From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 82DF94189DA; Tue, 21 Jul 2026 21:56:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784671010; cv=none; b=P1V+I+aq0qX5sKlsoaBGk86tKBDNUGXuuo6SwlqiieyAcHoEotQtRrOc6ToromY4PC7DNykTnudr/4qD9a3c0GKEuR50joN3vPPwGKxSUV4sTWPB5dv8FeF9Tkp0Z0LkNPicOVhLIiuQUH1ytVWy8sfO9Dx0bKq7sK8ykTV0VY4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784671010; c=relaxed/simple; bh=n0L1Khz+XKJTeTEqEKUKzAq/wklLqUIOos9LrAsha8Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PantTlRRncIBcR3Lonh3Oj1xtXvxlE2W+vdWDufB0aVWinRuUSwLsb7gPVJMiCpQxiRplYXRSRhuii5n3+OJcbF9oaAW8uuXiWBm2MV9yjOCJyfOrrFwiYJ+JYyVWG2NhqNB/9lJcQdZKhHB6WXfjQTtBRO4S0DqOPyIIT7uxxQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=PvlbQ3Y4; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="PvlbQ3Y4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E90401F000E9; Tue, 21 Jul 2026 21:56:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784671008; bh=2hJ9eEb/Avw0QdwBSOSjNxRo2geS9wAgzGomelBALoQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=PvlbQ3Y4nco78b7KdTgQaHFWNor2hQGhP/I0Xp15dLmGUvULZoMv5EUwd87k+Zh9D TKOLdFastgwIX8l7ulB3NxesDNQE9wu2SN5hp5ms6Fn7fQySjS0NB+RkM9xb+yIWv2 VsyPfq08SOSe8uNx0oPw7+wGZlLO982MZUfNBsEg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Michael Bommarito , Anna Schumaker , Sasha Levin Subject: [PATCH 5.15 041/843] NFSv4/flexfiles: reject zero filehandle version count Date: Tue, 21 Jul 2026 17:14:36 +0200 Message-ID: <20260721152406.900989799@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152405.946368001@linuxfoundation.org> References: <20260721152405.946368001@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michael Bommarito [ Upstream commit 2c6bb3c40bc24f6aa8dfbe6fe98c3ad6389203f2 ] ff_layout_alloc_lseg() decodes the filehandle-version array count from the flexfiles layout body. The value is used as the count for kzalloc_objs(), and the current code only rejects NULL. A zero count yields ZERO_SIZE_PTR, which can be stored in dss_info->fh_versions even though later flexfiles paths assume that at least one filehandle version exists. Reject fh_count == 0 before the allocation, matching the existing zero version_count validation in the flexfiles GETDEVICEINFO parser. A QEMU/KASAN run with a malformed flexfiles layout hit: KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] RIP: 0010:ff_layout_encode_ff_layoutupdate.isra.0+0x15f/0x750 ff_layout_encode_layoutreturn+0x683/0x970 nfs4_xdr_enc_layoutreturn+0x278/0x3a0 Kernel panic - not syncing: Fatal exception The patched kernel rejects the malformed layout without KASAN/oops/panic, and a valid fh_count=1 regression still opens, reads, and unmounts cleanly. Cc: stable@vger.kernel.org Fixes: d67ae825a59d ("pnfs/flexfiles: Add the FlexFile Layout Driver") Assisted-by: Claude:claude-opus-4-7 Signed-off-by: Michael Bommarito Signed-off-by: Anna Schumaker Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/nfs/flexfilelayout/flexfilelayout.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/fs/nfs/flexfilelayout/flexfilelayout.c +++ b/fs/nfs/flexfilelayout/flexfilelayout.c @@ -454,6 +454,10 @@ ff_layout_alloc_lseg(struct pnfs_layout_ if (!p) goto out_err_free; fh_count = be32_to_cpup(p); + if (fh_count == 0) { + rc = -EINVAL; + goto out_err_free; + } fls->mirror_array[i]->fh_versions = kcalloc(fh_count, sizeof(struct nfs_fh),