From: Ard Biesheuvel <ardb@kernel.org>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Denis Kenzior <denkenz@gmail.com>,
Andrew Zaborowski <andrew.zaborowski@intel.com>,
Paul Menzel <pmenzel@molgen.mpg.de>,
Caleb Jorden <caljorden@hotmail.com>,
Sasha Levin <sashal@kernel.org>,
iwd@lists.01.org, "# 3.4.x" <stable@vger.kernel.org>,
Greg KH <gregkh@linuxfoundation.org>,
LKML <linux-kernel@vger.kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Linux Crypto Mailing List <linux-crypto@vger.kernel.org>
Subject: Re: [v2 PATCH] crypto: af_alg - Work around empty control messages without MSG_MORE
Date: Thu, 27 Aug 2020 09:40:01 +0200 [thread overview]
Message-ID: <CAMj1kXGJWRXu1Mx=ObTkztTdBQusv0N8o-cH1f+KM7d7geD20w@mail.gmail.com> (raw)
In-Reply-To: <20200827071436.GA30281@gondor.apana.org.au>
On Thu, 27 Aug 2020 at 09:15, Herbert Xu <herbert@gondor.apana.org.au> wrote:
>
> On Thu, Aug 27, 2020 at 08:40:01AM +0200, Ard Biesheuvel wrote:
> >
> > It is part of iwd - just build that and run 'make check'
> >
> > With your patch applied, the occurrence of sendmsg() in
> > operate_cipher() triggers the warn_once(), but if I add MSG_MORE
> > there, the test hangs.
>
> I see. This is a different issue. The original kernel change
> was a bit too strict here and it is barfing at the fact that two
> successive sendmsg's of the same request both contain a control
> message.
>
> Here's an updated patch to allow this.
>
> ---8<---
> The iwd daemon uses libell which sets up the skcipher operation with
> two separate control messages. As the first control message is sent
> without MSG_MORE, it is interpreted as an empty request.
>
> While libell should be fixed to use MSG_MORE where appropriate, this
> patch works around the bug in the kernel so that existing binaries
> continue to work.
>
> We will print a warning however.
>
> A separate issue is that the new kernel code no longer allows the
> control message to be sent twice within the same request. This
> restriction is obviously incompatible with what iwd was doing (first
> setting an IV and then sending the real control message). This
> patch changes the kernel so that this is explicitly allowed.
>
> Reported-by: Caleb Jorden <caljorden@hotmail.com>
> Fixes: f3c802a1f300 ("crypto: algif_aead - Only wake up when...")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
>
> diff --git a/crypto/af_alg.c b/crypto/af_alg.c
> index a6f581ab200c..8be8bec07cdd 100644
> --- a/crypto/af_alg.c
> +++ b/crypto/af_alg.c
> @@ -16,6 +16,7 @@
> #include <linux/module.h>
> #include <linux/net.h>
> #include <linux/rwsem.h>
> +#include <linux/sched.h>
> #include <linux/sched/signal.h>
> #include <linux/security.h>
>
> @@ -845,9 +846,15 @@ int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
> }
>
> lock_sock(sk);
> - if (ctx->init && (init || !ctx->more)) {
> - err = -EINVAL;
> - goto unlock;
> + if (ctx->init && !ctx->more) {
> + if (ctx->used) {
> + err = -EINVAL;
> + goto unlock;
> + }
> +
> + pr_info_once(
> + "%s sent an empty control message without MSG_MORE.\n",
> + current->comm);
> }
> ctx->init = true;
>
Yep, that works.
next prev parent reply other threads:[~2020-08-27 7:40 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200826055150.2753.90553@ml01.vlan13.01.org>
2020-08-26 6:18 ` Issue with iwd + Linux 5.8.3 + WPA Enterprise Paul Menzel
2020-08-26 10:40 ` Ard Biesheuvel
2020-08-26 11:49 ` Herbert Xu
2020-08-26 11:59 ` Ard Biesheuvel
2020-08-26 12:08 ` Herbert Xu
2020-08-26 12:58 ` Andrew Zaborowski
2020-08-26 13:00 ` Herbert Xu
2020-08-26 13:57 ` Denis Kenzior
2020-08-26 14:19 ` Herbert Xu
2020-08-26 15:25 ` Denis Kenzior
2020-08-26 15:42 ` Ard Biesheuvel
2020-08-26 22:19 ` Herbert Xu
2020-08-27 6:40 ` Ard Biesheuvel
2020-08-27 7:14 ` [v2 PATCH] crypto: af_alg - Work around empty control messages without MSG_MORE Herbert Xu
2020-08-27 7:40 ` Ard Biesheuvel [this message]
[not found] ` <BL0PR11MB329980406FA0A14A8EF61A07B9550@BL0PR11MB3299.namprd11.prod.outlook.com>
2020-08-27 7:54 ` Issue with iwd + Linux 5.8.3 + WPA Enterprise Ard Biesheuvel
2020-08-26 13:29 ` [PATCH] crypto: af_alg - Work around empty control messages without MSG_MORE Herbert Xu
2020-08-26 13:56 ` Ard Biesheuvel
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