From 724942c4e6c4eaff2fa0b29839eb98456b8b1d02 Mon Sep 17 00:00:00 2001
From: penguindark <57967770+penguindark@users.noreply.github.com>
Date: Sun, 5 Sep 2021 03:48:59 +0200
Subject: [PATCH] regex: bug fixes (#11394)

---
 vlib/regex/regex.v      | 29 +++++++++++++++++++++++++++++
 vlib/regex/regex_test.v | 28 ++++++++++++++++++++++++++++
 vlib/regex/regex_util.v |  3 ++-
 3 files changed, 59 insertions(+), 1 deletion(-)

diff --git a/vlib/regex/regex.v b/vlib/regex/regex.v
index 9e630e1d5d..68ea823f5d 100644
--- a/vlib/regex/regex.v
+++ b/vlib/regex/regex.v
@@ -890,6 +890,10 @@ fn (re RE) parse_groups(in_txt string, in_i int) (int, bool, string, int) {
 	return -2, true, name, i
 }
 
+const (
+	quntifier_chars = [rune(`+`), `*`, `?`, `{`]
+)
+
 //
 // main compiler
 //
@@ -1036,20 +1040,37 @@ fn (mut re RE) impl_compile(in_txt string) (int, int) {
 
 		// Quantifiers
 		if char_len == 1 && pc > 0 {
+			mut char_next := rune(0)
+			mut char_next_len := 0
+			if (char_len + i) < in_txt.len {
+				char_next, char_next_len = re.get_char(in_txt, i + char_len)
+			}
 			mut quant_flag := true
 			match byte(char_tmp) {
 				`?` {
 					// println("q: ${char_tmp:c}")
+					// check illegal quantifier sequences
+					if char_next_len == 1 && char_next in regex.quntifier_chars {
+						return regex.err_syntax_error, i
+					}
 					re.prog[pc - 1].rep_min = 0
 					re.prog[pc - 1].rep_max = 1
 				}
 				`+` {
 					// println("q: ${char_tmp:c}")
+					// check illegal quantifier sequences
+					if char_next_len == 1 && char_next in regex.quntifier_chars {
+						return regex.err_syntax_error, i
+					}
 					re.prog[pc - 1].rep_min = 1
 					re.prog[pc - 1].rep_max = regex.max_quantifier
 				}
 				`*` {
 					// println("q: ${char_tmp:c}")
+					// check illegal quantifier sequences
+					if char_next_len == 1 && char_next in regex.quntifier_chars {
+						return regex.err_syntax_error, i
+					}
 					re.prog[pc - 1].rep_min = 0
 					re.prog[pc - 1].rep_max = regex.max_quantifier
 				}
@@ -1062,10 +1083,18 @@ fn (mut re RE) impl_compile(in_txt string) (int, int) {
 						re.prog[pc - 1].rep_min = min
 						re.prog[pc - 1].rep_max = max
 						re.prog[pc - 1].greedy = greedy
+						// check illegal quantifier sequences
+						if i <= in_txt.len {
+							char_next, char_next_len = re.get_char(in_txt, i)
+							if char_next_len == 1 && char_next in regex.quntifier_chars {
+								return regex.err_syntax_error, i
+							}
+						}
 						continue
 					} else {
 						return min, i
 					}
+
 					// TODO: decide if the open bracket can be conform without the close bracket
 					/*
 					// no conform, parse as normal char
diff --git a/vlib/regex/regex_test.v b/vlib/regex/regex_test.v
index aa6bf79f74..1239b250e4 100644
--- a/vlib/regex/regex_test.v
+++ b/vlib/regex/regex_test.v
@@ -340,6 +340,12 @@ find_all_test_suite = [
 		r"@for.+@endfor",
 		[0, 22, 23, 50, 63, 80, 89, 117],
 		['@for something @endfor', '@for something else @endfor', '@for body @endfor', '@for senza dire più @endfor']
+	},
+	Test_find_all{
+		"+++pippo+++\n elvo +++ pippo2 +++ +++ oggi+++",
+		r"\+{3}.*\+{3}",
+		[0, 11, 18, 32, 33, 44],
+		['+++pippo+++', '+++ pippo2 +++', '+++ oggi+++']
 	}
 
 ]
@@ -605,4 +611,26 @@ fn test_regex_func_replace(){
 		eprintln(txt2)
 	}
 	assert result == txt2
+}
+
+// test quantifier wrong sequences
+const(
+	test_quantifier_sequences_list = [
+		r'+{3}.*+{3}', 
+		r'+{3}.*?{3}', 
+		r'+{3}.**{3}',
+		r'+{3}.*\+{3}*',
+		r'+{3}.*\+{3}+',
+		r'+{3}.*\+{3}??',
+		r'+{3}.*\+{3}{4}'
+	]
+)
+fn test_quantifier_sequences(){
+	for pattern in test_quantifier_sequences_list {
+		re, re_err, err_pos := regex.regex_base(pattern)
+		if re_err != regex.err_syntax_error {
+			eprintln("pattern: $pattern => $re_err")
+		}
+		assert re_err == regex.err_syntax_error
+	}
 }
\ No newline at end of file
diff --git a/vlib/regex/regex_util.v b/vlib/regex/regex_util.v
index 0bf1a81269..bad5d727fc 100644
--- a/vlib/regex/regex_util.v
+++ b/vlib/regex/regex_util.v
@@ -283,8 +283,9 @@ pub fn (mut re RE) find_all_str(in_txt string) []string {
 
 			if s >= 0 && e > s {
 				tmp_str := tos(in_txt.str + i, in_txt.len - i)
+				mut tmp_e := if e > tmp_str.len { tmp_str.len } else { e }
 				// println("Found: $s:$e [${tmp_str[s..e]}]")
-				res << tmp_str[..e]
+				res << tmp_str[..tmp_e]
 				i += e
 				continue
 			}