diff options
Diffstat (limited to 'security/integrity/ima/ima_policy.c')
| -rw-r--r-- | security/integrity/ima/ima_policy.c | 217 |
1 files changed, 168 insertions, 49 deletions
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index c7dacd2eab7..40a7488f672 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -7,7 +7,7 @@ * the Free Software Foundation, version 2 of the License. * * ima_policy.c - * - initialize default measure policy rules + * - initialize default measure policy rules * */ #include <linux/module.h> @@ -16,15 +16,17 @@ #include <linux/magic.h> #include <linux/parser.h> #include <linux/slab.h> +#include <linux/genhd.h> #include "ima.h" /* flags definitions */ -#define IMA_FUNC 0x0001 -#define IMA_MASK 0x0002 +#define IMA_FUNC 0x0001 +#define IMA_MASK 0x0002 #define IMA_FSMAGIC 0x0004 #define IMA_UID 0x0008 #define IMA_FOWNER 0x0010 +#define IMA_FSUUID 0x0020 #define UNKNOWN 0 #define MEASURE 0x0001 /* same as IMA_MEASURE */ @@ -45,10 +47,12 @@ struct ima_rule_entry { enum ima_hooks func; int mask; unsigned long fsmagic; + u8 fsuuid[16]; kuid_t uid; kuid_t fowner; struct { void *rule; /* LSM file metadata specific */ + void *args_p; /* audit value */ int type; /* audit type */ } lsm[MAX_LSM_RULES]; }; @@ -65,35 +69,35 @@ struct ima_rule_entry { * and running executables. */ 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}, - {.action = DONT_MEASURE,.fsmagic = TMPFS_MAGIC,.flags = IMA_FSMAGIC}, - {.action = DONT_MEASURE,.fsmagic = RAMFS_MAGIC,.flags = IMA_FSMAGIC}, - {.action = DONT_MEASURE,.fsmagic = DEVPTS_SUPER_MAGIC,.flags = IMA_FSMAGIC}, - {.action = DONT_MEASURE,.fsmagic = BINFMTFS_MAGIC,.flags = IMA_FSMAGIC}, - {.action = DONT_MEASURE,.fsmagic = SECURITYFS_MAGIC,.flags = IMA_FSMAGIC}, - {.action = DONT_MEASURE,.fsmagic = SELINUX_MAGIC,.flags = IMA_FSMAGIC}, - {.action = MEASURE,.func = FILE_MMAP,.mask = MAY_EXEC, + {.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}, + {.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC}, + {.action = DONT_MEASURE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC}, + {.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC}, + {.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC}, + {.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC}, + {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC, .flags = IMA_FUNC | IMA_MASK}, - {.action = MEASURE,.func = BPRM_CHECK,.mask = MAY_EXEC, + {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC, .flags = IMA_FUNC | IMA_MASK}, - {.action = MEASURE,.func = FILE_CHECK,.mask = MAY_READ,.uid = GLOBAL_ROOT_UID, + {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ, .uid = GLOBAL_ROOT_UID, .flags = IMA_FUNC | IMA_MASK | IMA_UID}, + {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC}, }; 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 = GLOBAL_ROOT_UID,.flags = IMA_FOWNER}, + {.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 = GLOBAL_ROOT_UID, .flags = IMA_FOWNER}, }; static LIST_HEAD(ima_default_rules); @@ -118,6 +122,35 @@ static int __init default_appraise_policy_setup(char *str) } __setup("ima_appraise_tcb", default_appraise_policy_setup); +/* + * Although the IMA policy does not change, the LSM policy can be + * reloaded, leaving the IMA LSM based rules referring to the old, + * stale LSM policy. + * + * Update the IMA LSM based rules to reflect the reloaded LSM policy. + * We assume the rules still exist; and BUG_ON() if they don't. + */ +static void ima_lsm_update_rules(void) +{ + struct ima_rule_entry *entry, *tmp; + int result; + int i; + + mutex_lock(&ima_rules_mutex); + list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) { + for (i = 0; i < MAX_LSM_RULES; i++) { + if (!entry->lsm[i].rule) + continue; + result = security_filter_rule_init(entry->lsm[i].type, + Audit_equal, + entry->lsm[i].args_p, + &entry->lsm[i].rule); + BUG_ON(!entry->lsm[i].rule); + } + } + mutex_unlock(&ima_rules_mutex); +} + /** * ima_match_rules - determine whether an inode matches the measure rule. * @rule: a pointer to a rule @@ -134,13 +167,18 @@ static bool ima_match_rules(struct ima_rule_entry *rule, const struct cred *cred = current_cred(); int i; - if ((rule->flags & IMA_FUNC) && rule->func != func) + if ((rule->flags & IMA_FUNC) && + (rule->func != func && func != POST_SETATTR)) return false; - if ((rule->flags & IMA_MASK) && rule->mask != mask) + if ((rule->flags & IMA_MASK) && + (rule->mask != mask && func != POST_SETATTR)) return false; if ((rule->flags & IMA_FSMAGIC) && rule->fsmagic != inode->i_sb->s_magic) return false; + if ((rule->flags & IMA_FSUUID) && + memcmp(rule->fsuuid, inode->i_sb->s_uuid, sizeof(rule->fsuuid))) + return false; if ((rule->flags & IMA_UID) && !uid_eq(rule->uid, cred->uid)) return false; if ((rule->flags & IMA_FOWNER) && !uid_eq(rule->fowner, inode->i_uid)) @@ -148,10 +186,11 @@ static bool ima_match_rules(struct ima_rule_entry *rule, for (i = 0; i < MAX_LSM_RULES; i++) { int rc = 0; u32 osid, sid; + int retried = 0; if (!rule->lsm[i].rule) continue; - +retry: switch (i) { case LSM_OBJ_USER: case LSM_OBJ_ROLE: @@ -175,12 +214,39 @@ static bool ima_match_rules(struct ima_rule_entry *rule, default: break; } + if ((rc < 0) && (!retried)) { + retried = 1; + ima_lsm_update_rules(); + goto retry; + } if (!rc) return false; } return true; } +/* + * In addition to knowing that we need to appraise the file in general, + * we need to differentiate between calling hooks, for hook specific rules. + */ +static int get_subaction(struct ima_rule_entry *rule, int func) +{ + if (!(rule->flags & IMA_FUNC)) + return IMA_FILE_APPRAISE; + + switch (func) { + case MMAP_CHECK: + return IMA_MMAP_APPRAISE; + case BPRM_CHECK: + return IMA_BPRM_APPRAISE; + case MODULE_CHECK: + return IMA_MODULE_APPRAISE; + case FILE_CHECK: + default: + return IMA_FILE_APPRAISE; + } +} + /** * ima_match_policy - decision based on LSM and other conditions * @inode: pointer to an inode for which the policy decision is being made @@ -208,7 +274,12 @@ int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask, if (!ima_match_rules(entry, inode, func, mask)) continue; + action |= entry->flags & IMA_ACTION_FLAGS; + action |= entry->action & IMA_DO_MASK; + if (entry->action & IMA_APPRAISE) + action |= get_subaction(entry, func); + if (entry->action & IMA_DO_MASK) actmask &= ~(entry->action | entry->action << 1); else @@ -235,7 +306,7 @@ void __init ima_init_policy(void) 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, @@ -260,7 +331,7 @@ void __init ima_init_policy(void) */ void ima_update_policy(void) { - const char *op = "policy_update"; + static const char op[] = "policy_update"; const char *cause = "already exists"; int result = 1; int audit_info = 0; @@ -281,7 +352,8 @@ enum { 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 + Opt_func, Opt_mask, Opt_fsmagic, Opt_uid, Opt_fowner, + Opt_appraise_type, Opt_fsuuid, Opt_permit_directio }; static match_table_t policy_tokens = { @@ -299,25 +371,36 @@ static match_table_t policy_tokens = { {Opt_func, "func=%s"}, {Opt_mask, "mask=%s"}, {Opt_fsmagic, "fsmagic=%s"}, + {Opt_fsuuid, "fsuuid=%s"}, {Opt_uid, "uid=%s"}, {Opt_fowner, "fowner=%s"}, + {Opt_appraise_type, "appraise_type=%s"}, + {Opt_permit_directio, "permit_directio"}, {Opt_err, NULL} }; static int ima_lsm_rule_init(struct ima_rule_entry *entry, - char *args, int lsm_rule, int audit_type) + substring_t *args, int lsm_rule, int audit_type) { int result; if (entry->lsm[lsm_rule].rule) return -EINVAL; + entry->lsm[lsm_rule].args_p = match_strdup(args); + if (!entry->lsm[lsm_rule].args_p) + return -ENOMEM; + entry->lsm[lsm_rule].type = audit_type; result = security_filter_rule_init(entry->lsm[lsm_rule].type, - Audit_equal, args, + Audit_equal, + entry->lsm[lsm_rule].args_p, &entry->lsm[lsm_rule].rule); - if (!entry->lsm[lsm_rule].rule) + if (!entry->lsm[lsm_rule].rule) { + kfree(entry->lsm[lsm_rule].args_p); return -EINVAL; + } + return result; } @@ -401,8 +484,11 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) /* PATH_CHECK is for backwards compat */ else if (strcmp(args[0].from, "PATH_CHECK") == 0) entry->func = FILE_CHECK; - else if (strcmp(args[0].from, "FILE_MMAP") == 0) - entry->func = FILE_MMAP; + else if (strcmp(args[0].from, "MODULE_CHECK") == 0) + entry->func = MODULE_CHECK; + else if ((strcmp(args[0].from, "FILE_MMAP") == 0) + || (strcmp(args[0].from, "MMAP_CHECK") == 0)) + entry->func = MMAP_CHECK; else if (strcmp(args[0].from, "BPRM_CHECK") == 0) entry->func = BPRM_CHECK; else @@ -437,11 +523,24 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) break; } - result = strict_strtoul(args[0].from, 16, - &entry->fsmagic); + result = kstrtoul(args[0].from, 16, &entry->fsmagic); if (!result) entry->flags |= IMA_FSMAGIC; break; + case Opt_fsuuid: + ima_log_string(ab, "fsuuid", args[0].from); + + if (memchr_inv(entry->fsuuid, 0x00, + sizeof(entry->fsuuid))) { + result = -EINVAL; + break; + } + + result = blk_part_pack_uuid(args[0].from, + entry->fsuuid); + if (!result) + entry->flags |= IMA_FSUUID; + break; case Opt_uid: ima_log_string(ab, "uid", args[0].from); @@ -450,7 +549,7 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) break; } - result = strict_strtoul(args[0].from, 10, &lnum); + result = kstrtoul(args[0].from, 10, &lnum); if (!result) { entry->uid = make_kuid(current_user_ns(), (uid_t)lnum); if (!uid_valid(entry->uid) || (((uid_t)lnum) != lnum)) @@ -467,7 +566,7 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) break; } - result = strict_strtoul(args[0].from, 10, &lnum); + result = kstrtoul(args[0].from, 10, &lnum); if (!result) { entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum); if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum)) @@ -478,40 +577,55 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) break; case Opt_obj_user: ima_log_string(ab, "obj_user", args[0].from); - result = ima_lsm_rule_init(entry, args[0].from, + result = ima_lsm_rule_init(entry, args, LSM_OBJ_USER, AUDIT_OBJ_USER); break; case Opt_obj_role: ima_log_string(ab, "obj_role", args[0].from); - result = ima_lsm_rule_init(entry, args[0].from, + result = ima_lsm_rule_init(entry, args, LSM_OBJ_ROLE, AUDIT_OBJ_ROLE); break; case Opt_obj_type: ima_log_string(ab, "obj_type", args[0].from); - result = ima_lsm_rule_init(entry, args[0].from, + result = ima_lsm_rule_init(entry, args, LSM_OBJ_TYPE, AUDIT_OBJ_TYPE); break; case Opt_subj_user: ima_log_string(ab, "subj_user", args[0].from); - result = ima_lsm_rule_init(entry, args[0].from, + result = ima_lsm_rule_init(entry, args, LSM_SUBJ_USER, AUDIT_SUBJ_USER); break; case Opt_subj_role: ima_log_string(ab, "subj_role", args[0].from); - result = ima_lsm_rule_init(entry, args[0].from, + result = ima_lsm_rule_init(entry, args, LSM_SUBJ_ROLE, AUDIT_SUBJ_ROLE); break; case Opt_subj_type: ima_log_string(ab, "subj_type", args[0].from); - result = ima_lsm_rule_init(entry, args[0].from, + result = ima_lsm_rule_init(entry, args, LSM_SUBJ_TYPE, AUDIT_SUBJ_TYPE); break; + case Opt_appraise_type: + if (entry->action != APPRAISE) { + result = -EINVAL; + break; + } + + ima_log_string(ab, "appraise_type", args[0].from); + if ((strcmp(args[0].from, "imasig")) == 0) + entry->flags |= IMA_DIGSIG_REQUIRED; + else + result = -EINVAL; + break; + case Opt_permit_directio: + entry->flags |= IMA_PERMIT_DIRECTIO; + break; case Opt_err: ima_log_string(ab, "UNKNOWN", p); result = -EINVAL; @@ -520,7 +634,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) } if (!result && (entry->action == UNKNOWN)) result = -EINVAL; - + else if (entry->func == MODULE_CHECK) + ima_appraise |= IMA_APPRAISE_MODULES; audit_log_format(ab, "res=%d", !result); audit_log_end(ab); return result; @@ -535,7 +650,7 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) */ ssize_t ima_parse_add_rule(char *rule) { - const char *op = "update_policy"; + static const char op[] = "update_policy"; char *p; struct ima_rule_entry *entry; ssize_t result, len; @@ -586,9 +701,13 @@ ssize_t ima_parse_add_rule(char *rule) void ima_delete_rules(void) { struct ima_rule_entry *entry, *tmp; + int i; mutex_lock(&ima_rules_mutex); list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) { + for (i = 0; i < MAX_LSM_RULES; i++) + kfree(entry->lsm[i].args_p); + list_del(&entry->list); kfree(entry); } |