From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from r3-18.sinamail.sina.com.cn (r3-18.sinamail.sina.com.cn [202.108.3.18]) (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 9AC74242D78 for ; Thu, 21 Aug 2025 04:04:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=202.108.3.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755749056; cv=none; b=E9v7rv49plzCCjw2nkfqukEeKqma7XVktscgfqYK43cA2LsO6x4SB2XYyuhfT2sDHcXMW0gCCHOIlpnF+9uJnZ/rikJtBEZ+xDOE1fk4Lpsl2dfS1ggg5CbNdcGT1n15T1p60MxwHpQ6djYwbBufNvWFoXT599C0nj9p4NXPVnE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755749056; c=relaxed/simple; bh=zBQRPfsVS5B3BNl2UHRe10vG+whiglbv4Ci7X7F+878=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ghciXY2dWbU2yiBS1wsx5XFLKKLI1vShQ9Zgqehhq6WaPEQz48IPCb4TnYHnv6cqEIZZKrC0/971DnCN8dR9/3YgWALZlgnaFYQbJ2m//OBptB6BnL3fDyU/qR++HWtRXUK5HnL9KAlRd4z8afhPUs6oMYi/LRJc5fAjvrYVuAs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sina.com; spf=pass smtp.mailfrom=sina.com; dkim=pass (1024-bit key) header.d=sina.com header.i=@sina.com header.b=bUsKTurX; arc=none smtp.client-ip=202.108.3.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sina.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sina.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=sina.com header.i=@sina.com header.b="bUsKTurX" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sina.com; s=201208; t=1755749050; bh=4CGIDFXTccjUGO8hGRMDT2IYWwaKky6JequXto2IdCA=; h=From:Subject:Date:Message-ID; b=bUsKTurX4pWsT96cK3tm/vP3uuc6VqUbZBi3nyM7d4KSUbXoG9N2/DrvytVddK11i oPSNOBclWssvBd5FCZyYmYCiaqwSV8KZiVVoL1cYl8mZHr5NdWO48bVtNqJ18dzoab mTCGS6B2HxDGxNRB04OMH0AsvD4XQwpugDUZCwKo= X-SMAIL-HELO: localhost.localdomain Received: from unknown (HELO localhost.localdomain)([114.249.58.236]) by sina.com (10.54.253.32) with ESMTP id 68A69AB00000141E; Thu, 21 Aug 2025 12:04:02 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com Authentication-Results: sina.com; spf=none smtp.mailfrom=hdanton@sina.com; dkim=none header.i=none; dmarc=none action=none header.from=hdanton@sina.com X-SMAIL-MID: 1001474456813 X-SMAIL-UIID: 6A2E0F9D7D6644B0A3967CE276EC1BC9-20250821-120402-1 From: Hillf Danton To: syzbot Cc: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [atm?] general protection fault in atmtcp_c_send Date: Thu, 21 Aug 2025 12:03:49 +0800 Message-ID: <20250821040350.5170-1-hdanton@sina.com> In-Reply-To: <68a6767c.050a0220.3d78fd.0011.GAE@google.com> References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit > Date: Wed, 20 Aug 2025 18:29:32 -0700 [thread overview] > Hello, > > syzbot found the following issue on: > > HEAD commit: bab3ce404553 Merge branch '100GbE' of git://git.kernel.org.. > git tree: net-next > console+strace: https://syzkaller.appspot.com/x/log.txt?x=164893a2580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=412ee2f8b704a5e6 > dashboard link: https://syzkaller.appspot.com/bug?extid=1741b56d54536f4ec349 > compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1769faf0580000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=100eaba2580000 #syz test --- x/drivers/atm/atmtcp.c +++ y/drivers/atm/atmtcp.c @@ -294,6 +294,8 @@ static int atmtcp_c_send(struct atm_vcc dev = vcc->dev_data; hdr = (struct atmtcp_hdr *) skb->data; if (hdr->length == ATMTCP_HDR_MAGIC) { + if (skb->len < sizeof(struct atmtcp_control)) + goto done; result = atmtcp_recv_control( (struct atmtcp_control *) skb->data); goto done; --