iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
linux/security/integrity/integrity.h
Roberto Sassu 75a323e604 evm: Make it independent from 'integrity' LSM 
Define a new structure for EVM-specific metadata, called evm_iint_cache,
and embed it in the inode security blob. Introduce evm_iint_inode() to
retrieve metadata, and register evm_inode_alloc_security() for the
inode_alloc_security LSM hook, to initialize the structure (before
splitting metadata, this task was done by iint_init_always()).

Keep the non-NULL checks after calling evm_iint_inode() except in
evm_inode_alloc_security(), to take into account inodes for which
security_inode_alloc() was not called. When using shared metadata,
obtaining a NULL pointer from integrity_iint_find() meant that the file
wasn't in the IMA policy. Now, because IMA and EVM use disjoint metadata,
the EVM status has to be stored for every inode regardless of the IMA
policy.

Given that from now on EVM relies on its own metadata, remove the iint
parameter from evm_verifyxattr(). Also, directly retrieve the iint in
evm_verify_hmac(), called by both evm_verifyxattr() and
evm_verify_current_integrity(), since now there is no performance penalty
in retrieving EVM metadata (constant time).

Replicate the management of the IMA_NEW_FILE flag, by introducing
evm_post_path_mknod() and evm_file_release() to respectively set and clear
the newly introduced flag EVM_NEW_FILE, at the same time IMA does. Like for
IMA, select CONFIG_SECURITY_PATH when EVM is enabled, to ensure that files
are marked as new.

Unlike ima_post_path_mknod(), evm_post_path_mknod() cannot check if a file
must be appraised. Thus, it marks all affected files. Also, it does not
clear EVM_NEW_FILE depending on i_version, but that is not a problem
because IMA_NEW_FILE is always cleared when set in ima_check_last_writer().

Move the EVM-specific flag EVM_IMMUTABLE_DIGSIG to
security/integrity/evm/evm.h, since that definition is now unnecessary in
the common integrity layer.

Finally, switch to the LSM reservation mechanism for the EVM xattr, and
consequently decrement by one the number of xattrs to allocate in
security_inode_init_security().

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Acked-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15 23:43:47 -05:00

337 lines
8.9 KiB
C
Raw Blame History

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2009-2010 IBM Corporation
*
* Authors:
* Mimi Zohar <zohar@us.ibm.com>
*/
#ifdef pr_fmt
#undef pr_fmt
#endif
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/types.h>
#include <linux/integrity.h>
#include <crypto/sha1.h>
#include <crypto/hash.h>
#include <linux/key.h>
#include <linux/audit.h>
#include <linux/lsm_hooks.h>
/* iint action cache flags */
#define IMA_MEASURE 0x00000001
#define IMA_MEASURED 0x00000002
#define IMA_APPRAISE 0x00000004
#define IMA_APPRAISED 0x00000008
/*#define IMA_COLLECT 0x00000010 do not use this flag */
#define IMA_COLLECTED 0x00000020
#define IMA_AUDIT 0x00000040
#define IMA_AUDITED 0x00000080
#define IMA_HASH 0x00000100
#define IMA_HASHED 0x00000200
/* iint policy rule cache flags */
#define IMA_NONACTION_FLAGS 0xff000000
#define IMA_DIGSIG_REQUIRED 0x01000000
#define IMA_PERMIT_DIRECTIO 0x02000000
#define IMA_NEW_FILE 0x04000000
#define IMA_FAIL_UNVERIFIABLE_SIGS 0x10000000
#define IMA_MODSIG_ALLOWED 0x20000000
#define IMA_CHECK_BLACKLIST 0x40000000
#define IMA_VERITY_REQUIRED 0x80000000
#define IMA_DO_MASK (IMA_MEASURE | IMA_APPRAISE | IMA_AUDIT | \
IMA_HASH | IMA_APPRAISE_SUBMASK)
#define IMA_DONE_MASK (IMA_MEASURED | IMA_APPRAISED | IMA_AUDITED | \
IMA_HASHED | IMA_COLLECTED | \
IMA_APPRAISED_SUBMASK)
/* iint subaction appraise cache flags */
#define IMA_FILE_APPRAISE 0x00001000
#define IMA_FILE_APPRAISED 0x00002000
#define IMA_MMAP_APPRAISE 0x00004000
#define IMA_MMAP_APPRAISED 0x00008000
#define IMA_BPRM_APPRAISE 0x00010000
#define IMA_BPRM_APPRAISED 0x00020000
#define IMA_READ_APPRAISE 0x00040000
#define IMA_READ_APPRAISED 0x00080000
#define IMA_CREDS_APPRAISE 0x00100000
#define IMA_CREDS_APPRAISED 0x00200000
#define IMA_APPRAISE_SUBMASK (IMA_FILE_APPRAISE | IMA_MMAP_APPRAISE | \
IMA_BPRM_APPRAISE | IMA_READ_APPRAISE | \
IMA_CREDS_APPRAISE)
#define IMA_APPRAISED_SUBMASK (IMA_FILE_APPRAISED | IMA_MMAP_APPRAISED | \
IMA_BPRM_APPRAISED | IMA_READ_APPRAISED | \
IMA_CREDS_APPRAISED)
/* iint cache atomic_flags */
#define IMA_CHANGE_XATTR 0
#define IMA_UPDATE_XATTR 1
#define IMA_CHANGE_ATTR 2
#define IMA_DIGSIG 3
#define IMA_MUST_MEASURE 4
enum evm_ima_xattr_type {
IMA_XATTR_DIGEST = 0x01,
EVM_XATTR_HMAC,
EVM_IMA_XATTR_DIGSIG,
IMA_XATTR_DIGEST_NG,
EVM_XATTR_PORTABLE_DIGSIG,
IMA_VERITY_DIGSIG,
IMA_XATTR_LAST
};
struct evm_ima_xattr_data {
u8 type;
u8 data[];
} __packed;
/* Only used in the EVM HMAC code. */
struct evm_xattr {
struct evm_ima_xattr_data data;
u8 digest[SHA1_DIGEST_SIZE];
} __packed;
#define IMA_MAX_DIGEST_SIZE HASH_MAX_DIGESTSIZE
struct ima_digest_data {
u8 algo;
u8 length;
union {
struct {
u8 unused;
u8 type;
} sha1;
struct {
u8 type;
u8 algo;
} ng;
u8 data[2];
} xattr;
u8 digest[];
} __packed;
/*
* Instead of wrapping the ima_digest_data struct inside a local structure
* with the maximum hash size, define ima_max_digest_data struct.
*/
struct ima_max_digest_data {
struct ima_digest_data hdr;
u8 digest[HASH_MAX_DIGESTSIZE];
} __packed;
/*
* signature header format v2 - for using with asymmetric keys
*
* The signature_v2_hdr struct includes a signature format version
* to simplify defining new signature formats.
*
* signature format:
* version 2: regular file data hash based signature
* version 3: struct ima_file_id data based signature
*/
struct signature_v2_hdr {
uint8_t type; /* xattr type */
uint8_t version; /* signature format version */
uint8_t hash_algo; /* Digest algorithm [enum hash_algo] */
__be32 keyid; /* IMA key identifier - not X509/PGP specific */
__be16 sig_size; /* signature size */
uint8_t sig[]; /* signature payload */
} __packed;
/*
* IMA signature version 3 disambiguates the data that is signed, by
* indirectly signing the hash of the ima_file_id structure data,
* containing either the fsverity_descriptor struct digest or, in the
* future, the regular IMA file hash.
*
* (The hash of the ima_file_id structure is only of the portion used.)
*/
struct ima_file_id {
__u8 hash_type; /* xattr type [enum evm_ima_xattr_type] */
__u8 hash_algorithm; /* Digest algorithm [enum hash_algo] */
__u8 hash[HASH_MAX_DIGESTSIZE];
} __packed;
/* integrity data associated with an inode */
struct integrity_iint_cache {
struct rb_node rb_node; /* rooted in integrity_iint_tree */
struct mutex mutex; /* protects: version, flags, digest */
struct inode *inode; /* back pointer to inode in question */
u64 version; /* track inode changes */
unsigned long flags;
unsigned long measured_pcrs;
unsigned long atomic_flags;
unsigned long real_ino;
dev_t real_dev;
enum integrity_status ima_file_status:4;
enum integrity_status ima_mmap_status:4;
enum integrity_status ima_bprm_status:4;
enum integrity_status ima_read_status:4;
enum integrity_status ima_creds_status:4;
enum integrity_status evm_status:4;
struct ima_digest_data *ima_hash;
};
/* rbtree tree calls to lookup, insert, delete
* integrity data associated with an inode.
*/
struct integrity_iint_cache *integrity_iint_find(struct inode *inode);
int integrity_kernel_read(struct file *file, loff_t offset,
void *addr, unsigned long count);
#define INTEGRITY_KEYRING_EVM 0
#define INTEGRITY_KEYRING_IMA 1
#define INTEGRITY_KEYRING_PLATFORM 2
#define INTEGRITY_KEYRING_MACHINE 3
#define INTEGRITY_KEYRING_MAX 4
extern struct dentry *integrity_dir;
struct modsig;
#ifdef CONFIG_INTEGRITY_SIGNATURE
int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
const char *digest, int digestlen);
int integrity_modsig_verify(unsigned int id, const struct modsig *modsig);
int __init integrity_init_keyring(const unsigned int id);
int __init integrity_load_x509(const unsigned int id, const char *path);
int __init integrity_load_cert(const unsigned int id, const char *source,
const void *data, size_t len, key_perm_t perm);
#else
static inline int integrity_digsig_verify(const unsigned int id,
const char *sig, int siglen,
const char *digest, int digestlen)
{
return -EOPNOTSUPP;
}
static inline int integrity_modsig_verify(unsigned int id,
const struct modsig *modsig)
{
return -EOPNOTSUPP;
}
static inline int integrity_init_keyring(const unsigned int id)
{
return 0;
}
static inline int __init integrity_load_cert(const unsigned int id,
const char *source,
const void *data, size_t len,
key_perm_t perm)
{
return 0;
}
#endif /* CONFIG_INTEGRITY_SIGNATURE */
#ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS
int asymmetric_verify(struct key *keyring, const char *sig,
int siglen, const char *data, int datalen);
#else
static inline int asymmetric_verify(struct key *keyring, const char *sig,
int siglen, const char *data, int datalen)
{
return -EOPNOTSUPP;
}
#endif
#ifdef CONFIG_IMA_APPRAISE_MODSIG
int ima_modsig_verify(struct key *keyring, const struct modsig *modsig);
#else
static inline int ima_modsig_verify(struct key *keyring,
const struct modsig *modsig)
{
return -EOPNOTSUPP;
}
#endif
#ifdef CONFIG_IMA_LOAD_X509
void __init ima_load_x509(void);
#else
static inline void ima_load_x509(void)
{
}
#endif
#ifdef CONFIG_EVM_LOAD_X509
void __init evm_load_x509(void);
#else
static inline void evm_load_x509(void)
{
}
#endif
#ifdef CONFIG_INTEGRITY_AUDIT
/* declarations */
void integrity_audit_msg(int audit_msgno, struct inode *inode,
const unsigned char *fname, const char *op,
const char *cause, int result, int info);
void integrity_audit_message(int audit_msgno, struct inode *inode,
const unsigned char *fname, const char *op,
const char *cause, int result, int info,
int errno);
static inline struct audit_buffer *
integrity_audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, int type)
{
return audit_log_start(ctx, gfp_mask, type);
}
#else
static inline void integrity_audit_msg(int audit_msgno, struct inode *inode,
const unsigned char *fname,
const char *op, const char *cause,
int result, int info)
{
}
static inline void integrity_audit_message(int audit_msgno,
struct inode *inode,
const unsigned char *fname,
const char *op, const char *cause,
int result, int info, int errno)
{
}
static inline struct audit_buffer *
integrity_audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, int type)
{
return NULL;
}
#endif
#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
void __init add_to_platform_keyring(const char *source, const void *data,
size_t len);
#else
static inline void __init add_to_platform_keyring(const char *source,
const void *data, size_t len)
{
}
#endif
#ifdef CONFIG_INTEGRITY_MACHINE_KEYRING
void __init add_to_machine_keyring(const char *source, const void *data, size_t len);
bool __init imputed_trust_enabled(void);
#else
static inline void __init add_to_machine_keyring(const char *source,
const void *data, size_t len)
{
}
static inline bool __init imputed_trust_enabled(void)
{
return false;
}
#endif
Reference in New Issue View Git Blame Copy Permalink