From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 19508606A31E for ; Sat, 31 Oct 2026 09:45:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=JhV9oGMq Received: by kanga.kvack.org (Postfix) id 0C2246B05D5; Sat, 31 Oct 2026 05:45:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 072126B05D6; Sat, 31 Oct 2026 05:45:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E7D366B05D7; Sat, 31 Oct 2026 05:45:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id AD37D6B05D5 for ; Sat, 31 Oct 2026 05:45:46 -0400 (EDT) Received: from smtpin25.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 2D5A016083E for ; Sat, 31 Oct 2026 09:45:46 +0000 (UTC) X-FDA: 85382439492.25.A9DAA6C Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf17.hostedemail.com (Postfix) with ESMTP id 6FC6440003 for ; Sat, 31 Oct 2026 09:45:43 +0000 (UTC) Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=JhV9oGMq; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf17.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1793439943; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=foIE8/qjRxOslIMIVm5LWTcoDseO7kpGoD14hc0ILxg=; b=i2YE6XGtCyPJ7VBRY8DkUwNAEqT33FEUU35hZU2wVF2WEOQHiK4p2OR2ucncHr6lk597yV 2/t7cs0qluytnfu3+ETmBV4i6gmkfDyLOqLDBlW3Ns983/SFBIOU8jgSLHjLbrBrxnhFro edXrCKH0GhVNtQo04KQUGHMzrOG7fuk= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=JhV9oGMq; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf17.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1793439943; b=isHPrYYETagnbtX39OFG9wO3ZnTFyti4YhQprLvXYN6IuYTFwnU12S1C2eQWgtgrjxU8ea aQF5yf4ZzAbzCSZyt32IDGEpPVr7Tad/V0/U2I3z8S2Rc9UgEAcdoJhIUipDWG3sDrUIDE ftMgs+indjcPjXPFFHyqG56rSGoBG2Y= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id EFC7C605CF; Sat, 31 Oct 2026 09:45:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D56871F000C1; Sat, 31 Oct 2026 09:45:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793439942; bh=foIE8/qjRxOslIMIVm5LWTcoDseO7kpGoD14hc0ILxg=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=JhV9oGMqjIuZGgcbHEUsRikcUmJNTkInVxMbDD2McBF1KHRCOovytr11YurFRKmY+ bzpFUCXJV07KGchANo9OXAYly2i+TAjzzG2qyAyH0zYRfED/AUnwLW/4JR6ep8DOEp 3ob8fsc2zXmkJajPfwx9ACN5aMF4fl4RqsnmBccaStiOm1Ik3W84FuIM9kDgSEnVcs FnUcTU/F9+4T7XCWF7hfPk1mhEKqJzRhHlBbv4kVrzqvgm/NnX6C0xi3dX2J6sa5iR Ryhd7cB6JyGhcESjQmqHd0GH2cyaVRdT7FizFV9PWwZW6Rt8Hkhe6GmVGYIIMTUxku 0gFPxVWBEFA7Q== From: "David Hildenbrand (Arm)" Date: Sat, 31 Oct 2026 10:39:50 +0100 Subject: [PATCH v3 21/47] mm/gup: fix out-of-bounds write for nr_pages == 0 in GUP-fast X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261031-fixes_core-v3-21-d6437171ecc3@kernel.org> References: <20261031-fixes_core-v3-0-d6437171ecc3@kernel.org> In-Reply-To: <20261031-fixes_core-v3-0-d6437171ecc3@kernel.org> To: Andrew Morton , Johannes Weiner , Michal Hocko , Qi Zheng , Shakeel Butt , Lorenzo Stoakes , Kairui Song , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , Baolin Wang , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Kees Cook , Peter Zijlstra , Jann Horn , Pedro Falcato , Hugh Dickins , Pasha Tatashin , Pratyush Yadav , "Matthew Wilcox (Oracle)" , Jan Kara , Zi Yan , Lance Yang , Rik van Riel , Harry Yoo , Alistair Popple , Nico Pache , Ryan Roberts , Dev Jain , Usama Arif , Kiryl Shutsemau , Matthew Brost , John Hubbard , Peter Xu , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Oscar Salvador , Minchan Kim , Muchun Song , Xu Xin , Chengming Zhou , Chris Li , Kemeng Shi , Nhat Pham , Youngjun Park , Gregory Price , Joshua Hahn , Rakie Kim , Ying Huang , Jason Gunthorpe Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-cxl@vger.kernel.org, Chris Mason , stable@vger.kernel.org, Muhammad Usama Anjum , "David Hildenbrand (Arm)" X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1320; i=david@kernel.org; h=from:subject:message-id; bh=R62eMdMsJypxqcni0WbltJmOI5kqokR7T4ahYSHS7oQ=; b=owGbwMvMwCF2/OVpCdfQ3ZWMp9WSGLKebk9XufzzUt3qVRK79jW/zlzmvMenZ80MsUTHtrnHE 7tlXOZqdpSyMIhxMMiKKbIEBd83ePlyXW21Gx8zzBxWJpAhDFycAjCRtAqGv6InnopkrO0IDNHq 7pC+cvvWiW0b+d98XM7UJ9iq53RHYQ3Df69HC3Z+ryqu27DmAne4j/fJiz8+bFvAecZ3t5uDiFP eOk4A X-Developer-Key: i=david@kernel.org; a=openpgp; fpr=1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A X-Rspamd-Queue-Id: 6FC6440003 X-Stat-Signature: dzp6m4tmridngoairpwxdx14337hjrwz X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=4.0.1 X-Rspam-User: X-Rspamd-Server: rspam09 X-HE-Tag: 1793439943-67497 X-HE-Meta: U2FsdGVkX186bb8wkREVdMzv85HGp9h+EFaxziXU04rhbV8Z3RRVqoNGHqe5JRoDEzUv7l5ZpfQ+LlGZbVPB8/GIm0l/bmvcwLR+KSWxRE4ypEAmSyoce1BuFd6MmuhtnVoKjki4vcjfzqw6elIJSRNq/aYw9M2U6ib4RfYmkvzWcTz6fUrJ3ComQpFtfmLS6KAVlltaSh+fxCSo7l1m95jZl1duhYylPvy4KU12ZzavVMQ9vqs1hslOb8PzWWH6bRMXSY1Kdk7uieSV9sp2/wl4BTsuxZxz0WP4lVevNUuOH6CX0hJuWhkF8YhBwAkIZT/jiDiPwPpJiKEHYuO8VQ6NRZOBRi3fsbJpimCJshtmOvBF3YQrhLufcLyOh6ec3FQQ+FwnVA1RjozHXGeH/7FUMzsRVJ+isLBcndMk30XbBf5gq78v7BZO16kHfKKF0bLdzYVOZaS2tZihwQ2qGIQrApcXlVcpknM6PQYaa3KROlKhhYxO4pEPen+OZ1W5aTums2hHCZU+RgqQ+m79T7x2pTfasywysctK4egkoBWB3y70Blfzn04+6/Zumz0WJvCGYf0O4/cuOQoTFx/4azWYXhkgbuVOXAzMI3d/6NbEAEzrKkV5Xp6SoY+l8pBeEABFaluOrlLVxd07vRwKLwV4e1dzcgOj8bsOBLWbnI/6DNydc50hh0exwFMx+rfeW1BxZmcd+1TNBzFcvkkZNpC9AHeHbSgX7eBdj/jZnDwGZDAinnHYaHLPhX7xNPUQkKUit8rYZCw+Ep4sRmNYa9iFsSd02yfy7woaKJ9aERp/rTV5e0jer6rHJOP3b3pkPyZh37xyo5Rwmm1zl9+OYgNPwqUZQyoTUq5kAvjy0GhV6hFH9RGlPCdZlTLEPev7DQrQqvFK4Iolw/mMt1v7sllRCpy2/bYUr7KInabUNPYWBiL1D6QuoelRJ/cORcZ/jAJ0DLZTevRiwORhCeK APg//yre HM4NgUp800pA9mQZN/yt7K0h7XggikTKqIDUAwRl5yL3DHnMwPGxSyl0QLpkCVixQ7xuAI/QYUS4ywI/HqMgN+DIz4jupCxezJfMPPRuFi+miPuvvj9P+QGwQw6yRCcYBuEpQX0izDikvIqkUJ+tUiwPdfRD71NWe//Es5xo/mrV2Ta10/lCStMAHajMg5SsWQMGULO7eldSl5TbQB3MCZInfDjgxY7ADM6095eF7Rock0ZB5+X6kzgoN5jWrSyiCfLdHm7n3caVuanC5r9VfaC0fmFE4kGAqflnsU7IZsZrPgPhZzMRHOfCBcuUB/nflGdzScX+HgzX3MfoI0lvV4kJp1072JEFABsbpg55gK0k+yUeQ0Ez2GUla0QIDMkgk5pBzpR+eATAJ+Xau1iwwPx/0VEQPy3A9X6uIRl4SjwV1lHA= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 From: Chris Mason With nr_pages == 0, GUP-fast still enters its page table walk and can write past the caller's page array. The old end <= start check caught empty ranges, but was replaced with an overflow check. Users such as OrangeFS can pass a zero page count derived from a userspace-supplied length. So let's return zero for nr_pages == 0 before starting the walk, just like GUP-slow. Fix generated by an LLM and sent by Chris Mason in private. Fixes: c28b1fc70390 ("mm/gup: reorganize internal_get_user_pages_fast()") Cc: stable@vger.kernel.org Signed-off-by: Chris Mason [ david: simplify description ] Reviewed-by: Lorenzo Stoakes (ARM) Acked-by: Muchun Song Tested-by: Muhammad Usama Anjum Signed-off-by: David Hildenbrand (Arm) --- mm/gup.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/gup.c b/mm/gup.c index cc4fa18783ce0..1c2ac7c66c309 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -3215,6 +3215,9 @@ static int gup_fast_fallback(unsigned long start, unsigned long nr_pages, FOLL_PCI_P2PDMA | FOLL_HONOR_NUMA_FAULT))) return -EINVAL; + if (unlikely(!nr_pages)) + return 0; + if (gup_flags & FOLL_PIN) mm_set_has_pinned_flag(current->mm); -- 2.43.0