From: Kevin Day <thekevinday@gmail.com>
Date: Tue, 29 Sep 2020 02:44:18 +0000 (-0500)
Subject: Bugfix: the fl_string_dynamic_terminate() function is not correctly checking the... 
X-Git-Tag: 0.5.1~49
X-Git-Url: https://git.kevux.org/?a=commitdiff_plain;h=4301803a0231d0a42bc1fc1230fa250098c01dc3;p=fll

Bugfix: the fl_string_dynamic_terminate() function is not correctly checking the NULL.

In the case of when the array is not allocated (size == 0), the terminate is still checking the string index.
This is an invalid read.

Also, the logic is revered on the string index read.
The check needs to be "!0" instead of "0".
---

diff --git a/level_1/fl_string/c/string.c b/level_1/fl_string/c/string.c
index 6cc775c..ddd83af 100644
--- a/level_1/fl_string/c/string.c
+++ b/level_1/fl_string/c/string.c
@@ -1090,9 +1090,13 @@ extern "C" {
       if (destination->used > destination->size) return F_status_set_error(F_parameter);
     #endif // _di_level_1_parameter_checking_
 
-    if (!destination->used && destination->string[destination->used - 1]) return F_none;
+    if (!destination->used && destination->size && !destination->string[destination->used - 1]) {
+      return F_none;
+    }
 
-    if (destination->used == f_string_length_t_size) return F_status_set_error(F_string_too_large);
+    if (destination->used == f_string_length_t_size) {
+      return F_status_set_error(F_string_too_large);
+    }
 
     const f_string_length_t total = destination->used + 1;
 
@@ -1124,7 +1128,9 @@ extern "C" {
       } // for
     }
 
-    if (destination->used == f_string_length_t_size) return F_status_set_error(F_string_too_large);
+    if (destination->used == f_string_length_t_size) {
+      return F_status_set_error(F_string_too_large);
+    }
 
     const f_string_length_t total = destination->used + 1;