Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S376879AbdD2TDb (ORCPT ); Sat, 29 Apr 2017 15:03:31 -0400 Received: from smtp-sh2.infomaniak.ch ([128.65.195.6]:34010 "EHLO smtp-sh2.infomaniak.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S376863AbdD2TDY (ORCPT ); Sat, 29 Apr 2017 15:03:24 -0400 From: =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?= To: linux-kernel@vger.kernel.org Cc: =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?= , Casey Schaufler , James Morris , Kees Cook , "Serge E . Hallyn" , linux-security-module@vger.kernel.org Subject: [PATCH v1] LSM: Enable multiple calls to security_add_hooks() for the same LSM Date: Sat, 29 Apr 2017 21:02:57 +0200 Message-Id: <20170429190257.27137-1-mic@digikod.net> X-Mailer: git-send-email 2.11.0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Antivirus: Dr.Web (R) for Unix mail servers drweb plugin ver.6.0.2.8 X-Antivirus-Code: 0x100000 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2082 Lines: 72 Check if the registering LSM already registered hooks just before. This enable to split hook declarations into multiple files without registering multiple time the same LSM name, starting from commit d69dece5f5b6 ("LSM: Add /sys/kernel/security/lsm"). Signed-off-by: Mickaël Salaün Cc: Casey Schaufler Cc: James Morris Cc: Kees Cook Cc: Serge E. Hallyn Link: https://lkml.kernel.org/r/ccad825b-7a58-e499-e51b-bd7c98581afe@schaufler-ca.com --- security/security.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/security/security.c b/security/security.c index 549bddcc2116..6be65050b268 100644 --- a/security/security.c +++ b/security/security.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #define MAX_LSM_EVM_XATTR 2 @@ -86,6 +87,32 @@ static int __init choose_lsm(char *str) } __setup("security=", choose_lsm); +static bool match_last_lsm(const char *list, const char *last) +{ + size_t list_len, last_len, i; + + if (!list || !last) + return false; + list_len = strlen(list); + last_len = strlen(last); + if (!last_len || !list_len) + return false; + if (last_len > list_len) + return false; + + for (i = 0; i < last_len; i++) { + if (list[list_len - 1 - i] != last[last_len - 1 - i]) + return false; + } + /* Check if last_len == list_len */ + if (i == list_len) + return true; + /* Check if it is a full name */ + if (list[list_len - 1 - i] == ',') + return true; + return false; +} + static int lsm_append(char *new, char **result) { char *cp; @@ -93,6 +120,9 @@ static int lsm_append(char *new, char **result) if (*result == NULL) { *result = kstrdup(new, GFP_KERNEL); } else { + /* Check if it is the last registered name */ + if (match_last_lsm(*result, new)) + return 0; cp = kasprintf(GFP_KERNEL, "%s,%s", *result, new); if (cp == NULL) return -ENOMEM; -- 2.11.0