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From: Yann Droneaud <ydroneaud@opteya.com>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Yann Droneaud <ydroneaud@opteya.com>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	trivial@kernel.org
Subject: [PATCHv7 3/6] binfmt_misc: use get_unused_fd_flags(0) instead of get_unused_fd()
Date: Sun,  1 Jun 2014 15:58:44 +0200	[thread overview]
Message-ID: <1b727f379b7196c0854c41776a2d90261140274a.1401630396.git.ydroneaud@opteya.com> (raw)
In-Reply-To: <cover.1401630396.git.ydroneaud@opteya.com>
In-Reply-To: <cover.1401630396.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(), function get_unused_fd_flags()
(or anon_inode_getfd()) 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 get_unused_fd_flags() (or anon_inode_getfd()) 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.

Link: http://lkml.kernel.org/r/cover.1401630396.git.ydroneaud@opteya.com
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>
---
 fs/binfmt_misc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index b60500300dd7..3c9fcc08aec9 100644
--- a/fs/binfmt_misc.c
+++ b/fs/binfmt_misc.c
@@ -138,7 +138,7 @@ static int load_misc_binary(struct linux_binprm *bprm)
 		/* if the binary should be opened on behalf of the
 		 * interpreter than keep it open and assign descriptor
 		 * to it */
- 		fd_binary = get_unused_fd();
+		fd_binary = get_unused_fd_flags(0);
  		if (fd_binary < 0) {
  			retval = fd_binary;
  			goto _ret;
-- 
1.9.3


  parent reply	other threads:[~2014-06-01 13:59 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-01 13:58 [PATCHv7 0/6] Getting rid of get_unused_fd() / enable close-on-exec Yann Droneaud
2014-06-01 13:58 ` [PATCHv7 1/6] ia64: use get_unused_fd_flags(0) instead of get_unused_fd() Yann Droneaud
2014-06-01 13:58 ` [PATCHv7 2/6] ppc/cell: " Yann Droneaud
2014-06-01 13:58 ` Yann Droneaud [this message]
2014-06-01 13:58 ` [PATCHv7 4/6] file: " Yann Droneaud
2014-06-01 13:58 ` [PATCHv7 5/6] fanotify: enable close-on-exec on events' fd when requested in fanotify_init() Yann Droneaud
2014-06-01 14:00 ` [PATCHv7 6/6] file: remove macro get_unused_fd() Yann Droneaud

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