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Commit ac758e3c authored by Patrick McHardy's avatar Patrick McHardy Committed by David S. Miller
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[XFRM]: beet: fix worst case header_len calculation 



esp_init_state doesn't account for the beet pseudo header in the header_len
calculation, which may result in undersized skbs hitting xfrm4_beet_output,
causing unnecessary reallocations in ip_finish_output2.

The skbs should still always have enough room to avoid causing
skb_under_panic in skb_push since we have at least 16 bytes available
from LL_RESERVED_SPACE in xfrm_state_check_space.

Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c5c25238

net/ipv4/esp4.c

+2 −1
Original line number Diff line number Diff line
@@ -294,7 +294,6 @@ static u32 esp4_get_mtu(struct xfrm_state *x, int mtu) 
		break;

	case XFRM_MODE_BEET:

		/* The worst case. */

		mtu -= IPV4_BEET_PHMAXLEN;

		mtu += min_t(u32, IPV4_BEET_PHMAXLEN, rem);

		break;

	}
@@ -409,6 +408,8 @@ static int esp_init_state(struct xfrm_state *x) 
	x->props.header_len = sizeof(struct ip_esp_hdr) + esp->conf.ivlen;

	if (x->props.mode == XFRM_MODE_TUNNEL)

		x->props.header_len += sizeof(struct iphdr);

	else if (x->props.mode == XFRM_MODE_BEET)

		x->props.header_len += IPV4_BEET_PHMAXLEN;

	if (x->encap) {

		struct xfrm_encap_tmpl *encap = x->encap;

net/ipv4/xfrm4_mode_beet.c

+1 −1
Original line number Diff line number Diff line
@@ -40,7 +40,7 @@ static int xfrm4_beet_output(struct xfrm_state *x, struct sk_buff *skb) 
	if (unlikely(optlen))

		hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);



	skb_push(skb, x->props.header_len + hdrlen);

	skb_push(skb, x->props.header_len - IPV4_BEET_PHMAXLEN + hdrlen);

	skb_reset_network_header(skb);

	top_iph = ip_hdr(skb);

	skb->transport_header += sizeof(*iph) - hdrlen;