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| author | Rijo Thomas <Rijo-john.Thomas@amd.com> | 2023-09-29 10:00:24 +0300 |
|---|---|---|
| committer | Jens Wiklander <jens.wiklander@linaro.org> | 2023-10-03 20:13:53 +0300 |
| commit | f4384b3e54ea813868bb81a861bf5b2406e15d8f (patch) | |
| tree | 4aa08d8f1c2b5b51e792c2e482b7c44156f4f667 /drivers/tee | |
| parent | 2dde18cd1d8fac735875f2e4987f11817cc0bc2c (diff) | |
| download | linux-f4384b3e54ea813868bb81a861bf5b2406e15d8f.tar.xz | |
tee: amdtee: fix use-after-free vulnerability in amdtee_close_session
There is a potential race condition in amdtee_close_session that may
cause use-after-free in amdtee_open_session. For instance, if a session
has refcount == 1, and one thread tries to free this session via:
kref_put(&sess->refcount, destroy_session);
the reference count will get decremented, and the next step would be to
call destroy_session(). However, if in another thread,
amdtee_open_session() is called before destroy_session() has completed
execution, alloc_session() may return 'sess' that will be freed up
later in destroy_session() leading to use-after-free in
amdtee_open_session.
To fix this issue, treat decrement of sess->refcount and removal of
'sess' from session list in destroy_session() as a critical section, so
that it is executed atomically.
Fixes: 757cc3e9ff1d ("tee: add AMD-TEE driver")
Cc: stable@vger.kernel.org
Signed-off-by: Rijo Thomas <Rijo-john.Thomas@amd.com>
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Diffstat (limited to 'drivers/tee')
| -rw-r--r-- | drivers/tee/amdtee/core.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/tee/amdtee/core.c b/drivers/tee/amdtee/core.c index 372d64756ed6..3c15f6a9e91c 100644 --- a/drivers/tee/amdtee/core.c +++ b/drivers/tee/amdtee/core.c @@ -217,12 +217,12 @@ unlock: return rc; } +/* mutex must be held by caller */ static void destroy_session(struct kref *ref) { struct amdtee_session *sess = container_of(ref, struct amdtee_session, refcount); - mutex_lock(&session_list_mutex); list_del(&sess->list_node); mutex_unlock(&session_list_mutex); kfree(sess); @@ -272,7 +272,8 @@ int amdtee_open_session(struct tee_context *ctx, 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); + kref_put_mutex(&sess->refcount, destroy_session, + &session_list_mutex); goto out; } @@ -290,7 +291,8 @@ int amdtee_open_session(struct tee_context *ctx, 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); + kref_put_mutex(&sess->refcount, destroy_session, + &session_list_mutex); rc = -ENOMEM; goto out; } @@ -331,7 +333,7 @@ int amdtee_close_session(struct tee_context *ctx, u32 session) handle_close_session(ta_handle, session_info); handle_unload_ta(ta_handle); - kref_put(&sess->refcount, destroy_session); + kref_put_mutex(&sess->refcount, destroy_session, &session_list_mutex); return 0; } |