From: Christian Brauner <christian@brauner.io>
To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: cjwatson@ubuntu.com, ebiederm@xmission.com,
viro@zeniv.linux.org.uk, serge@hallyn.com,
Christian Brauner <christian@brauner.io>
Subject: [PATCH 0/1] getxattr: use correct xattr length
Date: Thu, 7 Jun 2018 13:43:47 +0200 [thread overview]
Message-ID: <20180607114348.23667-1-christian@brauner.io> (raw)
Hey,
When running in a container with a user namespace, if you call getxattr
with name = "system.posix_acl_access" and size % 8 != 4, then getxattr
silently skips the user namespace fixup that it normally does resulting in
un-fixed-up data being returned.
I think that the analysis that this is caused by
posix_acl_fix_xattr_to_user() being passed the total buffer size and not
the actual size of the xattr as returned by vfs_getxattr() is correct.
So this commit passes the actual length of the xattr as returned by
vfs_getxattr() down.
It might be worth considering making posix_acl_fix_xattr_userns() and
posix_acl_fix_xattr_to_user() return errors. Such that e.g.
posix_acl_xattr_count() errors can be caught in getxattr(). If that's
something we want I can send a follow-up patch.
More details of this can be found in
https://bugzilla.kernel.org/show_bug.cgi?id=199945
Thanks!
Christian
Christian Brauner (1):
getxattr: use correct xattr length
fs/xattr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--
2.17.0
next reply other threads:[~2018-06-07 11:43 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-07 11:43 Christian Brauner [this message]
2018-06-07 11:43 ` [PATCH 1/1] getxattr: use correct xattr length Christian Brauner
2018-06-13 15:45 ` Serge E. Hallyn
2018-06-13 16:42 ` Christian Brauner
2018-07-23 15:00 ` Christian Brauner
2018-07-23 15:14 ` Serge E. Hallyn
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