[PATCH 4.19 109/116] ipv6: record frag_max_size in atomic fragments in input path

[Greg Kroah-Hartman]

From: Francesco Ruggeri <fruggeri@xxxxxxxxxx>

[ Upstream commit e29f011e8fc04b2cdc742a2b9bbfa1b62518381a ]

Commit dbd1759e6a9c ("ipv6: on reassembly, record frag_max_size")
filled the frag_max_size field in IP6CB in the input path.
The field should also be filled in case of atomic fragments.

Fixes: dbd1759e6a9c ('ipv6: on reassembly, record frag_max_size')
Signed-off-by: Francesco Ruggeri <fruggeri@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 net/ipv6/reassembly.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
index c6132e39ab16..60dfd0d11851 100644
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -347,7 +347,7 @@ static int ipv6_frag_rcv(struct sk_buff *skb)
 	hdr = ipv6_hdr(skb);
 	fhdr = (struct frag_hdr *)skb_transport_header(skb);
 
-	if (!(fhdr->frag_off & htons(0xFFF9))) {
+	if (!(fhdr->frag_off & htons(IP6_OFFSET | IP6_MF))) {
 		/* It is not a fragmented frame */
 		skb->transport_header += sizeof(struct frag_hdr);
 		__IP6_INC_STATS(net,
@@ -355,6 +355,8 @@ static int ipv6_frag_rcv(struct sk_buff *skb)
 
 		IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
 		IP6CB(skb)->flags |= IP6SKB_FRAGMENTED;
+		IP6CB(skb)->frag_max_size = ntohs(hdr->payload_len) +
+					    sizeof(struct ipv6hdr);
 		return 1;
 	}
 
-- 
2.30.2