From: Yann Droneaud Date: Fri, 6 Sep 2013 10:39:00 +0000 (+0100) Subject: iio: use anon_inode_getfd() with O_CLOEXEC flag X-Git-Tag: firefly_0821_release~176^2~5057^2~694^2~60 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a646fbf0fd11256c59ea6233eb243516086dbf15;p=firefly-linux-kernel-4.4.55.git iio: use anon_inode_getfd() with O_CLOEXEC flag IIO uses anon_inode_get() to allocate file descriptors as part of its ioctls. But those ioctls are lacking a flag argument allowing userspace to choose options for the newly opened file descriptor. In such case it's advised to use O_CLOEXEC by default so that userspace is allowed to choose, without race, if the file descriptor is going to be inherited across exec(). KVM usage of anon_inode_getfd() was fixed in a previous patchset [1], so IIO is the only subsystem using anon_inode_getfd() with a fixed set of flags not including O_CLOEXEC. This patch set O_CLOEXEC flag on the event file descriptor created with anon_inode_getfd() to not leak file descriptors across exec(). Links: - Secure File Descriptor Handling (Ulrich Drepper, 2008) http://udrepper.livejournal.com/20407.html - Excuse me son, but your code is leaking !!! (Dan Walsh, March 2012) http://danwalsh.livejournal.com/53603.html - [1] kvm: use anon_inode_getfd() with O_CLOEXEC flag http://lkml.kernel.org/r/cover.1377372576.git.ydroneaud@opteya.com Signed-off-by: Yann Droneaud Signed-off-by: Jonathan Cameron --- diff --git a/drivers/iio/industrialio-event.c b/drivers/iio/industrialio-event.c index 10aa9ef86cec..2390e3d08e48 100644 --- a/drivers/iio/industrialio-event.c +++ b/drivers/iio/industrialio-event.c @@ -159,7 +159,7 @@ int iio_event_getfd(struct iio_dev *indio_dev) } spin_unlock_irq(&ev_int->wait.lock); fd = anon_inode_getfd("iio:event", - &iio_event_chrdev_fileops, ev_int, O_RDONLY); + &iio_event_chrdev_fileops, ev_int, O_RDONLY | O_CLOEXEC); if (fd < 0) { spin_lock_irq(&ev_int->wait.lock); __clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);