linux-kernel - [PATCH 20/24] Lock down /proc/kcore

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Message-ID: <152346400916.4030.1623673477529314083.stgit@warthog.procyon.org.uk>
Date:   Wed, 11 Apr 2018 17:26:49 +0100
From:   David Howells <dhowells@...hat.com>
To:     torvalds@...ux-foundation.org
Cc:     linux-man@...r.kernel.org, linux-api@...r.kernel.org,
        jmorris@...ei.org, linux-kernel@...r.kernel.org,
        dhowells@...hat.com, linux-security-module@...r.kernel.org
Subject: [PATCH 20/24] Lock down /proc/kcore

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>
---

 fs/proc/kcore.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index d1e82761de81..cdebdee81719 100644
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c
@@ -546,6 +546,8 @@ 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;