Locally generated TCP packets are usually cloned, so we
do skb_cow_data() on this packets. After that we need to
reload the pointer to the esp header. On udpencap this
header has an offset to skb_transport_header, so take this
offset into account.
Fixes: 67d349ed603 ("net/esp4: Fix invalid esph pointer crash")
Fixes: fca11ebde3f0 ("esp4: Reorganize esp_output")
Reported-by: Don Bowman <d...@donbowman.ca>
Signed-off-by: Steffen Klassert <steffen.klass...@secunet.com>
---
net/ipv4/esp4.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
index 65cc02b..93322f8 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -248,6 +248,7 @@ int esp_output_head(struct xfrm_state *x, struct sk_buff
*skb, struct esp_info *
u8 *tail;
u8 *vaddr;
int nfrags;
+ int esph_offset;
struct page *page;
struct sk_buff *trailer;
int tailen = esp->tailen;
@@ -313,11 +314,13 @@ int esp_output_head(struct xfrm_state *x, struct sk_buff
*skb, struct esp_info *
}
cow:
+ esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
+
nfrags = skb_cow_data(skb, tailen, &trailer);
if (nfrags < 0)
goto out;
tail = skb_tail_pointer(trailer);
- esp->esph = ip_esp_hdr(skb);
+ esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) +
esph_offset);
skip_cow:
esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
--
2.7.4
