From patchwork Mon Jul 29 11:26:45 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vit Mojzis X-Patchwork-Id: 13744764 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1B26A145B07 for ; Mon, 29 Jul 2024 11:32:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722252776; cv=none; b=Cm1nxMhKh2Ac9A42hiDnl0hMeRS7RWucuf1+owVtQO2Libgd8F1qy06QlgOedic30Xa0ollpr1BIF6W3Yz/d7R1u+6ZBiM0zqqWzmTKE7gKkF/nH4v2b2DzwSO+gghLPgcN3qpww3lWFzBIa+m6np5e+QT+HcyKcAGPKf7UUXJM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722252776; c=relaxed/simple; bh=2fMchte9/2M9ovHhcyNdcSrV7nc2l2ZXKtt6KAvc++w=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=jA/dTVkVoC6mu13Y8PEIMfyXkjnnJHYYFsg8tqX+MPl7hrsw5ei5j1IzVI5CSEIuuco+OzII6jlurPMRcsuXqcds7fMUc2GTuQtLjNgRA95mSECwwRWUVdq1GkmgRTxcyXKwIKwCVMAoL2u0dpKt/DCgKC8dqpIaqoPw66kFn7s= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=KwDBpU2X; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="KwDBpU2X" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1722252774; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=PQ9G0sz6wakPxRNikNBd2/KVtzHrTla+jFifm2LvxSw=; b=KwDBpU2XctpmhI7XU+qN6reqdfrE2EVpmXgRXeygOQYNeGLD3DFnFXtxn5qrHFeyScGxpD Qzb8OFOD9YFGtgH37sLGr5ChdyArRjvCHKDLYpAdQ1Oop+LoXCLZZcERoPBDTifWulHQvJ enO8PeizdxNhDCg+2/6Zjfic1GOpVEU= Received: from mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-689-OCQSG02mP2OX3J1GGGVc9Q-1; Mon, 29 Jul 2024 07:32:52 -0400 X-MC-Unique: OCQSG02mP2OX3J1GGGVc9Q-1 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B19EC1955D4D for ; Mon, 29 Jul 2024 11:32:51 +0000 (UTC) Received: from fedora.redhat.com (unknown [10.45.225.253]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id CB96819560AE for ; Mon, 29 Jul 2024 11:32:50 +0000 (UTC) From: Vit Mojzis To: selinux@vger.kernel.org Subject: [PATCH v5] libsemanage: Preserve file context and ownership in policy store Date: Mon, 29 Jul 2024 13:26:45 +0200 Message-ID: <20240729113247.1673713-1-vmojzis@redhat.com> In-Reply-To: References: Precedence: bulk X-Mailing-List: selinux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Make sure that file context (all parts) and ownership of files/directories in policy store does not change no matter which user and under which context executes policy rebuild. Fixes: # semodule -B # ls -lZ /etc/selinux/targeted/contexts/files -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 421397 Jul 11 09:57 file_contexts -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 593470 Jul 11 09:57 file_contexts.bin -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 14704 Jul 11 09:57 file_contexts.homedirs -rw-r--r--. 1 root root unconfined_u:object_r:file_context_t:s0 20289 Jul 11 09:57 file_contexts.homedirs.bin SELinux user changed from system_u to the user used to execute semodule # capsh --user=testuser --caps="cap_dac_override,cap_chown+eip" --addamb=cap_dac_override,cap_chown -- -c "semodule -B" # ls -lZ /etc/selinux/targeted/contexts/files -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 421397 Jul 19 09:10 file_contexts -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 593470 Jul 19 09:10 file_contexts.bin -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 14704 Jul 19 09:10 file_contexts.homedirs -rw-r--r--. 1 testuser testuser unconfined_u:object_r:file_context_t:s0 20289 Jul 19 09:10 file_contexts.homedirs.bin Both file context and ownership changed -- causes remote login failures and other issues in some scenarios. Signed-off-by: Vit Mojzis Acked-by: Stephen Smalley --- Changes in V5: - Check return value of fchown and warn user if it fails Should I start creating github pull requests for each patch to catch this type of issue in the future (so that I don't waste your time)? libsemanage/src/semanage_store.c | 32 ++++++++++++++++++++++++++++++++ libsemanage/src/semanage_store.h | 1 + 2 files changed, 33 insertions(+) diff --git a/libsemanage/src/semanage_store.c b/libsemanage/src/semanage_store.c index 27c5d349..0ac2e5b2 100644 --- a/libsemanage/src/semanage_store.c +++ b/libsemanage/src/semanage_store.c @@ -36,6 +36,7 @@ typedef struct dbase_policydb dbase_t; #include "database_policydb.h" #include "handle.h" +#include #include #include #include @@ -767,6 +768,7 @@ int semanage_copy_file(const char *src, const char *dst, mode_t mode, if (!retval && rename(tmp, dst) == -1) return -1; + semanage_setfiles(dst); out: errno = errsv; return retval; @@ -819,6 +821,8 @@ static int semanage_copy_dir_flags(const char *src, const char *dst, int flag) goto cleanup; } umask(mask); + + semanage_setfiles(dst); } for (i = 0; i < len; i++) { @@ -837,6 +841,7 @@ static int semanage_copy_dir_flags(const char *src, const char *dst, int flag) goto cleanup; } umask(mask); + semanage_setfiles(path2); } else if (S_ISREG(sb.st_mode) && flag == 1) { mask = umask(0077); if (semanage_copy_file(path, path2, sb.st_mode, @@ -938,6 +943,7 @@ int semanage_mkdir(semanage_handle_t *sh, const char *path) } umask(mask); + semanage_setfiles(path); } else { /* check that it really is a directory */ @@ -1614,16 +1620,19 @@ static int semanage_validate_and_compile_fcontexts(semanage_handle_t * sh) semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC)) != 0) { goto cleanup; } + semanage_setfiles(semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC_BIN)); if (sefcontext_compile(sh, semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC_LOCAL)) != 0) { goto cleanup; } + semanage_setfiles(semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC_LOCAL_BIN)); if (sefcontext_compile(sh, semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC_HOMEDIRS)) != 0) { goto cleanup; } + semanage_setfiles(semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC_HOMEDIRS_BIN)); status = 0; cleanup: @@ -3018,3 +3027,26 @@ int semanage_nc_sort(semanage_handle_t * sh, const char *buf, size_t buf_len, return 0; } + +/* Make sure the file context and ownership of files in the policy + * store does not change */ +void semanage_setfiles(const char *path){ + struct stat sb; + int fd; + /* Fix the user and role portions of the context, ignore errors + * since this is not a critical operation */ + selinux_restorecon(path, SELINUX_RESTORECON_SET_SPECFILE_CTX | SELINUX_RESTORECON_IGNORE_NOENTRY); + + /* Make sure "path" is owned by root */ + if ((geteuid() != 0 || getegid() != 0) && + ((fd = open(path, O_RDONLY)) != -1)){ + /* Skip files with the SUID or SGID bit set -- abuse protection */ + if ((fstat(fd, &sb) != -1) && + !(S_ISREG(sb.st_mode) && + (sb.st_mode & (S_ISUID | S_ISGID))) && + (fchown(fd, 0, 0) == -1)) + fprintf(stderr, "Warning! Could not set ownership of %s to root\n", path); + + close(fd); + } +} diff --git a/libsemanage/src/semanage_store.h b/libsemanage/src/semanage_store.h index 1fc77da8..e21dadeb 100644 --- a/libsemanage/src/semanage_store.h +++ b/libsemanage/src/semanage_store.h @@ -124,6 +124,7 @@ int semanage_get_cil_paths(semanage_handle_t * sh, semanage_module_info_t *modin int semanage_get_active_modules(semanage_handle_t *sh, semanage_module_info_t **modinfo, int *num_modules); +void semanage_setfiles(const char *path); /* lock file routines */ int semanage_get_trans_lock(semanage_handle_t * sh);