linux-kernel - [PATCH 21/27] Lock down /proc/kcore

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Message-Id: <20190325220954.29054-22-matthewgarrett@google.com>
Date:   Mon, 25 Mar 2019 15:09:48 -0700
From:   Matthew Garrett <matthewgarrett@...gle.com>
To:     jmorris@...ei.org
Cc:     linux-security-module@...r.kernel.org,
        linux-kernel@...r.kernel.org, dhowells@...hat.com,
        James Morris <james.l.morris@...cle.com>,
        Matthew Garrett <matthewgarrett@...gle.com>
Subject: [PATCH 21/27] Lock down /proc/kcore

From: David Howells <dhowells@...hat.com>

Disallow access to /proc/kcore when the kernel is locked down to prevent
access to cryptographic data.

Signed-off-by: David Howells <dhowells@...hat.com>
Reviewed-by: James Morris <james.l.morris@...cle.com>
Signed-off-by: Matthew Garrett <matthewgarrett@...gle.com>
---
 fs/proc/kcore.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index bbcc185062bb..d50ebfbf3dbb 100644
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c
@@ -518,6 +518,8 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
 
 static int open_kcore(struct inode *inode, struct file *filp)
 {
+	if (kernel_is_locked_down("/proc/kcore"))
+		return -EPERM;
 	if (!capable(CAP_SYS_RAWIO))
 		return -EPERM;
 
-- 
2.21.0.392.gf8f6787159e-goog