From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-dl1-f54.google.com (mail-dl1-f54.google.com [74.125.82.54]) (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 97794370D6E for ; Thu, 23 Apr 2026 15:58:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.54 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776959912; cv=none; b=oN8Kgkehsevnzci7T71APtua86fTYLLKByAdXaFwphH866nipR2LCUY6ZDq7I7u+5bF9WG3RN52S+rVxb82KkIPY9SybF6zROX5EmLKaFCCEVhWukuwx4xF3IVkKDV0ZyLKGhnAJEiKvtB2p+aOmb5eaOlc/fzQkudwT9WG09zE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776959912; c=relaxed/simple; bh=AR1tyKWtZeVWgHbhDNYPsmlXWN6qh8CcT0QwnDPOjPQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=CvYDG9+m7f6qKvAwsHjwixRpIQ9h4ibTbspbTxATQ6hnDAUKoIaqunNqwyvg6PP8Nbtj5skK8ggpVwLC/XlbKHLm8153Wt+u+PB2uqWyWUUEAkEp3NGoPLe6VW4pLNM56Ro8Y0X0EndJeCdrSbc6LDXmVP0Q5cuuAkQOCH1HJfU= 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=Qsnih13R; arc=none smtp.client-ip=74.125.82.54 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="Qsnih13R" Received: by mail-dl1-f54.google.com with SMTP id a92af1059eb24-12c8c9c4cd8so2359165c88.0 for ; Thu, 23 Apr 2026 08:58:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1776959910; x=1777564710; 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; bh=lw0eJ0HrBtMu/NfaNFWlMNPqLWJs3EMGa99HbAzS2UY=; b=Qsnih13RTYuif+n7XrE3Jslgh/QElLXemxDoJNesFb96kT9AylGiiHX0xD5JnlNsL/ 9bSD6pH6nvaXkTKsvPQWDbjRtWi6xWpvWj/w1YbyE35r6rizeuFPOO9Z8Dwn1K1V58TC nmoukm9yhFrSQiVEK9XmHxe/B+mK79N6TVkL+H+d+dz4L2XuHfiuph+SgjAqtoJitYmI JvF/nVeMURj8RE9QXpJ7HvjogC+ZYVSd96Ln/r9wHy7S66tL9l54JD+j8CKUyRyrMVSf 257IScf276DBNFDDQwzRdI+AUXvAAnn49Viw3rvImBj3Psdo4+hscmIaWMoqBDh2/Lff 7LCA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776959910; x=1777564710; 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; bh=lw0eJ0HrBtMu/NfaNFWlMNPqLWJs3EMGa99HbAzS2UY=; b=Yd+ySzf1BTGs1gbdWlt3MViBpsSl9IS28JQa8Q8kjZDx4Vcp/9Yh1ht7svGkkq6bxm x/JKmftJJ7xZASzoaImtLmwMFMATH8uGLy+f38drpkLdi6A6Sh2Kf4YY14zmbEJzqreL 9ddiP4/cYd+WEcL1S6fuNLgnZnLtEKkm4Oa9NlH5FpQw4ikUoR5svddg8YzT6hWQNwuh JEBkKGzDk6bTkjmz9lePHRqDuozphicLaAQVeJdNy+H5/5FeG62T5n8YSVRNqRyMKVRu Li9Yuajr3IZxFy+qNJP2IY/mv4IqNe9MUCQK6yv88o9RwKrH8ZVk800WOQV3xJ/+E1KG XMrA== X-Forwarded-Encrypted: i=1; AFNElJ+F5viiTby53A1cn7cUluI/SlryFA29P9/RVS6ZIK0cnCtMdQrF2FdMn3lCo360v9MJtYMDDQI=@vger.kernel.org X-Gm-Message-State: AOJu0Yxee/GUmwmVpoBCUkdgGEPHaLOScDacEKOXruBqJFiRN6Xo0KM+ ixQYwDCfSWELwT2mk6sAdEyR5YYGSFs2Ks0UoTyDFW7psPJ1zyykhXxm X-Gm-Gg: AeBDies1IfuuFslug9JNpimm8q1HyxJrQO6zUG50Funskz7Pb0UTz8fC6TELZ4oHqim BCwzn0t8T6++aZkixZcQsGBDwRqj+FZ7xAEmiAfEnS8DupDcWsQxpk5ZoetBMsGYtzOjBD4SMKq wegtw2YQwGKa6Kv5qEOE+rjbL7a5zz4aknxu1ip6emvnQn49tNmSgRL/UqUDEjDBRsbjAQ0VpWZ ncvIsAAL5OJwP7XsKswAiS2IhBAqu8AHSh7hqlv55clY5U9vLx712/vwSY0moXdpcbPs54t4udQ iJQbDdVTxTjKwom+QR4dZe6ACZGXXDgmN8qRikw8oibcyN1inN+gTVbTej6qp0Pk5DWRLB86gx+ mu4nfOvmWAumMvSjYOec/P/e4amSdm0wWWE4VIjkArt9jYAZHBA3XTneCar9FUq0VXGuLEqP1jz 41lSGD1Gd3qEnHUsPdV5Xq6EidKc62huVS3fQqesp7TqD9XjBotM/Fv/SQjutfb1iKk2UD90iwM AmLBJH2j0U0DY8RIMA1Qch/XLom7zk= X-Received: by 2002:a05:7022:b8d:b0:119:e569:f86d with SMTP id a92af1059eb24-12c73b26cc5mr12096979c88.10.1776959909284; Thu, 23 Apr 2026 08:58:29 -0700 (PDT) Received: from efaec68ba852.tailc0aff1.ts.net ([206.206.192.132]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-12c74a20eb5sm35656689c88.14.2026.04.23.08.58.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Apr 2026 08:58:28 -0700 (PDT) From: Weiming Shi To: Martin KaFai Lau , Daniel Borkmann , Alexei Starovoitov , Andrii Nakryiko , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: John Fastabend , Stanislav Fomichev , Eduard Zingerman , Song Liu , Yonghong Song , KP Singh , Hao Luo , Jiri Olsa , Simon Horman , bpf@vger.kernel.org, netdev@vger.kernel.org, Xiang Mei , Weiming Shi Subject: [PATCH bpf] bpf, sockmap: Fix wrong rsge offset in bpf_msg_push_data() Date: Thu, 23 Apr 2026 08:58:08 -0700 Message-ID: <20260423155807.1245644-2-bestswngs@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When bpf_msg_push_data() splits a scatterlist element into head and tail, the tail's page offset is advanced by `start` (absolute message byte offset) instead of `start - offset` (byte position within the element). This makes rsge.offset overshoot by `offset` bytes, pointing to the wrong location within the page or beyond its boundary. Consumers of the corrupted entry either silently read wrong data or trigger an out-of-bounds access. BUG: KASAN: slab-use-after-free in bpf_msg_pull_data (net/core/filter.c:2728) Read of size 32752 at addr ffff8881042f0010 by task poc/130 Call Trace: __asan_memcpy (mm/kasan/shadow.c:105) bpf_msg_pull_data (net/core/filter.c:2728) bpf_prog_run_pin_on_cpu (include/linux/bpf.h:1402) sk_psock_msg_verdict (net/core/skmsg.c:934) tcp_bpf_send_verdict (net/ipv4/tcp_bpf.c:421) sock_sendmsg_nosec (net/socket.c:727) Fixes: 6fff607e2f14 ("bpf: sk_msg program helper bpf_msg_push_data") Reported-by: Xiang Mei Signed-off-by: Weiming Shi --- net/core/filter.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/filter.c b/net/core/filter.c index 3e56b567bd18..f12fbc49bc03 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2865,7 +2865,7 @@ BPF_CALL_4(bpf_msg_push_data, struct sk_msg *, msg, u32, start, psge->length = start - offset; rsge.length -= psge->length; - rsge.offset += start; + rsge.offset += start - offset; sk_msg_iter_var_next(i); sg_unmark_end(psge); -- 2.43.0