From: Samuel Thibault Date: Mon, 10 Jul 2023 00:26:45 +0000 (+0200) Subject: TIOCSTI: always enable for CAP_SYS_ADMIN X-Git-Tag: v6.5-rc4~4^2~6 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=690c8b804ad2;p=thirdparty%2Fkernel%2Fstable.git TIOCSTI: always enable for CAP_SYS_ADMIN 83efeeeb3d04 ("tty: Allow TIOCSTI to be disabled") broke BRLTTY's ability to simulate keypresses on the console, thus effectively breaking braille keyboards of blind users. This restores the TIOCSTI feature for CAP_SYS_ADMIN processes, which BRLTTY is, thus fixing braille keyboards without re-opening the security issue. Signed-off-by: Samuel Thibault Acked-by: Kees Cook Fixes: 83efeeeb3d04 ("tty: Allow TIOCSTI to be disabled") Cc: stable@vger.kernel.org Reported-by: Nicolas Pitre Link: https://lore.kernel.org/r/20230710002645.v565c7xq5iddruse@begin Acked-by: Jiri Slaby Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 3959efc717aa1..63db04b9113aa 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -2285,7 +2285,7 @@ static int tiocsti(struct tty_struct *tty, char __user *p) char ch, mbz = 0; struct tty_ldisc *ld; - if (!tty_legacy_tiocsti) + if (!tty_legacy_tiocsti && !capable(CAP_SYS_ADMIN)) return -EIO; if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))