Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752329AbaALSnu (ORCPT ); Sun, 12 Jan 2014 13:43:50 -0500 Received: from terminus.zytor.com ([198.137.202.10]:46256 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752310AbaALSnp (ORCPT ); Sun, 12 Jan 2014 13:43:45 -0500 Date: Sun, 12 Jan 2014 10:43:06 -0800 From: tip-bot for Yann Droneaud Message-ID: Cc: linux-kernel@vger.kernel.org, paulus@samba.org, hpa@zytor.com, mingo@kernel.org, torvalds@linux-foundation.org, peterz@infradead.org, acme@ghostprotocols.net, ydroneaud@opteya.com, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, tglx@linutronix.de Reply-To: mingo@kernel.org, hpa@zytor.com, paulus@samba.org, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, acme@ghostprotocols.net, peterz@infradead.org, ydroneaud@opteya.com, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, tglx@linutronix.de In-Reply-To: <8c03f54e1598b1727c19706f3af03f98685d9fe6.1388952061.git.ydroneaud@opteya.com> References: <8c03f54e1598b1727c19706f3af03f98685d9fe6.1388952061.git.ydroneaud@opteya.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf: Introduce a flag to enable close-on-exec in perf_event_open() Git-Commit-ID: a21b0b354d4ac39be691f51c53562e2c24443d9e X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.1 (terminus.zytor.com [127.0.0.1]); Sun, 12 Jan 2014 10:43:13 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: a21b0b354d4ac39be691f51c53562e2c24443d9e Gitweb: http://git.kernel.org/tip/a21b0b354d4ac39be691f51c53562e2c24443d9e Author: Yann Droneaud AuthorDate: Sun, 5 Jan 2014 21:36:33 +0100 Committer: Ingo Molnar CommitDate: Sun, 12 Jan 2014 10:16:59 +0100 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 Cc: Arnaldo Carvalho de Melo Cc: Al Viro Cc: Andrew Morton Cc: Paul Mackerras Cc: Linus Torvalds Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/8c03f54e1598b1727c19706f3af03f98685d9fe6.1388952061.git.ydroneaud@opteya.com Signed-off-by: Ingo Molnar --- include/uapi/linux/perf_event.h | 1 + kernel/events/core.c | 12 +++++++++--- 2 files changed, 10 insertions(+), 3 deletions(-) diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index e1802d6..ca018b4 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; diff --git a/kernel/events/core.c b/kernel/events/core.c index c3b6c27..5c87264 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -119,7 +119,8 @@ static int cpu_function_call(int cpu, int (*func) (void *info), void *info) #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\ PERF_FLAG_FD_OUTPUT |\ - PERF_FLAG_PID_CGROUP) + PERF_FLAG_PID_CGROUP |\ + PERF_FLAG_FD_CLOEXEC) /* * branch priv levels that need permission checks @@ -6982,6 +6983,7 @@ SYSCALL_DEFINE5(perf_event_open, int event_fd; int move_group = 0; int err; + int f_flags = O_RDWR; /* for future expandability... */ if (flags & ~PERF_FLAG_ALL) @@ -7010,7 +7012,10 @@ SYSCALL_DEFINE5(perf_event_open, if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1)) return -EINVAL; - event_fd = get_unused_fd(); + if (flags & PERF_FLAG_FD_CLOEXEC) + f_flags |= O_CLOEXEC; + + event_fd = get_unused_fd_flags(f_flags); if (event_fd < 0) return event_fd; @@ -7132,7 +7137,8 @@ SYSCALL_DEFINE5(perf_event_open, goto err_context; } - event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, O_RDWR); + event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, + f_flags); if (IS_ERR(event_file)) { err = PTR_ERR(event_file); goto err_context; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/