From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 14992C433E0 for ; Tue, 9 Jun 2020 04:34:40 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C4B9520801 for ; Tue, 9 Jun 2020 04:34:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="B0AUDXHu" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C4B9520801 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6F8858D001D; Tue, 9 Jun 2020 00:34:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6A7508D0011; Tue, 9 Jun 2020 00:34:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5BD858D001D; Tue, 9 Jun 2020 00:34:39 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0050.hostedemail.com [216.40.44.50]) by kanga.kvack.org (Postfix) with ESMTP id 3F1248D0011 for ; Tue, 9 Jun 2020 00:34:39 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 05A60180883C8 for ; Tue, 9 Jun 2020 04:34:39 +0000 (UTC) X-FDA: 76908407478.25.ball99_2714fb126dbf Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin25.hostedemail.com (Postfix) with ESMTP id D22D3180B1E79 for ; Tue, 9 Jun 2020 04:34:38 +0000 (UTC) X-HE-Tag: ball99_2714fb126dbf X-Filterd-Recvd-Size: 2943 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf11.hostedemail.com (Postfix) with ESMTP for ; Tue, 9 Jun 2020 04:34:38 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 768E0208A9; Tue, 9 Jun 2020 04:34:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591677277; bh=BBza2sxUMwil0NjGgPSiMocKjScwa2WLKBXsTJqLbek=; h=Date:From:To:Subject:In-Reply-To:From; b=B0AUDXHuV8sYO9H2Zz8BNL9z/YZ96qgZsrDzV7L8ewWTE6UQQYUbZ9Ttz7k12w8T0 OJdF7RZPmDAHUXbI74R4jm68YhCmPk80yGx2sqmRNBqkIlHUXrBLDtif+cW3K4zF7z YKZ0Q62iTeLIJ32UXIPCllFrMnYUb44WatgQ/nPs= Date: Mon, 08 Jun 2020 21:34:37 -0700 From: Andrew Morton To: akpm@linux-foundation.org, ast@kernel.org, daniel@iogearbox.net, hch@lst.de, hpa@zytor.com, linux-mm@kvack.org, mhiramat@kernel.org, mingo@elte.hu, mm-commits@vger.kernel.org, tglx@linutronix.de, torvalds@linux-foundation.org Subject: [patch 84/93] bpf:bpf_seq_printf(): handle potentially unsafe format string better Message-ID: <20200609043437.8_el-FkSs%akpm@linux-foundation.org> In-Reply-To: <20200608212922.5b7fa74ca3f4e2444441b7f9@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Queue-Id: D22D3180B1E79 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Andrew Morton Subject: bpf:bpf_seq_printf(): handle potentially unsafe format string better User the proper helper for kernel or userspace addresses based on TASK_SIZE instead of the dangerous strncpy_from_unsafe function. Cc: Christoph Hellwig Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Masami Hiramatsu Cc: Thomas Gleixner Signed-off-by: Andrew Morton --- kernel/trace/bpf_trace.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/kernel/trace/bpf_trace.c~bpf-bpf_seq_printf-handle-potentially-unsafe-format-string-better +++ a/kernel/trace/bpf_trace.c @@ -588,15 +588,17 @@ BPF_CALL_5(bpf_seq_printf, struct seq_fi } if (fmt[i] == 's') { + void *unsafe_ptr; + /* try our best to copy */ if (memcpy_cnt >= MAX_SEQ_PRINTF_MAX_MEMCPY) { err = -E2BIG; goto out; } - err = strncpy_from_unsafe_strict(bufs->buf[memcpy_cnt], - (void *) (long) args[fmt_cnt], - MAX_SEQ_PRINTF_STR_LEN); + unsafe_ptr = (void *)(long)args[fmt_cnt]; + err = strncpy_from_kernel_nofault(bufs->buf[memcpy_cnt], + unsafe_ptr, MAX_SEQ_PRINTF_STR_LEN); if (err < 0) bufs->buf[memcpy_cnt][0] = '\0'; params[fmt_cnt] = (u64)(long)bufs->buf[memcpy_cnt]; _