From 36ff0dd39f9b88ca83e1733b735e9f22b7be893b Mon Sep 17 00:00:00 2001
From: Steffen Klassert <steffen.klassert@secunet.com>
Date: Fri, 25 Aug 2017 07:16:07 +0200
Subject: [PATCH] esp: Fix locking on page fragment allocation
Git-commit: 36ff0dd39f9b88ca83e1733b735e9f22b7be893b
Patch-mainline: v4.13
References: bsc#1051510
We allocate the page fragment for the ESP trailer inside
a spinlock, but consume it outside of the lock. This
is racy as some other cou could get the same page fragment
then. Fix this by consuming the page fragment inside the
lock too.
Fixes: cac2661c53f3 ("esp4: Avoid skb_cow_data whenever possible")
Fixes: 03e2a30f6a27 ("esp6: Avoid skb_cow_data whenever possible")
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
net/ipv4/esp4.c | 5 +++--
net/ipv6/esp6.c | 5 +++--
2 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
index dbb31a942dfa..a8ddb95e7f06 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -292,8 +292,6 @@ int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *
kunmap_atomic(vaddr);
- spin_unlock_bh(&x->lock);
-
nfrags = skb_shinfo(skb)->nr_frags;
__skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
@@ -301,6 +299,9 @@ int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *
skb_shinfo(skb)->nr_frags = ++nfrags;
pfrag->offset = pfrag->offset + allocsize;
+
+ spin_unlock_bh(&x->lock);
+
nfrags++;
skb->len += tailen;
diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c
index 392def1fcf21..4e3fdc888943 100644
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -260,8 +260,6 @@ int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info
kunmap_atomic(vaddr);
- spin_unlock_bh(&x->lock);
-
nfrags = skb_shinfo(skb)->nr_frags;
__skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
@@ -269,6 +267,9 @@ int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info
skb_shinfo(skb)->nr_frags = ++nfrags;
pfrag->offset = pfrag->offset + allocsize;
+
+ spin_unlock_bh(&x->lock);
+
nfrags++;
skb->len += tailen;
--
2.16.4