From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 3F10A39B4A5; Sat, 17 Oct 2026 16:33:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792254798; cv=none; b=SRWZcr5gFDhNjeNLS1SUAzaqVz00rjC3nMKZk5F16UdWxCHPO7hjHNw5hfDHzBL/r8gaiYKVLK4oEPvf2/kMqoWvfcm+yejvI4I9D5N0F7z/DKTfSPOIRItNbyhSKBbE9pkVes2CWerDOs2grrbbaI09f4QOyqH3f+y4jJuFt+s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792254798; c=relaxed/simple; bh=fL9wiEk9lyVa84I54PF16WwP6F6mygaXv4fCoHK32Zw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GJND5MAq/xVYoILIT4EZK2THEC8pC/2HT8Gaj3gPM09N4lzRGP9dzld6ppNT9xYsHLb4v7/2sI9B6mPk2ENIlgXIyeTeo3W2814+Qz5gOEk/KjkPF/b7hu4Qb3i6aRjsAW7YHWE+d4hrClQcWJ/hLtDLDrQTCoEx5XET8rslgZ4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=DPoTkvYQ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="DPoTkvYQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8C04D1F000C4; Sat, 17 Oct 2026 16:33:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792254797; bh=T0RBsl/mbkHrLlZjQPK66d1Mo/6nTuVncWIcjP9n/Qo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=DPoTkvYQ1loW93W8q2SMrZ+QNzIQyHe+v/p3g3ty/5ayKEeD4TWKA/wHQlzK2QqhA z/0kPQbesB7nA76JcvGb8CXYLTasYGECYu4+m9RerLwMKlSNqThvC7mqVim7HY+jsi 6QKuFyhJf7TesduGX1EJbeQ1gZbB39jJ/jVsBfZo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Akihiko Odaki , Willem de Bruijn , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.12 558/869] tap: Keep hdr_len in tap_get_user() Date: Sat, 17 Oct 2026 17:56:39 +0200 Message-ID: <20261017160051.386927646@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160036.979869304@linuxfoundation.org> References: <20261017160036.979869304@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Akihiko Odaki [ Upstream commit 74212f20f366db41dd3148b951284ac38ef9bb10 ] hdr_len is repeatedly used so keep it in a local variable. Signed-off-by: Akihiko Odaki Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20250207-tun-v6-6-fb49cf8b103e@daynix.com Signed-off-by: Jakub Kicinski Stable-dep-of: cbb35cbe8db2 ("net: tap: fix wrong transport_header when sending VLAN-tagged frame") Signed-off-by: Sasha Levin --- drivers/net/tap.c | 28 ++++++++++------------------ 1 file changed, 10 insertions(+), 18 deletions(-) diff --git a/drivers/net/tap.c b/drivers/net/tap.c index 018bc2941a967..d5a1ab9b2a37d 100644 --- a/drivers/net/tap.c +++ b/drivers/net/tap.c @@ -645,6 +645,7 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control, int err; struct virtio_net_hdr vnet_hdr = { 0 }; int vnet_hdr_len = 0; + int hdr_len = 0; int copylen = 0; int depth; bool zerocopy = false; @@ -663,13 +664,13 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control, if (!copy_from_iter_full(&vnet_hdr, sizeof(vnet_hdr), from)) goto err; iov_iter_advance(from, vnet_hdr_len - sizeof(vnet_hdr)); - if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && - tap16_to_cpu(q, vnet_hdr.csum_start) + - tap16_to_cpu(q, vnet_hdr.csum_offset) + 2 > - tap16_to_cpu(q, vnet_hdr.hdr_len)) - vnet_hdr.hdr_len = cpu_to_tap16(q, - tap16_to_cpu(q, vnet_hdr.csum_start) + - tap16_to_cpu(q, vnet_hdr.csum_offset) + 2); + hdr_len = tap16_to_cpu(q, vnet_hdr.hdr_len); + if (vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { + hdr_len = max(tap16_to_cpu(q, vnet_hdr.csum_start) + + tap16_to_cpu(q, vnet_hdr.csum_offset) + 2, + hdr_len); + vnet_hdr.hdr_len = cpu_to_tap16(q, hdr_len); + } err = -EINVAL; if (tap16_to_cpu(q, vnet_hdr.hdr_len) > len) goto err; @@ -682,12 +683,7 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control, if (msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) { struct iov_iter i; - copylen = vnet_hdr.hdr_len ? - tap16_to_cpu(q, vnet_hdr.hdr_len) : GOODCOPY_LEN; - if (copylen > good_linear) - copylen = good_linear; - else if (copylen < ETH_HLEN) - copylen = ETH_HLEN; + copylen = clamp(hdr_len ?: GOODCOPY_LEN, ETH_HLEN, good_linear); linear = copylen; i = *from; iov_iter_advance(&i, copylen); @@ -697,11 +693,7 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control, if (!zerocopy) { copylen = len; - linear = tap16_to_cpu(q, vnet_hdr.hdr_len); - if (linear > good_linear) - linear = good_linear; - else if (linear < ETH_HLEN) - linear = ETH_HLEN; + linear = clamp(hdr_len, ETH_HLEN, good_linear); } skb = tap_alloc_skb(&q->sk, TAP_RESERVE, copylen, -- 2.53.0