From c3c073f808b22dfae15ef8412b6f7b998644139a Mon Sep 17 00:00:00 2001 From: Al Viro Date: Tue, 21 Aug 2012 22:32:06 -0400 Subject: new helper: iterate_fd() iterates through the opened files in given descriptor table, calling a supplied function; we stop once non-zero is returned. Callback gets struct file *, descriptor number and const void * argument passed to iterator. It is called with files->file_lock held, so it is not allowed to block. tty_io, netprio_cgroup and selinux flush_unauthorized_files() converted to its use. Signed-off-by: Al Viro --- drivers/tty/tty_io.c | 36 +++++++++++++----------------------- 1 file changed, 13 insertions(+), 23 deletions(-) (limited to 'drivers/tty') diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index b425c79..71d95cf 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -2791,6 +2791,13 @@ static long tty_compat_ioctl(struct file *file, unsigned int cmd, } #endif +static int this_tty(const void *t, struct file *file, unsigned fd) +{ + if (likely(file->f_op->read != tty_read)) + return 0; + return file_tty(file) != t ? 0 : fd + 1; +} + /* * This implements the "Secure Attention Key" --- the idea is to * prevent trojan horses by killing all processes associated with this @@ -2818,8 +2825,6 @@ void __do_SAK(struct tty_struct *tty) struct task_struct *g, *p; struct pid *session; int i; - struct file *filp; - struct fdtable *fdt; if (!tty) return; @@ -2849,27 +2854,12 @@ void __do_SAK(struct tty_struct *tty) continue; } task_lock(p); - if (p->files) { - /* - * We don't take a ref to the file, so we must - * hold ->file_lock instead. - */ - spin_lock(&p->files->file_lock); - fdt = files_fdtable(p->files); - for (i = 0; i < fdt->max_fds; i++) { - filp = fcheck_files(p->files, i); - if (!filp) - continue; - if (filp->f_op->read == tty_read && - file_tty(filp) == tty) { - printk(KERN_NOTICE "SAK: killed process %d" - " (%s): fd#%d opened to the tty\n", - task_pid_nr(p), p->comm, i); - force_sig(SIGKILL, p); - break; - } - } - spin_unlock(&p->files->file_lock); + i = iterate_fd(p->files, 0, this_tty, tty); + if (i != 0) { + printk(KERN_NOTICE "SAK: killed process %d" + " (%s): fd#%d opened to the tty\n", + task_pid_nr(p), p->comm, i - 1); + force_sig(SIGKILL, p); } task_unlock(p); } while_each_thread(g, p); -- cgit v1.1 From cb0942b81249798e15c3f04eee2946ef543e8115 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 27 Aug 2012 14:48:26 -0400 Subject: make get_file() return its argument simplifies a bunch of callers... Signed-off-by: Al Viro --- drivers/tty/tty_io.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) (limited to 'drivers/tty') diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 71d95cf..c7561f2 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -1163,10 +1163,8 @@ ssize_t redirected_tty_write(struct file *file, const char __user *buf, struct file *p = NULL; spin_lock(&redirect_lock); - if (redirect) { - get_file(redirect); - p = redirect; - } + if (redirect) + p = get_file(redirect); spin_unlock(&redirect_lock); if (p) { @@ -2246,8 +2244,7 @@ static int tioccons(struct file *file) spin_unlock(&redirect_lock); return -EBUSY; } - get_file(file); - redirect = file; + redirect = get_file(file); spin_unlock(&redirect_lock); return 0; } -- cgit v1.1