Re: [PATCH] linux 2.9.10-rc1: Fix oops in unix_dgram_sendmsg when using SELinux and SOCK_SEQPACKET

[Chris Wright <chrisw@osdl.org>]

* Stephen Smalley (sds@epoch.ncsc.mil) wrote:
> On Sun, 2004-11-14 at 13:13, Ross Kendall Axe wrote:
> > With CONFIG_SECURITY_NETWORK=y and CONFIG_SECURITY_SELINUX=y, using
> > SOCK_SEQPACKET unix domain sockets causes an oops in the superfluous(?)
> > call to security_unix_may_send in sock_dgram_sendmsg. This patch avoids
> > making this call for SOCK_SEQPACKET sockets.
> 
> I'd prefer to track down the actual issue in the SELinux code and
> correct it than just omit the security hook call entirely.  Do you have
> the Oops output and a trivial test case?  Thanks.

Well, there is one simple case that will trigger the Oops.  Send a
SEQPACKET to a connected but not yet accepted socket.  In this case
other->sk_socket is still NULL, and SELinux will deref the NULL pointer
in selinux_socket_may_send() when geting other_isec.  There is already
a check in unix_stream_connect, which is all that's used for normal unix
stream sockets.  But the seqpacket socket then uses unix_dgram_sendmsg,
so triggers the may_send check as well.

thanks,
-chris
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