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 1D3BD471436; Fri, 7 Aug 2026 15:44:41 +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=1786117482; cv=none; b=Xz3Vk8SXJyAe4/yby0/amXnnBZx9YPDHgyYMIRITtDT08X9XT+9ffkywymhnL0Ib9Z5LKlKjbGB1Wq9PNQNlMdwiEYB6/Wy0bwudYk8f+m13jvk8acSYDWv0Q83Sb/hEWbQgmPycuPvQUo50HnpZEFyBUHY7ElIccehowPsoAZU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786117482; c=relaxed/simple; bh=kSMkEU6wqevhvjxFWgieFYJrLDMdNhVpX8sVn0gTP6Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TOphkrKecmugPCf+fzdzf1giI9JP5ul2jVztxVIamrIayadm7b5V0bQ35ZsXM+/FipZ7cH68lkc7oppjRmcTUYW5S9vzcRP19qDVQivO65InykEp8wPIPnF/qFJNOCRRRqGBAH9L2A8gAhpV+dGUTJ1pkX732h1FIChWELAhCyw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=TVoN9XIW; 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="TVoN9XIW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 684EF1F00A3E; Fri, 7 Aug 2026 15:44:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786117481; bh=QiMlpbipj+4dCqoUYBIdksBsVfiIjpf8IrDkVBjIepc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=TVoN9XIWdq2DmlsXOifXAjo0n90AsCkAiglXNyRXrdOXkTuVIlnAD3wZZqIigg2Vm OnSyLxcpsNy9BSf5Zvipdg7ArHCVjen1k41/x0lL4CMzbUKYjfOsdRs2Zqs22gN00m qV2C27R8X8xxukUayqlXhtxtIfKBb2vcl7go6spI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Jakub Kicinski Subject: [PATCH 7.1 307/438] vxlan: unclone skb head before modifying eth header in route_shortcircuit() Date: Fri, 7 Aug 2026 16:38:23 +0200 Message-ID: <20260807143434.517251113@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260807143428.008222056@linuxfoundation.org> References: <20260807143428.008222056@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 7.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet commit 760d36e737f2b3867762f42af36c663f55babcc4 upstream. When route_shortcircuit() performs L3 short-circuit routing, it modifies the Ethernet header of the skb in-place: memcpy(eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest, dev->addr_len); memcpy(eth_hdr(skb)->h_dest, n->ha, dev->addr_len); If the incoming skb is cloned (for example by packet sockets, tcpdump, or dev_queue_xmit), modifying the Ethernet header without uncloning can corrupt the packet header for other readers holding a reference to the cloned skb. Ensure the skb header is writable and unshared by calling skb_cow_head(skb, 0) prior to updating the Ethernet header. If skb_cow_head() fails, abort short-circuiting and return false to allow standard packet processing fallback. Fixes: e4f67addf158 ("add DOVE extensions for VXLAN") Cc: stable@vger.kernel.org Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260723144249.759100-3-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- drivers/net/vxlan/vxlan_core.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/net/vxlan/vxlan_core.c +++ b/drivers/net/vxlan/vxlan_core.c @@ -2164,6 +2164,10 @@ static bool route_shortcircuit(struct ne diff = !ether_addr_equal(eth_hdr(skb)->h_dest, n->ha); if (diff) { + if (skb_cow_head(skb, 0)) { + neigh_release(n); + return false; + } memcpy(eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest, dev->addr_len); memcpy(eth_hdr(skb)->h_dest, n->ha, dev->addr_len);