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* [PATCH] net: xfrm: fix return value check in ipcomp_compress
@ 2023-10-06 11:41 Ma Ke
  2023-10-06 11:47 ` Florian Westphal
  0 siblings, 1 reply; 3+ messages in thread
From: Ma Ke @ 2023-10-06 11:41 UTC (permalink / raw)
  To: steffen.klassert, herbert, davem, edumazet, kuba, pabeni
  Cc: netdev, linux-kernel, Ma Ke

In ipcomp_compress, to avoid an unexpected result returned by
pskb_trim, we should check the return value of pskb_trim().

Signed-off-by: Ma Ke <make_ruc2021@163•com>
---
 net/xfrm/xfrm_ipcomp.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/xfrm/xfrm_ipcomp.c b/net/xfrm/xfrm_ipcomp.c
index 9c0fa0e1786a..5f2e6edadf48 100644
--- a/net/xfrm/xfrm_ipcomp.c
+++ b/net/xfrm/xfrm_ipcomp.c
@@ -144,7 +144,9 @@ static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb)
 	memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
 	local_bh_enable();
 
-	pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr));
+	err = pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr));
+	if (unlikely(err))
+		goto out;
 	return 0;
 
 out:
-- 
2.37.2


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH] net: xfrm: fix return value check in ipcomp_compress
  2023-10-06 11:41 [PATCH] net: xfrm: fix return value check in ipcomp_compress Ma Ke
@ 2023-10-06 11:47 ` Florian Westphal
  2023-10-06 11:59   ` Florian Westphal
  0 siblings, 1 reply; 3+ messages in thread
From: Florian Westphal @ 2023-10-06 11:47 UTC (permalink / raw)
  To: Ma Ke
  Cc: steffen.klassert, herbert, davem, edumazet, kuba, pabeni, netdev,
	linux-kernel

Ma Ke <make_ruc2021@163•com> wrote:
> In ipcomp_compress, to avoid an unexpected result returned by
> pskb_trim, we should check the return value of pskb_trim().
> 
> Signed-off-by: Ma Ke <make_ruc2021@163•com>
> ---
>  net/xfrm/xfrm_ipcomp.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/net/xfrm/xfrm_ipcomp.c b/net/xfrm/xfrm_ipcomp.c
> index 9c0fa0e1786a..5f2e6edadf48 100644
> --- a/net/xfrm/xfrm_ipcomp.c
> +++ b/net/xfrm/xfrm_ipcomp.c
> @@ -144,7 +144,9 @@ static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb)
>  	memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
>  	local_bh_enable();
>  
> -	pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr));
> +	err = pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr));
> +	if (unlikely(err))
> +		goto out;

This can't be right, this now calls local_bh_enable() twice.

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] net: xfrm: fix return value check in ipcomp_compress
  2023-10-06 11:47 ` Florian Westphal
@ 2023-10-06 11:59   ` Florian Westphal
  0 siblings, 0 replies; 3+ messages in thread
From: Florian Westphal @ 2023-10-06 11:59 UTC (permalink / raw)
  To: Florian Westphal
  Cc: Ma Ke, steffen.klassert, herbert, davem, edumazet, kuba, pabeni,
	netdev, linux-kernel

Florian Westphal <fw@strlen•de> wrote:
> Ma Ke <make_ruc2021@163•com> wrote:
> > In ipcomp_compress, to avoid an unexpected result returned by
> > pskb_trim, we should check the return value of pskb_trim().
> > 
> > Signed-off-by: Ma Ke <make_ruc2021@163•com>
> > ---
> >  net/xfrm/xfrm_ipcomp.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/net/xfrm/xfrm_ipcomp.c b/net/xfrm/xfrm_ipcomp.c
> > index 9c0fa0e1786a..5f2e6edadf48 100644
> > --- a/net/xfrm/xfrm_ipcomp.c
> > +++ b/net/xfrm/xfrm_ipcomp.c
> > @@ -144,7 +144,9 @@ static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb)
> >  	memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);
> >  	local_bh_enable();
> >  
> > -	pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr));
> > +	err = pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr));
> > +	if (unlikely(err))
> > +		goto out;
> 
> This can't be right, this now calls local_bh_enable() twice.

Furthermore, looking at this:

1. skb went through skb_linearize_cow() before, so no paged data anymore

2. Right before there is a check to bail in case compression inflated
packet size.

IOW, this pskb_trim cannot fail, it boils down to __skb_trim().

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2023-10-06 11:59 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2023-10-06 11:41 [PATCH] net: xfrm: fix return value check in ipcomp_compress Ma Ke
2023-10-06 11:47 ` Florian Westphal
2023-10-06 11:59   ` Florian Westphal

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