diff options
| -rw-r--r-- | Documentation/ABI/testing/ima_policy | 25 | ||||
| -rw-r--r-- | Documentation/kernel-parameters.txt | 4 | ||||
| -rw-r--r-- | security/integrity/ima/ima_appraise.c | 5 | ||||
| -rw-r--r-- | security/integrity/ima/ima_policy.c | 151 |
4 files changed, 141 insertions, 44 deletions
diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index 6cd6daefaaed..dcff82205477 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -12,11 +12,14 @@ Description: then closing the file. The new policy takes effect after the file ima/policy is closed. + IMA appraisal, if configured, uses these file measurements + for local measurement appraisal. + rule format: action [condition ...] - action: measure | dont_measure + action: measure | dont_measure | appraise | dont_appraise condition:= base | lsm - base: [[func=] [mask=] [fsmagic=] [uid=]] + base: [[func=] [mask=] [fsmagic=] [uid=] [fowner]] lsm: [[subj_user=] [subj_role=] [subj_type=] [obj_user=] [obj_role=] [obj_type=]] @@ -24,36 +27,50 @@ Description: mask:= [MAY_READ] [MAY_WRITE] [MAY_APPEND] [MAY_EXEC] fsmagic:= hex value uid:= decimal value + fowner:=decimal value lsm: are LSM specific default policy: # PROC_SUPER_MAGIC dont_measure fsmagic=0x9fa0 + dont_appraise fsmagic=0x9fa0 # SYSFS_MAGIC dont_measure fsmagic=0x62656572 + dont_appraise fsmagic=0x62656572 # DEBUGFS_MAGIC dont_measure fsmagic=0x64626720 + dont_appraise fsmagic=0x64626720 # TMPFS_MAGIC dont_measure fsmagic=0x01021994 + dont_appraise fsmagic=0x01021994 + # RAMFS_MAGIC + dont_measure fsmagic=0x858458f6 + dont_appraise fsmagic=0x858458f6 # SECURITYFS_MAGIC dont_measure fsmagic=0x73636673 + dont_appraise fsmagic=0x73636673 measure func=BPRM_CHECK measure func=FILE_MMAP mask=MAY_EXEC measure func=FILE_CHECK mask=MAY_READ uid=0 + appraise fowner=0 The default policy measures all executables in bprm_check, all files mmapped executable in file_mmap, and all files - open for read by root in do_filp_open. + open for read by root in do_filp_open. The default appraisal + policy appraises all files owned by root. Examples of LSM specific definitions: SELinux: # SELINUX_MAGIC - dont_measure fsmagic=0xF97CFF8C + dont_measure fsmagic=0xf97cff8c + dont_appraise fsmagic=0xf97cff8c dont_measure obj_type=var_log_t + dont_appraise obj_type=var_log_t dont_measure obj_type=auditd_log_t + dont_appraise obj_type=auditd_log_t measure subj_user=system_u func=FILE_CHECK mask=MAY_READ measure subj_role=system_r func=FILE_CHECK mask=MAY_READ diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index fa09e64d9877..949dddcfd177 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1055,6 +1055,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Format: { "off" | "enforce" | "fix" } default: "enforce" + ima_appraise_tcb [IMA] + The builtin appraise policy appraises all files + owned by uid=0. + ima_audit= [IMA] Format: { "0" | "1" } 0 -- integrity auditing messages. (Default) diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c index 4865f61f9044..681cb6e72257 100644 --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -36,7 +36,10 @@ __setup("ima_appraise=", default_appraise_setup); */ int ima_must_appraise(struct inode *inode, enum ima_hooks func, int mask) { - return 0; + if (!ima_appraise) + return 0; + + return ima_match_policy(inode, func, mask, IMA_APPRAISE); } static void ima_fix_xattr(struct dentry *dentry, diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 3e22e17da295..0d6d60b4ba6f 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -24,6 +24,7 @@ #define IMA_MASK 0x0002 #define IMA_FSMAGIC 0x0004 #define IMA_UID 0x0008 +#define IMA_FOWNER 0x0010 #define UNKNOWN 0 #define MEASURE 1 /* same as IMA_MEASURE */ @@ -38,7 +39,7 @@ enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE, LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE }; -struct ima_measure_rule_entry { +struct ima_rule_entry { struct list_head list; int action; unsigned int flags; @@ -46,6 +47,7 @@ struct ima_measure_rule_entry { int mask; unsigned long fsmagic; uid_t uid; + uid_t fowner; struct { void *rule; /* LSM file metadata specific */ int type; /* audit type */ @@ -54,7 +56,7 @@ struct ima_measure_rule_entry { /* * Without LSM specific knowledge, the default policy can only be - * written in terms of .action, .func, .mask, .fsmagic, and .uid + * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner */ /* @@ -63,7 +65,7 @@ struct ima_measure_rule_entry { * normal users can easily run the machine out of memory simply building * and running executables. */ -static struct ima_measure_rule_entry default_rules[] = { +static struct ima_rule_entry default_rules[] = { {.action = DONT_MEASURE,.fsmagic = PROC_SUPER_MAGIC,.flags = IMA_FSMAGIC}, {.action = DONT_MEASURE,.fsmagic = SYSFS_MAGIC,.flags = IMA_FSMAGIC}, {.action = DONT_MEASURE,.fsmagic = DEBUGFS_MAGIC,.flags = IMA_FSMAGIC}, @@ -81,19 +83,41 @@ static struct ima_measure_rule_entry default_rules[] = { .flags = IMA_FUNC | IMA_MASK | IMA_UID}, }; -static LIST_HEAD(measure_default_rules); -static LIST_HEAD(measure_policy_rules); -static struct list_head *ima_measure; +static struct ima_rule_entry default_appraise_rules[] = { + {.action = DONT_APPRAISE,.fsmagic = PROC_SUPER_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = SYSFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = DEBUGFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = TMPFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = RAMFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = DEVPTS_SUPER_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = BINFMTFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = SECURITYFS_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = SELINUX_MAGIC,.flags = IMA_FSMAGIC}, + {.action = DONT_APPRAISE,.fsmagic = CGROUP_SUPER_MAGIC,.flags = IMA_FSMAGIC}, + {.action = APPRAISE,.fowner = 0,.flags = IMA_FOWNER}, +}; + +static LIST_HEAD(ima_default_rules); +static LIST_HEAD(ima_policy_rules); +static struct list_head *ima_rules; -static DEFINE_MUTEX(ima_measure_mutex); +static DEFINE_MUTEX(ima_rules_mutex); static bool ima_use_tcb __initdata; -static int __init default_policy_setup(char *str) +static int __init default_measure_policy_setup(char *str) { ima_use_tcb = 1; return 1; } -__setup("ima_tcb", default_policy_setup); +__setup("ima_tcb", default_measure_policy_setup); + +static bool ima_use_appraise_tcb __initdata; +static int __init default_appraise_policy_setup(char *str) +{ + ima_use_appraise_tcb = 1; + return 1; +} +__setup("ima_appraise_tcb", default_appraise_policy_setup); /** * ima_match_rules - determine whether an inode matches the measure rule. @@ -104,7 +128,7 @@ __setup("ima_tcb", default_policy_setup); * * Returns true on rule match, false on failure. */ -static bool ima_match_rules(struct ima_measure_rule_entry *rule, +static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode, enum ima_hooks func, int mask) { struct task_struct *tsk = current; @@ -120,6 +144,8 @@ static bool ima_match_rules(struct ima_measure_rule_entry *rule, return false; if ((rule->flags & IMA_UID) && rule->uid != cred->uid) return false; + if ((rule->flags & IMA_FOWNER) && rule->fowner != inode->i_uid) + return false; for (i = 0; i < MAX_LSM_RULES; i++) { int rc = 0; u32 osid, sid; @@ -172,10 +198,10 @@ static bool ima_match_rules(struct ima_measure_rule_entry *rule, int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask, int flags) { - struct ima_measure_rule_entry *entry; + struct ima_rule_entry *entry; int action = 0, actmask = flags | (flags << 1); - list_for_each_entry(entry, ima_measure, list) { + list_for_each_entry(entry, ima_rules, list) { if (!(entry->action & actmask)) continue; @@ -196,22 +222,31 @@ int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask, /** * ima_init_policy - initialize the default measure rules. * - * ima_measure points to either the measure_default_rules or the - * the new measure_policy_rules. + * ima_rules points to either the ima_default_rules or the + * the new ima_policy_rules. */ void __init ima_init_policy(void) { - int i, entries; + int i, measure_entries, appraise_entries; /* if !ima_use_tcb set entries = 0 so we load NO default rules */ - if (ima_use_tcb) - entries = ARRAY_SIZE(default_rules); - else - entries = 0; - - for (i = 0; i < entries; i++) - list_add_tail(&default_rules[i].list, &measure_default_rules); - ima_measure = &measure_default_rules; + measure_entries = ima_use_tcb ? ARRAY_SIZE(default_rules) : 0; + appraise_entries = ima_use_appraise_tcb ? + ARRAY_SIZE(default_appraise_rules) : 0; + + for (i = 0; i < measure_entries + appraise_entries; i++) { + if (i < measure_entries) + list_add_tail(&default_rules[i].list, + &ima_default_rules); + else { + int j = i - measure_entries; + + list_add_tail(&default_appraise_rules[j].list, + &ima_default_rules); + } + } + + ima_rules = &ima_default_rules; } /** @@ -228,8 +263,8 @@ void ima_update_policy(void) int result = 1; int audit_info = 0; - if (ima_measure == &measure_default_rules) { - ima_measure = &measure_policy_rules; + if (ima_rules == &ima_default_rules) { + ima_rules = &ima_policy_rules; cause = "complete"; result = 0; } @@ -240,14 +275,17 @@ void ima_update_policy(void) enum { Opt_err = -1, Opt_measure = 1, Opt_dont_measure, + Opt_appraise, Opt_dont_appraise, 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_func, Opt_mask, Opt_fsmagic, Opt_uid, Opt_fowner }; static match_table_t policy_tokens = { {Opt_measure, "measure"}, {Opt_dont_measure, "dont_measure"}, + {Opt_appraise, "appraise"}, + {Opt_dont_appraise, "dont_appraise"}, {Opt_obj_user, "obj_user=%s"}, {Opt_obj_role, "obj_role=%s"}, {Opt_obj_type, "obj_type=%s"}, @@ -258,10 +296,11 @@ static match_table_t policy_tokens = { {Opt_mask, "mask=%s"}, {Opt_fsmagic, "fsmagic=%s"}, {Opt_uid, "uid=%s"}, + {Opt_fowner, "fowner=%s"}, {Opt_err, NULL} }; -static int ima_lsm_rule_init(struct ima_measure_rule_entry *entry, +static int ima_lsm_rule_init(struct ima_rule_entry *entry, char *args, int lsm_rule, int audit_type) { int result; @@ -285,7 +324,7 @@ static void ima_log_string(struct audit_buffer *ab, char *key, char *value) audit_log_format(ab, " "); } -static int ima_parse_rule(char *rule, struct ima_measure_rule_entry *entry) +static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) { struct audit_buffer *ab; char *p; @@ -294,6 +333,7 @@ static int ima_parse_rule(char *rule, struct ima_measure_rule_entry *entry) ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE); entry->uid = -1; + entry->fowner = -1; entry->action = UNKNOWN; while ((p = strsep(&rule, " \t")) != NULL) { substring_t args[MAX_OPT_ARGS]; @@ -322,11 +362,27 @@ static int ima_parse_rule(char *rule, struct ima_measure_rule_entry *entry) entry->action = DONT_MEASURE; break; + case Opt_appraise: + ima_log_string(ab, "action", "appraise"); + + if (entry->action != UNKNOWN) + result = -EINVAL; + + entry->action = APPRAISE; + break; + case Opt_dont_appraise: + ima_log_string(ab, "action", "dont_appraise"); + + if (entry->action != UNKNOWN) + result = -EINVAL; + + entry->action = DONT_APPRAISE; + break; case Opt_func: ima_log_string(ab, "func", args[0].from); if (entry->func) - result = -EINVAL; + result = -EINVAL; if (strcmp(args[0].from, "FILE_CHECK") == 0) entry->func = FILE_CHECK; @@ -391,6 +447,23 @@ static int ima_parse_rule(char *rule, struct ima_measure_rule_entry *entry) entry->flags |= IMA_UID; } break; + case Opt_fowner: + ima_log_string(ab, "fowner", args[0].from); + + if (entry->fowner != -1) { + result = -EINVAL; + break; + } + + result = strict_strtoul(args[0].from, 10, &lnum); + if (!result) { + entry->fowner = (uid_t) lnum; + if (entry->fowner != lnum) + result = -EINVAL; + else + entry->flags |= IMA_FOWNER; + } + break; case Opt_obj_user: ima_log_string(ab, "obj_user", args[0].from); result = ima_lsm_rule_init(entry, args[0].from, @@ -442,7 +515,7 @@ static int ima_parse_rule(char *rule, struct ima_measure_rule_entry *entry) } /** - * ima_parse_add_rule - add a rule to measure_policy_rules + * ima_parse_add_rule - add a rule to ima_policy_rules * @rule - ima measurement policy rule * * Uses a mutex to protect the policy list from multiple concurrent writers. @@ -452,12 +525,12 @@ ssize_t ima_parse_add_rule(char *rule) { const char *op = "update_policy"; char *p; - struct ima_measure_rule_entry *entry; + struct ima_rule_entry *entry; ssize_t result, len; int audit_info = 0; /* Prevent installed policy from changing */ - if (ima_measure != &measure_default_rules) { + if (ima_rules != &ima_default_rules) { integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL, op, "already exists", -EACCES, audit_info); @@ -490,9 +563,9 @@ ssize_t ima_parse_add_rule(char *rule) return result; } - mutex_lock(&ima_measure_mutex); - list_add_tail(&entry->list, &measure_policy_rules); - mutex_unlock(&ima_measure_mutex); + mutex_lock(&ima_rules_mutex); + list_add_tail(&entry->list, &ima_policy_rules); + mutex_unlock(&ima_rules_mutex); return len; } @@ -500,12 +573,12 @@ ssize_t ima_parse_add_rule(char *rule) /* ima_delete_rules called to cleanup invalid policy */ void ima_delete_rules(void) { - struct ima_measure_rule_entry *entry, *tmp; + struct ima_rule_entry *entry, *tmp; - mutex_lock(&ima_measure_mutex); - list_for_each_entry_safe(entry, tmp, &measure_policy_rules, list) { + mutex_lock(&ima_rules_mutex); + list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) { list_del(&entry->list); kfree(entry); } - mutex_unlock(&ima_measure_mutex); + mutex_unlock(&ima_rules_mutex); } |