From 0e78a87306a6f55b1c7bbafad1de62c3975953ca Mon Sep 17 00:00:00 2001 From: Steffen Klassert Date: Wed, 3 May 2017 08:44:27 +0200 Subject: [PATCH] esp4: Fix udpencap for local TCP packets. 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 Signed-off-by: Steffen Klassert --- 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 65cc02bd82bc..93322f895eab 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);