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=1794585704; b=mKIcGSEgCSQ4ijQXEPJcKnsVnSwFC/OJB9ugq5w64et7cvhWnemkNEH3g5J6AFb1jmB0 Yu+o8WimWW7vJ4nyi614it05oCFUczg9pXYo5v+Le84ws1bjfUoIiBfm6Gf43IW+ZhJ7v 7mCY6DJzL2TcV0qGx17AsN/5XKF6YH1D02wAuyVyRmYqmAoHbIVinS1pYGhQVKgqdtbVi AgOdZmCqGK832j+GoEU+TC8dcgARf84VnSxra2zALGAB5m36jZ119kHG4Sa469XLPZDEU WN7HwXwkdKpVCM6DNKhqA7RsxzIdZzjjnmgqsanW8rhDI4xm1g/PhoT5Jou+anoDaBQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794585704; 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=kqpKFOo+lfqOqBjPwB1gDEb2HU10iJppfHYrQCa2Uns=; b=hfuwHEfT7xdlC1OpEnOydWG6xTBJnWLpAXZ/SXNqhJCS1SNJpXIm3IHYYB+UCiVJzzy6 Hqf4aZERhku3obyQSsTIMF5m3Nm2ugR9E3X9b1i1ERe0Bh6Ay/lJXlRNqtjL7bcSrDywy Tt7vVDAcqxhZjcMll3evB7hQ4aCSYV0LDcuUs5jtWn5X/tW2c2l53JrOJ6C4mCh8iXIMj KtjtBJ9ThhalChn0pKxiofoHTCCEd4KKLkXhriOiXP+084TLT5tfx5zWrLSOg7FwEZfXC VJUQ86i6Gvdr/5DgnYVV/P7p1lUf/rvlZjb8UGOPPRs894l7kBdIANCDKD2FChBYhvA== 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=Zf25FZx6; 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 59DAF606A8BE; Fri, 13 Nov 2026 16:01:44 +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=Zf25FZx6 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 09AB01F000C4; Fri, 13 Nov 2026 16:01:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794585704; bh=kqpKFOo+lfqOqBjPwB1gDEb2HU10iJppfHYrQCa2Uns=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Zf25FZx6HgF4MCIMCxvbmhAmCXb7JaiQ5fxVEJmiAhZFa8DMPpKtQT2L9Qrk5c946 zf7Ou0ZYRja3bcedLaj8hgp2e2MrjLKLfLrhzyXu3cIW7j05WBHmxQpFBo/whXti1J 54Lt2jq4GZUQIOpaCbKVvcY9dZtGTdg2nQ509ViY= 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 7.3 309/507] mm/gup: fix out-of-bounds write for nr_pages == 0 in GUP-fast Date: Fri, 13 Nov 2026 10:50:13 -0500 Message-ID: <20261113153805.813784188@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153753.358973689@linuxfoundation.org> References: <20261113153753.358973689@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.3-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 cc63c6a0e5f37..17f4150a6d7c6 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -3190,6 +3190,9 @@ 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); -- 2.53.0