From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794591188; b=ND8oICGXRQWxDXVpqXmDgEQNlfrDJMBOKtiCCm3mv6OQYd88WoVIkqozGi/o8KANsrRJ PrrrX81tKUVDoc4lQEYfAsxbrXN0k/dLNvXu6eEaZELPurwdXoFANxCtMmJKkCdQIfi1v BzB3A7Z4BPeyjW0iQ99G6l3EF5Lv/ZiF1tbNIVpWOVXzBg3P4/pzs81F9WO2BNdBoFw41 eBV8a42fvQoG23nWy/b/09EqIB3MsMxLvcz1sSmlIhtid0PRkDeVVjLTTNvex5jgh5VM7 jPkXzalBxZq4VkVIIjJLeXWJgZWldzU1Wf7URnmNSPjLit/1Hz4BBJ/g3aKtIjV6O1g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794591188; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=epB/hAn//qTgzMnltx3Ft4g0CugDWMkKQ+jNij6DXVo=; b=VHEzUkbuvqyPopxd1I200pxYp8ah2mWgcCWZSz9Hwkii9crxTz6e6PQnS7RvBbWpRrC4 XG2J4naEaWHBUiiwUR4dcxzAac8qV/ab0d7P35Ls0oXfdunSDWWn6A9xPWFWLIcGMHq2J pmz2hx66GCAG53AluM4l+jkLs6y2fNX86Y8liTH9Kr2LHGvyDnWK7aKGDhJrguJlOoHVY bO2f+Q/FDhbo7PpcU0MFDcSFboNHOjLJ8WHvl3eNvOLz/4904fOqAYC1Ikv7A7Ced1sxm /WiFbHAhnzacuazWUi71P0kAqX8T3VH9+0ayBvXXQFBXsznP85YOLBfNFcV84F7ZXdg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=ElNH4T71; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3FFBA606C0B1; Fri, 13 Nov 2026 17:33:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=ElNH4T71 Received: by smtp.kernel.org (Postfix) with ESMTPSA id B2C131F000C6; Fri, 13 Nov 2026 17:33:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794591187; bh=epB/hAn//qTgzMnltx3Ft4g0CugDWMkKQ+jNij6DXVo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ElNH4T71OJUNka2NbrWKuWBpwxKzgGCIcQSIFsewcbcJkjPgAoPZ7/Qbob13uI5nI 3DbXsTKVPnZ+0otSQ/2X0NHXfupp8d/7ofl5JJRO4msu53BFsts2pFR4NLqdogbAos 0qhxTtZ4vBIxb8/U4Sj3w1m83hqK1cAWjjXpL7Yg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chris Mason , "Lorenzo Stoakes (ARM)" , Muchun Song , Muhammad Usama Anjum , "David Hildenbrand (Arm)" , Sasha Levin Subject: [PATCH 6.12 324/670] mm/gup: fix out-of-bounds write for nr_pages == 0 in GUP-fast Date: Fri, 13 Nov 2026 10:48:08 -0500 Message-ID: <20261113153822.871238468@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153811.177190860@linuxfoundation.org> References: <20261113153811.177190860@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chris Mason [ Upstream commit 1dfe4b276c23189394afb42d114ee8a54cc3aff2 ] 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 Link: https://patch.msgid.link/20261031-fixes_core-v3-21-d6437171ecc3@kernel.org Signed-off-by: David Hildenbrand (Arm) Signed-off-by: Sasha Levin --- mm/gup.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/gup.c b/mm/gup.c index b4746ab82dd15..c3df6f7d0bf2c 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -3448,6 +3448,9 @@ 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(¤t->mm->flags); -- 2.53.0