From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 5E6C038AC78 for ; Fri, 24 Apr 2026 09:42:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777023752; cv=none; b=t5bKvDe+CFH6BV7GYeTXYBrcgtZr6YTpEP30kMgDXvy9BOVOV7Utg4sdvOmW0PkRRmdbLOEruipAo5ks+ugN9N7XK8g2q/uALIL3JaDMsJp3VKCjLwWA5m6AGriRpZjbh65fkKrJh4EvQUJcYl6MYTACWRVMGxNH4294606Gspg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777023752; c=relaxed/simple; bh=7q45AS8/LJsuOvOWPNQpj8iE48BjZmyzjws/D3Uj8/A=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=rxi1Vrps1lv0bMYz3tzGN82JpJy2CeJXtw/4DGSl+WzVMIN9SRwY4emlUPOmWDpHMXpW1fg4MSnSd8WjGsCNubdZMDEmT6YOTXX23CXvGUxstah74OTLZMiXFCOanrxSnqqjdSR5VfEqNkwgBKYfsPu1/t/ADxlUW3/+/EvyLAY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=PzDkZkoJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="PzDkZkoJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E7C8EC19425; Fri, 24 Apr 2026 09:42:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1777023752; bh=7q45AS8/LJsuOvOWPNQpj8iE48BjZmyzjws/D3Uj8/A=; h=Subject:To:Cc:From:Date:From; b=PzDkZkoJdJRAFX3asr21u4brM7EfESJSj9ZaP1YejcSFLOPUY33GMEedDcUtX/Xx6 6UKYyNs+Jm9FEfqHPp+HsYLcMdCW/AMIZ/ZPwULYgFrXdvvg9OjQJQGFObz0CtHsfl KXg5Q317kDxsgP8hokQPkrbdRoUfmc0d2HglX7FQ= Subject: FAILED: patch "[PATCH] smb: client: require a full NFS mode SID before reading mode" failed to apply to 5.15-stable tree To: michael.bommarito@gmail.com,stfrench@microsoft.com Cc: From: Date: Fri, 24 Apr 2026 11:42:29 +0200 Message-ID: <2026042429-hanky-simplify-54ff@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 2757ad3e4b6f9e0fed4c7739594e702abc5cab21 # git commit -s git send-email --to '' --in-reply-to '2026042429-hanky-simplify-54ff@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 2757ad3e4b6f9e0fed4c7739594e702abc5cab21 Mon Sep 17 00:00:00 2001 From: Michael Bommarito Date: Mon, 20 Apr 2026 09:50:58 -0400 Subject: [PATCH] smb: client: require a full NFS mode SID before reading mode bits parse_dacl() treats an ACE SID matching sid_unix_NFS_mode as an NFS mode SID and reads sid.sub_auth[2] to recover the mode bits. That assumes the ACE carries three subauthorities, but compare_sids() only compares min(a, b) subauthorities. A malicious server can return an ACE with num_subauth = 2 and sub_auth[] = {88, 3}, which still matches sid_unix_NFS_mode and then drives the sub_auth[2] read four bytes past the end of the ACE. Require num_subauth >= 3 before treating the ACE as an NFS mode SID. This keeps the fix local to the special-SID mode path without changing compare_sids() semantics for the rest of cifsacl. Fixes: e2f8fbfb8d09 ("cifs: get mode bits from special sid on stat") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-6 Signed-off-by: Michael Bommarito Signed-off-by: Steve French diff --git a/fs/smb/client/cifsacl.c b/fs/smb/client/cifsacl.c index cb4060ba5e31..4ec204d2c774 100644 --- a/fs/smb/client/cifsacl.c +++ b/fs/smb/client/cifsacl.c @@ -879,6 +879,7 @@ static void parse_dacl(struct smb_acl *pdacl, char *end_of_acl, dump_ace(ppace[i], end_of_dacl); #endif if (mode_from_special_sid && + ppace[i]->sid.num_subauth >= 3 && (compare_sids(&(ppace[i]->sid), &sid_unix_NFS_mode) == 0)) { /*