BUG/MEDIUM: dns: make the port numbers unsigned
Mustafa Yildirim reported in Discourse that ports >32767 advertised
in SRV records are wrong. Given the high value they definitely
correspond to a sign extension of a negative number. The cause was
indeed that the port is declared as a signed int in the dns_answer_item
structure, and Lukas confirmed in github issue #103 that turning it to
unsigned addresses the issue.
It is worth noting that there are other such fields in this structure
that don't look right (ttl, priority, class, type) and that someone
should audit this part to be certain they are properly typed.
This fix must be backported to 1.9 and likely to 1.8 as well.
diff --git a/include/types/dns.h b/include/types/dns.h
index 81cd6d2..5a60c07 100644
--- a/include/types/dns.h
+++ b/include/types/dns.h
@@ -146,7 +146,7 @@
int32_t ttl; /* response TTL */
int16_t priority; /* SRV type priority */
uint16_t weight; /* SRV type weight */
- int16_t port; /* SRV type port */
+ uint16_t port; /* SRV type port */
uint16_t data_len; /* number of bytes in target below */
struct sockaddr address; /* IPv4 or IPv6, network format */
char target[DNS_MAX_NAME_SIZE+1]; /* Response data: SRV or CNAME type target */