KEYS: trusted: tee: Refactor register SHM usage

The OP-TEE driver using the old SMC based ABI permits overlapping shared
buffers, but with the new FF-A based ABI each physical page may only
be registered once.

As the key and blob buffer are allocated adjancently, there is no need
for redundant register shared memory invocation. Also, it is incompatibile
with FF-A based ABI limitation. So refactor register shared memory
implementation to use only single invocation to register both key and blob
buffers.

[jarkko: Added cc to stable.]
Cc: stable@vger.kernel.org # v5.16+
Fixes: 4615e5a ("optee: add FF-A support")
Reported-by: Jens Wiklander <jens.wiklander@linaro.org>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Tested-by: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>

security/keys/trusted-keys/trusted_tee.c

@@ -65,38 +65,30 @@ static int trusted_tee_seal(struct trusted_key_payload *p, char *datablob)
 	int ret;
 	struct tee_ioctl_invoke_arg inv_arg;
 	struct tee_param param[4];
-	struct tee_shm *reg_shm_in = NULL, *reg_shm_out = NULL;
+	struct tee_shm *reg_shm = NULL;
 
 	memset(&inv_arg, 0, sizeof(inv_arg));
 	memset(&param, 0, sizeof(param));
 
-	reg_shm_in = tee_shm_register_kernel_buf(pvt_data.ctx, p->key,
-						 p->key_len);
-	if (IS_ERR(reg_shm_in)) {
-		dev_err(pvt_data.dev, "key shm register failed\n");
-		return PTR_ERR(reg_shm_in);
-	}
-
-	reg_shm_out = tee_shm_register_kernel_buf(pvt_data.ctx, p->blob,
-						  sizeof(p->blob));
-	if (IS_ERR(reg_shm_out)) {
-		dev_err(pvt_data.dev, "blob shm register failed\n");
-		ret = PTR_ERR(reg_shm_out);
-		goto out;
+	reg_shm = tee_shm_register_kernel_buf(pvt_data.ctx, p->key,
+					      sizeof(p->key) + sizeof(p->blob));
+	if (IS_ERR(reg_shm)) {
+		dev_err(pvt_data.dev, "shm register failed\n");
+		return PTR_ERR(reg_shm);
 	}
 
 	inv_arg.func = TA_CMD_SEAL;
 	inv_arg.session = pvt_data.session_id;
 	inv_arg.num_params = 4;
 
 	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT;
-	param[0].u.memref.shm = reg_shm_in;
+	param[0].u.memref.shm = reg_shm;
 	param[0].u.memref.size = p->key_len;
 	param[0].u.memref.shm_offs = 0;
 	param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
-	param[1].u.memref.shm = reg_shm_out;
+	param[1].u.memref.shm = reg_shm;
 	param[1].u.memref.size = sizeof(p->blob);
-	param[1].u.memref.shm_offs = 0;
+	param[1].u.memref.shm_offs = sizeof(p->key);
 
 	ret = tee_client_invoke_func(pvt_data.ctx, &inv_arg, param);
 	if ((ret < 0) || (inv_arg.ret != 0)) {
@@ -107,11 +99,7 @@ static int trusted_tee_seal(struct trusted_key_payload *p, char *datablob)
 		p->blob_len = param[1].u.memref.size;
 	}
 
-out:
-	if (reg_shm_out)
-		tee_shm_free(reg_shm_out);
-	if (reg_shm_in)
-		tee_shm_free(reg_shm_in);
+	tee_shm_free(reg_shm);
 
 	return ret;
 }
@@ -124,36 +112,28 @@ static int trusted_tee_unseal(struct trusted_key_payload *p, char *datablob)
 	int ret;
 	struct tee_ioctl_invoke_arg inv_arg;
 	struct tee_param param[4];
-	struct tee_shm *reg_shm_in = NULL, *reg_shm_out = NULL;
+	struct tee_shm *reg_shm = NULL;
 
 	memset(&inv_arg, 0, sizeof(inv_arg));
 	memset(&param, 0, sizeof(param));
 
-	reg_shm_in = tee_shm_register_kernel_buf(pvt_data.ctx, p->blob,
-						 p->blob_len);
-	if (IS_ERR(reg_shm_in)) {
-		dev_err(pvt_data.dev, "blob shm register failed\n");
-		return PTR_ERR(reg_shm_in);
-	}
-
-	reg_shm_out = tee_shm_register_kernel_buf(pvt_data.ctx, p->key,
-						  sizeof(p->key));
-	if (IS_ERR(reg_shm_out)) {
-		dev_err(pvt_data.dev, "key shm register failed\n");
-		ret = PTR_ERR(reg_shm_out);
-		goto out;
+	reg_shm = tee_shm_register_kernel_buf(pvt_data.ctx, p->key,
+					      sizeof(p->key) + sizeof(p->blob));
+	if (IS_ERR(reg_shm)) {
+		dev_err(pvt_data.dev, "shm register failed\n");
+		return PTR_ERR(reg_shm);
 	}
 
 	inv_arg.func = TA_CMD_UNSEAL;
 	inv_arg.session = pvt_data.session_id;
 	inv_arg.num_params = 4;
 
 	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT;
-	param[0].u.memref.shm = reg_shm_in;
+	param[0].u.memref.shm = reg_shm;
 	param[0].u.memref.size = p->blob_len;
-	param[0].u.memref.shm_offs = 0;
+	param[0].u.memref.shm_offs = sizeof(p->key);
 	param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
-	param[1].u.memref.shm = reg_shm_out;
+	param[1].u.memref.shm = reg_shm;
 	param[1].u.memref.size = sizeof(p->key);
 	param[1].u.memref.shm_offs = 0;
 
@@ -166,11 +146,7 @@ static int trusted_tee_unseal(struct trusted_key_payload *p, char *datablob)
 		p->key_len = param[1].u.memref.size;
 	}
 
-out:
-	if (reg_shm_out)
-		tee_shm_free(reg_shm_out);
-	if (reg_shm_in)
-		tee_shm_free(reg_shm_in);
+	tee_shm_free(reg_shm);
 
 	return ret;
 }