Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756834AbbHDOml (ORCPT ); Tue, 4 Aug 2015 10:42:41 -0400 Received: from mx2.suse.de ([195.135.220.15]:59329 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756776AbbHDOmd (ORCPT ); Tue, 4 Aug 2015 10:42:33 -0400 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Vasily Averin , Kees Cook , Josh Boyer , Eric Paris , Andrew Morton , Linus Torvalds , Jiri Slaby Subject: [PATCH 3.12 104/123] security_syslog() should be called once only Date: Tue, 4 Aug 2015 16:40:48 +0200 Message-Id: <54d5bb3fd06b0f070c298a07644bb705ab5c193f.1438699154.git.jslaby@suse.cz> X-Mailer: git-send-email 2.5.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2662 Lines: 85 From: Vasily Averin 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit d194e5d666225b04c7754471df0948f645b6ab3a upstream. The final version of commit 637241a900cb ("kmsg: honor dmesg_restrict sysctl on /dev/kmsg") lost few hooks, as result security_syslog() are processed incorrectly: - open of /dev/kmsg checks syslog access permissions by using check_syslog_permissions() where security_syslog() is not called if dmesg_restrict is set. - syslog syscall and /proc/kmsg calls do_syslog() where security_syslog can be executed twice (inside check_syslog_permissions() and then directly in do_syslog()) With this patch security_syslog() is called once only in all syslog-related operations regardless of dmesg_restrict value. Fixes: 637241a900cb ("kmsg: honor dmesg_restrict sysctl on /dev/kmsg") Signed-off-by: Vasily Averin Cc: Kees Cook Cc: Josh Boyer Cc: Eric Paris Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Jiri Slaby --- kernel/printk/printk.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index fbafa885eee1..e736e50d2d08 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -383,11 +383,11 @@ static int check_syslog_permissions(int type, bool from_file) * already done the capabilities checks at open time. */ if (from_file && type != SYSLOG_ACTION_OPEN) - return 0; + goto ok; if (syslog_action_restricted(type)) { if (capable(CAP_SYSLOG)) - return 0; + goto ok; /* * For historical reasons, accept CAP_SYS_ADMIN too, with * a warning. @@ -397,10 +397,11 @@ static int check_syslog_permissions(int type, bool from_file) "CAP_SYS_ADMIN but no CAP_SYSLOG " "(deprecated).\n", current->comm, task_pid_nr(current)); - return 0; + goto ok; } return -EPERM; } +ok: return security_syslog(type); } @@ -1130,10 +1131,6 @@ int do_syslog(int type, char __user *buf, int len, bool from_file) if (error) goto out; - error = security_syslog(type); - if (error) - return error; - switch (type) { case SYSLOG_ACTION_CLOSE: /* Close log */ break; -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/