From patchwork Fri Apr 2 08:56:19 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ondrej Mosnacek X-Patchwork-Id: 12180413 X-Patchwork-Delegate: paul@paul-moore.com 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=-18.8 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, USER_AGENT_GIT autolearn=ham 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 DDE37C43461 for ; Fri, 2 Apr 2021 08:56:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9C05C61104 for ; Fri, 2 Apr 2021 08:56:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229742AbhDBI4c (ORCPT ); Fri, 2 Apr 2021 04:56:32 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:38305 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230387AbhDBI4a (ORCPT ); Fri, 2 Apr 2021 04:56:30 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1617353789; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=KqtLciy0NCnMCuCAwUfSIdViMNmabRdW2NYsYS45WhI=; b=C8zYyMc0g6xQF11iOZfQlSUhRlnP82TGJ7ZHewWSyepChNdnOs4XnYm5wieESZtQYP0jpy acl8MTWcFhchnCnu8+AbRjuM0zV1B1YL4W+yBKifB1u319peWV5JVkw+v09BMbVscDrVQF VJ900kWP7CrGjkKlsvRfbbc6nKhGArU= Received: from mail-ej1-f71.google.com (mail-ej1-f71.google.com [209.85.218.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-148-2SRwNYLAOCCTiMro1nK05g-1; Fri, 02 Apr 2021 04:56:26 -0400 X-MC-Unique: 2SRwNYLAOCCTiMro1nK05g-1 Received: by mail-ej1-f71.google.com with SMTP id au15so3030953ejc.8 for ; Fri, 02 Apr 2021 01:56:26 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=KqtLciy0NCnMCuCAwUfSIdViMNmabRdW2NYsYS45WhI=; b=G3IXX/0NFlsKMWxNzbEkbz8Kjr1LEWIhF9Sh/D8PsmSdUN5vISpESbTO1B4/UtwH+l xMhh+hc0Zllj1enkFFuNuG8N9N0b5xaa06jqgnf0JHmTAqphmEq4AKWIlfQhxXI5nLni TUHN5IGRsGSF74pd8iU7KKbd0BEG3jJBeoYPIeDYW4svm4XLvlnK2DrFoqJYgaO/ybTF jGj+yABkgSlinRluX/NNuuSgTvDolsfXdCd0n6vUYpn+K9/sSexHzvLW02KiDGnNsTN0 nLMac8cc16Z0s43XvYSBqeymvOLp612ulB5+Bs0qyHcSPQ+U8fXl3RZ7nqczNyfF6fMB zmZw== X-Gm-Message-State: AOAM533Uj7hCtloFZSItgmzzrdC432zcYkeHPE4CndDeVJP26mOhcgk/ xDAiIO3ULhSCoeZLJZIfj4DSLQxRBRwqhBo+qcqJZB/WyDPl9Nxr5ouca+OlL10JPtsuND5bMtI 0b6N18zzToE9+pfiVacQJNIBQEcf8wtRlWEH+FhP69IY3h0stV2VXH7AkDP1K7PgleX1qKg== X-Received: by 2002:a17:906:5203:: with SMTP id g3mr12649284ejm.95.1617353785284; Fri, 02 Apr 2021 01:56:25 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyalREvGGWJDIn717F/KoWVFdIBGv7Ypq6UZqq56AdQmP4lRA37h+RsRGAzt7xBg5FbnL2PZw== X-Received: by 2002:a17:906:5203:: with SMTP id g3mr12649275ejm.95.1617353785091; Fri, 02 Apr 2021 01:56:25 -0700 (PDT) Received: from localhost.localdomain ([2a02:8308:b105:dd00:277b:6436:24db:9466]) by smtp.gmail.com with ESMTPSA id u13sm4019726ejn.59.2021.04.02.01.56.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Apr 2021 01:56:24 -0700 (PDT) From: Ondrej Mosnacek To: selinux@vger.kernel.org, Paul Moore Cc: Stephen Smalley Subject: [PATCH v3 2/2] selinux: fix cond_list corruption when changing booleans Date: Fri, 2 Apr 2021 10:56:19 +0200 Message-Id: <20210402085619.1763971-3-omosnace@redhat.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210402085619.1763971-1-omosnace@redhat.com> References: <20210402085619.1763971-1-omosnace@redhat.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org Currently, duplicate_policydb_cond_list() first copies the whole conditional avtab and then tries to link to the correct entries in cond_dup_av_list() using avtab_search(). However, since the conditional avtab may contain multiple entries with the same key, this approach often fails to find the right entry, potentially leading to wrong rules being activated/deactivated when booleans are changed. To fix this, instead start with an empty conditional avtab and add the individual entries one-by-one while building the new av_lists. This approach leads to the correct result, since each entry is present in the av_lists exactly once. The issue can be reproduced with Fedora policy as follows: # sesearch -s ftpd_t -t public_content_rw_t -c dir -p create -A allow ftpd_t non_security_file_type:dir { add_name create getattr ioctl link lock open read remove_name rename reparent rmdir search setattr unlink watch watch_reads write }; [ ftpd_full_access ]:True allow ftpd_t public_content_rw_t:dir { add_name create link remove_name rename reparent rmdir setattr unlink watch watch_reads write }; [ ftpd_anon_write ]:True # setsebool ftpd_anon_write=off ftpd_connect_all_unreserved=off ftpd_connect_db=off ftpd_full_access=off On fixed kernels, the sesearch output is the same after the setsebool command: # sesearch -s ftpd_t -t public_content_rw_t -c dir -p create -A allow ftpd_t non_security_file_type:dir { add_name create getattr ioctl link lock open read remove_name rename reparent rmdir search setattr unlink watch watch_reads write }; [ ftpd_full_access ]:True allow ftpd_t public_content_rw_t:dir { add_name create link remove_name rename reparent rmdir setattr unlink watch watch_reads write }; [ ftpd_anon_write ]:True While on the broken kernels, it will be different: # sesearch -s ftpd_t -t public_content_rw_t -c dir -p create -A allow ftpd_t non_security_file_type:dir { add_name create getattr ioctl link lock open read remove_name rename reparent rmdir search setattr unlink watch watch_reads write }; [ ftpd_full_access ]:True allow ftpd_t non_security_file_type:dir { add_name create getattr ioctl link lock open read remove_name rename reparent rmdir search setattr unlink watch watch_reads write }; [ ftpd_full_access ]:True allow ftpd_t non_security_file_type:dir { add_name create getattr ioctl link lock open read remove_name rename reparent rmdir search setattr unlink watch watch_reads write }; [ ftpd_full_access ]:True While there, also simplify the computation of nslots. This changes the nslots values for nrules 2 or 3 to just two slots instead of 4, which makes the sequence more consistent. Fixes: c7c556f1e81b ("selinux: refactor changing booleans") Signed-off-by: Ondrej Mosnacek --- security/selinux/ss/avtab.c | 88 +++++++++---------------------- security/selinux/ss/avtab.h | 2 +- security/selinux/ss/conditional.c | 12 ++--- 3 files changed, 33 insertions(+), 69 deletions(-) diff --git a/security/selinux/ss/avtab.c b/security/selinux/ss/avtab.c index 2aee4c965c25..75df32906055 100644 --- a/security/selinux/ss/avtab.c +++ b/security/selinux/ss/avtab.c @@ -308,24 +308,10 @@ void avtab_init(struct avtab *h) h->mask = 0; } -int avtab_alloc(struct avtab *h, u32 nrules) +static int avtab_alloc_common(struct avtab *h, u32 nslot) { - u32 shift = 0; - u32 work = nrules; - u32 nslot; - - if (nrules == 0) - goto avtab_alloc_out; - - while (work) { - work = work >> 1; - shift++; - } - if (shift > 2) - shift = shift - 2; - nslot = 1 << shift; - if (nslot > MAX_AVTAB_HASH_BUCKETS) - nslot = MAX_AVTAB_HASH_BUCKETS; + if (!nslot) + return 0; h->htable = kvcalloc(nslot, sizeof(void *), GFP_KERNEL); if (!h->htable) @@ -333,59 +319,37 @@ int avtab_alloc(struct avtab *h, u32 nrules) h->nslot = nslot; h->mask = nslot - 1; - -avtab_alloc_out: - pr_debug("SELinux: %d avtab hash slots, %d rules.\n", - h->nslot, nrules); return 0; } -int avtab_duplicate(struct avtab *new, struct avtab *orig) +int avtab_alloc(struct avtab *h, u32 nrules) { - int i; - struct avtab_node *node, *tmp, *tail; - - memset(new, 0, sizeof(*new)); - - new->htable = kvcalloc(orig->nslot, sizeof(void *), GFP_KERNEL); - if (!new->htable) - return -ENOMEM; - new->nslot = orig->nslot; - new->mask = orig->mask; - - for (i = 0; i < orig->nslot; i++) { - tail = NULL; - for (node = orig->htable[i]; node; node = node->next) { - tmp = kmem_cache_zalloc(avtab_node_cachep, GFP_KERNEL); - if (!tmp) - goto error; - tmp->key = node->key; - if (tmp->key.specified & AVTAB_XPERMS) { - tmp->datum.u.xperms = - kmem_cache_zalloc(avtab_xperms_cachep, - GFP_KERNEL); - if (!tmp->datum.u.xperms) { - kmem_cache_free(avtab_node_cachep, tmp); - goto error; - } - tmp->datum.u.xperms = node->datum.u.xperms; - } else - tmp->datum.u.data = node->datum.u.data; - - if (tail) - tail->next = tmp; - else - new->htable[i] = tmp; - - tail = tmp; - new->nel++; + int rc; + u32 nslot = 0; + + if (nrules != 0) { + u32 shift = 1; + u32 work = nrules >> 3; + while (work) { + work >>= 1; + shift++; } + nslot = 1 << shift; + if (nslot > MAX_AVTAB_HASH_BUCKETS) + nslot = MAX_AVTAB_HASH_BUCKETS; + + rc = avtab_alloc_common(h, nslot); + if (rc) + return rc; } + pr_debug("SELinux: %d avtab hash slots, %d rules.\n", nslot, nrules); return 0; -error: - avtab_destroy(new); - return -ENOMEM; +} + +int avtab_alloc_dup(struct avtab *new, const struct avtab *orig) +{ + return avtab_alloc_common(new, orig->nslot); } void avtab_hash_eval(struct avtab *h, char *tag) diff --git a/security/selinux/ss/avtab.h b/security/selinux/ss/avtab.h index 4c4445ca9118..f2eeb36265d1 100644 --- a/security/selinux/ss/avtab.h +++ b/security/selinux/ss/avtab.h @@ -89,7 +89,7 @@ struct avtab { void avtab_init(struct avtab *h); int avtab_alloc(struct avtab *, u32); -int avtab_duplicate(struct avtab *new, struct avtab *orig); +int avtab_alloc_dup(struct avtab *new, const struct avtab *orig); struct avtab_datum *avtab_search(struct avtab *h, struct avtab_key *k); void avtab_destroy(struct avtab *h); void avtab_hash_eval(struct avtab *h, char *tag); diff --git a/security/selinux/ss/conditional.c b/security/selinux/ss/conditional.c index 0b32f3ab025e..1ef74c085f2b 100644 --- a/security/selinux/ss/conditional.c +++ b/security/selinux/ss/conditional.c @@ -605,7 +605,6 @@ static int cond_dup_av_list(struct cond_av_list *new, struct cond_av_list *orig, struct avtab *avtab) { - struct avtab_node *avnode; u32 i; memset(new, 0, sizeof(*new)); @@ -615,10 +614,11 @@ static int cond_dup_av_list(struct cond_av_list *new, return -ENOMEM; for (i = 0; i < orig->len; i++) { - avnode = avtab_search_node(avtab, &orig->nodes[i]->key); - if (WARN_ON(!avnode)) - return -EINVAL; - new->nodes[i] = avnode; + new->nodes[i] = avtab_insert_nonunique(avtab, + &orig->nodes[i]->key, + &orig->nodes[i]->datum); + if (!new->nodes[i]) + return -ENOMEM; new->len++; } @@ -630,7 +630,7 @@ static int duplicate_policydb_cond_list(struct policydb *newp, { int rc, i, j; - rc = avtab_duplicate(&newp->te_cond_avtab, &origp->te_cond_avtab); + rc = avtab_alloc_dup(&newp->te_cond_avtab, &origp->te_cond_avtab); if (rc) return rc;