2021-08-30 09:20:58

by Yajun Deng

Subject: [PATCH net-next] net: ipv4: Fix the warning for dereference

Add a if statements to avoid the warning.

Dan Carpenter report:
The patch faf482ca196a: "net: ipv4: Move ip_options_fragment() out of
loop" from Aug 23, 2021, leads to the following Smatch complaint:

net/ipv4/ip_output.c:833 ip_do_fragment()
warn: variable dereferenced before check 'iter.frag' (see line 828)

Reported-by: Dan Carpenter <[email protected]>
Fixes: faf482ca196a ("net: ipv4: Move ip_options_fragment() out of loop")
Link: https://lore.kernel.org/netdev/20210830073802.GR7722@kadam/T/#t
Signed-off-by: Yajun Deng <[email protected]>
---
net/ipv4/ip_output.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 9a8f05d5476e..9bca57ef8b83 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -825,7 +825,9 @@ int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,

/* Everything is OK. Generate! */
ip_fraglist_init(skb, iph, hlen, &iter);
- ip_options_fragment(iter.frag);
+
+ if (iter.frag)
+ ip_options_fragment(iter.frag);

for (;;) {
/* Prepare header of the next frame,
--
2.32.0

2021-08-30 11:50:59

by patchwork-bot+netdevbpf

Subject: Re: [PATCH net-next] net: ipv4: Fix the warning for dereference

Hello:

This patch was applied to netdev/net-next.git (refs/heads/master):

On Mon, 30 Aug 2021 17:16:40 +0800 you wrote:
> Add a if statements to avoid the warning.
>
> Dan Carpenter report:
> The patch faf482ca196a: "net: ipv4: Move ip_options_fragment() out of
> loop" from Aug 23, 2021, leads to the following Smatch complaint:
>
> net/ipv4/ip_output.c:833 ip_do_fragment()
> warn: variable dereferenced before check 'iter.frag' (see line 828)
>
> [...]

Here is the summary with links:
- [net-next] net: ipv4: Fix the warning for dereference
https://git.kernel.org/netdev/net-next/c/1b9fbe813016

You are awesome, thank you!
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