From mboxrd@z Thu Jan 1 00:00:00 1970 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4989DC54E90 for ; Wed, 21 May 2025 04:51:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=zCKMxvzPzWiBF7+sNkG+s8zks7Q+hQ37qVi5e+mukgA=; b=EUYLP6mD4qSnb2eCE1DFOdu3cH nlT7RGmBnMrxmL3pJbFrFp5ww726tYpTFbGLQCAPyIxw3WcIbaJik2Xvc9lZdjl4jGdvR9Ke/MOwY PM8tMmihqYwttugtArmq94G7s483pIZtKqj7F5j7pTpUuWf3irAaO9WPm686OWUUV558BPBXHCXRz JzkYf/NMOXYZCi3/ZCvSwUNSa6/wO5/gozXcZHkCz/UnxRextS8BRk5Lpx55vXqBwQb+6rpm+WS4m 3Ddc2Yes/xgn9p+UdwI77pyJrQxilfWKlyfddKp0aBj9mtLgebr5C7IX24a8dUOgN/ny/dBscuvkg UPjK1Tog==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uHbQr-0000000EmRp-3RaZ; Wed, 21 May 2025 04:51:57 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uHVUR-0000000EGzS-2LHI for linux-nvme@lists.infradead.org; Tue, 20 May 2025 22:31:15 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 0127E62A34; Tue, 20 May 2025 22:31:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8CF8AC4CEF2; Tue, 20 May 2025 22:31:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1747780274; bh=7Qa/IpuQKFOWRWF79NofDyxxIjQyXX1yFfRlJmNAhpQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BOwFhMEvnncEbt04sunuSxfflgKvjcUp7JSXl1Rx49NjhAjlJs3CnmgFEO2OjYLFS FnxMRf+Y0l8NIw9qbw2FBVhJEmGUfzmI3o5rYjb5Xats4x1tM2hRAQqRSZlsxW/PVs 99R5M0bnHfVohXHQoaW/qQCm7BPLAGEzVl0pXcL5Vst2Vc6khbh8bQjuyOktICMffX U3L1qVyImNx2jT/9p34tb3ykRcqoI2oa5OpAV4Lpy5hLXCv+0K7HtW4O6s6vPI/P8i l2MNooYeY9cP5g1ou6cmJiHAiz4cPxZ+ZQeRqLYZPnvcGd3eMSvAungNxE2YUbqYgG 83Ywtr100ZzXw== From: Kees Cook To: Kuniyuki Iwashima Cc: Kees Cook , Eric Dumazet , Jakub Kicinski , "David S. Miller" , Paolo Abeni , Simon Horman , Ido Schimmel , netdev@vger.kernel.org, Christoph Hellwig , Sagi Grimberg , Chaitanya Kulkarni , "Martin K. Petersen" , Mike Christie , Max Gurtovoy , Maurizio Lombardi , Dmitry Bogdanov , Mingzhe Zou , Christophe Leroy , "Dr. David Alan Gilbert" , Andrew Lunn , Stanislav Fomichev , Cosmin Ratiu , Lei Yang , Samuel Mendoza-Jonas , Paul Fertser , Alexander Aring , Stefan Schmidt , Miquel Raynal , Hayes Wang , Douglas Anderson , Grant Grundler , Jay Vosburgh , "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Jiri Pirko , Eric Biggers , Milan Broz , Philipp Hahn , Ard Biesheuvel , Al Viro , Ahmed Zaki , Alexander Lobakin , Xiao Liang , linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, linux-wpan@vger.kernel.org, linux-usb@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH 7/7] rtnetlink: do_setlink: Use struct sockaddr_storage Date: Tue, 20 May 2025 15:31:06 -0700 Message-Id: <20250520223108.2672023-7-kees@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250520222452.work.063-kees@kernel.org> References: <20250520222452.work.063-kees@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2093; i=kees@kernel.org; h=from:subject; bh=7Qa/IpuQKFOWRWF79NofDyxxIjQyXX1yFfRlJmNAhpQ=; b=owGbwMvMwCVmps19z/KJym7G02pJDBm6TKtmnOlUkkri/PtTpKuJWcgyguPHyic/Ci2ju8tye j+JT8rrKGVhEONikBVTZAmyc49z8XjbHu4+VxFmDisTyBAGLk4BmIiyHcP/5OXSpk/zfC1KOKbI rnhQbaXzKEa72P+m2Oa4bIZV4bfXMzKsmyNVf+e5ovVutyS7NQKZupb5O/XKFvdZxT2fsS5DZR0 TAA== X-Developer-Key: i=kees@kernel.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Content-Transfer-Encoding: 8bit X-Mailman-Approved-At: Tue, 20 May 2025 21:51:54 -0700 X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org Instead of a heap allocating a variably sized struct sockaddr and lying about the type in the call to netif_set_mac_address(), use a stack allocated struct sockaddr_storage. This lets us drop the cast and avoid the allocation. Putting "ss" on the stack means it will get a reused stack slot since it is the same size (128B) as other existing single-scope stack variables, like the vfinfo array (128B), so no additional stack space is used by this function. Signed-off-by: Kees Cook --- Cc: Kuniyuki Iwashima Cc: Eric Dumazet Cc: Jakub Kicinski Cc: "David S. Miller" Cc: Paolo Abeni Cc: Simon Horman Cc: Ido Schimmel Cc: --- net/core/rtnetlink.c | 19 ++++--------------- 1 file changed, 4 insertions(+), 15 deletions(-) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 9743f1c2ae3c..f9a35bdc58ad 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -3080,17 +3080,7 @@ static int do_setlink(const struct sk_buff *skb, struct net_device *dev, } if (tb[IFLA_ADDRESS]) { - struct sockaddr *sa; - int len; - - len = sizeof(sa_family_t) + max_t(size_t, dev->addr_len, - sizeof(*sa)); - sa = kmalloc(len, GFP_KERNEL); - if (!sa) { - err = -ENOMEM; - goto errout; - } - sa->sa_family = dev->type; + struct sockaddr_storage ss = { }; netdev_unlock_ops(dev); @@ -3098,10 +3088,9 @@ static int do_setlink(const struct sk_buff *skb, struct net_device *dev, down_write(&dev_addr_sem); netdev_lock_ops(dev); - memcpy(sa->sa_data, nla_data(tb[IFLA_ADDRESS]), - dev->addr_len); - err = netif_set_mac_address(dev, (struct sockaddr_storage *)sa, extack); - kfree(sa); + ss.ss_family = dev->type; + memcpy(ss.__data, nla_data(tb[IFLA_ADDRESS]), dev->addr_len); + err = netif_set_mac_address(dev, &ss, extack); if (err) { up_write(&dev_addr_sem); goto errout; -- 2.34.1