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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 C91A8C433EF for ; Mon, 13 Sep 2021 13:20:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AFA24610E7 for ; Mon, 13 Sep 2021 13:20:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240829AbhIMNVl (ORCPT ); Mon, 13 Sep 2021 09:21:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:35054 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240365AbhIMNU2 (ORCPT ); Mon, 13 Sep 2021 09:20:28 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 768956108B; Mon, 13 Sep 2021 13:18:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1631539129; bh=W2ISwMdnPyCwnJiP7cxVsBm/OiemhP1eI/40S9FsmAw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=R6VERJFLHHJ5whxgUtKEXeIN8sgUmYge9zmvKVh9yyR5TEljvJVH+qa40bofYpGVy h7ucNH0pjTbId0o+LG6Vh5wAcoiq7T41iRPK07UfIqXbqqHYeZUkumCnhJkisHHEPM cK+cfQgU6tYdjclORKxo+kg/KaYo+3gSjsKfV2NQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, He Fengqing , Alexei Starovoitov , Song Liu , Sasha Levin Subject: [PATCH 5.4 051/144] bpf: Fix potential memleak and UAF in the verifier. Date: Mon, 13 Sep 2021 15:13:52 +0200 Message-Id: <20210913131049.650854559@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210913131047.974309396@linuxfoundation.org> References: <20210913131047.974309396@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: He Fengqing [ Upstream commit 75f0fc7b48ad45a2e5736bcf8de26c8872fe8695 ] In bpf_patch_insn_data(), we first use the bpf_patch_insn_single() to insert new instructions, then use adjust_insn_aux_data() to adjust insn_aux_data. If the old env->prog have no enough room for new inserted instructions, we use bpf_prog_realloc to construct new_prog and free the old env->prog. There have two errors here. First, if adjust_insn_aux_data() return ENOMEM, we should free the new_prog. Second, if adjust_insn_aux_data() return ENOMEM, bpf_patch_insn_data() will return NULL, and env->prog has been freed in bpf_prog_realloc, but we will use it in bpf_check(). So in this patch, we make the adjust_insn_aux_data() never fails. In bpf_patch_insn_data(), we first pre-malloc memory for the new insn_aux_data, then call bpf_patch_insn_single() to insert new instructions, at last call adjust_insn_aux_data() to adjust insn_aux_data. Fixes: 8041902dae52 ("bpf: adjust insn_aux_data when patching insns") Signed-off-by: He Fengqing Signed-off-by: Alexei Starovoitov Acked-by: Song Liu Link: https://lore.kernel.org/bpf/20210714101815.164322-1-hefengqing@huawei.com Signed-off-by: Sasha Levin --- kernel/bpf/verifier.c | 27 ++++++++++++++++----------- 1 file changed, 16 insertions(+), 11 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 4deaf15b7618..80b219d27e37 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -8401,10 +8401,11 @@ static void convert_pseudo_ld_imm64(struct bpf_verifier_env *env) * insni[off, off + cnt). Adjust corresponding insn_aux_data by copying * [0, off) and [off, end) to new locations, so the patched range stays zero */ -static int adjust_insn_aux_data(struct bpf_verifier_env *env, - struct bpf_prog *new_prog, u32 off, u32 cnt) +static void adjust_insn_aux_data(struct bpf_verifier_env *env, + struct bpf_insn_aux_data *new_data, + struct bpf_prog *new_prog, u32 off, u32 cnt) { - struct bpf_insn_aux_data *new_data, *old_data = env->insn_aux_data; + struct bpf_insn_aux_data *old_data = env->insn_aux_data; struct bpf_insn *insn = new_prog->insnsi; bool old_seen = old_data[off].seen; u32 prog_len; @@ -8417,12 +8418,9 @@ static int adjust_insn_aux_data(struct bpf_verifier_env *env, old_data[off].zext_dst = insn_has_def32(env, insn + off + cnt - 1); if (cnt == 1) - return 0; + return; prog_len = new_prog->len; - new_data = vzalloc(array_size(prog_len, - sizeof(struct bpf_insn_aux_data))); - if (!new_data) - return -ENOMEM; + memcpy(new_data, old_data, sizeof(struct bpf_insn_aux_data) * off); memcpy(new_data + off + cnt - 1, old_data + off, sizeof(struct bpf_insn_aux_data) * (prog_len - off - cnt + 1)); @@ -8433,7 +8431,6 @@ static int adjust_insn_aux_data(struct bpf_verifier_env *env, } env->insn_aux_data = new_data; vfree(old_data); - return 0; } static void adjust_subprog_starts(struct bpf_verifier_env *env, u32 off, u32 len) @@ -8454,6 +8451,14 @@ static struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 of const struct bpf_insn *patch, u32 len) { struct bpf_prog *new_prog; + struct bpf_insn_aux_data *new_data = NULL; + + if (len > 1) { + new_data = vzalloc(array_size(env->prog->len + len - 1, + sizeof(struct bpf_insn_aux_data))); + if (!new_data) + return NULL; + } new_prog = bpf_patch_insn_single(env->prog, off, patch, len); if (IS_ERR(new_prog)) { @@ -8461,10 +8466,10 @@ static struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 of verbose(env, "insn %d cannot be patched due to 16-bit range\n", env->insn_aux_data[off].orig_idx); + vfree(new_data); return NULL; } - if (adjust_insn_aux_data(env, new_prog, off, len)) - return NULL; + adjust_insn_aux_data(env, new_data, new_prog, off, len); adjust_subprog_starts(env, off, len); return new_prog; } -- 2.30.2