mctp: Use output netdev to allocate skb headroom

Previously the skb was allocated with headroom MCTP_HEADER_MAXLEN,
but that isn't sufficient if we are using devs that are not MCTP
specific.

This also adds a check that the smctp_halen provided to sendmsg for
extended addressing is the correct size for the netdev.

Fixes: 833ef3b91d ("mctp: Populate socket implementation")
Reported-by: Matthew Rinaldi <mjrinal@g.clemson.edu>
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Matt Johnston
2022-04-01 10:48:44 +08:00
committed by David S. Miller
parent 8ce40a2fd3
commit 4a9dda1c1d
3 changed files with 44 additions and 18 deletions

View File

@@ -503,6 +503,11 @@ static int mctp_route_output(struct mctp_route *route, struct sk_buff *skb)
if (cb->ifindex) {
/* direct route; use the hwaddr we stashed in sendmsg */
if (cb->halen != skb->dev->addr_len) {
/* sanity check, sendmsg should have already caught this */
kfree_skb(skb);
return -EMSGSIZE;
}
daddr = cb->haddr;
} else {
/* If lookup fails let the device handle daddr==NULL */
@@ -756,7 +761,7 @@ static int mctp_do_fragment_route(struct mctp_route *rt, struct sk_buff *skb,
{
const unsigned int hlen = sizeof(struct mctp_hdr);
struct mctp_hdr *hdr, *hdr2;
unsigned int pos, size;
unsigned int pos, size, headroom;
struct sk_buff *skb2;
int rc;
u8 seq;
@@ -770,6 +775,9 @@ static int mctp_do_fragment_route(struct mctp_route *rt, struct sk_buff *skb,
return -EMSGSIZE;
}
/* keep same headroom as the original skb */
headroom = skb_headroom(skb);
/* we've got the header */
skb_pull(skb, hlen);
@@ -777,7 +785,7 @@ static int mctp_do_fragment_route(struct mctp_route *rt, struct sk_buff *skb,
/* size of message payload */
size = min(mtu - hlen, skb->len - pos);
skb2 = alloc_skb(MCTP_HEADER_MAXLEN + hlen + size, GFP_KERNEL);
skb2 = alloc_skb(headroom + hlen + size, GFP_KERNEL);
if (!skb2) {
rc = -ENOMEM;
break;
@@ -793,7 +801,7 @@ static int mctp_do_fragment_route(struct mctp_route *rt, struct sk_buff *skb,
skb_set_owner_w(skb2, skb->sk);
/* establish packet */
skb_reserve(skb2, MCTP_HEADER_MAXLEN);
skb_reserve(skb2, headroom);
skb_reset_network_header(skb2);
skb_put(skb2, hlen + size);
skb2->transport_header = skb2->network_header + hlen;