From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-3.4 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED, RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 4786 invoked from network); 5 Sep 2020 08:40:36 -0000 Received: from mother.openwall.net (195.42.179.200) by inbox.vuxu.org with ESMTPUTF8; 5 Sep 2020 08:40:36 -0000 Received: (qmail 9786 invoked by uid 550); 5 Sep 2020 08:40:31 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 9764 invoked from network); 5 Sep 2020 08:40:30 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fastmail.com; h= mime-version:message-id:in-reply-to:references:date:from:to :subject:content-type; s=fm3; bh=0mGzwNPqx3vB/LuuAJ+z3+asWwF61NN cYVekGCwuXXQ=; b=n/tjonxDx409zhwkVwdVDzjNqnlh/EFDIzXv6TJrEmnrHmf NCUEo+lzPujdYouPt7DSakHr201kBMCHFy/3EzuxoV1FybPJTqAXJroTMVU0grNh XjYyStlusRqcTbHl4T/Eg57NX8FFFm+mDUS7Lx+gK+LAZJvxv82x/5U1GepW9P4p /iu+ABdG80CnqUS77n9ml1YUgy9SX9DbpVZTKWTrrocOYyVahEM7Jo9/muvmf2Ru /eSLldJRgJLwmeV67rcAm3CqykJa/aho8jl6pviXBiNnzw/Pj+TDSpGsUY6jBzHh bdKS/ATQ34igQqYruBWY359Z/E1aSO7/4Vn7T4g== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm3; bh=0mGzwN Pqx3vB/LuuAJ+z3+asWwF61NNcYVekGCwuXXQ=; b=jQLzuZDixpX/pUuX4Scg/H N/41egKeLogYPxCpNDWNtlAMcN6QLHwVg0jgXO4Z0OEqM4nMSMDgFRSAlDPgh1z3 ZKwlufXLUUSRdtmuFYl4n0L8DS5ixmPlsLNSkBwUiDVfnkpanftZzDSTwnOu7n85 iTSWyXMSMQJHLq9ZRihcXsb60VW3PVDsguh1/WASiqu5tUMS66Zuv5QF6Tf2PhW2 H0DKStgoW37n4SZwY+fmnf+wrMXreqzW+TWUfHNa1YthORPlKaE0VLHG72pQ/hkv wKNHj5K4MzKl60AiEkWnzsmVDRzCfVH+O42exq8w6VigU1YfYtRxC+ADeBCCBO/Q == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduiedrudeghedgtdehucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucenucfjughrpefofgggkfgjfhffhffvufgtsehttd ertderredtnecuhfhrohhmpedfufhtvghfrghnucfqkdftvggrrhdfuceoshhorhgvrghr sehfrghsthhmrghilhdrtghomheqnecuggftrfgrthhtvghrnhepieejjeetheeggefftd dvtddvfeevfedukeetgffhleetledvudfhgefgheegiefgnecuvehluhhsthgvrhfuihii vgeptdenucfrrghrrghmpehmrghilhhfrhhomhepshhorhgvrghrsehfrghsthhmrghilh drtghomh X-ME-Proxy: X-Mailer: MessagingEngine.com Webmail Interface User-Agent: Cyrus-JMAP/3.3.0-259-g88fbbfa-fm-20200903.003-g88fbbfa3 Mime-Version: 1.0 Message-Id: In-Reply-To: <20200904195251.GA2139@voyager> References: <20200904195251.GA2139@voyager> Date: Sat, 05 Sep 2020 04:39:57 -0400 From: "Stefan O'Rear" To: musl@lists.openwall.com Content-Type: text/plain Subject: Re: [musl] Bug in mmap_fixed() On Fri, Sep 4, 2020, at 3:52 PM, Markus Wichmann wrote: > touch (one byte in front of the buffer). I don't know, can this crash on > NOMMU systems? I am aware there were systems in the past lacking an MMU, > but having a memory protection unit. I just don't know if Linux runs on > any of them. To answer the other question here, Linux runs on Cortex-M systems and has code to program the memory protection unit; I was under the impression it could do so on a per-process basis but I just checked arch/arm/mm/pmsa-v[78].c and it's configured once at boot time. There is an ARM FDPIC ABI but it is not implemented in musl at this time. Although even without precise bounds you could get a crash later if it overwrites something important. -s