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From: Matthew Garrett <matthewgarrett@google.com>
To: jmorris@namei.org
Cc: linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org, dhowells@redhat.com,
	linux-api@vger.kernel.org, luto@kernel.org,
	Matthew Garrett <mjg59@google.com>,
	gregkh@linuxfoundation.org
Subject: [PATCH V31 25/25] debugfs: Disable open() when kernel is locked down
Date: Tue, 26 Mar 2019 11:27:41 -0700	[thread overview]
Message-ID: <20190326182742.16950-26-matthewgarrett@google.com> (raw)
In-Reply-To: <20190326182742.16950-1-matthewgarrett@google.com>

From: Matthew Garrett <mjg59@google.com>

debugfs has not been meaningfully audited in terms of ensuring that
userland cannot trample over the kernel. At Greg's request, disable
access to it entirely when the kernel is locked down. This is done at
open() time rather than init time as the kernel lockdown status may be
made stricter at runtime.

Signed-off-by: Matthew Garrett <mjg59@google.com>
Cc: gregkh@linuxfoundation.org
---
 fs/debugfs/file.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index 4fce1da7db23..9ae12ef29ba0 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -142,6 +142,9 @@ static int open_proxy_open(struct inode *inode, struct file *filp)
 	const struct file_operations *real_fops = NULL;
 	int r;
 
+	if (kernel_is_locked_down("debugfs", LOCKDOWN_INTEGRITY))
+		return -EPERM;
+
 	r = debugfs_file_get(dentry);
 	if (r)
 		return r == -EIO ? -ENOENT : r;
@@ -267,6 +270,9 @@ static int full_proxy_open(struct inode *inode, struct file *filp)
 	struct file_operations *proxy_fops = NULL;
 	int r;
 
+	if (kernel_is_locked_down("debugfs", LOCKDOWN_INTEGRITY))
+		return -EPERM;
+
 	r = debugfs_file_get(dentry);
 	if (r)
 		return r == -EIO ? -ENOENT : r;
-- 
2.21.0.392.gf8f6787159e-goog


  parent reply	other threads:[~2019-03-26 18:29 UTC|newest]

Thread overview: 78+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-26 18:27 [PATCH V31 00/25] Add support for kernel lockdown Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 01/25] Add the ability to lock down access to the running kernel image Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 02/25] Enforce module signatures if the kernel is locked down Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 03/25] Restrict /dev/{mem,kmem,port} when " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 04/25] kexec_load: Disable at runtime if " Matthew Garrett
2019-03-26 18:27   ` Matthew Garrett
2019-03-26 18:27   ` Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 05/25] Copy secure_boot flag in boot params across kexec reboot Matthew Garrett
2019-03-26 18:27   ` Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 06/25] kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE Matthew Garrett
2019-03-26 18:27   ` Matthew Garrett
2019-06-21  6:34   ` Dave Young
2019-06-21  6:34     ` Dave Young
2019-06-21  6:34     ` Dave Young
2019-06-21 20:13     ` Matthew Garrett
2019-06-21 20:13       ` Matthew Garrett
2019-06-21 20:14       ` Matthew Garrett
2019-06-21 20:14         ` Matthew Garrett
2019-06-21 20:14         ` Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 07/25] kexec_file: Restrict at runtime if the kernel is locked down Matthew Garrett
2019-03-26 18:27   ` Matthew Garrett
2019-06-21  6:43   ` Dave Young
2019-06-21  6:43     ` Dave Young
2019-06-21 20:18     ` Matthew Garrett
2019-06-21 20:18       ` Matthew Garrett
2019-06-21 20:18       ` Matthew Garrett
2019-06-24  1:52       ` Dave Young
2019-06-24  1:52         ` Dave Young
2019-06-24 21:06         ` Matthew Garrett
2019-06-24 21:06           ` Matthew Garrett
2019-06-24 21:27           ` Mimi Zohar
2019-06-24 21:27             ` Mimi Zohar
2019-06-25  0:02             ` Matthew Garrett
2019-06-25  0:02               ` Matthew Garrett
2019-06-25  1:46               ` Mimi Zohar
2019-06-25  1:46                 ` Mimi Zohar
2019-06-25  2:51           ` Dave Young
2019-06-25  2:51             ` Dave Young
2019-03-26 18:27 ` [PATCH V31 08/25] hibernate: Disable when " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 09/25] uswsusp: " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 10/25] PCI: Lock down BAR access " Matthew Garrett
2019-03-26 20:55   ` Andy Lutomirski
2019-03-26 21:19     ` Alex Williamson
2019-03-26 18:27 ` [PATCH V31 11/25] x86: Lock down IO port " Matthew Garrett
2019-03-26 20:56   ` Andy Lutomirski
2019-03-26 18:27 ` [PATCH V31 12/25] x86/msr: Restrict MSR " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 13/25] ACPI: Limit access to custom_method " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 14/25] acpi: Ignore acpi_rsdp kernel param when the kernel has been " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 15/25] acpi: Disable ACPI table override if the kernel is " Matthew Garrett
2019-03-26 18:27   ` Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 16/25] Prohibit PCMCIA CIS storage when " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 17/25] Lock down TIOCSSERIAL Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 18/25] Lock down module params that specify hardware parameters (eg. ioport) Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 19/25] x86/mmiotrace: Lock down the testmmiotrace module Matthew Garrett
2019-03-27 15:57   ` Steven Rostedt
2019-03-27 16:55     ` Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 20/25] Lock down /proc/kcore Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 21/25] Lock down kprobes when in confidentiality mode Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 22/25] bpf: Restrict bpf when kernel lockdown is " Matthew Garrett
2019-03-26 19:21   ` Andy Lutomirski
2019-03-26 18:27 ` [PATCH V31 23/25] Lock down perf when " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 24/25] lockdown: Print current->comm in restriction messages Matthew Garrett
2019-03-26 18:27 ` Matthew Garrett [this message]
2019-03-26 19:20   ` [PATCH V31 25/25] debugfs: Disable open() when kernel is locked down Andy Lutomirski
2019-03-26 19:21     ` Matthew Garrett
2019-03-27  0:30     ` Greg KH
2019-03-27  4:29       ` Andy Lutomirski
2019-03-27  5:06         ` Greg KH
2019-03-27  5:29           ` Andy Lutomirski
2019-03-27  5:33             ` Greg KH
2019-03-27 16:53               ` James Morris
2019-03-27 17:39               ` Andy Lutomirski
2019-03-27 17:42                 ` Matthew Garrett
2019-03-27 18:29                   ` Greg KH
2019-03-27 18:31                 ` Greg KH
2019-03-27  0:31   ` Greg KH
2019-03-27  2:06     ` Matthew Garrett
2019-03-27  2:35       ` Greg KH

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