On Sun, Jan 05, 2014 at 09:36:33PM +0100, Yann Droneaud wrote: > Unlike recent modern userspace API such as > epoll_create1 (EPOLL_CLOEXEC), eventfd (EFD_CLOEXEC), > fanotify_init (FAN_CLOEXEC), inotify_init1 (IN_CLOEXEC), > signalfd (SFD_CLOEXEC), timerfd_create (TFD_CLOEXEC), > or the venerable general purpose open (O_CLOEXEC), > perf_event_open() syscall lack a flag to atomically set FD_CLOEXEC > (eg. close-on-exec) flag on file descriptor it returns to userspace. > > The present patch adds a PERF_FLAG_FD_CLOEXEC flag to allow > perf_event_open() syscall to atomically set close-on-exec. > > Having this flag will enable userspace to remove the file descriptor > from the list of file descriptors being inherited across exec, > without the need to call fcntl(fd, F_SETFD, FD_CLOEXEC) and the > associated race condition between the current thread and another > thread calling fork(2) then execve(2). > > 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 > > - Notes in DMA buffer sharing: leak and security hole > > http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/dma-buf-sharing.txt?id=v3.13-rc3#n428 > > Cc: Peter Zijlstra <pet...@infradead.org> > Cc: Al Viro <v...@zeniv.linux.org.uk> > Signed-off-by: Yann Droneaud <ydrone...@opteya.com>
Seems sane enough. Thanks! -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
