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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 72096C07E9C for ; Wed, 7 Jul 2021 03:53:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4C59C61CB3 for ; Wed, 7 Jul 2021 03:53:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230228AbhGGDzj (ORCPT ); Tue, 6 Jul 2021 23:55:39 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:6437 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230120AbhGGDzc (ORCPT ); Tue, 6 Jul 2021 23:55:32 -0400 Received: from dggeme751-chm.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4GKQQq0ySnz77vJ; Wed, 7 Jul 2021 11:49:23 +0800 (CST) Received: from k03.huawei.com (10.67.174.111) by dggeme751-chm.china.huawei.com (10.3.19.97) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Wed, 7 Jul 2021 11:52:50 +0800 From: He Fengqing To: , , , , , , , CC: , , , , Subject: [bpf-next 3/3] bpf: Fix a use after free in bpf_check() Date: Wed, 7 Jul 2021 04:38:11 +0000 Message-ID: <20210707043811.5349-4-hefengqing@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210707043811.5349-1-hefengqing@huawei.com> References: <20210707043811.5349-1-hefengqing@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.67.174.111] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggeme751-chm.china.huawei.com (10.3.19.97) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org In bpf_patch_insn_data, env->prog was input parameter of bpf_patch_insn_single function. bpf_patch_insn_single call bpf_prog_realloc to realloc ebpf prog. When we need to malloc new prog, bpf_prog_realloc will free the old prog, in this scenery is the env->prog. Then bpf_patch_insn_data function call adjust_insn_aux_data function, if adjust_insn_aux_data function return error, bpf_patch_insn_data will return NULL. In bpf_check->convert_ctx_accesses->bpf_patch_insn_data call chain, if bpf_patch_insn_data return NULL, env->prog has been freed in bpf_prog_realloc, then bpf_check will use the freed env->prog. Signed-off-by: He Fengqing --- include/linux/filter.h | 2 +- kernel/bpf/core.c | 9 ++++--- kernel/bpf/verifier.c | 53 ++++++++++++++++++++++++++++++++---------- net/core/filter.c | 2 +- 4 files changed, 49 insertions(+), 17 deletions(-) diff --git a/include/linux/filter.h b/include/linux/filter.h index f39e008a377d..ec11a5ae92c2 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -881,7 +881,7 @@ void bpf_prog_jit_attempt_done(struct bpf_prog *prog); struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags); struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags); struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, - gfp_t gfp_extra_flags); + gfp_t gfp_extra_flags, bool free_old); void __bpf_prog_free(struct bpf_prog *fp); static inline void bpf_prog_clone_free(struct bpf_prog *fp) diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 49b0311f48c1..e5616bb1665b 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -218,7 +218,7 @@ void bpf_prog_fill_jited_linfo(struct bpf_prog *prog, } struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, - gfp_t gfp_extra_flags) + gfp_t gfp_extra_flags, bool free_old) { gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __GFP_ZERO | gfp_extra_flags; struct bpf_prog *fp; @@ -238,7 +238,8 @@ struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, /* We keep fp->aux from fp_old around in the new * reallocated structure. */ - bpf_prog_clone_free(fp_old); + if (free_old) + bpf_prog_clone_free(fp_old); } return fp; @@ -456,7 +457,7 @@ struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, * last page could have large enough tailroom. */ prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt), - GFP_USER); + GFP_USER, false); if (!prog_adj) return ERR_PTR(-ENOMEM); @@ -1150,6 +1151,8 @@ struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) return tmp; } + if (tmp != clone) + bpf_prog_clone_free(clone); clone = tmp; insn_delta = rewritten - 1; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 41109f49b724..e75b933f69e4 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -11855,7 +11855,10 @@ static int opt_subreg_zext_lo32_rnd_hi32(struct bpf_verifier_env *env, new_prog = bpf_patch_insn_data(env, adj_idx, patch, patch_len); if (!new_prog) return -ENOMEM; - env->prog = new_prog; + if (new_prog != env->prog) { + bpf_prog_clone_free(env->prog); + env->prog = new_prog; + } insns = new_prog->insnsi; aux = env->insn_aux_data; delta += patch_len - 1; @@ -11895,7 +11898,10 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) if (!new_prog) return -ENOMEM; - env->prog = new_prog; + if (new_prog != env->prog) { + bpf_prog_clone_free(env->prog); + env->prog = new_prog; + } delta += cnt - 1; } } @@ -11944,7 +11950,10 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) return -ENOMEM; delta += cnt - 1; - env->prog = new_prog; + if (new_prog != env->prog) { + bpf_prog_clone_free(env->prog); + env->prog = new_prog; + } insn = new_prog->insnsi + i + delta; continue; } @@ -12042,9 +12051,11 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) return -ENOMEM; delta += cnt - 1; - - /* keep walking new program and skip insns we just inserted */ - env->prog = new_prog; + if (new_prog != env->prog) { + bpf_prog_clone_free(env->prog); + /* keep walking new program and skip insns we just inserted */ + env->prog = new_prog; + } insn = new_prog->insnsi + i + delta; } @@ -12419,7 +12430,10 @@ static int do_misc_fixups(struct bpf_verifier_env *env) return -ENOMEM; delta += cnt - 1; - env->prog = prog = new_prog; + if (new_prog != env->prog) { + bpf_prog_clone_free(env->prog); + env->prog = prog = new_prog; + } insn = new_prog->insnsi + i + delta; continue; } @@ -12439,7 +12453,10 @@ static int do_misc_fixups(struct bpf_verifier_env *env) return -ENOMEM; delta += cnt - 1; - env->prog = prog = new_prog; + if (new_prog != env->prog) { + bpf_prog_clone_free(env->prog); + env->prog = prog = new_prog; + } insn = new_prog->insnsi + i + delta; continue; } @@ -12492,7 +12509,10 @@ static int do_misc_fixups(struct bpf_verifier_env *env) return -ENOMEM; delta += cnt - 1; - env->prog = prog = new_prog; + if (new_prog != env->prog) { + bpf_prog_clone_free(env->prog); + env->prog = prog = new_prog; + } insn = new_prog->insnsi + i + delta; continue; } @@ -12584,7 +12604,10 @@ static int do_misc_fixups(struct bpf_verifier_env *env) return -ENOMEM; delta += cnt - 1; - env->prog = prog = new_prog; + if (new_prog != env->prog) { + bpf_prog_clone_free(env->prog); + env->prog = prog = new_prog; + } insn = new_prog->insnsi + i + delta; continue; } @@ -12623,7 +12646,10 @@ static int do_misc_fixups(struct bpf_verifier_env *env) return -ENOMEM; delta += cnt - 1; - env->prog = prog = new_prog; + if (new_prog != env->prog) { + bpf_prog_clone_free(env->prog); + env->prog = prog = new_prog; + } insn = new_prog->insnsi + i + delta; continue; } @@ -12700,7 +12726,10 @@ static int do_misc_fixups(struct bpf_verifier_env *env) return -ENOMEM; delta += cnt - 1; - env->prog = prog = new_prog; + if (new_prog != env->prog) { + bpf_prog_clone_free(env->prog); + env->prog = prog = new_prog; + } insn = new_prog->insnsi + i + delta; continue; } diff --git a/net/core/filter.c b/net/core/filter.c index d70187ce851b..8a8d1a3ba5c2 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -1268,7 +1268,7 @@ static struct bpf_prog *bpf_migrate_filter(struct bpf_prog *fp) /* Expand fp for appending the new filter representation. */ old_fp = fp; - fp = bpf_prog_realloc(old_fp, bpf_prog_size(new_len), 0); + fp = bpf_prog_realloc(old_fp, bpf_prog_size(new_len), 0, true); if (!fp) { /* The old_fp is still around in case we couldn't * allocate new memory, so uncharge on that one. -- 2.25.1