BUG/MAJOR: fix listening IP address storage for frontends
When compiled with GCC 6, the IP address specified for a frontend was
ignored and HAProxy was listening on all addresses instead. This is
caused by an incomplete copy of a "struct sockaddr_storage".
With the GNU Libc, "struct sockaddr_storage" is defined as this:
struct sockaddr_storage
{
sa_family_t ss_family;
unsigned long int __ss_align;
char __ss_padding[(128 - (2 * sizeof (unsigned long int)))];
};
Doing an aggregate copy (ss1 = ss2) is different than using memcpy():
only members of the aggregate have to be copied. Notably, padding can be
or not be copied. In GCC 6, some optimizations use this fact and if a
"struct sockaddr_storage" contains a "struct sockaddr_in", the port and
the address are part of the padding (between sa_family and __ss_align)
and can be not copied over.
Therefore, we replace any aggregate copy by a memcpy(). There is another
place using the same pattern. We also fix a function receiving a "struct
sockaddr_storage" by copy instead of by reference. Since it only needs a
read-only copy, the function is converted to request a reference.
diff --git a/src/connection.c b/src/connection.c
index 330f3ef..5515188 100644
--- a/src/connection.c
+++ b/src/connection.c
@@ -744,7 +744,7 @@
const char pp2_signature[] = PP2_SIGNATURE;
int ret = 0;
struct proxy_hdr_v2 *hdr = (struct proxy_hdr_v2 *)buf;
- struct sockaddr_storage null_addr = {0};
+ struct sockaddr_storage null_addr = { .ss_family = 0 };
struct sockaddr_storage *src = &null_addr;
struct sockaddr_storage *dst = &null_addr;