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From: Yann Droneaud <ydroneaud@opteya.com>
To: linux-kernel@vger.kernel.org,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Paul Mackerras <paulus@samba.org>, Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Yann Droneaud <ydroneaud@opteya.com>
Subject: [PATCH v3 6/8] events: use get_unused_fd_flags(0) instead of get_unused_fd()
Date: Fri,  6 Sep 2013 12:39:56 +0200	[thread overview]
Message-ID: <1d9862e4cdccc52c4bb29e673834514cd263b181.1378460926.git.ydroneaud@opteya.com> (raw)
In-Reply-To: <cover.1378460926.git.ydroneaud@opteya.com>
In-Reply-To: <cover.1378460926.git.ydroneaud@opteya.com>

Macro get_unused_fd() is used to allocate a file descriptor with
default flags. Those default flags (0) can be "unsafe":
O_CLOEXEC must be used by default to not leak file descriptor
across exec().

Instead of macro get_unused_fd(), functions anon_inode_getfd()
or get_unused_fd_flags() should be used with flags given by userspace.
If not possible, flags should be set to O_CLOEXEC to provide userspace
with a default safe behavor.

In a further patch, get_unused_fd() will be removed so that
new code start using anon_inode_getfd() or get_unused_fd_flags()
with correct flags.

This patch replaces calls to get_unused_fd() with equivalent call to
get_unused_fd_flags(0) to preserve current behavor for existing code.

The hard coded flag value (0) should be reviewed on a per-subsystem basis,
and, if possible, set to O_CLOEXEC.

Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>
Link: http://lkml.kernel.org/r/cover.1378460926.git.ydroneaud@opteya.com
---
 kernel/events/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 2207efc..b12fdd3 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6935,7 +6935,7 @@ SYSCALL_DEFINE5(perf_event_open,
 	if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
 		return -EINVAL;
 
-	event_fd = get_unused_fd();
+	event_fd = get_unused_fd_flags(0);
 	if (event_fd < 0)
 		return event_fd;
 
-- 
1.8.3.1


  parent reply	other threads:[~2013-09-06 10:42 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-06 10:39 [PATCH v3 0/8] Getting rid of get_unused_fd() / use O_CLOEXEC Yann Droneaud
2013-09-06 10:39 ` [PATCH v3 1/8] ia64: use get_unused_fd_flags(0) instead of get_unused_fd() Yann Droneaud
2013-09-06 10:39 ` [PATCH v3 2/8] ppc/cell: " Yann Droneaud
2013-09-06 10:39 ` [PATCH v3 3/8] binfmt_misc: " Yann Droneaud
2013-09-06 10:39 ` [PATCH v3 4/8] file: " Yann Droneaud
2013-09-06 10:39 ` [PATCH v3 5/8] fanotify: " Yann Droneaud
2013-09-06 10:39 ` Yann Droneaud [this message]
2013-09-06 10:39 ` [PATCH v3 7/8] file: remove get_unused_fd() Yann Droneaud
2013-09-06 10:39 ` [PATCH v3 8/8] industrialio: use anon_inode_getfd() with O_CLOEXEC flag Yann Droneaud
2013-09-15 16:26   ` Jonathan Cameron
2013-09-15 16:34     ` Yann Droneaud

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