On 09/06/13 11:39, Yann Droneaud wrote: > 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@xxxxxxxxxx > > Signed-off-by: Yann Droneaud <ydroneaud@xxxxxxxxxx> > Link: http://lkml.kernel.org/r/cover.1378460926.git.ydroneaud@xxxxxxxxxx Thanks Yann. I had no idea about this issue but your well supported description above made this easy to review. Applied to the togreg branch of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git as it's not a regression but if there is support for pushing this back to stable I personally am not against it. Jonathan > --- > drivers/iio/industrialio-event.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/iio/industrialio-event.c b/drivers/iio/industrialio-event.c > index 10aa9ef..2390e3d 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); > -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
