linux-kernel - [PATCH] tee: fix illegal pointer dereference in tee_shm

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Message-Id: <20251106102008.1310234-1-yangzhao@kylinos.cn>
Date: Thu,  6 Nov 2025 18:20:08 +0800
From: yangzhao <yangzhao@...inos.cn>
To: op-tee@...ts.trustedfirmware.org,
	linux-kernel@...r.kernel.org
Cc: Jens Wiklander <jens.wiklander@...aro.org>,
	Sumit Garg <sumit.garg@...nel.org>,
	yangzhao <yangzhao@...inos.cn>
Subject: [PATCH] tee: fix illegal pointer dereference in tee_shm_put()

In tee_shm_put(), there is not only the NULL pointer dereference,
but also the illegal pointer dereference.

shutdown() --->
    __optee_disable_shm_cache -->
        shm = reg_pair_to_ptr(...);
        tee_shm_free(shm); -->
            tee_shm_put(shm); //crash: shm->ctx maybe NULL pointer or illegal pointer

Check whether the pointer is NULL and whether the pointer address is valid.

This issue occurs when rich world uses the 6.x version of the kernel and
optee secure world uses a lower version (such as version 3.2), and it is
highly likely to trigger a kernel panic when conducting hibernate tests.

Fixes: e4a718a3a47e ("tee: fix NULL pointer dereference in tee_shm_put")
Signed-off-by: yangzhao <yangzhao@...inos.cn>
---
 drivers/tee/tee_shm.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
index 4a47de4bb2e5..de01d16409c1 100644
--- a/drivers/tee/tee_shm.c
+++ b/drivers/tee/tee_shm.c
@@ -722,7 +722,14 @@ void tee_shm_put(struct tee_shm *shm)
 	struct tee_device *teedev;
 	bool do_release = false;
 
-	if (!shm || !shm->ctx || !shm->ctx->teedev)
+	/* checking pointer */
+	if (IS_ERR_OR_NULL(shm) || !virt_addr_valid(shm))
+		return;
+
+	if (IS_ERR_OR_NULL(shm->ctx) || !virt_addr_valid(shm->ctx))
+		return;
+
+	if (IS_ERR_OR_NULL(shm->ctx->teedev) || !virt_addr_valid(shm->ctx->teedev))
 		return;
 
 	teedev = shm->ctx->teedev;
-- 
2.25.1