From patchwork Tue Mar 3 17:42:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 230045 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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY, 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 69D55C3F2C6 for ; Tue, 3 Mar 2020 17:47:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3D26620CC7 for ; Tue, 3 Mar 2020 17:47:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583257675; bh=fLUXpRZ6kvhbDnqKO57WORhRZO9tCoIFRvf9WuY/EKk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=cusOpAJ2pvdam5Gh239gbkBYrmquEh18TxA4XH0UaLSgzjg52IbOB70FquDv+4XMM s4HJzeHAdRAi7oqImYfqqaMLsxGkyvDAAtdbra+M/9mB3igddwDK5MYQ47IbGJ7whV BN7KTsVTjQuew73YKchoFAThj+/jt/smkNHtoni8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731426AbgCCRry (ORCPT ); Tue, 3 Mar 2020 12:47:54 -0500 Received: from mail.kernel.org ([198.145.29.99]:54872 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731445AbgCCRry (ORCPT ); Tue, 3 Mar 2020 12:47:54 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 776CE208C3; Tue, 3 Mar 2020 17:47:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583257672; bh=fLUXpRZ6kvhbDnqKO57WORhRZO9tCoIFRvf9WuY/EKk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AnaReL/26l4u6SNYq2yu7Bg5iCdak9/H5pmK3htQuZkmTxIrxcYpeiKYi7tRIbUKt fW9MDac7sUMJNqNEEcH/lXSXA4nS7gEweV1eGehv/8Erh0IfkPW2lQnPHQBPCAmYWg CAJyx7KUx+sh8SFwmBNSSqjmfrc0QIlapjhMiHYQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+1f4d90ead370d72e450b@syzkaller.appspotmail.com, Paul Moore Subject: [PATCH 5.5 085/176] audit: fix error handling in audit_data_to_entry() Date: Tue, 3 Mar 2020 18:42:29 +0100 Message-Id: <20200303174314.517029522@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200303174304.593872177@linuxfoundation.org> References: <20200303174304.593872177@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Paul Moore commit 2ad3e17ebf94b7b7f3f64c050ff168f9915345eb upstream. Commit 219ca39427bf ("audit: use union for audit_field values since they are mutually exclusive") combined a number of separate fields in the audit_field struct into a single union. Generally this worked just fine because they are generally mutually exclusive. Unfortunately in audit_data_to_entry() the overlap can be a problem when a specific error case is triggered that causes the error path code to attempt to cleanup an audit_field struct and the cleanup involves attempting to free a stored LSM string (the lsm_str field). Currently the code always has a non-NULL value in the audit_field.lsm_str field as the top of the for-loop transfers a value into audit_field.val (both .lsm_str and .val are part of the same union); if audit_data_to_entry() fails and the audit_field struct is specified to contain a LSM string, but the audit_field.lsm_str has not yet been properly set, the error handling code will attempt to free the bogus audit_field.lsm_str value that was set with audit_field.val at the top of the for-loop. This patch corrects this by ensuring that the audit_field.val is only set when needed (it is cleared when the audit_field struct is allocated with kcalloc()). It also corrects a few other issues to ensure that in case of error the proper error code is returned. Cc: stable@vger.kernel.org Fixes: 219ca39427bf ("audit: use union for audit_field values since they are mutually exclusive") Reported-by: syzbot+1f4d90ead370d72e450b@syzkaller.appspotmail.com Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman --- kernel/auditfilter.c | 71 ++++++++++++++++++++++++++++----------------------- 1 file changed, 39 insertions(+), 32 deletions(-) --- a/kernel/auditfilter.c +++ b/kernel/auditfilter.c @@ -456,6 +456,7 @@ static struct audit_entry *audit_data_to bufp = data->buf; for (i = 0; i < data->field_count; i++) { struct audit_field *f = &entry->rule.fields[i]; + u32 f_val; err = -EINVAL; @@ -464,12 +465,12 @@ static struct audit_entry *audit_data_to goto exit_free; f->type = data->fields[i]; - f->val = data->values[i]; + f_val = data->values[i]; /* Support legacy tests for a valid loginuid */ - if ((f->type == AUDIT_LOGINUID) && (f->val == AUDIT_UID_UNSET)) { + if ((f->type == AUDIT_LOGINUID) && (f_val == AUDIT_UID_UNSET)) { f->type = AUDIT_LOGINUID_SET; - f->val = 0; + f_val = 0; entry->rule.pflags |= AUDIT_LOGINUID_LEGACY; } @@ -485,7 +486,7 @@ static struct audit_entry *audit_data_to case AUDIT_SUID: case AUDIT_FSUID: case AUDIT_OBJ_UID: - f->uid = make_kuid(current_user_ns(), f->val); + f->uid = make_kuid(current_user_ns(), f_val); if (!uid_valid(f->uid)) goto exit_free; break; @@ -494,11 +495,12 @@ static struct audit_entry *audit_data_to case AUDIT_SGID: case AUDIT_FSGID: case AUDIT_OBJ_GID: - f->gid = make_kgid(current_user_ns(), f->val); + f->gid = make_kgid(current_user_ns(), f_val); if (!gid_valid(f->gid)) goto exit_free; break; case AUDIT_ARCH: + f->val = f_val; entry->rule.arch_f = f; break; case AUDIT_SUBJ_USER: @@ -511,11 +513,13 @@ static struct audit_entry *audit_data_to case AUDIT_OBJ_TYPE: case AUDIT_OBJ_LEV_LOW: case AUDIT_OBJ_LEV_HIGH: - str = audit_unpack_string(&bufp, &remain, f->val); - if (IS_ERR(str)) + str = audit_unpack_string(&bufp, &remain, f_val); + if (IS_ERR(str)) { + err = PTR_ERR(str); goto exit_free; - entry->rule.buflen += f->val; - + } + entry->rule.buflen += f_val; + f->lsm_str = str; err = security_audit_rule_init(f->type, f->op, str, (void **)&f->lsm_rule); /* Keep currently invalid fields around in case they @@ -524,68 +528,71 @@ static struct audit_entry *audit_data_to pr_warn("audit rule for LSM \'%s\' is invalid\n", str); err = 0; - } - if (err) { - kfree(str); + } else if (err) goto exit_free; - } else - f->lsm_str = str; break; case AUDIT_WATCH: - str = audit_unpack_string(&bufp, &remain, f->val); - if (IS_ERR(str)) + str = audit_unpack_string(&bufp, &remain, f_val); + if (IS_ERR(str)) { + err = PTR_ERR(str); goto exit_free; - entry->rule.buflen += f->val; - - err = audit_to_watch(&entry->rule, str, f->val, f->op); + } + err = audit_to_watch(&entry->rule, str, f_val, f->op); if (err) { kfree(str); goto exit_free; } + entry->rule.buflen += f_val; break; case AUDIT_DIR: - str = audit_unpack_string(&bufp, &remain, f->val); - if (IS_ERR(str)) + str = audit_unpack_string(&bufp, &remain, f_val); + if (IS_ERR(str)) { + err = PTR_ERR(str); goto exit_free; - entry->rule.buflen += f->val; - + } err = audit_make_tree(&entry->rule, str, f->op); kfree(str); if (err) goto exit_free; + entry->rule.buflen += f_val; break; case AUDIT_INODE: + f->val = f_val; err = audit_to_inode(&entry->rule, f); if (err) goto exit_free; break; case AUDIT_FILTERKEY: - if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN) + if (entry->rule.filterkey || f_val > AUDIT_MAX_KEY_LEN) goto exit_free; - str = audit_unpack_string(&bufp, &remain, f->val); - if (IS_ERR(str)) + str = audit_unpack_string(&bufp, &remain, f_val); + if (IS_ERR(str)) { + err = PTR_ERR(str); goto exit_free; - entry->rule.buflen += f->val; + } + entry->rule.buflen += f_val; entry->rule.filterkey = str; break; case AUDIT_EXE: - if (entry->rule.exe || f->val > PATH_MAX) + if (entry->rule.exe || f_val > PATH_MAX) goto exit_free; - str = audit_unpack_string(&bufp, &remain, f->val); + str = audit_unpack_string(&bufp, &remain, f_val); if (IS_ERR(str)) { err = PTR_ERR(str); goto exit_free; } - entry->rule.buflen += f->val; - - audit_mark = audit_alloc_mark(&entry->rule, str, f->val); + audit_mark = audit_alloc_mark(&entry->rule, str, f_val); if (IS_ERR(audit_mark)) { kfree(str); err = PTR_ERR(audit_mark); goto exit_free; } + entry->rule.buflen += f_val; entry->rule.exe = audit_mark; break; + default: + f->val = f_val; + break; } }