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Commit 02e935bf authored by David Howells's avatar David Howells Committed by James Morris
Browse files

lockdown: Lock down /proc/kcore 



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: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarMatthew Garrett <mjg59@google.com>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarJames Morris <jmorris@namei.org>
parent 906357f7

fs/proc/kcore.c

+5 −0
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ 
#include <linux/ioport.h>

#include <linux/memory.h>

#include <linux/sched/task.h>

#include <linux/security.h>

#include <asm/sections.h>

#include "internal.h"
@@ -545,6 +546,10 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) 


static int open_kcore(struct inode *inode, struct file *filp)

{

	int ret = security_locked_down(LOCKDOWN_KCORE);



	if (ret)

		return ret;

	if (!capable(CAP_SYS_RAWIO))

		return -EPERM;

include/linux/security.h

+1 −0
Original line number Diff line number Diff line
@@ -116,6 +116,7 @@ enum lockdown_reason { 
	LOCKDOWN_MODULE_PARAMETERS,

	LOCKDOWN_MMIOTRACE,

	LOCKDOWN_INTEGRITY_MAX,

	LOCKDOWN_KCORE,

	LOCKDOWN_CONFIDENTIALITY_MAX,

};

security/lockdown/lockdown.c

+1 −0
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ static char *lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1] = { 
	[LOCKDOWN_MODULE_PARAMETERS] = "unsafe module parameters",

	[LOCKDOWN_MMIOTRACE] = "unsafe mmio",

	[LOCKDOWN_INTEGRITY_MAX] = "integrity",

	[LOCKDOWN_KCORE] = "/proc/kcore access",

	[LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality",

};