From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj2-f13.google.com (mail-pj2-f13.google.com [74.125.227.141]) (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 DE0DE38D3ED for ; Sat, 19 Sep 2026 21:36:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.227.141 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789853806; cv=none; b=EGp0LGuCcwy02EqYFG3PxMlVQRK7TwRtjGeRI+Uq0bM+w9Au90E9+1GSJQVMBkXKYWDHVvApVVmBsavGLK/gsC6UZktX5s/NWaPnKnopLU4bl2esPWhOOfHMBHst8XfOVXxMUSd+1M7biLEWWfWDABxB+P4PaE9AiatjH5GkZLQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789853806; c=relaxed/simple; bh=JzVmTdq3Q7Iq2TH3qdkMpYUeDuu0LJqEMcRNJCqtMFQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=dvK3ct2PMN1RJUwfHfGn/xzfixn41bVML5snysahrn2RBbk+MnKJAaTDGvrjlD/27Sv46851R2/2poRrCXHSA99NCCVUQEfc2BfVUha57vdzcTOJ3/matNFSd+txoPnn3VUDQiKP9aT/GkBMP/4+b4xHDJ+R09Ha0F5XPMAD5Qg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=aSkGLWk9; arc=none smtp.client-ip=74.125.227.141 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="aSkGLWk9" Received: by mail-pj2-f13.google.com with SMTP id d9443c01a7336-2d747f066d8so6558685ad.1 for ; Sat, 19 Sep 2026 14:36:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1789853799; x=1790458599; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=lRiAGPXf/bDE6W3u+fknYqS6n6eKeAu3CAyIqYAtulg=; b=aSkGLWk93vpkFmPKP4eU5BGpqsr026Sz1L4HmhdQCM/eM4pQD+q5xWUZ5X+VGDsdHx fk+sXPrMbzKOHgzjUsiOnNeEBwWcJZ9zxo7W+jxoYwWlcvU/kU6HEOqPr0IIfdSlZsJy HlROJgXVKQTEzh+k3+By4yQ6/qFC9To3ehNs6o7firnZZhnWBUiUCCM2FF9Iw+GCY3Ro vgCYu/Vm/S/4DZvG5FtQwtmex/w7xK2EsoJ8NuWnO6dzjrBCfM1oIGly2q7cTdKvSdkU gKSGX780UkR2b5GR9xXuJJRrRCMTnd+Fey/bJOmO2pGjLdc4yt5OECDxJJFv4w/Wf3Lx QEVA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1789853799; x=1790458599; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=lRiAGPXf/bDE6W3u+fknYqS6n6eKeAu3CAyIqYAtulg=; b=sX2LcKkYXThIRIsoPQXT3rlIgRY0pev8uAFWvlqaDU206zrcj8QTVP31rrab0RvDTa xQVVWDTqjYVfDyz90hiobX0Hf82uNAv5t5euatHyamFTcYxHCGIcOuQWtC1TGlts9ait OUItxeep6yfZ/8rZluDZIEJ61wKd4AunS15clsHHYyKlLKUagOFXJwKbw39rmBI7WIzX l9r3/TGsdDvQStEFtsEEjKNu4r4qiwVZIRarLwLXwy6BcvbFFiId2W47/4ys/49td05F grJppq2hqw8QzxorUC4f1DN5PE8+tC2J3a4LcH5yRFArL0gsiXM3s/ApPxlN3m+iWZJz J9nw== X-Forwarded-Encrypted: i=1; AKwUvBzMUlPOiFKZKJo142RZUDqBa/bXrCxVoBPvOZQp4aFgFb+ZQpz7NE2bX/2bcKAnKYxy8ql7SEpepZn6f7U=@vger.kernel.org X-Gm-Message-State: AFuF++kQqtr8N//9RwgIj/aOhQeBr4nVGspq+5SnoqF5NuYrVMmqLDZO 9HMlw/VB4qNZZQjsEB3k9XugOWWVjdtlIRPffkvm8W3Wfml2HY83eElC X-Gm-Gg: AYBFou3IYgYZlOdKRnJc1lMVyHG08IgMTZZddCd8jt0t9nvhsDcI7ya9/jm1fJPNadP 8AA2clmYGGng6lHxVrNoCDsbOeJXQM3uSlM1h3h8UFoB/SUpD3+mpOFUCGlX9bt9UuaR1LjJyek obaf6iXxvoAqpK6UquGNaGW8tDkA7ksgVkqp2+EU33DVTZO3d93z1hXtD08Um7W8ou0Br06adI4 4QOTXVdMMcaygP6YVJK51wMJvrvZYCQ7eZxTlpy/AzayPlPfWfT3tD6bBcEDzWYPBPIDkS9jW43 05RrHZVWyV88w9ZCX01Av5bVcv9e7Ue4mNgtlYeP2fWF/GBW7G+Sq7vOyR98t3A3nflSsk8kcYx tdm8vTwz23nLBDgex4TRIL4Y3/jorfDjJOPDU13U/y/yH70/3SOMu0ny/ftfOR5hITmir6Vq85r 2+Jtc5LfWwl+p3OzAKktXo03E8xpHcfneiVVve25BT0dI++3QKhfhyuQXHOAy43hBbcCXLZCE10 f1hlpLWr5MkUNsgJO2BZ+VXQVGvIR337+OIVjNvguEMnqBumn/mZ9Qfsemmt2Ydv3mcydv7Yatn /eCaq5ZrIg== X-Received: by 2002:a17:902:e946:b0:2dd:c100:2516 with SMTP id d9443c01a7336-2ddc1002577mr36107355ad.31.1789853799128; Sat, 19 Sep 2026 14:36:39 -0700 (PDT) Received: from phui-2.c.googlers.com.com (78.123.83.34.bc.googleusercontent.com. [34.83.123.78]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2ddc1803813sm12928885ad.82.2026.09.19.14.36.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 19 Sep 2026 14:36:38 -0700 (PDT) From: Hui Peng To: alex.aring@gmail.com, marcel@holtmann.org, luiz.dentz@gmail.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com Cc: linux-bluetooth@vger.kernel.org, linux-wpan@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] 6lowpan: add missing pskb_may_pull() checks in IPHC and NHC compression Date: Sat, 19 Sep 2026 21:36:38 +0000 Message-ID: <20260919213638.3314763-1-benquike@gmail.com> X-Mailer: git-send-email 2.55.0.1082.g2b9226bbc0-goog Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit In `lowpan_header_compress()` (`net/6lowpan/iphc.c`) and `lowpan_nhc_do_compression()` (`net/6lowpan/nhc.c`), the transmit compression path reads `ipv6_hdr(skb)` (`sizeof(struct ipv6hdr)`) and the next-header transport header (`nhc->nexthdrlen`, e.g., `sizeof(struct udphdr)`), and then calls `skb_pull(skb, nhc->nexthdrlen)` and `skb_pull(skb, sizeof(struct ipv6hdr))` without verifying via `pskb_may_pull()` that those headers are present in the linear data area of `skb`. When a short or non-linear `ETH_P_IPV6` frame is transmitted over a 6LoWPAN interface (for example, via `AF_PACKET`), `lowpan_header_compress()` and `lowpan_nhc_do_compression()` read past `skb_tail_pointer(skb)` and trigger `BUG_ON(skb->len < skb->data_len)` in `skb_pull()`. Check `pskb_may_pull(skb, sizeof(struct ipv6hdr))` in `lowpan_header_compress()` and `pskb_may_pull(skb, sizeof(struct ipv6hdr) + nhc->nexthdrlen)` in `lowpan_nhc_do_compression()`. Fixes: 8df8c56a5abc ("6lowpan: Moving generic compression code into 6lowpan_iphc.c") Fixes: 92aa7c65d295 ("6lowpan: add generic nhc layer interface") Assisted-by: LLM Signed-off-by: Hui Peng --- net/6lowpan/iphc.c | 3 +++ net/6lowpan/nhc.c | 5 +++++ 2 files changed, 8 insertions(+) diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c index 37eaff3f7b69..b2be70036ee7 100644 --- a/net/6lowpan/iphc.c +++ b/net/6lowpan/iphc.c @@ -1140,6 +1140,9 @@ int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev, if (skb->protocol != htons(ETH_P_IPV6)) return -EINVAL; + if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) + return -EINVAL; + hdr = ipv6_hdr(skb); hc_ptr = head + 2; diff --git a/net/6lowpan/nhc.c b/net/6lowpan/nhc.c index a4dde85664f2..a9bf340c090a 100644 --- a/net/6lowpan/nhc.c +++ b/net/6lowpan/nhc.c @@ -79,6 +79,11 @@ int lowpan_nhc_do_compression(struct sk_buff *skb, const struct ipv6hdr *hdr, goto out; } + if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + nhc->nexthdrlen)) { + ret = -EINVAL; + goto out; + } + /* In the case of RAW sockets the transport header is not set by * the ip6 stack so we must set it ourselves */ -- 2.55.0.1082.g2b9226bbc0-goog