--- zzzz-none-000/linux-3.10.107/security/smack/smack_access.c 2017-06-27 09:49:32.000000000 +0000 +++ scorpion-7490-727/linux-3.10.107/security/smack/smack_access.c 2021-02-04 17:41:59.000000000 +0000 @@ -84,6 +84,8 @@ * * Do the object check first because that is more * likely to differ. + * + * Allowing write access implies allowing locking. */ int smk_access_entry(char *subject_label, char *object_label, struct list_head *rule_list) @@ -92,20 +94,25 @@ struct smack_rule *srp; list_for_each_entry_rcu(srp, rule_list, list) { - if (srp->smk_object == object_label && - srp->smk_subject == subject_label) { + if (srp->smk_object->smk_known == object_label && + srp->smk_subject->smk_known == subject_label) { may = srp->smk_access; break; } } + /* + * MAY_WRITE implies MAY_LOCK. + */ + if ((may & MAY_WRITE) == MAY_WRITE) + may |= MAY_LOCK; return may; } /** * smk_access - determine if a subject has a specific access to an object - * @subject_label: a pointer to the subject's Smack label - * @object_label: a pointer to the object's Smack label + * @subject: a pointer to the subject's Smack label entry + * @object: a pointer to the object's Smack label entry * @request: the access requested, in "MAY" format * @a : a pointer to the audit data * @@ -115,19 +122,19 @@ * * Smack labels are shared on smack_list */ -int smk_access(char *subject_label, char *object_label, int request, - struct smk_audit_info *a) +int smk_access(struct smack_known *subject, struct smack_known *object, + int request, struct smk_audit_info *a) { - struct smack_known *skp; int may = MAY_NOT; int rc = 0; /* * Hardcoded comparisons. - * + */ + /* * A star subject can't access any object. */ - if (subject_label == smack_known_star.smk_known) { + if (subject == &smack_known_star) { rc = -EACCES; goto out_audit; } @@ -136,28 +143,28 @@ * Tasks cannot be assigned the internet label. * An internet subject can access any object. */ - if (object_label == smack_known_web.smk_known || - subject_label == smack_known_web.smk_known) + if (object == &smack_known_web || subject == &smack_known_web) goto out_audit; /* * A star object can be accessed by any subject. */ - if (object_label == smack_known_star.smk_known) + if (object == &smack_known_star) goto out_audit; /* * An object can be accessed in any way by a subject * with the same label. */ - if (subject_label == object_label) + if (subject->smk_known == object->smk_known) goto out_audit; /* - * A hat subject can read any object. - * A floor object can be read by any subject. + * A hat subject can read or lock any object. + * A floor object can be read or locked by any subject. */ - if ((request & MAY_ANYREAD) == request) { - if (object_label == smack_known_floor.smk_known) + if ((request & MAY_ANYREAD) == request || + (request & MAY_LOCK) == request) { + if (object == &smack_known_floor) goto out_audit; - if (subject_label == smack_known_hat.smk_known) + if (subject == &smack_known_hat) goto out_audit; } /* @@ -167,51 +174,76 @@ * good. A negative response from smk_access_entry() * indicates there is no entry for this pair. */ - skp = smk_find_entry(subject_label); rcu_read_lock(); - may = smk_access_entry(subject_label, object_label, &skp->smk_rules); + may = smk_access_entry(subject->smk_known, object->smk_known, + &subject->smk_rules); rcu_read_unlock(); - if (may > 0 && (request & may) == request) + if (may <= 0 || (request & may) != request) { + rc = -EACCES; goto out_audit; + } +#ifdef CONFIG_SECURITY_SMACK_BRINGUP + /* + * Return a positive value if using bringup mode. + * This allows the hooks to identify checks that + * succeed because of "b" rules. + */ + if (may & MAY_BRINGUP) + rc = SMACK_BRINGUP_ALLOW; +#endif - rc = -EACCES; out_audit: + +#ifdef CONFIG_SECURITY_SMACK_BRINGUP + if (rc < 0) { + if (object == smack_unconfined) + rc = SMACK_UNCONFINED_OBJECT; + if (subject == smack_unconfined) + rc = SMACK_UNCONFINED_SUBJECT; + } +#endif + #ifdef CONFIG_AUDIT if (a) - smack_log(subject_label, object_label, request, rc, a); + smack_log(subject->smk_known, object->smk_known, + request, rc, a); #endif + return rc; } /** - * smk_curacc - determine if current has a specific access to an object - * @obj_label: a pointer to the object's Smack label + * smk_tskacc - determine if a task has a specific access to an object + * @tsp: a pointer to the subject's task + * @obj_known: a pointer to the object's label entry * @mode: the access requested, in "MAY" format * @a : common audit data * - * This function checks the current subject label/object label pair + * This function checks the subject task's label/object label pair * in the access rule list and returns 0 if the access is permitted, - * non zero otherwise. It allows that current may have the capability + * non zero otherwise. It allows that the task may have the capability * to override the rules. */ -int smk_curacc(char *obj_label, u32 mode, struct smk_audit_info *a) +int smk_tskacc(struct task_smack *tsp, struct smack_known *obj_known, + u32 mode, struct smk_audit_info *a) { - struct task_smack *tsp = current_security(); - char *sp = smk_of_task(tsp); + struct smack_known *sbj_known = smk_of_task(tsp); int may; int rc; /* * Check the global rule list */ - rc = smk_access(sp, obj_label, mode, NULL); - if (rc == 0) { + rc = smk_access(sbj_known, obj_known, mode, NULL); + if (rc >= 0) { /* * If there is an entry in the task's rule list * it can further restrict access. */ - may = smk_access_entry(sp, obj_label, &tsp->smk_rules); + may = smk_access_entry(sbj_known->smk_known, + obj_known->smk_known, + &tsp->smk_rules); if (may < 0) goto out_audit; if ((mode & may) == mode) @@ -228,11 +260,31 @@ out_audit: #ifdef CONFIG_AUDIT if (a) - smack_log(sp, obj_label, mode, rc, a); + smack_log(sbj_known->smk_known, obj_known->smk_known, + mode, rc, a); #endif return rc; } +/** + * smk_curacc - determine if current has a specific access to an object + * @obj_known: a pointer to the object's Smack label entry + * @mode: the access requested, in "MAY" format + * @a : common audit data + * + * This function checks the current subject label/object label pair + * in the access rule list and returns 0 if the access is permitted, + * non zero otherwise. It allows that current may have the capability + * to override the rules. + */ +int smk_curacc(struct smack_known *obj_known, + u32 mode, struct smk_audit_info *a) +{ + struct task_smack *tsp = current_security(); + + return smk_tskacc(tsp, obj_known, mode, a); +} + #ifdef CONFIG_AUDIT /** * smack_str_from_perm : helper to transalate an int to a @@ -244,6 +296,7 @@ static inline void smack_str_from_perm(char *string, int access) { int i = 0; + if (access & MAY_READ) string[i++] = 'r'; if (access & MAY_WRITE) @@ -254,6 +307,8 @@ string[i++] = 'a'; if (access & MAY_TRANSMUTE) string[i++] = 't'; + if (access & MAY_LOCK) + string[i++] = 'l'; string[i] = '\0'; } /** @@ -274,7 +329,10 @@ audit_log_untrustedstring(ab, sad->subject); audit_log_format(ab, " object="); audit_log_untrustedstring(ab, sad->object); - audit_log_format(ab, " requested=%s", sad->request); + if (sad->request[0] == '\0') + audit_log_format(ab, " labels_differ"); + else + audit_log_format(ab, " requested=%s", sad->request); } /** @@ -291,12 +349,16 @@ void smack_log(char *subject_label, char *object_label, int request, int result, struct smk_audit_info *ad) { +#ifdef CONFIG_SECURITY_SMACK_BRINGUP + char request_buffer[SMK_NUM_ACCESS_TYPE + 5]; +#else char request_buffer[SMK_NUM_ACCESS_TYPE + 1]; +#endif struct smack_audit_data *sad; struct common_audit_data *a = &ad->a; /* check if we have to log the current event */ - if (result != 0 && (log_policy & SMACK_AUDIT_DENIED) == 0) + if (result < 0 && (log_policy & SMACK_AUDIT_DENIED) == 0) return; if (result == 0 && (log_policy & SMACK_AUDIT_ACCEPT) == 0) return; @@ -310,6 +372,21 @@ smack_str_from_perm(request_buffer, request); sad->subject = subject_label; sad->object = object_label; +#ifdef CONFIG_SECURITY_SMACK_BRINGUP + /* + * The result may be positive in bringup mode. + * A positive result is an allow, but not for normal reasons. + * Mark it as successful, but don't filter it out even if + * the logging policy says to do so. + */ + if (result == SMACK_UNCONFINED_SUBJECT) + strcat(request_buffer, "(US)"); + else if (result == SMACK_UNCONFINED_OBJECT) + strcat(request_buffer, "(UO)"); + + if (result > 0) + result = 0; +#endif sad->request = request_buffer; sad->result = result; @@ -324,21 +401,44 @@ DEFINE_MUTEX(smack_known_lock); +struct hlist_head smack_known_hash[SMACK_HASH_SLOTS]; + +/** + * smk_insert_entry - insert a smack label into a hash map, + * + * this function must be called under smack_known_lock + */ +void smk_insert_entry(struct smack_known *skp) +{ + unsigned int hash; + struct hlist_head *head; + + hash = full_name_hash(skp->smk_known, strlen(skp->smk_known)); + head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)]; + + hlist_add_head_rcu(&skp->smk_hashed, head); + list_add_rcu(&skp->list, &smack_known_list); +} + /** * smk_find_entry - find a label on the list, return the list entry * @string: a text string that might be a Smack label * * Returns a pointer to the entry in the label list that - * matches the passed string. + * matches the passed string or NULL if not found. */ struct smack_known *smk_find_entry(const char *string) { + unsigned int hash; + struct hlist_head *head; struct smack_known *skp; - list_for_each_entry_rcu(skp, &smack_known_list, list) { + hash = full_name_hash(string, strlen(string)); + head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)]; + + hlist_for_each_entry_rcu(skp, head, smk_hashed) if (strcmp(skp->smk_known, string) == 0) return skp; - } return NULL; } @@ -348,7 +448,7 @@ * @string: a text string that might contain a Smack label * @len: the maximum size, or zero if it is NULL terminated. * - * Returns a pointer to the clean label, or NULL + * Returns a pointer to the clean label or an error code. */ char *smk_parse_smack(const char *string, int len) { @@ -364,7 +464,7 @@ * including /smack/cipso and /smack/cipso2 */ if (string[0] == '-') - return NULL; + return ERR_PTR(-EINVAL); for (i = 0; i < len; i++) if (string[i] > '~' || string[i] <= ' ' || string[i] == '/' || @@ -372,13 +472,14 @@ break; if (i == 0 || i >= SMK_LONGLABEL) - return NULL; + return ERR_PTR(-EINVAL); smack = kzalloc(i + 1, GFP_KERNEL); - if (smack != NULL) { - strncpy(smack, string, i + 1); - smack[i] = '\0'; - } + if (smack == NULL) + return ERR_PTR(-ENOMEM); + + strncpy(smack, string, i); + return smack; } @@ -401,17 +502,16 @@ sap->flags |= NETLBL_SECATTR_MLS_CAT; sap->attr.mls.lvl = level; - sap->attr.mls.cat = netlbl_secattr_catmap_alloc(GFP_ATOMIC); - sap->attr.mls.cat->startbit = 0; + sap->attr.mls.cat = NULL; for (cat = 1, cp = catset, byte = 0; byte < len; cp++, byte++) for (m = 0x80; m != 0; m >>= 1, cat++) { if ((m & *cp) == 0) continue; - rc = netlbl_secattr_catmap_setbit(sap->attr.mls.cat, - cat, GFP_ATOMIC); + rc = netlbl_catmap_setbit(&sap->attr.mls.cat, + cat, GFP_ATOMIC); if (rc < 0) { - netlbl_secattr_catmap_free(sap->attr.mls.cat); + netlbl_catmap_free(sap->attr.mls.cat); return rc; } } @@ -425,7 +525,8 @@ * @len: the maximum size, or zero if it is NULL terminated. * * Returns a pointer to the entry in the label list that - * matches the passed string, adding it if necessary. + * matches the passed string, adding it if necessary, + * or an error code. */ struct smack_known *smk_import_entry(const char *string, int len) { @@ -435,8 +536,8 @@ int rc; smack = smk_parse_smack(string, len); - if (smack == NULL) - return NULL; + if (IS_ERR(smack)) + return ERR_CAST(smack); mutex_lock(&smack_known_lock); @@ -445,8 +546,10 @@ goto freeout; skp = kzalloc(sizeof(*skp), GFP_KERNEL); - if (skp == NULL) + if (skp == NULL) { + skp = ERR_PTR(-ENOMEM); goto freeout; + } skp->smk_known = smack; skp->smk_secid = smack_next_secid++; @@ -472,14 +575,14 @@ * Make sure that the entry is actually * filled before putting it on the list. */ - list_add_rcu(&skp->list, &smack_known_list); + smk_insert_entry(skp); goto unlockout; } /* * smk_netlbl_mls failed. */ kfree(skp); - skp = NULL; + skp = ERR_PTR(rc); freeout: kfree(smack); unlockout: @@ -489,34 +592,13 @@ } /** - * smk_import - import a smack label - * @string: a text string that might be a Smack label - * @len: the maximum size, or zero if it is NULL terminated. - * - * Returns a pointer to the label in the label list that - * matches the passed string, adding it if necessary. - */ -char *smk_import(const char *string, int len) -{ - struct smack_known *skp; - - /* labels cannot begin with a '-' */ - if (string[0] == '-') - return NULL; - skp = smk_import_entry(string, len); - if (skp == NULL) - return NULL; - return skp->smk_known; -} - -/** * smack_from_secid - find the Smack label associated with a secid * @secid: an integer that might be associated with a Smack label * - * Returns a pointer to the appropriate Smack label if there is one, + * Returns a pointer to the appropriate Smack label entry if there is one, * otherwise a pointer to the invalid Smack label. */ -char *smack_from_secid(const u32 secid) +struct smack_known *smack_from_secid(const u32 secid) { struct smack_known *skp; @@ -524,7 +606,7 @@ list_for_each_entry_rcu(skp, &smack_known_list, list) { if (skp->smk_secid == secid) { rcu_read_unlock(); - return skp->smk_known; + return skp; } } @@ -533,21 +615,52 @@ * of a secid that is not on the list. */ rcu_read_unlock(); - return smack_known_invalid.smk_known; + return &smack_known_invalid; } -/** - * smack_to_secid - find the secid associated with a Smack label - * @smack: the Smack label +/* + * Unless a process is running with one of these labels + * even having CAP_MAC_OVERRIDE isn't enough to grant + * privilege to violate MAC policy. If no labels are + * designated (the empty list case) capabilities apply to + * everyone. + */ +LIST_HEAD(smack_onlycap_list); +DEFINE_MUTEX(smack_onlycap_lock); + +/* + * Is the task privileged and allowed to be privileged + * by the onlycap rule. * - * Returns the appropriate secid if there is one, - * otherwise 0 + * Returns 1 if the task is allowed to be privileged, 0 if it's not. */ -u32 smack_to_secid(const char *smack) +int smack_privileged(int cap) { - struct smack_known *skp = smk_find_entry(smack); + struct smack_known *skp = smk_of_current(); + struct smack_known_list_elem *sklep; + + /* + * All kernel tasks are privileged + */ + if (unlikely(current->flags & PF_KTHREAD)) + return 1; - if (skp == NULL) + if (!capable(cap)) return 0; - return skp->smk_secid; + + rcu_read_lock(); + if (list_empty(&smack_onlycap_list)) { + rcu_read_unlock(); + return 1; + } + + list_for_each_entry_rcu(sklep, &smack_onlycap_list, list) { + if (sklep->smk_label == skp) { + rcu_read_unlock(); + return 1; + } + } + rcu_read_unlock(); + + return 0; }