audit: add syscall information to CONFIG_CHANGE records

Tie syscall information to all CONFIG_CHANGE calls since they are all a
result of user actions.

Exclude user records from syscall context:
Since the function audit_log_common_recv_msg() is shared by a number of
AUDIT_CONFIG_CHANGE and the entire range of AUDIT_USER_* record types,
and since the AUDIT_CONFIG_CHANGE message type has been converted to a
syscall accompanied record type, special-case the AUDIT_USER_* range of
messages so they remain standalone records.

See: https://github.com/linux-audit/audit-kernel/issues/59
See: https://github.com/linux-audit/audit-kernel/issues/50

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: fix line lengths in kernel/audit.c]
Signed-off-by: Paul Moore <paul@paul-moore.com>

1 files changed, 19 insertions, 9 deletions

diff --git a/kernel/audit.c b/kernel/audit.c
index d412fb4ae6d5..c2a7662cc254 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -396,7 +396,7 @@ static int audit_log_config_change(char *function_name, u32 new, u32 old,
         struct audit_buffer *ab;
         int rc = 0;
 
-        ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
+        ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
         if (unlikely(!ab))
                 return rc;
         audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
@@ -1053,7 +1053,8 @@ static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
         return err;
 }
 
-static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
+static void audit_log_common_recv_msg(struct audit_context *context,
+                                        struct audit_buffer **ab, u16 msg_type)
 {
         uid_t uid = from_kuid(&init_user_ns, current_uid());
         pid_t pid = task_tgid_nr(current);
@@ -1063,7 +1064,7 @@ static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
                 return;
         }
 
-        *ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
+        *ab = audit_log_start(context, GFP_KERNEL, msg_type);
         if (unlikely(!*ab))
                 return;
         audit_log_format(*ab, "pid=%d uid=%u ", pid, uid);
@@ -1071,6 +1072,12 @@ static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
         audit_log_task_context(*ab);
 }
 
+static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
+                                           u16 msg_type)
+{
+        audit_log_common_recv_msg(NULL, ab, msg_type);
+}
+
 int is_audit_feature_set(int i)
 {
         return af.features & AUDIT_FEATURE_TO_MASK(i);
@@ -1338,7 +1345,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                                 if (err)
                                         break;
                         }
-                        audit_log_common_recv_msg(&ab, msg_type);
+                        audit_log_user_recv_msg(&ab, msg_type);
                         if (msg_type != AUDIT_USER_TTY)
                                 audit_log_format(ab, " msg='%.*s'",
                                                  AUDIT_MESSAGE_TEXT_MAX,
@@ -1361,7 +1368,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                 if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
                         return -EINVAL;
                 if (audit_enabled == AUDIT_LOCKED) {
-                        audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
+                        audit_log_common_recv_msg(audit_context(), &ab,
+                                                  AUDIT_CONFIG_CHANGE);
                         audit_log_format(ab, " op=%s audit_enabled=%d res=0",
                                          msg_type == AUDIT_ADD_RULE ?
                                                 "add_rule" : "remove_rule",
@@ -1376,7 +1384,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                 break;
         case AUDIT_TRIM:
                 audit_trim_trees();
-                audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
+                audit_log_common_recv_msg(audit_context(), &ab,
+                                          AUDIT_CONFIG_CHANGE);
                 audit_log_format(ab, " op=trim res=1");
                 audit_log_end(ab);
                 break;
@@ -1406,8 +1415,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                 /* OK, here comes... */
                 err = audit_tag_tree(old, new);
 
-                audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
-
+                audit_log_common_recv_msg(audit_context(), &ab,
+                                          AUDIT_CONFIG_CHANGE);
                 audit_log_format(ab, " op=make_equiv old=");
                 audit_log_untrustedstring(ab, old);
                 audit_log_format(ab, " new=");
@@ -1474,7 +1483,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                 old.enabled = t & AUDIT_TTY_ENABLE;
                 old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
 
-                audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
+                audit_log_common_recv_msg(audit_context(), &ab,
+                                          AUDIT_CONFIG_CHANGE);
                 audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
                                  " old-log_passwd=%d new-log_passwd=%d res=%d",
                                  old.enabled, s.enabled, old.log_passwd,