lists: don't crash if reason ptr is NULL

commit 15fec92ed75c3de0b32c40d005e93e3f61aef77e
(Update list item, if it already exists) can make ngircd
crash because 'Reason' can be NULL, as reported by
Cahata on the ngircd mailing list.

Doesn't affect any released ngircd versions.

Also, make sure that we do not pass NULL as arguments
to a '%s' printf-like function.

1 files changed, 5 insertions, 9 deletions

diff --git a/src/ngircd/lists.c b/src/ngircd/lists.c
index d3f26e2e..fd86f301 100644
--- a/src/ngircd/lists.c
+++ b/src/ngircd/lists.c
@@ -60,13 +60,13 @@ Lists_GetMask(const struct list_elem *e)
  * Get optional "reason" text stored in list element.
  *
  * @param list_elem List element.
- * @return Pointer to "reason" text or NULL.
+ * @return Pointer to "reason" text or empty string ("").
  */
 GLOBAL const char *
 Lists_GetReason(const struct list_elem *e)
 {
 	assert(e != NULL);
-	return e->reason;
+	return e->reason ? e->reason : "";
 }
 
 /**
@@ -129,14 +129,10 @@ Lists_Add(struct list_head *h, const char *Mask, time_t ValidUntil,
 	e = Lists_CheckDupeMask(h, Mask);
 	if (e) {
 		e->valid_until = ValidUntil;
-		if (e->reason)
+		if (Reason) {
 			free(e->reason);
-		e->reason = malloc(strlen(Reason) + 1);
-		if (e->reason)
-			strlcpy(e->reason, Reason, strlen(Reason) + 1);
-		else
-			Log(LOG_EMERG,
-			    "Can't allocate memory for new list reason text!");
+			e->reason = strdup(Reason);
+		}
 		return true;
 	}