Files
Harshit Mogalapalli 10d1c75ed4 ima: verify the previous kernel's IMA buffer lies in addressable RAM
Patch series "Address page fault in ima_restore_measurement_list()", v3.

When the second-stage kernel is booted via kexec with a limiting command
line such as "mem=<size>" we observe a pafe fault that happens.

    BUG: unable to handle page fault for address: ffff97793ff47000
    RIP: ima_restore_measurement_list+0xdc/0x45a
    #PF: error_code(0x0000)  not-present page

This happens on x86_64 only, as this is already fixed in aarch64 in
commit: cbf9c4b961 ("of: check previous kernel's ima-kexec-buffer
against memory bounds")


This patch (of 3):

When the second-stage kernel is booted with a limiting command line (e.g. 
"mem=<size>"), the IMA measurement buffer handed over from the previous
kernel may fall outside the addressable RAM of the new kernel.  Accessing
such a buffer can fault during early restore.

Introduce a small generic helper, ima_validate_range(), which verifies
that a physical [start, end] range for the previous-kernel IMA buffer lies
within addressable memory:
	- On x86, use pfn_range_is_mapped().
	- On OF based architectures, use page_is_ram().

Link: https://lkml.kernel.org/r/20251231061609.907170-1-harshit.m.mogalapalli@oracle.com
Link: https://lkml.kernel.org/r/20251231061609.907170-2-harshit.m.mogalapalli@oracle.com
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Cc: Alexander Graf <graf@amazon.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: guoweikang <guoweikang.kernel@gmail.com>
Cc: Henry Willard <henry.willard@oracle.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Bohac <jbohac@suse.cz>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: Jonathan McDowell <noodles@fb.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Paul Webb <paul.x.webb@oracle.com>
Cc: Sohil Mehta <sohil.mehta@intel.com>
Cc: Sourabh Jain <sourabhjain@linux.ibm.com>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Yifei Liu <yifei.l.liu@oracle.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26 19:07:10 -08:00

115 lines
2.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2008 IBM Corporation
* Author: Mimi Zohar <zohar@us.ibm.com>
*/
#ifndef _LINUX_IMA_H
#define _LINUX_IMA_H
#include <linux/kernel_read_file.h>
#include <linux/fs.h>
#include <linux/security.h>
#include <linux/kexec.h>
#include <crypto/hash_info.h>
struct linux_binprm;
#ifdef CONFIG_IMA
extern enum hash_algo ima_get_current_hash_algo(void);
extern int ima_file_hash(struct file *file, char *buf, size_t buf_size);
extern int ima_inode_hash(struct inode *inode, char *buf, size_t buf_size);
extern void ima_kexec_cmdline(int kernel_fd, const void *buf, int size);
extern int ima_measure_critical_data(const char *event_label,
const char *event_name,
const void *buf, size_t buf_len,
bool hash, u8 *digest, size_t digest_len);
#ifdef CONFIG_IMA_APPRAISE_BOOTPARAM
extern void ima_appraise_parse_cmdline(void);
#else
static inline void ima_appraise_parse_cmdline(void) {}
#endif
#ifdef CONFIG_IMA_KEXEC
extern void ima_add_kexec_buffer(struct kimage *image);
extern void ima_kexec_post_load(struct kimage *image);
#else
static inline void ima_kexec_post_load(struct kimage *image) {}
#endif
#else
static inline enum hash_algo ima_get_current_hash_algo(void)
{
return HASH_ALGO__LAST;
}
static inline int ima_file_hash(struct file *file, char *buf, size_t buf_size)
{
return -EOPNOTSUPP;
}
static inline int ima_inode_hash(struct inode *inode, char *buf, size_t buf_size)
{
return -EOPNOTSUPP;
}
static inline void ima_kexec_cmdline(int kernel_fd, const void *buf, int size) {}
static inline int ima_measure_critical_data(const char *event_label,
const char *event_name,
const void *buf, size_t buf_len,
bool hash, u8 *digest,
size_t digest_len)
{
return -ENOENT;
}
#endif /* CONFIG_IMA */
#ifdef CONFIG_HAVE_IMA_KEXEC
int __init ima_free_kexec_buffer(void);
int __init ima_get_kexec_buffer(void **addr, size_t *size);
int ima_validate_range(phys_addr_t phys, size_t size);
#endif
#ifdef CONFIG_IMA_SECURE_AND_OR_TRUSTED_BOOT
extern bool arch_ima_get_secureboot(void);
extern const char * const *arch_get_ima_policy(void);
#else
static inline bool arch_ima_get_secureboot(void)
{
return false;
}
static inline const char * const *arch_get_ima_policy(void)
{
return NULL;
}
#endif
#ifndef CONFIG_IMA_KEXEC
struct kimage;
static inline void ima_add_kexec_buffer(struct kimage *image)
{}
#endif
#ifdef CONFIG_IMA_APPRAISE
extern bool is_ima_appraise_enabled(void);
#else
static inline bool is_ima_appraise_enabled(void)
{
return 0;
}
#endif /* CONFIG_IMA_APPRAISE */
#if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING)
extern bool ima_appraise_signature(enum kernel_read_file_id func);
#else
static inline bool ima_appraise_signature(enum kernel_read_file_id func)
{
return false;
}
#endif /* CONFIG_IMA_APPRAISE && CONFIG_INTEGRITY_TRUSTED_KEYRING */
#endif /* _LINUX_IMA_H */