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Date: Mon, 22 Feb 2021 09:21:50 -0700
From: Shuah Khan <skhan@...uxfoundation.org>
To: Romain Perier <romain.perier@...il.com>, Kees Cook
<keescook@...omium.org>, kernel-hardening@...ts.openwall.com,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Valentina Manea <valentina.manea.m@...il.com>, Shuah Khan <shuah@...nel.org>
Cc: linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
Shuah Khan <skhan@...uxfoundation.org>
Subject: Re: [PATCH 19/20] usbip: usbip_host: Manual replacement of the
deprecated strlcpy() with return values
On 2/22/21 8:12 AM, Romain Perier wrote:
> The strlcpy() reads the entire source buffer first, it is dangerous if
> the source buffer lenght is unbounded or possibility non NULL-terminated.
> It can lead to linear read overflows, crashes, etc...
>
> As recommended in the deprecated interfaces [1], it should be replaced
> by strscpy.
>
> This commit replaces all calls to strlcpy that handle the return values
> by the corresponding strscpy calls with new handling of the return
> values (as it is quite different between the two functions).
>
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
>
> Signed-off-by: Romain Perier <romain.perier@...il.com>
> ---
> drivers/usb/usbip/stub_main.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/usb/usbip/stub_main.c b/drivers/usb/usbip/stub_main.c
> index 77a5b3f8736a..5bc2c09c0d10 100644
> --- a/drivers/usb/usbip/stub_main.c
> +++ b/drivers/usb/usbip/stub_main.c
> @@ -167,15 +167,15 @@ static ssize_t match_busid_show(struct device_driver *drv, char *buf)
> static ssize_t match_busid_store(struct device_driver *dev, const char *buf,
> size_t count)
> {
> - int len;
> + ssize_t len;
> char busid[BUSID_SIZE];
>
> if (count < 5)
> return -EINVAL;
>
> /* busid needs to include \0 termination */
> - len = strlcpy(busid, buf + 4, BUSID_SIZE);
> - if (sizeof(busid) <= len)
> + len = strscpy(busid, buf + 4, BUSID_SIZE);
> + if (len == -E2BIG)
> return -EINVAL;
>
> if (!strncmp(buf, "add ", 4)) {
>
Looks good to me. Thank you.
Acked-by: Shuah Khan <skhan@...uxfoundation.org>
thanks,
-- Shuah
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