[PATCH V31 20/25] Lock down /proc/kcore

From: Matthew Garrett
Date: Tue Mar 26 2019 - 14:28:52 EST


From: David Howells <dhowells@xxxxxxxxxx>

Disallow access to /proc/kcore when the kernel is locked down to prevent
access to cryptographic data. This is limited to lockdown
confidentiality mode and is still permitted in integrity mode.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Signed-off-by: Matthew Garrett <mjg59@xxxxxxxxxx>
---
fs/proc/kcore.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index bbcc185062bb..1c556a453569 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", LOCKDOWN_CONFIDENTIALITY))
+ return -EPERM;
if (!capable(CAP_SYS_RAWIO))
return -EPERM;

--
2.21.0.392.gf8f6787159e-goog