From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: John Fastabend <john.fastabend@gmail.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] bpf: sockmap, fix uninitialized variable
Date: Thu, 17 May 2018 13:12:43 -0500 [thread overview]
Message-ID: <98d55ad8-e5c8-7f1c-ea9b-940be45787d6@embeddedor.com> (raw)
In-Reply-To: <dd511eb3-abbf-1822-8bcc-7bcc6ca68b6c@gmail.com>
Hi John,
On 05/17/2018 12:27 PM, John Fastabend wrote:
> On 05/17/2018 07:08 AM, Gustavo A. R. Silva wrote:
>> There is a potential execution path in which variable err is
>> returned without being properly initialized previously.
>>
>> Fix this by initializing variable err to 0.
>>
>> Addresses-Coverity-ID: 1468964 ("Uninitialized scalar variable")
>> Fixes: e5cd3abcb31a ("bpf: sockmap, refactor sockmap routines to work
>> with hashmap")
>> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
>> ---
>> kernel/bpf/sockmap.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c
>> index c6de139..41b41fc 100644
>> --- a/kernel/bpf/sockmap.c
>> +++ b/kernel/bpf/sockmap.c
>> @@ -1713,7 +1713,7 @@ static int __sock_map_ctx_update_elem(struct bpf_map *map,
>> struct smap_psock_map_entry *e = NULL;
>> struct smap_psock *psock;
>> bool new = false;
>> - int err;
>> + int err = 0;
>>
>> /* 1. If sock map has BPF programs those will be inherited by the
>> * sock being added. If the sock is already attached to BPF programs
>>
>
> Thanks for catching this and the quick fix. The path to hit this case
> is to add a sock to a map (without a BPF program) where the sock already
> has been added to another map. I don't have any tests for the case with
> socks in multiple maps so I'll add some to the selftests so I remember
> this case.
>
Glad to help. :)
> The alternative fix would be to always 'return 0' at the end of the
> function, but I think its probably better to init err here like above.
>
Yeah. I think initializing err is better in this case.
> Acked-by: John Fastabend <john.fastabend@gmail.com>
>
Thank you
--
Gustavo
next prev parent reply other threads:[~2018-05-17 18:59 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-17 14:04 [PATCH 0/2] bpf: sockmap, fix uninitialized variable and double-free Gustavo A. R. Silva
2018-05-17 14:08 ` [PATCH 1/2] bpf: sockmap, fix uninitialized variable Gustavo A. R. Silva
2018-05-17 17:27 ` John Fastabend
2018-05-17 18:12 ` Gustavo A. R. Silva [this message]
2018-05-17 14:11 ` [PATCH 2/2] bpf: sockmap, fix double-free Gustavo A. R. Silva
2018-05-17 17:26 ` John Fastabend
2018-05-17 20:51 ` [PATCH 0/2] bpf: sockmap, fix uninitialized variable and double-free Daniel Borkmann
2018-05-17 20:53 ` Gustavo A. R. Silva
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=98d55ad8-e5c8-7f1c-ea9b-940be45787d6@embeddedor.com \
--to=gustavo@embeddedor.com \
--cc=ast@kernel.org \
--cc=daniel@iogearbox.net \
--cc=john.fastabend@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).