[PATCH 3/4 v2] libsepol/cil: Limit the neverallow violations reported

[James Carter <jwcart2@gmail.com>]

When there is a neverallow violation, a search is made for all of
the rules that violate the neverallow. The violating rules as well
as their parents are written out to make it easier to find these
rules.

If there is a lot of rules that violate a neverallow, then this
amount of reporting is too much. Instead, only print out the first
four rules (with their parents) that match the violated neverallow
rule along with the total number of rules that violate the
neverallow at the default log level. Report all the violations when
at a higher verbosity level.

Signed-off-by: James Carter <jwcart2@gmail.com>
---
 libsepol/cil/src/cil_binary.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/libsepol/cil/src/cil_binary.c b/libsepol/cil/src/cil_binary.c
index b7da8241..8b64b37a 100644
--- a/libsepol/cil/src/cil_binary.c
+++ b/libsepol/cil/src/cil_binary.c
@@ -4640,6 +4640,9 @@ static int __cil_print_neverallow_failure(const struct cil_db *db, struct cil_tr
 	char *neverallow_str;
 	char *allow_str;
 	enum cil_flavor avrule_flavor;
+	int num_matching = 0;
+	int count_matching = 0;
+	enum cil_log_level log_level = cil_get_log_level();
 
 	target.rule_kind = CIL_AVRULE_ALLOWED;
 	target.is_extended = cil_rule->is_extended;
@@ -4666,11 +4669,19 @@ static int __cil_print_neverallow_failure(const struct cil_db *db, struct cil_tr
 		goto exit;
 	}
 
+	cil_list_for_each(i2, matching) {
+		num_matching++;
+	}
 	cil_list_for_each(i2, matching) {
 		n2 = i2->data;
 		r2 = n2->data;
 		__cil_print_parents("    ", n2);
 		__cil_print_rule("      ", allow_str, r2);
+		count_matching++;
+		if (count_matching >= 4 && num_matching > 4 && log_level == CIL_ERR) {
+			cil_log(CIL_ERR, "    Only first 4 of %d matching rules shown (use \"-v\" to show all)\n", num_matching);
+			break;
+		}
 	}
 	cil_log(CIL_ERR,"\n");
 	cil_list_destroy(&matching, CIL_FALSE);
-- 
2.31.1