linux-kernel - [PATCHv8 6/6] file: remove get_unused

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

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

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/