From nobody Fri Jan 2 15:25:35 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6FEF5CD80CE for ; Tue, 10 Oct 2023 13:00:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232414AbjJJNAh (ORCPT ); Tue, 10 Oct 2023 09:00:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32802 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232469AbjJJNAX (ORCPT ); Tue, 10 Oct 2023 09:00:23 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 798BD1BC for ; Tue, 10 Oct 2023 06:00:01 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 73107C433C9; Tue, 10 Oct 2023 12:59:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1696942801; bh=Xi+Z6sMFlQ/asWuwXVb1mQI8aYoKAasoVIf0fri5JUU=; h=Date:From:To:Cc:Subject:From; b=fG2qWorUWCfvQAcOdg2BtGbv9Ro/K0B2CpaODoS/VnH9d1Bet0rngO4Io+dDpjVP+ xWEeIBTjpNic9yaaI0woBajR4QdJvM7htlnYU95Xy+b+dWPiDRtOzdFoWFNbHGJmGX jmTIBA72fAJPmxZmwZ6Nxx2gFhjRkcOaKLXGDedAo6tWBD/JxLZ0NR9aEkEjJX5HOw pIa+ZKnY0cG2xrcPx6nOz/ZuRjwXweE0onrNwFHyXr/8Goo2WFFtFHdmdJFUnlP/2D 8EVzEEDBVdK45ixmVGgQvtNo5YFccXrQ0B3xmoUrBzrmyF7B225nBkSc8Pd2jaXkqA Drz3Xk1UTpdiA== Date: Tue, 10 Oct 2023 06:59:44 -0600 From: "Gustavo A. R. Silva" To: David Howells , Marc Dionne Cc: linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" , linux-hardening@vger.kernel.org Subject: [PATCH][next] afs: Add __counted_by for struct afs_acl and use struct_size() Message-ID: MIME-Version: 1.0 Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Prepare for the coming implementation by GCC and Clang of the __counted_by attribute. Flexible array members annotated with __counted_by can have their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions). While there, use struct_size() helper, instead of the open-coded version, to calculate the size for the allocation of the whole flexible structure, including of course, the flexible-array member. This code was found with the help of Coccinelle, and audited and fixed manually. Signed-off-by: Gustavo A. R. Silva Reviewed-by: Kees Cook --- fs/afs/internal.h | 2 +- fs/afs/xattr.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/afs/internal.h b/fs/afs/internal.h index 469a717467a4..e263a58b82ba 100644 --- a/fs/afs/internal.h +++ b/fs/afs/internal.h @@ -1116,7 +1116,7 @@ extern void afs_fs_inline_bulk_status(struct afs_oper= ation *); =20 struct afs_acl { u32 size; - u8 data[]; + u8 data[] __counted_by(size); }; =20 extern void afs_fs_fetch_acl(struct afs_operation *); diff --git a/fs/afs/xattr.c b/fs/afs/xattr.c index 9048d8ccc715..8b42cac51660 100644 --- a/fs/afs/xattr.c +++ b/fs/afs/xattr.c @@ -75,7 +75,7 @@ static bool afs_make_acl(struct afs_operation *op, { struct afs_acl *acl; =20 - acl =3D kmalloc(sizeof(*acl) + size, GFP_KERNEL); + acl =3D kmalloc(struct_size(acl, data, size), GFP_KERNEL); if (!acl) { afs_op_nomem(op); return false; --=20 2.34.1