From: Linus Torvalds <torvalds@linux-foundation.org>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: Linux Security Module list
<linux-security-module@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [GIT PULL] Smack patches for v5.4 - retry
Date: Mon, 23 Sep 2019 14:35:28 -0700 [thread overview]
Message-ID: <CAHk-=wg1zkUTdnx5pNVOf=uuSJiEywNiztQe4oRiPb1pfA399w@mail.gmail.com> (raw)
In-Reply-To: <745ac819-f2ae-4525-1855-535daf783638@schaufler-ca.com>
On Mon, Sep 23, 2019 at 1:14 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
>
> Thank for the instruction. I think this is correct.
Looks fine, pulled.
That said, when I look closer:
> Jia-Ju Bai (1):
> security: smack: Fix possible null-pointer dereferences in smack_socket_sock_rcv_skb()
This one seems wrong.
Not seriously so, but the quoting the logic from the commit:
In smack_socket_sock_rcv_skb(), there is an if statement
on line 3920 to check whether skb is NULL:
if (skb && skb->secmark != 0)
This check indicates skb can be NULL in some cases.
and the fact is, skb _cannot_ be NULL, because when you test the
security of receiving an skb, you by definition always have an skb.
There is one single place that calls security_sock_rcv_skb(), and it
very much has a real skb.
So instead of adding a _new_ test for skb being NULL, the old test for
a NULL skb should just have been removed. It really doesn't make any
sense to have a NULL skb in that path - if some memory allocation had
failed on the receive path, that just means that the receive is never
done, it doesn't mean that you'd test a NULL skb for security policy
violations.
Anyway, it's pulled, but I think somebody should have checked and
thought about the automated tool reports a bit more..
Linus
next prev parent reply other threads:[~2019-09-23 21:35 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-23 20:14 [GIT PULL] Smack patches for v5.4 - retry Casey Schaufler
2019-09-23 21:35 ` Linus Torvalds [this message]
2019-09-23 21:38 ` Linus Torvalds
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