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Re: [Qemu-devel] [PATCH] TextConsole: saturate escape parameter in TTY_S
From: |
Markus Armbruster |
Subject: |
Re: [Qemu-devel] [PATCH] TextConsole: saturate escape parameter in TTY_STATE_CSI |
Date: |
Mon, 17 Sep 2012 13:56:27 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) |
Laszlo Ersek <address@hidden> writes:
> Signed-off-by: Laszlo Ersek <address@hidden>
> ---
> Build tested.
> console.c | 7 +++++--
> 1 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/console.c b/console.c
> index c1ed5e0..67080f4 100644
> --- a/console.c
> +++ b/console.c
> @@ -938,8 +938,11 @@ static void console_putchar(TextConsole *s, int ch)
> case TTY_STATE_CSI: /* handle escape sequence parameters */
> if (ch >= '0' && ch <= '9') {
> if (s->nb_esc_params < MAX_ESC_PARAMS) {
> - s->esc_params[s->nb_esc_params] =
> - s->esc_params[s->nb_esc_params] * 10 + ch - '0';
> + int *param = &s->esc_params[s->nb_esc_params];
> + int digit = (ch - '0');
> +
> + *param = (*param <= (INT_MAX - digit) / 10) ?
> + *param * 10 + digit : INT_MAX;
> }
> } else {
> if (s->nb_esc_params < MAX_ESC_PARAMS)
Before this patch, silent integer overflow. Exact behavior depends on
hosts int type. For instance, \e[4294967296 is the same as \e[0 with 32
bit int, but with 64 bit int.
What does a real vt100 do? I don't have one anymore. For what it's
worth, both xterm and Xfce Terminal appear to saturate at some "big"
number ("big" compared to the argument values that are actually useful;
INT_MAX should do fine). In particular, \e[4294967296 does *not* behave
like \e[0.
Therefore, changing QEMU to saturate makes sense.
Reviewed-by: Markus Armbruster <address@hidden>