From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qt1-f202.google.com (mail-qt1-f202.google.com [209.85.160.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8B125333426 for ; Fri, 3 Apr 2026 22:15:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775254548; cv=none; b=g6H/20EYRIaE1ogicujiKuX0ZJ+YOhyS8QM99/Ob8cHY78HRa3MSvsvtOZL44AwQI4FPHqj4R0sFNAW5CUejYoaeBGnVKPBFnVY80Z0O662PvZdGIHNGV6IbHsZyzHSZLLsl369LfgSFXLA3Nk3VCUOHhILv2s4fD+A/JMZs6vk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775254548; c=relaxed/simple; bh=9yVrLQtKK+yaEcRxTc+wkj5nY8yqp/9Eywt/Xe8iKgk=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Vikc8o70o8IA/enXEOuS8Dp2ysU7oMKhpEw+a6TK44x6oDbKi3UdZy42gQ9yGUdkbksK1ZaaVmq7aj8lzBBCjDSjbE/14UKSkmJmdT8lzIlD44nB1XEDVPQJ8TPlhBntFVnPP5KxyMKEwyrtgEmKtnNRijPvPrLmewbxX456i7Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=FSdwMPhb; arc=none smtp.client-ip=209.85.160.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="FSdwMPhb" Received: by mail-qt1-f202.google.com with SMTP id d75a77b69052e-50b4b81c632so42912891cf.1 for ; Fri, 03 Apr 2026 15:15:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1775254546; x=1775859346; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=+qvL/NUINTIX6ZrUZ8Spdes0hjtaxFpUVM8RixIYSfQ=; b=FSdwMPhbAr4zx7eC5lVZnJvQ+VNKkdkZNeL+cZIo9IQnOt0gkLhB4SS6uPSj8EeAJz 9x9XcmPGj7mETsaBHGCnvSdOMAYd9JIoncW7TYFQ1onUo894T//gxJP8h66QvP7RECUR 9BNk2j7VeBv/aD9KvegBeovJfK90caoWTLAxJY+crZkLF6hwUvo6Pi6sOxd72XayaJV7 pCevVAda5arAMzSb7Lxdh58rSauTQNJ8PK3fwLsSc6i8gRzdBm1uQK6/VTND3v9nF+0f ELfge/0fzQ1L9+aZk7m0w5uX2rGeYS57kCL5RmkEhfv6kwEpAGhCCp1XXmtSLC3pXOEY fSdQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1775254546; x=1775859346; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=+qvL/NUINTIX6ZrUZ8Spdes0hjtaxFpUVM8RixIYSfQ=; b=naT8CvEf0N/Kehw3nXBRE5OcH5ombLb5aFavi0pCHjL6x926Vr7/VgycLJFcSagS3l qJ1l8wYHCjvoUziljWEa0J905m7ay8ckqVEkU+YKd971PBxlcSpG2xWXONrl7m4eQqSL IgDGP/YRgqbgY7K2uCoJTPXjQCdI0HDVtBiEi31DpyS5ew9wSXbH+v2AjKrrfom0vchn z6o1rnaD+Q7EWymGLeAR9IEPHXNzEfPUl2QFD0+3nzjfy4QJFXBQghbMalvBvki4KomH 6wAz7qaW2UFE1YRiNZloPbiggRpdYQgtaJT6X4NzOguxQjyK95g0Vt5ILzTHhr6Tcqot u4iw== X-Forwarded-Encrypted: i=1; AJvYcCWsFrdvpHuZi3eeRaHhim7B6Agpmp2rUz+1Ud25gpYcdEjoqCBaiq0RW737b36JFfgw3N0apco=@vger.kernel.org X-Gm-Message-State: AOJu0YwkE/qmTrIelXUTEZB3sAX+9VJlFfDW3/FKu7PgUa2h6W4vyjLE fmgmokWosU1S8VF57jS0wXkWm2x5PznSgh0z9EHUv+rCMbGfRrgHM8i/1ZdhmNwxIhFZS9KUMvd hyvRdCw9YI9QAtw== X-Received: from qtqx7.prod.google.com ([2002:ac8:4a07:0:b0:50b:8bf1:9fc0]) (user=edumazet job=prod-delivery.src-stubby-dispatcher) by 2002:a05:622a:738f:b0:50b:47b2:5591 with SMTP id d75a77b69052e-50d62a8d37emr55692711cf.42.1775254546173; Fri, 03 Apr 2026 15:15:46 -0700 (PDT) Date: Fri, 3 Apr 2026 22:15:40 +0000 In-Reply-To: <20260403221540.3297753-1-edumazet@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260403221540.3297753-1-edumazet@google.com> X-Mailer: git-send-email 2.53.0.1213.gd9a14994de-goog Message-ID: <20260403221540.3297753-3-edumazet@google.com> Subject: [PATCH net-next 2/2] net: pull headers in qdisc_pkt_len_segs_init() From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: Simon Horman , Andrew Lunn , Joe Damato , netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet Content-Type: text/plain; charset="UTF-8" Most ndo_start_xmit() methods expects headers of gso packets to be already in skb->head. net/core/tso.c users are particularly at risk, because tso_build_hdr() does a memcpy(hdr, skb->data, hdr_len); qdisc_pkt_len_segs_init() already does a dissection of gso packets. Use pskb_may_pull() instead of skb_header_pointer() to make sure drivers do not have to reimplement this. Some malicious packets could be fed, detect them so that we can drop them sooner with a new SKB_DROP_REASON_SKB_BAD_GSO drop_reason. Fixes: e876f208af18 ("net: Add a software TSO helper API") Signed-off-by: Eric Dumazet --- include/net/dropreason-core.h | 3 +++ net/core/dev.c | 51 +++++++++++++++++++++-------------- 2 files changed, 34 insertions(+), 20 deletions(-) diff --git a/include/net/dropreason-core.h b/include/net/dropreason-core.h index de61dd5dbfd9dc7d91d22d79a510d42fb69eb60a..51855de5d20819bff950e1c5846a6a4f3f8a3b95 100644 --- a/include/net/dropreason-core.h +++ b/include/net/dropreason-core.h @@ -74,6 +74,7 @@ FN(UNHANDLED_PROTO) \ FN(SKB_CSUM) \ FN(SKB_GSO_SEG) \ + FN(SKB_BAD_GSO) \ FN(SKB_UCOPY_FAULT) \ FN(DEV_HDR) \ FN(DEV_READY) \ @@ -392,6 +393,8 @@ enum skb_drop_reason { SKB_DROP_REASON_SKB_CSUM, /** @SKB_DROP_REASON_SKB_GSO_SEG: gso segmentation error */ SKB_DROP_REASON_SKB_GSO_SEG, + /** @SKB_DROP_REASON_SKB_BAD_GSO: malicious gso packet. */ + SKB_DROP_REASON_SKB_BAD_GSO, /** * @SKB_DROP_REASON_SKB_UCOPY_FAULT: failed to copy data from user space, * e.g., via zerocopy_sg_from_iter() or skb_orphan_frags_rx() diff --git a/net/core/dev.c b/net/core/dev.c index 3eb2f50f516564c6a6465c19a6d802c136e0ddde..5a31f9d2128c28d07d2dd5d58baa2374d469ed82 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4101,16 +4101,16 @@ struct sk_buff *validate_xmit_skb_list(struct sk_buff *skb, struct net_device *d } EXPORT_SYMBOL_GPL(validate_xmit_skb_list); -static void qdisc_pkt_len_segs_init(struct sk_buff *skb) +static enum skb_drop_reason qdisc_pkt_len_segs_init(struct sk_buff *skb) { struct skb_shared_info *shinfo = skb_shinfo(skb); - unsigned int hdr_len; + unsigned int hdr_len, tlen; u16 gso_segs; qdisc_skb_cb(skb)->pkt_len = skb->len; if (!shinfo->gso_size) { qdisc_skb_cb(skb)->pkt_segs = 1; - return; + return SKB_NOT_DROPPED_YET; } qdisc_skb_cb(skb)->pkt_segs = gso_segs = shinfo->gso_segs; @@ -4118,43 +4118,49 @@ static void qdisc_pkt_len_segs_init(struct sk_buff *skb) /* To get more precise estimation of bytes sent on wire, * we add to pkt_len the headers size of all segments */ - if (unlikely(!skb_transport_header_was_set(skb))) - return; /* mac layer + network layer */ - if (!skb->encapsulation) + if (!skb->encapsulation) { + if (unlikely(!skb_transport_header_was_set(skb))) + return SKB_NOT_DROPPED_YET; hdr_len = skb_transport_offset(skb); - else + } else { hdr_len = skb_inner_transport_offset(skb); - + } /* + transport layer */ if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))) { const struct tcphdr *th; - struct tcphdr _tcphdr; - th = skb_header_pointer(skb, hdr_len, - sizeof(_tcphdr), &_tcphdr); - if (likely(th)) - hdr_len += __tcp_hdrlen(th); - } else if (shinfo->gso_type & SKB_GSO_UDP_L4) { - struct udphdr _udphdr; + if (!pskb_may_pull(skb, hdr_len + sizeof(struct tcphdr))) + return SKB_DROP_REASON_SKB_BAD_GSO; - if (skb_header_pointer(skb, hdr_len, - sizeof(_udphdr), &_udphdr)) - hdr_len += sizeof(struct udphdr); + th = (const struct tcphdr *)(skb->data + hdr_len); + tlen = __tcp_hdrlen(th); + if (tlen < sizeof(*th)) + return SKB_DROP_REASON_SKB_BAD_GSO; + hdr_len += tlen; + if (!pskb_may_pull(skb, hdr_len)) + return SKB_DROP_REASON_SKB_BAD_GSO; + } else if (shinfo->gso_type & SKB_GSO_UDP_L4) { + if (!pskb_may_pull(skb, hdr_len + sizeof(struct udphdr))) + return SKB_DROP_REASON_SKB_BAD_GSO; + hdr_len += sizeof(struct udphdr); } + /* prior pskb_may_pull() might have changed skb->head. */ + shinfo = skb_shinfo(skb); if (unlikely(shinfo->gso_type & SKB_GSO_DODGY)) { int payload = skb->len - hdr_len; /* Malicious packet. */ if (payload <= 0) - return; + return SKB_DROP_REASON_SKB_BAD_GSO; gso_segs = DIV_ROUND_UP(payload, shinfo->gso_size); shinfo->gso_segs = gso_segs; qdisc_skb_cb(skb)->pkt_segs = gso_segs; } qdisc_skb_cb(skb)->pkt_len += (gso_segs - 1) * hdr_len; + return SKB_NOT_DROPPED_YET; } static int dev_qdisc_enqueue(struct sk_buff *skb, struct Qdisc *q, @@ -4771,6 +4777,12 @@ int __dev_queue_xmit(struct sk_buff *skb, struct net_device *sb_dev) (SKBTX_SCHED_TSTAMP | SKBTX_BPF))) __skb_tstamp_tx(skb, NULL, NULL, skb->sk, SCM_TSTAMP_SCHED); + reason = qdisc_pkt_len_segs_init(skb); + if (unlikely(reason)) { + dev_core_stats_tx_dropped_inc(dev); + kfree_skb_reason(skb, reason); + return -EINVAL; + } /* Disable soft irqs for various locks below. Also * stops preemption for RCU. */ @@ -4778,7 +4790,6 @@ int __dev_queue_xmit(struct sk_buff *skb, struct net_device *sb_dev) skb_update_prio(skb); - qdisc_pkt_len_segs_init(skb); tcx_set_ingress(skb, false); #ifdef CONFIG_NET_EGRESS if (static_branch_unlikely(&egress_needed_key)) { -- 2.53.0.1213.gd9a14994de-goog