Le 13/05/2021 à 12:03, Juergen Gross a écrit :
> Xen frontends shouldn't BUG() in case of illegal data received from
> their backends. So replace the BUG_ON()s when reading illegal data from
> the ring page with negative return values.
>
> Signed-off-by: Juergen Gross <jgross@suse.com>
> ---
> drivers/tty/hvc/hvc_xen.c | 15 +++++++++++++--
> 1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
> index 92c9a476defc..30d7ffb1e04c 100644
> --- a/drivers/tty/hvc/hvc_xen.c
> +++ b/drivers/tty/hvc/hvc_xen.c
> @@ -86,6 +86,11 @@ static int __write_console(struct xencons_info *xencons,
> cons = intf->out_cons;
> prod = intf->out_prod;
> mb(); /* update queue values before going on */
> +
> + if (WARN_ONCE((prod - cons) > sizeof(intf->out),
> + "Illegal ring page indices"))
> + return -EINVAL;
> +
> BUG_ON((prod - cons) > sizeof(intf->out));
Why keep the BUG_ON() ?
>
> while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
> @@ -114,7 +119,10 @@ static int domU_write_console(uint32_t vtermno, const char *data, int len)
> */
> while (len) {
> int sent = __write_console(cons, data, len);
> -
> +
> + if (sent < 0)
> + return sent;
> +
> data += sent;
> len -= sent;
>
> @@ -138,7 +146,10 @@ static int domU_read_console(uint32_t vtermno, char *buf, int len)
> cons = intf->in_cons;
> prod = intf->in_prod;
> mb(); /* get pointers before reading ring */
> - BUG_ON((prod - cons) > sizeof(intf->in));
> +
> + if (WARN_ONCE((prod - cons) > sizeof(intf->in),
> + "Illegal ring page indices"))
> + return -EINVAL;
>
> while (cons != prod && recv < len)
> buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];
>