From e7c568e0fd0cf6d9c8ab8ea537ba8f3a3ae7c3d8 Mon Sep 17 00:00:00 2001 From: Peter Moody Date: Thu, 14 Jun 2012 10:04:36 -0700 Subject: ima: audit log hashes This adds an 'audit' policy action which audit logs file measurements. Changelog v6: - use new action flag handling (Dmitry Kasatkin). - removed whitespace (Mimi) Changelog v5: - use audit_log_untrustedstring. Changelog v4: - cleanup digest -> hash conversion. - use filename rather than d_path in ima_audit_measurement. Changelog v3: - Use newly exported audit_log_task_info for logging pid/ppid/uid/etc. - Update the ima_policy ABI documentation. Changelog v2: - Use 'audit' action rather than 'measure_and_audit' to permit auditing in the absence of measuring.. Changelog v1: - Initial posting. Signed-off-by: Peter Moody Signed-off-by: Mimi Zohar --- security/integrity/ima/ima.h | 2 ++ security/integrity/ima/ima_api.c | 32 +++++++++++++++++++++++++++++++- security/integrity/ima/ima_main.c | 9 ++++++--- security/integrity/ima/ima_policy.c | 11 +++++++++++ security/integrity/integrity.h | 7 +++++-- 5 files changed, 55 insertions(+), 6 deletions(-) (limited to 'security/integrity') diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index 48aa0d46d3e7..8180adde10b7 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -114,6 +114,8 @@ int ima_collect_measurement(struct integrity_iint_cache *iint, struct file *file); void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file, const unsigned char *filename); +void ima_audit_measurement(struct integrity_iint_cache *iint, + const unsigned char *filename); int ima_store_template(struct ima_template_entry *entry, int violation, struct inode *inode); void ima_template_show(struct seq_file *m, void *e, enum ima_show_type show); diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c index f0d60e754b3e..b356884fb3ef 100644 --- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -114,7 +114,7 @@ err_out: */ int ima_get_action(struct inode *inode, int mask, int function) { - int flags = IMA_MEASURE | IMA_APPRAISE; + int flags = IMA_MEASURE | IMA_AUDIT | IMA_APPRAISE; if (!ima_appraise) flags &= ~IMA_APPRAISE; @@ -207,3 +207,33 @@ void ima_store_measurement(struct integrity_iint_cache *iint, if (result < 0) kfree(entry); } + +void ima_audit_measurement(struct integrity_iint_cache *iint, + const unsigned char *filename) +{ + struct audit_buffer *ab; + char hash[(IMA_DIGEST_SIZE * 2) + 1]; + int i; + + if (iint->flags & IMA_AUDITED) + return; + + for (i = 0; i < IMA_DIGEST_SIZE; i++) + hex_byte_pack(hash + (i * 2), iint->ima_xattr.digest[i]); + hash[i * 2] = '\0'; + + ab = audit_log_start(current->audit_context, GFP_KERNEL, + AUDIT_INTEGRITY_RULE); + if (!ab) + return; + + audit_log_format(ab, "file="); + audit_log_untrustedstring(ab, filename); + audit_log_format(ab, " hash="); + audit_log_untrustedstring(ab, hash); + + audit_log_task_info(ab, current); + audit_log_end(ab); + + iint->flags |= IMA_AUDITED; +} diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 5da08b75d367..73c9a268253e 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -156,8 +156,8 @@ static int process_measurement(struct file *file, const unsigned char *filename, if (!ima_initialized || !S_ISREG(inode->i_mode)) return 0; - /* Determine if in appraise/measurement policy, - * returns IMA_MEASURE, IMA_APPRAISE bitmask. */ + /* Determine if in appraise/audit/measurement policy, + * returns IMA_MEASURE, IMA_APPRAISE, IMA_AUDIT bitmask. */ action = ima_get_action(inode, mask, function); if (!action) return 0; @@ -171,7 +171,8 @@ static int process_measurement(struct file *file, const unsigned char *filename, goto out; /* Determine if already appraised/measured based on bitmask - * (IMA_MEASURE, IMA_MEASURED, IMA_APPRAISE, IMA_APPRAISED) */ + * (IMA_MEASURE, IMA_MEASURED, IMA_APPRAISE, IMA_APPRAISED, + * IMA_AUDIT, IMA_AUDITED) */ iint->flags |= action; action &= ~((iint->flags & IMA_DONE_MASK) >> 1); @@ -202,6 +203,8 @@ static int process_measurement(struct file *file, const unsigned char *filename, if (action & IMA_APPRAISE) rc = ima_appraise_measurement(iint, file, !pathname ? filename : pathname); + if (action & IMA_AUDIT) + ima_audit_measurement(iint, !pathname ? filename : pathname); kfree(pathbuf); out: mutex_unlock(&inode->i_mutex); diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index f46f685a1711..cda903131dbf 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -31,6 +31,7 @@ #define DONT_MEASURE 0x0002 #define APPRAISE 0x0004 /* same as IMA_APPRAISE */ #define DONT_APPRAISE 0x0008 +#define AUDIT 0x0040 #define MAX_LSM_RULES 6 enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE, @@ -277,6 +278,7 @@ enum { Opt_err = -1, Opt_measure = 1, Opt_dont_measure, Opt_appraise, Opt_dont_appraise, + Opt_audit, Opt_obj_user, Opt_obj_role, Opt_obj_type, Opt_subj_user, Opt_subj_role, Opt_subj_type, Opt_func, Opt_mask, Opt_fsmagic, Opt_uid, Opt_fowner @@ -287,6 +289,7 @@ static match_table_t policy_tokens = { {Opt_dont_measure, "dont_measure"}, {Opt_appraise, "appraise"}, {Opt_dont_appraise, "dont_appraise"}, + {Opt_audit, "audit"}, {Opt_obj_user, "obj_user=%s"}, {Opt_obj_role, "obj_role=%s"}, {Opt_obj_type, "obj_type=%s"}, @@ -379,6 +382,14 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) entry->action = DONT_APPRAISE; break; + case Opt_audit: + ima_log_string(ab, "action", "audit"); + + if (entry->action != UNKNOWN) + result = -EINVAL; + + entry->action = AUDIT; + break; case Opt_func: ima_log_string(ab, "func", args[0].from); diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h index 564ba7db5f6a..403ba319a06a 100644 --- a/security/integrity/integrity.h +++ b/security/integrity/integrity.h @@ -22,12 +22,15 @@ #define IMA_APPRAISED 0x0008 /*#define IMA_COLLECT 0x0010 do not use this flag */ #define IMA_COLLECTED 0x0020 +#define IMA_AUDIT 0x0040 +#define IMA_AUDITED 0x0080 /* iint cache flags */ #define IMA_DIGSIG 0x0100 -#define IMA_DO_MASK (IMA_MEASURE | IMA_APPRAISE) -#define IMA_DONE_MASK (IMA_MEASURED | IMA_APPRAISED | IMA_COLLECTED) +#define IMA_DO_MASK (IMA_MEASURE | IMA_APPRAISE | IMA_AUDIT) +#define IMA_DONE_MASK (IMA_MEASURED | IMA_APPRAISED | IMA_AUDITED \ + | IMA_COLLECTED) enum evm_ima_xattr_type { IMA_XATTR_DIGEST = 0x01, -- cgit v1.2.3