[PATCH 21/27] Lock down /proc/kcore

Matthew Garrett matthewgarrett at google.com
Mon Mar 25 22:09:48 UTC 2019

From: David Howells <dhowells at redhat.com>

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

Signed-off-by: David Howells <dhowells at redhat.com>
Reviewed-by: James Morris <james.l.morris at oracle.com>
Signed-off-by: Matthew Garrett <matthewgarrett at google.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;

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