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From: Serge Hallyn <serge.hallyn@ubuntu.com>
To: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Serge Hallyn <serge.hallyn@canonical.com>,
	linux-security-module@vger.kernel.org, linux-nfs@vger.kernel.org,
	"David P. Quigley" <dpquigl@tycho.nsa.gov>,
	Steve Dickson <SteveD@redhat.com>
Subject: Re: [PATCH] security: cap_inode_getsecctx returning garbage
Date: Thu, 9 May 2013 10:13:33 -0500	[thread overview]
Message-ID: <20130509151333.GA2211@tp> (raw)
In-Reply-To: <20130509140820.GB9316@fieldses.org>

Quoting J. Bruce Fields (bfields@fieldses.org):
> On Thu, May 09, 2013 at 12:49:26AM -0500, Serge Hallyn wrote:
> > Quoting J. Bruce Fields (bfields@fieldses.org):
> > > From: "J. Bruce Fields" <bfields@redhat.com>
> > > 
> > > We shouldn't be returning success from this function without also
> > > filling in the return values ctx and ctxlen.
> > > 
> > > Note currently this doesn't appear to cause bugs since the only
> > > inode_getsecctx caller I can find is fs/sysfs/inode.c, which only calls
> > > this if security_inode_setsecurity succeeds.  Assuming
> > > security_inode_setsecurity is set to cap_inode_setsecurity whenever
> > > inode_getsecctx is set to cap_inode_getsecctx, this function can never
> > > actually called.
> > > 
> > > So I noticed this only because the server labeled NFS patches add a real
> > > caller.
> > > 
> > > Signed-off-by: J. Bruce Fields <bfields@redhat.com>
> > 
> > Thanks, the comment in include/linux/security.h doesn't mention the
> > return value at all, but based on the other implementations this looks
> > right.
> > 
> > Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
> 
> Thanks!  Hm, would something like this help clarify?:
> 
> @@ -1412,7 +1412,8 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
>   * 	@ctxlen contains the length of @ctx.
>   *
>   * @inode_getsecctx:
> - *	Returns a string containing all relevant security context information
> + *	On success, fills out @ctx and @ctxlen with the security context
> + *	for the given @inode.

...  and returns 0.

That would be great, thanks!

Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

>   *
>   * 	@inode we wish to get the security context of.
>   *	@ctx is a pointer in which to place the allocated security context.
> 
> --b.

  reply	other threads:[~2013-05-09 15:13 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-09  1:43 [PATCH] security: cap_inode_getsecctx returning garbage J. Bruce Fields
2013-05-09  5:49 ` Serge Hallyn
2013-05-09 14:08   ` J. Bruce Fields
2013-05-09 15:13     ` Serge Hallyn [this message]
2013-05-09 15:41       ` [PATCH] security: clarify cap_inode_getsecctx description J. Bruce Fields
2013-05-12 11:37         ` James Morris

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