From: Willem de Bruijn willemb@google.com
[ Upstream commit 9bd6b629c39e3fa9e14243a6d8820492be1a5b2e ]
esp(6)_output_head uses skb_page_frag_refill to allocate a buffer for the esp trailer.
It accesses the page with kmap_atomic to handle highmem. But skb_page_frag_refill can return compound pages, of which kmap_atomic only maps the first underlying page.
skb_page_frag_refill does not return highmem, because flag __GFP_HIGHMEM is not set. ESP uses it in the same manner as TCP. That also does not call kmap_atomic, but directly uses page_address, in skb_copy_to_page_nocache. Do the same for ESP.
This issue has become easier to trigger with recent kmap local debugging feature CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP.
Fixes: cac2661c53f3 ("esp4: Avoid skb_cow_data whenever possible") Fixes: 03e2a30f6a27 ("esp6: Avoid skb_cow_data whenever possible") Signed-off-by: Willem de Bruijn willemb@google.com Acked-by: Steffen Klassert steffen.klassert@secunet.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/esp4.c | 7 +------ net/ipv6/esp6.c | 7 +------ 2 files changed, 2 insertions(+), 12 deletions(-)
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c index 114f9def1ec54..0792a9e2a555f 100644 --- a/net/ipv4/esp4.c +++ b/net/ipv4/esp4.c @@ -270,7 +270,6 @@ static int esp_output_udp_encap(struct xfrm_state *x, struct sk_buff *skb, struc int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) { u8 *tail; - u8 *vaddr; int nfrags; int esph_offset; struct page *page; @@ -312,14 +311,10 @@ int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info * page = pfrag->page; get_page(page);
- vaddr = kmap_atomic(page); - - tail = vaddr + pfrag->offset; + tail = page_address(page) + pfrag->offset;
esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
- kunmap_atomic(vaddr); - nfrags = skb_shinfo(skb)->nr_frags;
__skb_fill_page_desc(skb, nfrags, page, pfrag->offset, diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c index a7d996148eeda..25317d5ccf2cc 100644 --- a/net/ipv6/esp6.c +++ b/net/ipv6/esp6.c @@ -237,7 +237,6 @@ static void esp_output_fill_trailer(u8 *tail, int tfclen, int plen, __u8 proto) int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) { u8 *tail; - u8 *vaddr; int nfrags; struct page *page; struct sk_buff *trailer; @@ -270,14 +269,10 @@ int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info page = pfrag->page; get_page(page);
- vaddr = kmap_atomic(page); - - tail = vaddr + pfrag->offset; + tail = page_address(page) + pfrag->offset;
esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
- kunmap_atomic(vaddr); - nfrags = skb_shinfo(skb)->nr_frags;
__skb_fill_page_desc(skb, nfrags, page, pfrag->offset,