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Message-ID: <b65f4d0b-cc2a-f4d6-5d9d-a14e6a9cc444@linaro.org>
Date: Mon, 12 Jun 2023 11:57:28 +0100
From: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To: Sukrut Bellary <sukrut.bellary@...ux.com>,
Amol Maheshwari <amahesh@....qualcomm.com>,
Arnd Bergmann <arnd@...db.de>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Dan Carpenter <dan.carpenter@...aro.org>,
Abel Vesa <abel.vesa@...aro.org>
Cc: linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
kernel-janitors@...r.kernel.org,
Shuah Khan <skhan@...uxfoundation.org>
Subject: Re: [PATCH v2] misc: fastrpc: Fix double free of 'buf' in error path
On 02/06/2023 12:36, Sukrut Bellary wrote:
> smatch warning:
> drivers/misc/fastrpc.c:1926 fastrpc_req_mmap() error: double free of 'buf'
>
> In fastrpc_req_mmap() error path, the fastrpc buffer is freed in
> fastrpc_req_munmap_impl() if unmap is successful.
>
> But in the end, there is an unconditional call to fastrpc_buf_free().
> So the above case triggers the double free of fastrpc buf.
>
> Fixes: 72fa6f7820c4 ("misc: fastrpc: Rework fastrpc_req_munmap")
> Reviewed-by: Shuah Khan <skhan@...uxfoundation.org>
> Reviewed-by: Dan Carpenter <dan.carpenter@...aro.org>
> Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Not sure how was this reviewed-by picked up on this patch.
Suggested-by will be a right choice here.
Will manually edit before applying it.
--srini
> Signed-off-by: Sukrut Bellary <sukrut.bellary@...ux.com>
> ---
> This is based on static analysis. Compilation tested.
> ---
> Changes in v2:
> - Fixed the commit message.
> - Addressed the review comment about deleting buf from the list
> before freeing.
> - Link to v1: https://lore.kernel.org/all/20230518100829.515143-1-sukrut.bellary@linux.com/
> ---
> drivers/misc/fastrpc.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
> index f48466960f1b..b3b520fcfb75 100644
> --- a/drivers/misc/fastrpc.c
> +++ b/drivers/misc/fastrpc.c
> @@ -1882,7 +1882,8 @@ static int fastrpc_req_mmap(struct fastrpc_user *fl, char __user *argp)
> &args[0]);
> if (err) {
> dev_err(dev, "mmap error (len 0x%08llx)\n", buf->size);
> - goto err_invoke;
> + fastrpc_buf_free(buf);
> + return err;
> }
>
> /* update the buffer to be able to deallocate the memory on the DSP */
> @@ -1922,8 +1923,6 @@ static int fastrpc_req_mmap(struct fastrpc_user *fl, char __user *argp)
>
> err_assign:
> fastrpc_req_munmap_impl(fl, buf);
> -err_invoke:
> - fastrpc_buf_free(buf);
>
> return err;
> }
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