diff options
Diffstat (limited to 'security/smack/smack_access.c')
| -rw-r--r-- | security/smack/smack_access.c | 141 |
1 files changed, 126 insertions, 15 deletions
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c index ac0a2707f6d..513dc1aa16d 100644 --- a/security/smack/smack_access.c +++ b/security/smack/smack_access.c @@ -59,11 +59,18 @@ LIST_HEAD(smack_known_list); */ static u32 smack_next_secid = 10; +/* + * what events do we log + * can be overwritten at run-time by /smack/logging + */ +int log_policy = SMACK_AUDIT_DENIED; + /** * 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 * @request: the access requested, in "MAY" format + * @a : a pointer to the audit data * * This function looks up the subject/object pair in the * access rule list and returns 0 if the access is permitted, @@ -78,10 +85,12 @@ static u32 smack_next_secid = 10; * will be on the list, so checking the pointers may be a worthwhile * optimization. */ -int smk_access(char *subject_label, char *object_label, int request) +int smk_access(char *subject_label, char *object_label, int request, + struct smk_audit_info *a) { u32 may = MAY_NOT; struct smack_rule *srp; + int rc = 0; /* * Hardcoded comparisons. @@ -89,8 +98,10 @@ int smk_access(char *subject_label, char *object_label, int request) * A star subject can't access any object. */ if (subject_label == smack_known_star.smk_known || - strcmp(subject_label, smack_known_star.smk_known) == 0) - return -EACCES; + strcmp(subject_label, smack_known_star.smk_known) == 0) { + rc = -EACCES; + goto out_audit; + } /* * An internet object can be accessed by any subject. * Tasks cannot be assigned the internet label. @@ -100,20 +111,20 @@ int smk_access(char *subject_label, char *object_label, int request) subject_label == smack_known_web.smk_known || strcmp(object_label, smack_known_web.smk_known) == 0 || strcmp(subject_label, smack_known_web.smk_known) == 0) - return 0; + goto out_audit; /* * A star object can be accessed by any subject. */ if (object_label == smack_known_star.smk_known || strcmp(object_label, smack_known_star.smk_known) == 0) - return 0; + goto out_audit; /* * An object can be accessed in any way by a subject * with the same label. */ if (subject_label == object_label || strcmp(subject_label, object_label) == 0) - return 0; + goto out_audit; /* * A hat subject can read any object. * A floor object can be read by any subject. @@ -121,10 +132,10 @@ int smk_access(char *subject_label, char *object_label, int request) if ((request & MAY_ANYREAD) == request) { if (object_label == smack_known_floor.smk_known || strcmp(object_label, smack_known_floor.smk_known) == 0) - return 0; + goto out_audit; if (subject_label == smack_known_hat.smk_known || strcmp(subject_label, smack_known_hat.smk_known) == 0) - return 0; + goto out_audit; } /* * Beyond here an explicit relationship is required. @@ -148,28 +159,36 @@ int smk_access(char *subject_label, char *object_label, int request) * This is a bit map operation. */ if ((request & may) == request) - return 0; + goto out_audit; - return -EACCES; + rc = -EACCES; +out_audit: +#ifdef CONFIG_AUDIT + if (a) + smack_log(subject_label, object_label, 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 * @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(char *obj_label, u32 mode) +int smk_curacc(char *obj_label, u32 mode, struct smk_audit_info *a) { int rc; + char *sp = current_security(); - rc = smk_access(current_security(), obj_label, mode); + rc = smk_access(sp, obj_label, mode, NULL); if (rc == 0) - return 0; + goto out_audit; /* * Return if a specific label has been designated as the @@ -177,14 +196,105 @@ int smk_curacc(char *obj_label, u32 mode) * have that label. */ if (smack_onlycap != NULL && smack_onlycap != current->cred->security) - return rc; + goto out_audit; if (capable(CAP_MAC_OVERRIDE)) return 0; +out_audit: +#ifdef CONFIG_AUDIT + if (a) + smack_log(sp, obj_label, mode, rc, a); +#endif return rc; } +#ifdef CONFIG_AUDIT +/** + * smack_str_from_perm : helper to transalate an int to a + * readable string + * @string : the string to fill + * @access : the int + * + */ +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) + string[i++] = 'w'; + if (access & MAY_EXEC) + string[i++] = 'x'; + if (access & MAY_APPEND) + string[i++] = 'a'; + string[i] = '\0'; +} +/** + * smack_log_callback - SMACK specific information + * will be called by generic audit code + * @ab : the audit_buffer + * @a : audit_data + * + */ +static void smack_log_callback(struct audit_buffer *ab, void *a) +{ + struct common_audit_data *ad = a; + struct smack_audit_data *sad = &ad->lsm_priv.smack_audit_data; + audit_log_format(ab, "lsm=SMACK fn=%s action=%s", ad->function, + sad->result ? "denied" : "granted"); + audit_log_format(ab, " subject="); + 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); +} + +/** + * smack_log - Audit the granting or denial of permissions. + * @subject_label : smack label of the requester + * @object_label : smack label of the object being accessed + * @request: requested permissions + * @result: result from smk_access + * @a: auxiliary audit data + * + * Audit the granting or denial of permissions in accordance + * with the policy. + */ +void smack_log(char *subject_label, char *object_label, int request, + int result, struct smk_audit_info *ad) +{ + char request_buffer[SMK_NUM_ACCESS_TYPE + 1]; + 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) + return; + if (result == 0 && (log_policy & SMACK_AUDIT_ACCEPT) == 0) + return; + + if (a->function == NULL) + a->function = "unknown"; + + /* end preparing the audit data */ + sad = &a->lsm_priv.smack_audit_data; + smack_str_from_perm(request_buffer, request); + sad->subject = subject_label; + sad->object = object_label; + sad->request = request_buffer; + sad->result = result; + a->lsm_pre_audit = smack_log_callback; + + common_lsm_audit(a); +} +#else /* #ifdef CONFIG_AUDIT */ +void smack_log(char *subject_label, char *object_label, int request, + int result, struct smk_audit_info *ad) +{ +} +#endif + static DEFINE_MUTEX(smack_known_lock); /** @@ -209,7 +319,8 @@ struct smack_known *smk_import_entry(const char *string, int len) if (found) smack[i] = '\0'; else if (i >= len || string[i] > '~' || string[i] <= ' ' || - string[i] == '/') { + string[i] == '/' || string[i] == '"' || + string[i] == '\\' || string[i] == '\'') { smack[i] = '\0'; found = 1; } else |