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From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Ingo Molnar <mingo@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Matthew Garrett <matthewgarrett@google.com>,
	James Morris James Morris <jmorris@namei.org>,
	LSM List <linux-security-module@vger.kernel.org>,
	Linux API <linux-api@vger.kernel.org>,
	Ben Hutchings <ben@decadent.org.uk>,
	Al Viro <viro@zeniv.linux.org.uk>
Subject: [PATCH 7/7 v2] tracing: Do not create tracefs files if tracefs lockdown is in effect
Date: Fri, 11 Oct 2019 20:57:54 -0400
Message-ID: <20191012005921.580293464@goodmis.org> (raw)
In-Reply-To: <20191012005747.210722465@goodmis.org>

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

If on boot up, lockdown is activated for tracefs, don't even bother creating
the files. This can also prevent instances from being created if lockdown is
in effect.

Link: http://lkml.kernel.org/r/CAHk-=whC6Ji=fWnjh2+eS4b15TnbsS4VPVtvBOwCy1jjEG_JHQ@mail.gmail.com

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 fs/tracefs/inode.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index eeeae0475da9..0caa151cae4e 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -16,6 +16,7 @@
 #include <linux/namei.h>
 #include <linux/tracefs.h>
 #include <linux/fsnotify.h>
+#include <linux/security.h>
 #include <linux/seq_file.h>
 #include <linux/parser.h>
 #include <linux/magic.h>
@@ -390,6 +391,9 @@ struct dentry *tracefs_create_file(const char *name, umode_t mode,
 	struct dentry *dentry;
 	struct inode *inode;
 
+	if (security_locked_down(LOCKDOWN_TRACEFS))
+		return NULL;
+
 	if (!(mode & S_IFMT))
 		mode |= S_IFREG;
 	BUG_ON(!S_ISREG(mode));
-- 
2.23.0



      parent reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-12  0:57 [PATCH 0/7 v2] tracing: Fix tracefs lockdown and various clean ups Steven Rostedt
2019-10-12  0:57 ` [PATCH 1/7 v2] tracefs: Revert ccbd54ff54e8 ("tracefs: Restrict tracefs when the kernel is locked down") Steven Rostedt
2019-10-12 22:56   ` Linus Torvalds
2019-10-13  0:35     ` Steven Rostedt
2019-10-13  0:39       ` Steven Rostedt
2019-10-12  0:57 ` [PATCH 2/7 v2] ftrace: Get a reference counter for the trace_array on filter files Steven Rostedt
2019-10-12  0:57 ` [PATCH 3/7 v2] tracing: Get trace_array reference for available_tracers files Steven Rostedt
2019-10-12  0:57 ` [PATCH 4/7 v2] tracing: Have trace events system open call tracing_open_generic_tr() Steven Rostedt
2019-10-12  2:09   ` Steven Rostedt
2019-10-12  0:57 ` [PATCH 5/7 v2] tracing: Add tracing_check_open_get_tr() Steven Rostedt
2019-10-12  0:57 ` [PATCH 6/7 v2] tracing: Add some more locked_down checks Steven Rostedt
2019-10-12  0:57 ` Steven Rostedt [this message]

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