From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933442AbcEQBrH (ORCPT ); Mon, 16 May 2016 21:47:07 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:34350 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755430AbcEQBYd (ORCPT ); Mon, 16 May 2016 21:24:33 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jann Horn , Alexei Starovoitov , Daniel Borkmann , "David S. Miller" Subject: [PATCH 4.5 022/101] bpf: fix check_map_func_compatibility logic Date: Mon, 16 May 2016 18:20:27 -0700 Message-Id: <20160517011507.178098579@linuxfoundation.org> X-Mailer: git-send-email 2.8.2 In-Reply-To: <20160517011506.359924439@linuxfoundation.org> References: <20160517011506.359924439@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexei Starovoitov [ Upstream commit 6aff67c85c9e5a4bc99e5211c1bac547936626ca ] The commit 35578d798400 ("bpf: Implement function bpf_perf_event_read() that get the selected hardware PMU conuter") introduced clever way to check bpf_helper<->map_type compatibility. Later on commit a43eec304259 ("bpf: introduce bpf_perf_event_output() helper") adjusted the logic and inadvertently broke it. Get rid of the clever bool compare and go back to two-way check from map and from helper perspective. Fixes: a43eec304259 ("bpf: introduce bpf_perf_event_output() helper") Reported-by: Jann Horn Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- kernel/bpf/verifier.c | 53 ++++++++++++++++++++++++++++++-------------------- 1 file changed, 32 insertions(+), 21 deletions(-) --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -239,15 +239,6 @@ static const char * const reg_type_str[] [CONST_IMM] = "imm", }; -static const struct { - int map_type; - int func_id; -} func_limit[] = { - {BPF_MAP_TYPE_PROG_ARRAY, BPF_FUNC_tail_call}, - {BPF_MAP_TYPE_PERF_EVENT_ARRAY, BPF_FUNC_perf_event_read}, - {BPF_MAP_TYPE_PERF_EVENT_ARRAY, BPF_FUNC_perf_event_output}, -}; - static void print_verifier_state(struct verifier_env *env) { enum bpf_reg_type t; @@ -898,24 +889,44 @@ static int check_func_arg(struct verifie static int check_map_func_compatibility(struct bpf_map *map, int func_id) { - bool bool_map, bool_func; - int i; - if (!map) return 0; - for (i = 0; i < ARRAY_SIZE(func_limit); i++) { - bool_map = (map->map_type == func_limit[i].map_type); - bool_func = (func_id == func_limit[i].func_id); - /* only when map & func pair match it can continue. - * don't allow any other map type to be passed into - * the special func; - */ - if (bool_func && bool_map != bool_func) - return -EINVAL; + /* We need a two way check, first is from map perspective ... */ + switch (map->map_type) { + case BPF_MAP_TYPE_PROG_ARRAY: + if (func_id != BPF_FUNC_tail_call) + goto error; + break; + case BPF_MAP_TYPE_PERF_EVENT_ARRAY: + if (func_id != BPF_FUNC_perf_event_read && + func_id != BPF_FUNC_perf_event_output) + goto error; + break; + default: + break; + } + + /* ... and second from the function itself. */ + switch (func_id) { + case BPF_FUNC_tail_call: + if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY) + goto error; + break; + case BPF_FUNC_perf_event_read: + case BPF_FUNC_perf_event_output: + if (map->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) + goto error; + break; + default: + break; } return 0; +error: + verbose("cannot pass map_type %d into func %d\n", + map->map_type, func_id); + return -EINVAL; } static int check_call(struct verifier_env *env, int func_id)