From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f46.google.com (mail-wr1-f46.google.com [209.85.221.46]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 380B536D for ; Thu, 5 May 2022 03:14:55 +0000 (UTC) Received: by mail-wr1-f46.google.com with SMTP id w4so4312019wrg.12 for ; Wed, 04 May 2022 20:14:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=paul-moore-com.20210112.gappssmtp.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=6ucVUJA/3XuUnAZZDdzrSa00V5OM/xNG80G7w+rY/AM=; b=TuxTKLvOuI4WPEKhesTppN+S/ZTkV+RZI5Wf5W2p+hsrw7/gyfISF8EIiT+rnx8Zu6 zyyiN1wYwPcxjcCA2Sf5xnxirRkddqYIXy2R06dd7qAEUind0ZWDkOOMEqGzEQWPzWzC ZTGq5qihhGmXwhHHxuYfhzg3wQjnC+ThZO+LDVhD9+QIb89VKx3wO1YbUFwWrxXrBCMa SL8UA4+69pMFcpj8M2pJPoNe1J5xXeNZwxQABf1kR5+ALPhLTrYwt5fLtjpY8BeYkBF4 nHH6g/sC5IM5M9d/Ecm/JssJwuDneWf8+Vn5nXmTehGUz+AEuc9+Pt2ztZNda+z83bgG KQkQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=6ucVUJA/3XuUnAZZDdzrSa00V5OM/xNG80G7w+rY/AM=; b=mZ22hO3V6YlsF4GXVjpLFvobXN1CRInrCgNVEKYTrSgxQxjUo3NWuiAkZKXfTi3eje 69Vpw2c4XWeiSXLgPX0acIreX/wK2Lr35/AJ2jqZPey2yuXidbmmgxFF3U9g4FQsIKjJ uklt99fGKxxO5y0Udz0wUe7sY/DdyF7Bz/X5Gli5hpZEbbnG7IW1vN3sm6nfNhfpvMkS AMLnuvkpgClTKrvX5km3tIAuEmY4JzYG32/GLYHjpRBqCxw34kEGPflKECeKTw9CugNZ YNl5ja4UTdBZPH7wtoZQeuw5XMAmjXF7S8jnJqM2hi3E32vfgdoLdi7/f+VeKxjMv0+X WfsQ== X-Gm-Message-State: AOAM531SRey7YCzo2lj0BuZxy2OZUNhH0haxr8ia6Va0Y82tD4xu+scr bD6F1tim9628FjMLbjVAIHsoRvG1xJczsy+jQGh1 X-Google-Smtp-Source: ABdhPJzVMX+BMHIo/6Rx3rt/EGt5DUCiA1Xs3vZE5oz5hLJkbM0bMmp2okAEnKI/au/mDAitpvRIKuXqsxBU1V8TuLw= X-Received: by 2002:a5d:590d:0:b0:20a:c3eb:2584 with SMTP id v13-20020a5d590d000000b0020ac3eb2584mr18412244wrd.18.1651720493308; Wed, 04 May 2022 20:14:53 -0700 (PDT) Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20220504014440.3697851-1-keescook@chromium.org> <20220504014440.3697851-29-keescook@chromium.org> <20220504234324.GA12556@embeddedor> In-Reply-To: <20220504234324.GA12556@embeddedor> From: Paul Moore Date: Wed, 4 May 2022 23:14:42 -0400 Message-ID: Subject: Re: [PATCH 28/32] selinux: Use mem_to_flex_dup() with xfrm and sidtab To: "Gustavo A. R. Silva" Cc: Kees Cook , Steffen Klassert , Herbert Xu , "David S. Miller" , Stephen Smalley , Eric Paris , Nick Desaulniers , Xiu Jianfeng , =?UTF-8?Q?Christian_G=C3=B6ttsche?= , netdev@vger.kernel.org, selinux@vger.kernel.org, Alexei Starovoitov , alsa-devel@alsa-project.org, Al Viro , Andrew Gabbasov , Andrew Morton , Andy Gross , Andy Lavr , Arend van Spriel , Baowen Zheng , Bjorn Andersson , Boris Ostrovsky , Bradley Grove , brcm80211-dev-list.pdl@broadcom.com, Christian Brauner , Christian Lamparter , Chris Zankel , Cong Wang , Daniel Axtens , Daniel Vetter , Dan Williams , David Gow , David Howells , Dennis Dalessandro , devicetree@vger.kernel.org, Dexuan Cui , Dmitry Kasatkin , Eli Cohen , Eric Dumazet , Eugeniu Rosca , Felipe Balbi , Francis Laniel , Frank Rowand , Franky Lin , Greg Kroah-Hartman , Gregory Greenman , Guenter Roeck , Haiyang Zhang , Hante Meuleman , Hulk Robot , Jakub Kicinski , "James E.J. Bottomley" , James Morris , Jarkko Sakkinen , Jaroslav Kysela , Jason Gunthorpe , Jens Axboe , Johan Hedberg , Johannes Berg , Johannes Berg , John Keeping , Juergen Gross , Kalle Valo , Keith Packard , keyrings@vger.kernel.org, kunit-dev@googlegroups.com, Kuniyuki Iwashima , "K. Y. Srinivasan" , Lars-Peter Clausen , Lee Jones , Leon Romanovsky , Liam Girdwood , linux1394-devel@lists.sourceforge.net, linux-afs@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-bluetooth@vger.kernel.org, linux-hardening@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-integrity@vger.kernel.org, linux-rdma@vger.kernel.org, linux-scsi@vger.kernel.org, linux-security-module@vger.kernel.org, linux-usb@vger.kernel.org, linux-wireless@vger.kernel.org, linux-xtensa@linux-xtensa.org, llvm@lists.linux.dev, Loic Poulain , Louis Peens , Luca Coelho , Luiz Augusto von Dentz , Marc Dionne , Marcel Holtmann , Mark Brown , "Martin K. Petersen" , Max Filippov , Mimi Zohar , Muchun Song , Nathan Chancellor , =?UTF-8?B?TnVubyBTw6E=?= , Paolo Abeni , Rich Felker , Rob Herring , Russell King , "Serge E. Hallyn" , SHA-cyfmac-dev-list@infineon.com, Simon Horman , Stefano Stabellini , Stefan Richter , Stephen Hemminger , Tadeusz Struk , Takashi Iwai , Tom Rix , Udipto Goswami , Vincenzo Frascino , wcn36xx@lists.infradead.org, Wei Liu , xen-devel@lists.xenproject.org, Yang Yingliang Content-Type: text/plain; charset="UTF-8" On Wed, May 4, 2022 at 7:34 PM Gustavo A. R. Silva wrote: > > Hi Paul, > > On Wed, May 04, 2022 at 06:57:28PM -0400, Paul Moore wrote: > > On Tue, May 3, 2022 at 9:57 PM Kees Cook wrote: > > [..] > > > > +++ b/include/uapi/linux/xfrm.h > > > @@ -31,9 +31,9 @@ struct xfrm_id { > > > struct xfrm_sec_ctx { > > > __u8 ctx_doi; > > > __u8 ctx_alg; > > > - __u16 ctx_len; > > > + __DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(__u16, ctx_len); > > > __u32 ctx_sid; > > > - char ctx_str[0]; > > > + __DECLARE_FLEX_ARRAY_ELEMENTS(char, ctx_str); > > > }; > > > > While I like the idea of this in principle, I'd like to hear about the > > testing you've done on these patches. A previous flex array > > conversion in the audit uapi headers ended up causing a problem with > > I'm curious about which commit caused those problems...? Commit ed98ea2128b6 ("audit: replace zero-length array with flexible-array member"), however, as I said earlier, the problem was actually with SWIG, it just happened to be triggered by the kernel commit. There was a brief fedora-devel mail thread about the problem, see the link below: * https://www.spinics.net/lists/fedora-devel/msg297991.html To reiterate, I'm supportive of changes like this, but I would like to hear how it was tested to ensure there are no unexpected problems with userspace. If there are userspace problems it doesn't mean we can't make changes like this, it just means we need to ensure that the userspace issues are resolved first. -- paul-moore.com