From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: [patch 83/93] bpf: handle the compat string in bpf_trace_copy_string better Date: Mon, 08 Jun 2020 21:34:33 -0700 Message-ID: <20200609043433.cOkjJVDq-%akpm@linux-foundation.org> References: <20200608212922.5b7fa74ca3f4e2444441b7f9@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.99]:58536 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726831AbgFIEeg (ORCPT ); Tue, 9 Jun 2020 00:34:36 -0400 In-Reply-To: <20200608212922.5b7fa74ca3f4e2444441b7f9@linux-foundation.org> Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org 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 From: Christoph Hellwig Subject: bpf: handle the compat string in bpf_trace_copy_string better User the proper helper for kernel or userspace addresses based on TASK_SIZE instead of the dangerous strncpy_from_unsafe function. Link: http://lkml.kernel.org/r/20200521152301.2587579-13-hch@lst.de Signed-off-by: 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 | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/kernel/trace/bpf_trace.c~bpf-handle-the-compat-string-in-bpf_trace_copy_string-better +++ a/kernel/trace/bpf_trace.c @@ -334,8 +334,11 @@ static void bpf_trace_copy_string(char * switch (fmt_ptype) { case 's': #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE - strncpy_from_unsafe(buf, unsafe_ptr, bufsz); - break; + if ((unsigned long)unsafe_ptr < TASK_SIZE) { + strncpy_from_user_nofault(buf, user_ptr, bufsz); + break; + } + fallthrough; #endif case 'k': strncpy_from_kernel_nofault(buf, unsafe_ptr, bufsz); _