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Message-Id: <28ff601c10cc16940919c0c45dc47f73c870c16b.1411562410.git.ydroneaud@opteya.com>
Date: Wed, 24 Sep 2014 15:11:11 +0200
From: Yann Droneaud <ydroneaud@...eya.com>
To: Al Viro <viro@...iv.linux.org.uk>,
Andrew Morton <akpm@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, Yann Droneaud <ydroneaud@...eya.com>,
linux-fsdevel@...r.kernel.org
Subject: [PATCHv8 6/6] file: remove get_unused_fd() macro
Macro get_unused_fd() is used to allocate a file descriptor
with default flags. Those default flags (0) don't enable
close-on-exec.
This can be seen as an unsafe default: in most case close-on-exec
should be enabled to not leak file descriptor across exec().
It would be better to have a "safer" default set of flags, eg.
O_CLOEXEC must be used to enable close-on-exec.
Instead this patch removes get_unused_fd() so that out of tree
modules won't be affect by a runtime behavor change which might
introduce other kind of bugs: it's better to catch the change at
build time, making it easier to fix.
Removing the macro will also promote use of get_unused_fd_flags()
(or anon_inode_getfd()) with flags provided by userspace. Or, if
flags cannot be given by userspace, with flags set to O_CLOEXEC
by default.
Link: http://lkml.kernel.org/r/cover.1411562410.git.ydroneaud@opteya.com
Cc: Al Viro <viro@...iv.linux.org.uk>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Yann Droneaud <ydroneaud@...eya.com>
---
include/linux/file.h | 1 -
1 file changed, 1 deletion(-)
diff --git a/include/linux/file.h b/include/linux/file.h
index 4d69123377a2..f87d30882a24 100644
--- a/include/linux/file.h
+++ b/include/linux/file.h
@@ -66,7 +66,6 @@ extern void set_close_on_exec(unsigned int fd, int flag);
extern bool get_close_on_exec(unsigned int fd);
extern void put_filp(struct file *);
extern int get_unused_fd_flags(unsigned flags);
-#define get_unused_fd() get_unused_fd_flags(0)
extern void put_unused_fd(unsigned int fd);
extern void fd_install(unsigned int fd, struct file *file);
--
1.9.3
--
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