linux-stable/include/linux/integrity.h
Roberto Sassu cdef685be5 evm: Allow xattr/attr operations for portable signatures
If files with portable signatures are copied from one location to another
or are extracted from an archive, verification can temporarily fail until
all xattrs/attrs are set in the destination. Only portable signatures may
be moved or copied from one file to another, as they don't depend on
system-specific information such as the inode generation. Instead portable
signatures must include security.ima.

Unlike other security.evm types, EVM portable signatures are also
immutable. Thus, it wouldn't be a problem to allow xattr/attr operations
when verification fails, as portable signatures will never be replaced with
the HMAC on possibly corrupted xattrs/attrs.

This patch first introduces a new integrity status called
INTEGRITY_FAIL_IMMUTABLE, that allows callers of
evm_verify_current_integrity() to detect that a portable signature didn't
pass verification and then adds an exception in evm_protect_xattr() and
evm_inode_setattr() for this status and returns 0 instead of -EPERM.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-05-21 12:48:39 -04:00

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1.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2009 IBM Corporation
* Author: Mimi Zohar <zohar@us.ibm.com>
*/
#ifndef _LINUX_INTEGRITY_H
#define _LINUX_INTEGRITY_H
#include <linux/fs.h>
enum integrity_status {
INTEGRITY_PASS = 0,
INTEGRITY_PASS_IMMUTABLE,
INTEGRITY_FAIL,
INTEGRITY_FAIL_IMMUTABLE,
INTEGRITY_NOLABEL,
INTEGRITY_NOXATTRS,
INTEGRITY_UNKNOWN,
};
/* List of EVM protected security xattrs */
#ifdef CONFIG_INTEGRITY
extern struct integrity_iint_cache *integrity_inode_get(struct inode *inode);
extern void integrity_inode_free(struct inode *inode);
extern void __init integrity_load_keys(void);
#else
static inline struct integrity_iint_cache *
integrity_inode_get(struct inode *inode)
{
return NULL;
}
static inline void integrity_inode_free(struct inode *inode)
{
return;
}
static inline void integrity_load_keys(void)
{
}
#endif /* CONFIG_INTEGRITY */
#ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS
extern int integrity_kernel_module_request(char *kmod_name);
#else
static inline int integrity_kernel_module_request(char *kmod_name)
{
return 0;
}
#endif /* CONFIG_INTEGRITY_ASYMMETRIC_KEYS */
#endif /* _LINUX_INTEGRITY_H */