f9b2a735bd
Files are measured or appraised based on the IMA policy. When a file, in policy, is opened with the O_DIRECT flag, a deadlock occurs. The first attempt at resolving this lockdep temporarily removed the O_DIRECT flag and restored it, after calculating the hash. The second attempt introduced the O_DIRECT_HAVELOCK flag. Based on this flag, do_blockdev_direct_IO() would skip taking the i_mutex a second time. The third attempt, by Dmitry Kasatkin, resolves the i_mutex locking issue, by re-introducing the IMA mutex, but uncovered another problem. Reading a file with O_DIRECT flag set, writes directly to userspace pages. A second patch allocates a user-space like memory. This works for all IMA hooks, except ima_file_free(), which is called on __fput() to recalculate the file hash. Until this last issue is addressed, do not 'collect' the measurement for measuring, appraising, or auditing files opened with the O_DIRECT flag set. Based on policy, permit or deny file access. This patch defines a new IMA policy rule option named 'permit_directio'. Policy rules could be defined, based on LSM or other criteria, to permit specific applications to open files with the O_DIRECT flag set. Changelog v1: - permit or deny file access based IMA policy rules Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Acked-by: Dmitry Kasatkin <d.kasatkin@samsung.com> Cc: <stable@vger.kernel.org>
164 lines
4.5 KiB
C
164 lines
4.5 KiB
C
/*
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* Copyright (C) 2009-2010 IBM Corporation
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*
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* Authors:
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* Mimi Zohar <zohar@us.ibm.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, version 2 of the
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* License.
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*
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*/
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#include <linux/types.h>
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#include <linux/integrity.h>
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#include <crypto/sha.h>
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#include <linux/key.h>
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/* iint action cache flags */
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#define IMA_MEASURE 0x00000001
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#define IMA_MEASURED 0x00000002
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#define IMA_APPRAISE 0x00000004
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#define IMA_APPRAISED 0x00000008
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/*#define IMA_COLLECT 0x00000010 do not use this flag */
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#define IMA_COLLECTED 0x00000020
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#define IMA_AUDIT 0x00000040
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#define IMA_AUDITED 0x00000080
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/* iint cache flags */
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#define IMA_ACTION_FLAGS 0xff000000
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#define IMA_DIGSIG 0x01000000
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#define IMA_DIGSIG_REQUIRED 0x02000000
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#define IMA_PERMIT_DIRECTIO 0x04000000
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#define IMA_DO_MASK (IMA_MEASURE | IMA_APPRAISE | IMA_AUDIT | \
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IMA_APPRAISE_SUBMASK)
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#define IMA_DONE_MASK (IMA_MEASURED | IMA_APPRAISED | IMA_AUDITED | \
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IMA_COLLECTED | IMA_APPRAISED_SUBMASK)
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/* iint subaction appraise cache flags */
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#define IMA_FILE_APPRAISE 0x00000100
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#define IMA_FILE_APPRAISED 0x00000200
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#define IMA_MMAP_APPRAISE 0x00000400
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#define IMA_MMAP_APPRAISED 0x00000800
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#define IMA_BPRM_APPRAISE 0x00001000
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#define IMA_BPRM_APPRAISED 0x00002000
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#define IMA_MODULE_APPRAISE 0x00004000
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#define IMA_MODULE_APPRAISED 0x00008000
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#define IMA_APPRAISE_SUBMASK (IMA_FILE_APPRAISE | IMA_MMAP_APPRAISE | \
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IMA_BPRM_APPRAISE | IMA_MODULE_APPRAISE)
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#define IMA_APPRAISED_SUBMASK (IMA_FILE_APPRAISED | IMA_MMAP_APPRAISED | \
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IMA_BPRM_APPRAISED | IMA_MODULE_APPRAISED)
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enum evm_ima_xattr_type {
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IMA_XATTR_DIGEST = 0x01,
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EVM_XATTR_HMAC,
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EVM_IMA_XATTR_DIGSIG,
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IMA_XATTR_DIGEST_NG,
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};
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struct evm_ima_xattr_data {
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u8 type;
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u8 digest[SHA1_DIGEST_SIZE];
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} __packed;
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#define IMA_MAX_DIGEST_SIZE 64
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struct ima_digest_data {
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u8 algo;
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u8 length;
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union {
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struct {
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u8 unused;
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u8 type;
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} sha1;
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struct {
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u8 type;
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u8 algo;
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} ng;
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u8 data[2];
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} xattr;
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u8 digest[0];
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} __packed;
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/*
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* signature format v2 - for using with asymmetric keys
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*/
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struct signature_v2_hdr {
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uint8_t type; /* xattr type */
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uint8_t version; /* signature format version */
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uint8_t hash_algo; /* Digest algorithm [enum pkey_hash_algo] */
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uint32_t keyid; /* IMA key identifier - not X509/PGP specific */
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uint16_t sig_size; /* signature size */
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uint8_t sig[0]; /* signature payload */
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} __packed;
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/* integrity data associated with an inode */
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struct integrity_iint_cache {
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struct rb_node rb_node; /* rooted in integrity_iint_tree */
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struct inode *inode; /* back pointer to inode in question */
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u64 version; /* track inode changes */
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unsigned long flags;
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enum integrity_status ima_file_status:4;
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enum integrity_status ima_mmap_status:4;
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enum integrity_status ima_bprm_status:4;
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enum integrity_status ima_module_status:4;
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enum integrity_status evm_status:4;
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struct ima_digest_data *ima_hash;
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};
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/* rbtree tree calls to lookup, insert, delete
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* integrity data associated with an inode.
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*/
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struct integrity_iint_cache *integrity_iint_insert(struct inode *inode);
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struct integrity_iint_cache *integrity_iint_find(struct inode *inode);
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#define INTEGRITY_KEYRING_EVM 0
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#define INTEGRITY_KEYRING_MODULE 1
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#define INTEGRITY_KEYRING_IMA 2
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#define INTEGRITY_KEYRING_MAX 3
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#ifdef CONFIG_INTEGRITY_SIGNATURE
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int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
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const char *digest, int digestlen);
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#else
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static inline int integrity_digsig_verify(const unsigned int id,
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const char *sig, int siglen,
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const char *digest, int digestlen)
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{
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return -EOPNOTSUPP;
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}
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#endif /* CONFIG_INTEGRITY_SIGNATURE */
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#ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS
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int asymmetric_verify(struct key *keyring, const char *sig,
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int siglen, const char *data, int datalen);
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#else
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static inline int asymmetric_verify(struct key *keyring, const char *sig,
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int siglen, const char *data, int datalen)
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{
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return -EOPNOTSUPP;
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}
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#endif
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#ifdef CONFIG_INTEGRITY_AUDIT
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/* declarations */
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void integrity_audit_msg(int audit_msgno, struct inode *inode,
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const unsigned char *fname, const char *op,
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const char *cause, int result, int info);
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#else
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static inline void integrity_audit_msg(int audit_msgno, struct inode *inode,
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const unsigned char *fname,
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const char *op, const char *cause,
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int result, int info)
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{
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}
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#endif
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/* set during initialization */
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extern int iint_initialized;
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