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authorYann Droneaud <ydroneaud@opteya.com>2014-01-05 21:36:33 +0100
committerIngo Molnar <mingo@kernel.org>2014-01-12 10:16:59 +0100
commita21b0b354d4ac39be691f51c53562e2c24443d9e (patch)
tree2625e7436b90c91966c5797f2fae3a980694d8c7 /include/uapi/linux/perf_event.h
parentf228c5b882602697a1adb50d61ff688b0df1eced (diff)
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perf: Introduce a flag to enable close-on-exec in perf_event_open()
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 Signed-off-by: Yann Droneaud <ydroneaud@opteya.com> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/8c03f54e1598b1727c19706f3af03f98685d9fe6.1388952061.git.ydroneaud@opteya.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/uapi/linux/perf_event.h')
-rw-r--r--include/uapi/linux/perf_event.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index e1802d6153ae..ca018b4085c6 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -724,6 +724,7 @@ enum perf_callchain_context {
#define PERF_FLAG_FD_NO_GROUP (1U << 0)
#define PERF_FLAG_FD_OUTPUT (1U << 1)
#define PERF_FLAG_PID_CGROUP (1U << 2) /* pid=cgroup id, per-cpu mode only */
+#define PERF_FLAG_FD_CLOEXEC (1U << 3) /* O_CLOEXEC */
union perf_mem_data_src {
__u64 val;