(arg, &session_info, param);
- if (arg->ret != TEEC_SUCCESS) {
- pr_err("open_session failed %d\n", arg->ret);
- spin_lock(&sess->lock);
- clear_bit(i, sess->sess_mask);
- spin_unlock(&sess->lock);
- handle_unload_ta(ta_handle);
- kref_put(&sess->refcount, destroy_session);
- goto out;
- }
-
- sess->session_info[i] = session_info;
- set_session_id(ta_handle, i, &arg->session);
out:
free_pages((u64)ta, get_order(ta_size));
return rc;
Patches currently in stable-queue which might be from Rijo-john.Thomas@xxxxxxx are
queue-6.1/tee-amdtee-fix-race-condition-in-amdtee_open_session.patch
