Re: [PATCH] setterm: avoid restoring flags from uninitialized memory

[Dragan Simic <dsimic@manjaro.org>]

On 2023-10-31 14:52, Chris Hofstaedtler wrote:
> Depending on the used compiler and flags, previously either F_SETFL was 
> called
> with 0 or with a random value. Never with the intended previous flags.
> 
> Signed-off-by: Chris Hofstaedtler <zeha@debian.org>
> Tested-by: Emanuele Rocca <ema@debian.org>

Looks good to me, FWIW.

> ---
>  term-utils/setterm.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/term-utils/setterm.c b/term-utils/setterm.c
> index 1bf9a5bb4..92bf75a46 100644
> --- a/term-utils/setterm.c
> +++ b/term-utils/setterm.c
> @@ -846,7 +846,10 @@ static void tty_raw(struct termios
> *saved_attributes, int *saved_fl)
>  {
>  	struct termios tattr;
> 
> -	fcntl(STDIN_FILENO, F_GETFL, saved_fl);
> +	*saved_fl = fcntl(STDIN_FILENO, F_GETFL);
> +	if (*saved_fl == -1) {
> +		err(EXIT_FAILURE, _("fcntl failed"));
> +	}
>  	tcgetattr(STDIN_FILENO, saved_attributes);
>  	fcntl(STDIN_FILENO, F_SETFL, O_NONBLOCK);
>  	memcpy(&tattr, saved_attributes, sizeof(struct termios));
> @@ -898,7 +901,7 @@ static int resizetty(void)
>  	ssize_t rc;
>  	struct winsize ws;
>  	struct termios saved_attributes;
> -	int saved_fl;
> +	int saved_fl = 0;
> 
>  	if (!isatty(STDIN_FILENO))
>  		errx(EXIT_FAILURE, _("stdin does not refer to a terminal"));