From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:36772 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754054AbeA2UNI (ORCPT ); Mon, 29 Jan 2018 15:13:08 -0500 Subject: Patch "bpf: fix divides by zero" has been added to the 4.9-stable tree To: daniel@iogearbox.net, ast@kernel.org, edumazet@google.com, gregkh@linuxfoundation.org, syzkaller@googlegroups.com Cc: , From: Date: Mon, 29 Jan 2018 13:35:01 +0100 In-Reply-To: Message-ID: <1517229301200101@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled bpf: fix divides by zero to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: bpf-fix-divides-by-zero.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Mon Jan 29 13:22:08 CET 2018 From: Daniel Borkmann Date: Mon, 29 Jan 2018 02:48:59 +0100 Subject: bpf: fix divides by zero To: gregkh@linuxfoundation.org Cc: ast@kernel.org, stable@vger.kernel.org, Eric Dumazet Message-ID: From: Eric Dumazet [ upstream commit c366287ebd698ef5e3de300d90cd62ee9ee7373e ] Divides by zero are not nice, lets avoid them if possible. Also do_div() seems not needed when dealing with 32bit operands, but this seems a minor detail. Fixes: bd4cf0ed331a ("net: filter: rework/optimize internal BPF interpreter's instruction set") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: Alexei Starovoitov Signed-off-by: Greg Kroah-Hartman --- kernel/bpf/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -642,7 +642,7 @@ select_insn: DST = tmp; CONT; ALU_MOD_X: - if (unlikely(SRC == 0)) + if (unlikely((u32)SRC == 0)) return 0; tmp = (u32) DST; DST = do_div(tmp, (u32) SRC); @@ -661,7 +661,7 @@ select_insn: DST = div64_u64(DST, SRC); CONT; ALU_DIV_X: - if (unlikely(SRC == 0)) + if (unlikely((u32)SRC == 0)) return 0; tmp = (u32) DST; do_div(tmp, (u32) SRC); Patches currently in stable-queue which might be from daniel@iogearbox.net are queue-4.9/bpf-avoid-false-sharing-of-map-refcount-with-max_entries.patch queue-4.9/x86-bpf_jit-small-optimization-in-emit_bpf_tail_call.patch queue-4.9/bpf-reject-stores-into-ctx-via-st-and-xadd.patch queue-4.9/bpf-fix-32-bit-divide-by-zero.patch queue-4.9/bpf-fix-bpf_tail_call-x64-jit.patch queue-4.9/bpf-arsh-is-not-supported-in-32-bit-alu-thus-reject-it.patch queue-4.9/bpf-fix-divides-by-zero.patch queue-4.9/bpf-introduce-bpf_jit_always_on-config.patch