From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-174.mta0.migadu.com (out-174.mta0.migadu.com [91.218.175.174]) (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 0C93323909F for ; Mon, 15 Jun 2026 02:20:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.174 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781490037; cv=none; b=Jd4Wyph53PetJy3y1FHlx2E0FdsgwY3V/o/66nLgN2zASI8/7RKhVSPkWsIOrOIQxWRdQ0inYcneMduuHQL9eEUim4BDuspuihS9eroghEnNeQdTB/0NRsbAf7+dMNYt2xuqWjLF3wKNYNjMb15xeyP2nDo37gldJ2eYzviTDS0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781490037; c=relaxed/simple; bh=uwybBJJJS67trTAs68fbSohQDQntqGwBcy6+LwRg8z8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RHfENNyge1fCGyovJnffp+2dgZXP7Ym54qsYe9GPhhsJf8cQCJUDX/M9FlCW14X/M/pdQh9tIQNdBXXytSMYYZvRWazp6bPASCA3+cQaZp2E4IMsD13aEJ3d7TrBqy1y+xk3t/v+4w2bSBhcV6vJW/LKYx4/0gjpxGh1FeFvvQI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=doNJOq35; arc=none smtp.client-ip=91.218.175.174 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="doNJOq35" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1781490034; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+4wRjg/VBX6jMXCUra998SaBMXKUnzqQsMOSm/pi5ks=; b=doNJOq35ajZRo3gd0o1g5q3TQMFcPpqOGyUjRBwVJQr4KMzA05DWEPslwIOCchnkqn4NL9 g2TGWR21ghGOssJyfT6mZZyv6HHYTYaTJqjQE23q44Q6GfvoG2CBTsBjJFh32HR1nfbcKF WCvEbt5w8hsNTaWoejycPOWsTJsDDig= From: Jiayuan Chen To: bpf@vger.kernel.org Cc: jiayuan.chen@linux.dev Subject: [PATCH bpf-next v4 1/6] bpf, sockmap: reject overflowing copy + len in bpf_msg_push_data() Date: Mon, 15 Jun 2026 10:19:54 +0800 Message-ID: <20260615021959.140010-2-jiayuan.chen@linux.dev> In-Reply-To: <20260615021959.140010-1-jiayuan.chen@linux.dev> References: <20260615021959.140010-1-jiayuan.chen@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT From: Weiming Shi When the scatterlist ring is full or nearly full, bpf_msg_push_data() enters a copy fallback path and computes copy + len for the page allocation size. Since len comes from BPF with arg3_type = ARG_ANYTHING and both are u32, a crafted len can wrap the sum to a small value, causing an undersized allocation followed by an out-of-bounds memcpy. BUG: unable to handle page fault for address: ffffed104089a402 Oops: Oops: 0000 [#1] SMP KASAN NOPTI Call Trace: __asan_memcpy (mm/kasan/shadow.c:105) bpf_msg_push_data (net/core/filter.c:2852 net/core/filter.c:2788) bpf_prog_9ed8b5711920a7d7+0x2e/0x36 sk_psock_msg_verdict (net/core/skmsg.c:934) tcp_bpf_sendmsg (net/ipv4/tcp_bpf.c:421 net/ipv4/tcp_bpf.c:584) __sys_sendto (net/socket.c:2206) do_syscall_64 (arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) Add an overflow check before the allocation. Link: https://lore.kernel.org/all/20260424155913.A19FDC19425@smtp.kernel.org Fixes: 6fff607e2f14 ("bpf: sk_msg program helper bpf_msg_push_data") Tested-by: Xiang Mei Tested-by: Xinyu Ma Reviewed-by: Jiayuan Chen Reviewed-by: Emil Tsalapatis Reviewed-by: Kuniyuki Iwashima Signed-off-by: Weiming Shi Signed-off-by: Jiayuan Chen --- net/core/filter.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/core/filter.c b/net/core/filter.c index 9590877b0714f..3c8f1cedb217f 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2829,6 +2829,9 @@ BPF_CALL_4(bpf_msg_push_data, struct sk_msg *, msg, u32, start, if (!space || (space == 1 && start != offset)) copy = msg->sg.data[i].length; + if (unlikely(copy + len < copy)) + return -EINVAL; + page = alloc_pages(__GFP_NOWARN | GFP_ATOMIC | __GFP_COMP, get_order(copy + len)); if (unlikely(!page)) -- 2.43.0