Re: [PATCH v3] audit: add fields to exclude filter by reusing user filter

RFE: add additional fields for use in audit filter exclude rules https://github.com/linux-audit/audit-kernel/issues/5 Re-factor and combine audit_filter_type() with audit_filter_user() to use audit_filter_user_rules() to enable the exclude filter to additionally filter on PID, UID, GID, AUID, LOGINUID_SET, SUBJ_*. The process of combining the similar audit_filter_user() and audit_filter_type() functions, required inverting the meaning and including the ALWAYS action of the latter. Include audit_filter_user_rules() into audit_filter(), removing unneeded logic in the process. Keep the check to quit early if the list is empty. Signed-off-by: Richard Guy Briggs <rgb(a)redhat.com&gt; --- v3: pull audit_filter_user_rules() into audit_filter() and simplify logic. v2: combine audit_filter_user() and audit_filter_type() into audit_filter(). --- include/linux/audit.h | 2 - kernel/audit.c | 4 +- kernel/audit.h | 2 + kernel/auditfilter.c | 147 ++++++++++++++++++------------------------------- 4 files changed, 57 insertions(+), 98 deletions(-)

diff --git a/include/linux/audit.h b/include/linux/audit.h index 32cdafb..539c1d9 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -160,8 +160,6 @@ extern void audit_log_task_info(struct audit_buffer *ab, extern int audit_update_lsm_rules(void); /* Private API (for audit.c only) */ -extern int audit_filter_user(int type); -extern int audit_filter_type(int type); extern int audit_rule_change(int type, __u32 portid, int seq, void *data, size_t datasz); extern int audit_list_rules_send(struct sk_buff *request_skb, int seq); diff --git a/kernel/audit.c b/kernel/audit.c index 384374a..2dfaa19 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -914,7 +914,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) if (!audit_enabled && msg_type != AUDIT_USER_AVC) return 0; - err = audit_filter_user(msg_type); + err = audit_filter(msg_type, AUDIT_FILTER_USER); if (err == 1) { /* match or error */ err = 0; if (msg_type == AUDIT_USER_TTY) { @@ -1362,7 +1362,7 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, if (audit_initialized != AUDIT_INITIALIZED) return NULL; - if (unlikely(audit_filter_type(type))) + if (unlikely(!audit_filter(type, AUDIT_FILTER_TYPE))) return NULL; if (gfp_mask & __GFP_DIRECT_RECLAIM) { diff --git a/kernel/audit.h b/kernel/audit.h index cbbe6bb..1879f02 100644 --- a/kernel/audit.h +++ b/kernel/audit.h @@ -327,6 +327,8 @@ extern pid_t audit_sig_pid; extern kuid_t audit_sig_uid; extern u32 audit_sig_sid; +extern int audit_filter(int msgtype, unsigned int listtype); + #ifdef CONFIG_AUDITSYSCALL extern int __audit_signal_info(int sig, struct task_struct *t); static inline int audit_signal_info(int sig, struct task_struct *t) diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c index 96c9a1b..60579ec 100644 --- a/kernel/auditfilter.c +++ b/kernel/auditfilter.c @@ -1290,113 +1290,72 @@ int audit_compare_dname_path(const char *dname, const char *path, int parentlen) return strncmp(p, dname, dlen); } -static int audit_filter_user_rules(struct audit_krule *rule, int type, - enum audit_state *state) +int audit_filter(int msgtype, unsigned int listtype) { - int i; - - for (i = 0; i < rule->field_count; i++) { - struct audit_field *f = &rule->fields[i]; - pid_t pid; - int result = 0; - u32 sid; - - switch (f->type) { - case AUDIT_PID: - pid = task_pid_nr(current); - result = audit_comparator(pid, f->op, f->val); - break; - case AUDIT_UID: - result = audit_uid_comparator(current_uid(), f->op, f->uid); - break; - case AUDIT_GID: - result = audit_gid_comparator(current_gid(), f->op, f->gid); - break; - case AUDIT_LOGINUID: - result = audit_uid_comparator(audit_get_loginuid(current), - f->op, f->uid); - break; - case AUDIT_LOGINUID_SET: - result = audit_comparator(audit_loginuid_set(current), - f->op, f->val); - break; - case AUDIT_MSGTYPE: - result = audit_comparator(type, f->op, f->val); - break; - case AUDIT_SUBJ_USER: - case AUDIT_SUBJ_ROLE: - case AUDIT_SUBJ_TYPE: - case AUDIT_SUBJ_SEN: - case AUDIT_SUBJ_CLR: - if (f->lsm_rule) { - security_task_getsecid(current, &sid); - result = security_audit_rule_match(sid, - f->type, - f->op, - f->lsm_rule, - NULL); - } - break; - } - - if (result <= 0) - return result; - } - switch (rule->action) { - case AUDIT_NEVER: *state = AUDIT_DISABLED; break; - case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break; - } - return 1; -} - -int audit_filter_user(int type) -{ - enum audit_state state = AUDIT_DISABLED; struct audit_entry *e; - int rc, ret; - - ret = 1; /* Audit by default */ - - rcu_read_lock(); - list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) { - rc = audit_filter_user_rules(&e->rule, type, &state); - if (rc) { - if (rc > 0 && state == AUDIT_DISABLED) - ret = 0; - break; - } - } - rcu_read_unlock(); - - return ret; -} - -int audit_filter_type(int type) -{ - struct audit_entry *e; - int result = 0; + int ret = 1; /* Audit by default */ rcu_read_lock(); - if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE])) + if (list_empty(&audit_filter_list[listtype])) goto unlock_and_return; + list_for_each_entry_rcu(e, &audit_filter_list[listtype], list) { + int i, result = 0; - list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE], - list) { - int i; for (i = 0; i < e->rule.field_count; i++) { struct audit_field *f = &e->rule.fields[i]; - if (f->type == AUDIT_MSGTYPE) { - result = audit_comparator(type, f->op, f->val); - if (!result) - break; + pid_t pid; + u32 sid; + + switch (f->type) { + case AUDIT_PID: + pid = task_pid_nr(current); + result = audit_comparator(pid, f->op, f->val); + break; + case AUDIT_UID: + result = audit_uid_comparator(current_uid(), f->op, f->uid); + break; + case AUDIT_GID: + result = audit_gid_comparator(current_gid(), f->op, f->gid); + break; + case AUDIT_LOGINUID: + result = audit_uid_comparator(audit_get_loginuid(current), + f->op, f->uid); + break; + case AUDIT_LOGINUID_SET: + result = audit_comparator(audit_loginuid_set(current), + f->op, f->val); + break; + case AUDIT_MSGTYPE: + result = audit_comparator(msgtype, f->op, f->val); + break; + case AUDIT_SUBJ_USER: + case AUDIT_SUBJ_ROLE: + case AUDIT_SUBJ_TYPE: + case AUDIT_SUBJ_SEN: + case AUDIT_SUBJ_CLR: + if (f->lsm_rule) { + security_task_getsecid(current, &sid); + result = security_audit_rule_match(sid, + f->type, f->op, f->lsm_rule, NULL); + } + break; + default: + goto unlock_and_return; } + if (result < 0) /* error */ + goto unlock_and_return; + if (!result) + break; + } + if (result > 0) { + if (e->rule.action == AUDIT_NEVER || listtype == AUDIT_FILTER_TYPE) + ret = 0; + break; } - if (result) - goto unlock_and_return; } unlock_and_return: rcu_read_unlock(); - return result; + return ret; } static int update_lsm_rule(struct audit_krule *r) -- 1.7.1 -- Linux-audit mailing list Linux-audit(a)redhat.com https://www.redhat.com/mailman/listinfo/linux-audit