From: Willem de Bruijn <will...@google.com>
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 <will...@google.com>
Cc: Steffen Klassert <steffen.klass...@secunet.com>
---
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 8b07f3a4f2db..a3271ec3e162 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -443,7 +443,6 @@ static int esp_output_encap(struct xfrm_state *x, struct
sk_buff *skb,
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;
@@ -485,14 +484,10 @@ 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 52c2f063529f..2b804fcebcc6 100644
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -478,7 +478,6 @@ static int esp6_output_encap(struct xfrm_state *x, struct
sk_buff *skb,
int esp6_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;
@@ -519,14 +518,10 @@ 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,
--
2.30.0.284.gd98b1dd5eaa7-goog
