![Zhizhou Zhang](/assets/img/avatar_default.png)
This bug occurs when: - a new request arrives, one thread(let's call it A) is pending in optee_supp_req() with req->busy is initial value false. - tee-supplicant is killed, then optee_supp_release() is called, this function calls list_del(&req->link), and set supp->ctx to NULL. And it also wake up process A. - process A continues, it firstly checks supp->ctx which is NULL, then checks req->busy which is false, at last run list_del(&req->link). This triggers double list_del() and results kernel panic. For solve this problem, we rename req->busy to req->in_queue, and associate it with state of whether req is linked to supp->reqs. So we can just only check req->in_queue to make decision calling list_del() or not. Signed-off-by: Zhizhou Zhang <zhizhouzhang@asrmicro.com> Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
384 lines
9.1 KiB
C
384 lines
9.1 KiB
C
/*
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* Copyright (c) 2015, Linaro Limited
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <linux/device.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include "optee_private.h"
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struct optee_supp_req {
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struct list_head link;
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bool in_queue;
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u32 func;
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u32 ret;
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size_t num_params;
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struct tee_param *param;
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struct completion c;
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};
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void optee_supp_init(struct optee_supp *supp)
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{
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memset(supp, 0, sizeof(*supp));
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mutex_init(&supp->mutex);
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init_completion(&supp->reqs_c);
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idr_init(&supp->idr);
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INIT_LIST_HEAD(&supp->reqs);
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supp->req_id = -1;
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}
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void optee_supp_uninit(struct optee_supp *supp)
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{
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mutex_destroy(&supp->mutex);
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idr_destroy(&supp->idr);
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}
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void optee_supp_release(struct optee_supp *supp)
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{
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int id;
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struct optee_supp_req *req;
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struct optee_supp_req *req_tmp;
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mutex_lock(&supp->mutex);
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/* Abort all request retrieved by supplicant */
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idr_for_each_entry(&supp->idr, req, id) {
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idr_remove(&supp->idr, id);
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req->ret = TEEC_ERROR_COMMUNICATION;
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complete(&req->c);
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}
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/* Abort all queued requests */
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list_for_each_entry_safe(req, req_tmp, &supp->reqs, link) {
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list_del(&req->link);
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req->in_queue = false;
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req->ret = TEEC_ERROR_COMMUNICATION;
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complete(&req->c);
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}
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supp->ctx = NULL;
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supp->req_id = -1;
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mutex_unlock(&supp->mutex);
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}
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/**
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* optee_supp_thrd_req() - request service from supplicant
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* @ctx: context doing the request
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* @func: function requested
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* @num_params: number of elements in @param array
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* @param: parameters for function
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*
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* Returns result of operation to be passed to secure world
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*/
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u32 optee_supp_thrd_req(struct tee_context *ctx, u32 func, size_t num_params,
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struct tee_param *param)
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{
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struct optee *optee = tee_get_drvdata(ctx->teedev);
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struct optee_supp *supp = &optee->supp;
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struct optee_supp_req *req = kzalloc(sizeof(*req), GFP_KERNEL);
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bool interruptable;
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u32 ret;
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if (!req)
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return TEEC_ERROR_OUT_OF_MEMORY;
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init_completion(&req->c);
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req->func = func;
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req->num_params = num_params;
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req->param = param;
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/* Insert the request in the request list */
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mutex_lock(&supp->mutex);
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list_add_tail(&req->link, &supp->reqs);
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req->in_queue = true;
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mutex_unlock(&supp->mutex);
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/* Tell an eventual waiter there's a new request */
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complete(&supp->reqs_c);
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/*
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* Wait for supplicant to process and return result, once we've
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* returned from wait_for_completion(&req->c) successfully we have
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* exclusive access again.
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*/
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while (wait_for_completion_interruptible(&req->c)) {
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mutex_lock(&supp->mutex);
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interruptable = !supp->ctx;
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if (interruptable) {
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/*
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* There's no supplicant available and since the
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* supp->mutex currently is held none can
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* become available until the mutex released
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* again.
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*
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* Interrupting an RPC to supplicant is only
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* allowed as a way of slightly improving the user
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* experience in case the supplicant hasn't been
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* started yet. During normal operation the supplicant
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* will serve all requests in a timely manner and
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* interrupting then wouldn't make sense.
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*/
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if (req->in_queue) {
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list_del(&req->link);
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req->in_queue = false;
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}
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}
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mutex_unlock(&supp->mutex);
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if (interruptable) {
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req->ret = TEEC_ERROR_COMMUNICATION;
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break;
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}
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}
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ret = req->ret;
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kfree(req);
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return ret;
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}
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static struct optee_supp_req *supp_pop_entry(struct optee_supp *supp,
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int num_params, int *id)
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{
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struct optee_supp_req *req;
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if (supp->req_id != -1) {
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/*
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* Supplicant should not mix synchronous and asnynchronous
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* requests.
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*/
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return ERR_PTR(-EINVAL);
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}
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if (list_empty(&supp->reqs))
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return NULL;
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req = list_first_entry(&supp->reqs, struct optee_supp_req, link);
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if (num_params < req->num_params) {
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/* Not enough room for parameters */
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return ERR_PTR(-EINVAL);
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}
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*id = idr_alloc(&supp->idr, req, 1, 0, GFP_KERNEL);
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if (*id < 0)
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return ERR_PTR(-ENOMEM);
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list_del(&req->link);
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req->in_queue = false;
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return req;
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}
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static int supp_check_recv_params(size_t num_params, struct tee_param *params,
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size_t *num_meta)
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{
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size_t n;
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if (!num_params)
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return -EINVAL;
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/*
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* If there's memrefs we need to decrease those as they where
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* increased earlier and we'll even refuse to accept any below.
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*/
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for (n = 0; n < num_params; n++)
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if (tee_param_is_memref(params + n) && params[n].u.memref.shm)
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tee_shm_put(params[n].u.memref.shm);
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/*
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* We only expect parameters as TEE_IOCTL_PARAM_ATTR_TYPE_NONE with
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* or without the TEE_IOCTL_PARAM_ATTR_META bit set.
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*/
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for (n = 0; n < num_params; n++)
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if (params[n].attr &&
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params[n].attr != TEE_IOCTL_PARAM_ATTR_META)
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return -EINVAL;
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/* At most we'll need one meta parameter so no need to check for more */
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if (params->attr == TEE_IOCTL_PARAM_ATTR_META)
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*num_meta = 1;
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else
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*num_meta = 0;
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return 0;
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}
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/**
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* optee_supp_recv() - receive request for supplicant
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* @ctx: context receiving the request
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* @func: requested function in supplicant
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* @num_params: number of elements allocated in @param, updated with number
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* used elements
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* @param: space for parameters for @func
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*
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* Returns 0 on success or <0 on failure
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*/
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int optee_supp_recv(struct tee_context *ctx, u32 *func, u32 *num_params,
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struct tee_param *param)
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{
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struct tee_device *teedev = ctx->teedev;
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struct optee *optee = tee_get_drvdata(teedev);
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struct optee_supp *supp = &optee->supp;
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struct optee_supp_req *req = NULL;
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int id;
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size_t num_meta;
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int rc;
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rc = supp_check_recv_params(*num_params, param, &num_meta);
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if (rc)
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return rc;
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while (true) {
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mutex_lock(&supp->mutex);
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req = supp_pop_entry(supp, *num_params - num_meta, &id);
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mutex_unlock(&supp->mutex);
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if (req) {
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if (IS_ERR(req))
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return PTR_ERR(req);
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break;
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}
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/*
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* If we didn't get a request we'll block in
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* wait_for_completion() to avoid needless spinning.
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*
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* This is where supplicant will be hanging most of
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* the time, let's make this interruptable so we
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* can easily restart supplicant if needed.
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*/
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if (wait_for_completion_interruptible(&supp->reqs_c))
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return -ERESTARTSYS;
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}
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if (num_meta) {
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/*
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* tee-supplicant support meta parameters -> requsts can be
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* processed asynchronously.
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*/
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param->attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT |
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TEE_IOCTL_PARAM_ATTR_META;
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param->u.value.a = id;
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param->u.value.b = 0;
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param->u.value.c = 0;
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} else {
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mutex_lock(&supp->mutex);
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supp->req_id = id;
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mutex_unlock(&supp->mutex);
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}
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*func = req->func;
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*num_params = req->num_params + num_meta;
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memcpy(param + num_meta, req->param,
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sizeof(struct tee_param) * req->num_params);
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return 0;
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}
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static struct optee_supp_req *supp_pop_req(struct optee_supp *supp,
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size_t num_params,
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struct tee_param *param,
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size_t *num_meta)
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{
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struct optee_supp_req *req;
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int id;
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size_t nm;
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const u32 attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT |
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TEE_IOCTL_PARAM_ATTR_META;
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if (!num_params)
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return ERR_PTR(-EINVAL);
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if (supp->req_id == -1) {
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if (param->attr != attr)
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return ERR_PTR(-EINVAL);
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id = param->u.value.a;
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nm = 1;
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} else {
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id = supp->req_id;
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nm = 0;
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}
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req = idr_find(&supp->idr, id);
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if (!req)
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return ERR_PTR(-ENOENT);
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if ((num_params - nm) != req->num_params)
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return ERR_PTR(-EINVAL);
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idr_remove(&supp->idr, id);
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supp->req_id = -1;
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*num_meta = nm;
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return req;
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}
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/**
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* optee_supp_send() - send result of request from supplicant
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* @ctx: context sending result
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* @ret: return value of request
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* @num_params: number of parameters returned
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* @param: returned parameters
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*
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* Returns 0 on success or <0 on failure.
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*/
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int optee_supp_send(struct tee_context *ctx, u32 ret, u32 num_params,
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struct tee_param *param)
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{
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struct tee_device *teedev = ctx->teedev;
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struct optee *optee = tee_get_drvdata(teedev);
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struct optee_supp *supp = &optee->supp;
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struct optee_supp_req *req;
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size_t n;
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size_t num_meta;
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mutex_lock(&supp->mutex);
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req = supp_pop_req(supp, num_params, param, &num_meta);
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mutex_unlock(&supp->mutex);
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if (IS_ERR(req)) {
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/* Something is wrong, let supplicant restart. */
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return PTR_ERR(req);
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}
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/* Update out and in/out parameters */
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for (n = 0; n < req->num_params; n++) {
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struct tee_param *p = req->param + n;
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switch (p->attr & TEE_IOCTL_PARAM_ATTR_TYPE_MASK) {
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case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT:
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case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT:
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p->u.value.a = param[n + num_meta].u.value.a;
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p->u.value.b = param[n + num_meta].u.value.b;
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p->u.value.c = param[n + num_meta].u.value.c;
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break;
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case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
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case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
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p->u.memref.size = param[n + num_meta].u.memref.size;
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break;
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default:
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break;
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}
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}
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req->ret = ret;
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/* Let the requesting thread continue */
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complete(&req->c);
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return 0;
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}
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