5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Maciej Żenczykowski <maze@xxxxxxxxxx>
[ Upstream commit bd4a816752bab609dd6d65ae021387beb9e2ddbd ]
Lorenzo points out that we effectively clear all unknown
flags from PIO when copying them to userspace in the netlink
RTM_NEWPREFIX notification.
We could fix this one at a time as new flags are defined,
or in one fell swoop - I choose the latter.
We could either define 6 new reserved flags (reserved1..6) and handle
them individually (and rename them as new flags are defined), or we
could simply copy the entire unmodified byte over - I choose the latter.
This unfortunately requires some anonymous union/struct magic,
so we add a static assert on the struct size for a little extra safety.
Cc: David Ahern <dsahern@xxxxxxxxxx>
Cc: Lorenzo Colitti <lorenzo@xxxxxxxxxx>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Maciej Żenczykowski <maze@xxxxxxxxxx>
Reviewed-by: David Ahern <dsahern@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
include/net/addrconf.h | 12 ++++++++++--
include/net/if_inet6.h | 4 ----
net/ipv6/addrconf.c | 6 +-----
3 files changed, 11 insertions(+), 11 deletions(-)
diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index 880e609b7352a..32685eaba28fc 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -31,17 +31,22 @@ struct prefix_info {
__u8 length;
__u8 prefix_len;
+ union __packed {
+ __u8 flags;
+ struct __packed {
#if defined(__BIG_ENDIAN_BITFIELD)
- __u8 onlink : 1,
+ __u8 onlink : 1,
autoconf : 1,
reserved : 6;
#elif defined(__LITTLE_ENDIAN_BITFIELD)
- __u8 reserved : 6,
+ __u8 reserved : 6,
autoconf : 1,
onlink : 1;
#else
#error "Please fix <asm/byteorder.h>"
#endif
+ };
+ };
__be32 valid;
__be32 prefered;
__be32 reserved2;
@@ -49,6 +54,9 @@ struct prefix_info {
struct in6_addr prefix;
};
+/* rfc4861 4.6.2: IPv6 PIO is 32 bytes in size */
+static_assert(sizeof(struct prefix_info) == 32);
+
#include <linux/ipv6.h>
#include <linux/netdevice.h>
#include <net/if_inet6.h>
diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h
index f6d614926e9e9..601bedda91c00 100644
--- a/include/net/if_inet6.h
+++ b/include/net/if_inet6.h
@@ -22,10 +22,6 @@
#define IF_RS_SENT 0x10
#define IF_READY 0x80000000
-/* prefix flags */
-#define IF_PREFIX_ONLINK 0x01
-#define IF_PREFIX_AUTOCONF 0x02
-
enum {
INET6_IFADDR_STATE_PREDAD,
INET6_IFADDR_STATE_DAD,
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index c523236d934eb..4bec4c0617412 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -5977,11 +5977,7 @@ static int inet6_fill_prefix(struct sk_buff *skb, struct inet6_dev *idev,
pmsg->prefix_len = pinfo->prefix_len;
pmsg->prefix_type = pinfo->type;
pmsg->prefix_pad3 = 0;
- pmsg->prefix_flags = 0;
- if (pinfo->onlink)
- pmsg->prefix_flags |= IF_PREFIX_ONLINK;
- if (pinfo->autoconf)
- pmsg->prefix_flags |= IF_PREFIX_AUTOCONF;
+ pmsg->prefix_flags = pinfo->flags;
if (nla_put(skb, PREFIX_ADDRESS, sizeof(pinfo->prefix), &pinfo->prefix))
goto nla_put_failure;
--
2.43.0
