From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from omta036.useast.a.cloudfilter.net (omta036.useast.a.cloudfilter.net [44.202.169.35]) (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 B311544C7C; Tue, 20 May 2025 23:46:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=44.202.169.35 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747784804; cv=none; b=e7o1j9LbPyGK8DHmeetQeuz9gPqjCK8uGpXsiBcYLtg/d8baf+t1d84A7zIOs6e9noaRE2NGRBiu0VV7HGugD80B9iw/Rc5h3HJjiFKzV2/WBeUw0BL9bktCnDKncSO+luAXpcmLVq5v3+yPhdkQCtFryWQNs6yHvxZRtvmeajg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747784804; c=relaxed/simple; bh=bLUFl9S0ppuDBraRW5HPCuSaH2HqBMXggxUmwVMjqpY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=g2gG/HeyNXm/i6m5oHezu4Iff6iGGIL64VhHD9UYCXLf1+N669MtX1iWOnUZdiwyZZI9VnQNKUc+1Q4K6VP6k8MR09HmhA5/8VTgIY+fGAzF9aQMNLp0pWPcLGlmlZldmKyEgszpKgeh8P6NeEM/I7gG6jV/n6r/oIugaGd9KrY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=embeddedor.com; spf=pass smtp.mailfrom=embeddedor.com; dkim=pass (2048-bit key) header.d=embeddedor.com header.i=@embeddedor.com header.b=RkOEIL8H; arc=none smtp.client-ip=44.202.169.35 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=embeddedor.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=embeddedor.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=embeddedor.com header.i=@embeddedor.com header.b="RkOEIL8H" Received: from eig-obgw-5002a.ext.cloudfilter.net ([10.0.29.215]) by cmsmtp with ESMTPS id HV1mulW5czZPaHWfQuWA9E; Tue, 20 May 2025 23:46:40 +0000 Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with ESMTPS id HWfPupK4YJ4PgHWfPuXVMp; Tue, 20 May 2025 23:46:40 +0000 X-Authority-Analysis: v=2.4 cv=ZaLWNdVA c=1 sm=1 tr=0 ts=682d1460 a=1YbLdUo/zbTtOZ3uB5T3HA==:117 a=efVMuJ2jJG67FGuSm7J3ww==:17 a=IkcTkHD0fZMA:10 a=dt9VzEwgFbYA:10 a=7T7KSl7uo7wA:10 a=VwQbUJbxAAAA:8 a=vggBfdFIAAAA:8 a=1XWaLZrsAAAA:8 a=J1Y8HTJGAAAA:8 a=20KFwNOVAAAA:8 a=Ikd4Dj_1AAAA:8 a=80Ll13GqqWtdygCPsrQA:9 a=QEXdDO2ut3YA:10 a=y1Q9-5lHfBjTkpIzbSAN:22 a=xYX6OU9JNrHFPr8prv8u:22 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=embeddedor.com; s=default; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=GCSOMPC5nSp6vXCJCOyw43TeCqRPw0aHopDjgStRrEo=; b=RkOEIL8HdLqtSdBneGawhJ03KC V5lylhiwlA4tjpIzNUfTJZWG/JI7KZeu0R6u6RT1Wgrna+sdG1TDsjQp636L0eq6FZoYKWChuB7Fw OZ0G0KSPZ070n11fgREH1/0pK0bKpUB1DPc5b1W9aIcMOqclPtiHhEqQxW+bGAm7kgVZE2mo/dh/j 6zJNBFSYvPNpVvAkrfTJ/WhewMnZXFW4+yGGQzgISc7mhKsZql+BSiIpOk5uDOG5GEinCO8EkqnBy s1A4m2PG6KKo5ero7hH8QxQugRIrdkWVBAN3yDhtTyq0bNE9UoLHmAnxwgN9oLTnhDbcmdEAAKCgY iZ1Mg+vw==; Received: from [177.238.17.151] (port=45184 helo=[192.168.0.27]) by gator4166.hostgator.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.98.1) (envelope-from ) id 1uHVnL-00000001711-3dD6; Tue, 20 May 2025 17:50:47 -0500 Message-ID: <2af2857c-d4b9-45c1-b241-dffa23ff4f32@embeddedor.com> Date: Tue, 20 May 2025 16:50:29 -0600 Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 7/7] rtnetlink: do_setlink: Use struct sockaddr_storage To: Kees Cook , Kuniyuki Iwashima Cc: 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 References: <20250520222452.work.063-kees@kernel.org> <20250520223108.2672023-7-kees@kernel.org> Content-Language: en-US From: "Gustavo A. R. Silva" In-Reply-To: <20250520223108.2672023-7-kees@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 177.238.17.151 X-Source-L: No X-Exim-ID: 1uHVnL-00000001711-3dD6 X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: ([192.168.0.27]) [177.238.17.151]:45184 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 0 X-Org: HG=hgshared;ORG=hostgator; X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes X-CMAE-Envelope: MS4xfBhr7T620cDl5hmzjg9cEWPDyFpOpeDCN3E8pMcuns6h52ziAfClC024x3YzYQB9UuuHs0ergmKEnlhuUPx2EMZeelFPRFED6kM2tjNFw0h4tTPU82ev k0jzQe6m/V3iFOQr0NTmNrdVZG8pspKVOYw6Br7t7Ur9kNaso/5mMlupVCzYCafeWP003u6gI6CmPk0m5LdWdY1XQ+F2WpHR6N+OvSC2JJjhskRms7+0iVRl vddpxGoS1RcLWQdFZQuohRk40h+aC25VdQcOSD+kKHTNcv/e4zjBNTW6mbc6UyKjiD3b/zDiGan5FKTXK+JOmGvqL/QGnvXubkU1Afr1fcPynffeDhr/X+DP hQSfaTcViH/DPoSSPDTfs09bDhuRWa6IMguBtVWRJhIBkVdJNU2WSCkEO+9JUONeFp65nquPRuULRWDFfjZktxL8PEhi9JpQDHEPxLGh0jWvqoQePSAYTtj/ 517k4M1TV2Tf2IMlI5gBCNFLKR2Bs00YNWYe/w== On 20/05/25 16:31, Kees Cook wrote: > 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 Acked-by: Gustavo A. R. Silva Thanks! -Gustavo > --- > 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;