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    SubjectRe: [PATCHv5 6/7] perf: introduce a flag to enable close-on-exec in perf_event_open()
    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 <peterz@infradead.org>
    > Cc: Al Viro <viro@zeniv.linux.org.uk>
    > Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>

    Seems sane enough.

    Thanks!


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