Re: [PATCH] Fix listxattr() for generic security attributes

From: Stephen Smalley
Date: Thu Dec 08 2005 - 11:28:20 EST


On Thu, 2005-12-08 at 16:13 +0000, Daniel Drake wrote:
> Commit f549d6c18c0e8e6cf1bf0e7a47acc1daf7e2cec1 introduced a generic fallback
> for security xattrs, but appears to include a subtle bug.
>
> Gentoo users with kernels with selinux compiled in, and coreutils compiled
> with acl support, noticed that they could not copy files on tmpfs using 'cp'.
>
> cp (compiled with acl support) copies the file, lists the extended attributes
> on the old file, copies them all to the new file, and then exits. However the
> listxattr() calls were failing with this odd behaviour:
>
> llistxattr("a.out", (nil), 0) = 17
> llistxattr("a.out", 0x7fffff8c6cb0, 17) = -1 ERANGE (Numerical result out of
> range)
>
> I believe this is a simple problem in the logic used to check the buffer
> sizes; if the user sends a buffer the exact size of the data, then its ok :)
>
> This patch solves the problem. Please apply for 2.6.15.
> More info can be found at http://bugs.gentoo.org/113138
>
> Signed-off-by: Daniel Drake <dsd@xxxxxxxxxx>

Acked-by: Stephen Smalley <sds@xxxxxxxxxxxxx>

--
Stephen Smalley
National Security Agency

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