Messages in this thread Patch in this message | | | From | Matt Brown <> | Subject | [PATCH 3/4] restrict unprivileged TIOCSTI tty ioctl | Date | Mon, 17 Apr 2017 02:07:05 -0400 |
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this patch depends on patch 1 and 2
enforces restrictions on unprivileged users injecting commands into other processes in the same tty session using the TIOCSTI ioctl
Signed-off-by: Matt Brown <matt@nmatt.com> --- drivers/tty/tty_io.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index e6d1a65..31894e8 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -2296,11 +2296,15 @@ static int tty_fasync(int fd, struct file *filp, int on) * FIXME: may race normal receive processing */ +int tiocsti_restrict = IS_ENABLED(CONFIG_SECURITY_TIOCSTI_RESTRICT); + static int tiocsti(struct tty_struct *tty, char __user *p) { char ch, mbz = 0; struct tty_ldisc *ld; + if (tiocsti_restrict && !capable(CAP_SYS_ADMIN)) + return -EPERM; if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN)) return -EPERM; if (get_user(ch, p)) -- 2.10.2
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