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 B24F317E8 for ; Fri, 18 Nov 2022 03:39:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B5972C433C1; Fri, 18 Nov 2022 03:39:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1668742747; bh=b5Ciezt8/hFEbDXdb8acMLPYQDDy/7lEA3tkZKMdX6w=; h=From:To:Cc:Subject:Date:From; b=FpA9tixOUEdwKECfANNO1oO5psY3Tvy5RB3aGnSKSSlUp/n/Jb53jmCQMYIFidDN8 MRIz7aw7DD5AyDU1VMDRMTleOsi3zOGjtw4jDFayfrnjN94QEdZmjlTtClACm1Y9Nc d68qWdWmCGMvdZ6XPBaMitLNoPQUpE1gXaWwSJumrVLkiSi3sQAmCbpRrsm/kflT+M 2cK9h9djnhwss8Ow7heQRCzLM4TEvHJQq2F4MTCE4XZs49jBuA7pa9nWdGMfqbApXV +cxXD3PhNR/4weFJDOFBYra7s+Udlw6E0HVaReAUIkxvIW3TptWT7hKvRyRPiPgPw0 Z5GlG8Prs1uqw== From: Jakub Kicinski To: davem@davemloft.net Cc: netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, Jakub Kicinski , Kees Cook , nathan@kernel.org, ndesaulniers@google.com, trix@redhat.com, llvm@lists.linux.dev Subject: [PATCH net-next] netlink: remove the flex array from struct nlmsghdr Date: Thu, 17 Nov 2022 19:39:03 -0800 Message-Id: <20221118033903.1651026-1-kuba@kernel.org> X-Mailer: git-send-email 2.38.1 Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit I've added a flex array to struct nlmsghdr in commit 738136a0e375 ("netlink: split up copies in the ack construction") to allow accessing the data easily. It leads to warnings with clang, if user space wraps this structure into another struct and the flex array is not at the end of the container. Reviewed-by: Kees Cook Link: https://lore.kernel.org/all/20221114023927.GA685@u2004-local/ Signed-off-by: Jakub Kicinski --- CC: nathan@kernel.org CC: ndesaulniers@google.com CC: trix@redhat.com CC: llvm@lists.linux.dev --- include/uapi/linux/netlink.h | 2 -- net/netlink/af_netlink.c | 2 +- 2 files changed, 1 insertion(+), 3 deletions(-) diff --git a/include/uapi/linux/netlink.h b/include/uapi/linux/netlink.h index 5da0da59bf01..e2ae82e3f9f7 100644 --- a/include/uapi/linux/netlink.h +++ b/include/uapi/linux/netlink.h @@ -48,7 +48,6 @@ struct sockaddr_nl { * @nlmsg_flags: Additional flags * @nlmsg_seq: Sequence number * @nlmsg_pid: Sending process port ID - * @nlmsg_data: Message payload */ struct nlmsghdr { __u32 nlmsg_len; @@ -56,7 +55,6 @@ struct nlmsghdr { __u16 nlmsg_flags; __u32 nlmsg_seq; __u32 nlmsg_pid; - __u8 nlmsg_data[]; }; /* Flags values */ diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 9ebdf3262015..d73091f6bb0f 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -2514,7 +2514,7 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err, if (!nlmsg_append(skb, nlmsg_len(nlh))) goto err_bad_put; - memcpy(errmsg->msg.nlmsg_data, nlh->nlmsg_data, + memcpy(nlmsg_data(&errmsg->msg), nlmsg_data(nlh), nlmsg_len(nlh)); } -- 2.38.1