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 17B4E4A33F2 for ; Thu, 2 Jul 2026 13:55:48 +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=1783000550; cv=none; b=W8bBmQF0JCrzfc8zCLMcROzKpf1+c8FT0qnWKS25R/ocTUc43tnnIuGG+SKumWW/nYGlOLaBuydV5/FLmLFBAYRntL5yfKO+vjxmhP3CdtLykxf+KOFXwIEVwLpMStgoBTtVDmqUoIRVDCTRue5aCGNQoTTYnNXLlRY8zyZ7ztU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783000550; c=relaxed/simple; bh=885aQwHY/II9qCujXZXiC9kDxGv/U0oTnBfgk4Ly9HE=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=EH+MxjxDW4RNuKYMwPSyI1tfoxAmd/Q7xogSlKacJhnQU9IHMncI8/e0XXL7Lcx3m11Syt9s+npOfTJrB/nT7VJ7yQNmG5LtkMJyeOHBC7OOqxir2IhmIEgqrD9QxbKZ771R/85nRdknR6pLJfc5b7NWMJgDh/p0dKtWmE1TW/c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=cHCYZzfC; 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="cHCYZzfC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3F48F1F000E9; Thu, 2 Jul 2026 13:55:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1783000548; bh=zIPXaAz4DhoWSzyNe0MkJV/gfBfCe8AymT5guzH6Jcc=; h=Subject:To:Cc:From:Date; b=cHCYZzfC+g8bR4c/+QrZR7/NgPQxUaFb1Fn2diFBsD4hkoWUeLL8inlRNvVu1fARO /ZLusUi8kCgciFc7aRzKMjenKs+yXztYfN0a7v7O/D6f7Riljd1oxOZ06r7Vv2w7vc 6o7nDy7MZtOxRqjjr5MMVZd4OINJwyiGH+pJ9afQ= Subject: FAILED: patch "[PATCH] NFSv4/flexfiles: reject zero filehandle version count" failed to apply to 5.15-stable tree To: michael.bommarito@gmail.com,anna.schumaker@hammerspace.com Cc: From: Date: Thu, 02 Jul 2026 15:55:44 +0200 Message-ID: <2026070244-vehicular-daintily-d589@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 2c6bb3c40bc24f6aa8dfbe6fe98c3ad6389203f2 # git commit -s git send-email --to '' --in-reply-to '2026070244-vehicular-daintily-d589@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 2c6bb3c40bc24f6aa8dfbe6fe98c3ad6389203f2 Mon Sep 17 00:00:00 2001 From: Michael Bommarito Date: Wed, 13 May 2026 12:26:56 -0400 Subject: [PATCH] NFSv4/flexfiles: reject zero filehandle version count 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 diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c index 6a84d85e0651..99caa8d28c25 100644 --- a/fs/nfs/flexfilelayout/flexfilelayout.c +++ b/fs/nfs/flexfilelayout/flexfilelayout.c @@ -551,6 +551,10 @@ ff_layout_alloc_lseg(struct pnfs_layout_hdr *lh, if (!p) goto out_err_free; fh_count = be32_to_cpup(p); + if (fh_count == 0) { + rc = -EINVAL; + goto out_err_free; + } dss_info->fh_versions = kzalloc_objs(struct nfs_fh, fh_count, gfp_flags);