lib: pdn: return error on pdn_ctx_configure if apn is too large

Return error when pdn_ctx_configure is called with a large (faulty) apn
to avoid unnecessary processing and consumption of memory.

Signed-off-by: Eivind Jølsgard <[email protected]>

Author: eivindj-nordic

lib/pdn/pdn.c

@@ -24,6 +24,8 @@ LOG_MODULE_REGISTER(pdn, CONFIG_PDN_LOG_LEVEL);
 #define PDN_ACT_REASON_IPV4_ONLY (0)
 #define PDN_ACT_REASON_IPV6_ONLY (1)
 
+#define APN_STR_MAX_LEN 64
+
 struct pdn {
 	pdn_event_handler_t callback;
 	int8_t context_id;
@@ -249,6 +251,10 @@ int pdn_ctx_configure(uint8_t cid, const char *apn, enum pdn_fam fam,
 		return -EFAULT;
 	}
 
+	if (strlen(apn) >= APN_STR_MAX_LEN) {
+		return -EINVAL;
+	}
+
 	switch (fam) {
 	case PDN_FAM_IPV4:
 		strncpy(family, "IP", sizeof(family));