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From: Namjae Jeon <linkinjeon@kernel.org>
To: Ralph Boehme <slow@samba.org>
Cc: linux-cifs@vger.kernel.org,
	Ronnie Sahlberg <ronniesahlberg@gmail.com>,
	Steve French <smfrench@gmail.com>,
	Ronnie Sahlberg <lsahlber@redhat.com>
Subject: Re: [PATCH v3] ksmbd: fix invalid request buffer access in compound request
Date: Thu, 23 Sep 2021 08:15:11 +0900	[thread overview]
Message-ID: <CAKYAXd8S7Vc7MpOgHQ5+u0Fje92c417Ti48vDdZsPv8FTcwVwQ@mail.gmail.com> (raw)
In-Reply-To: <447d958e-2470-4ddb-2064-0aeaf1a47ba0@samba.org>

2021-09-22 23:23 GMT+09:00, Ralph Boehme <slow@samba.org>:
> Am 22.09.21 um 14:01 schrieb Namjae Jeon:
>> Ronnie reported invalid request buffer access in chained command when
>> inserting garbage value to NextCommand of compound request.
>> This patch add validation check to avoid this issue.
>>
>> Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
>> Cc: Ralph Böhme <slow@samba.org>
>> Cc: Steve French <smfrench@gmail.com>
>> Reported-by: Ronnie Sahlberg <lsahlber@redhat.com>
>> Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
>> ---
>>    v2:
>>     - fix integer overflow from work->next_smb2_rcv_hdr_off.
>>    v3:
>>     - check next command offset and at least header size of next pdu at
>>       the same time.
>>   fs/ksmbd/smb2pdu.c | 7 +++++++
>>   1 file changed, 7 insertions(+)
>>
>> diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
>> index 4f11eb85bb6b..3d250e2539e6 100644
>> --- a/fs/ksmbd/smb2pdu.c
>> +++ b/fs/ksmbd/smb2pdu.c
>> @@ -466,6 +466,13 @@ bool is_chained_smb2_message(struct ksmbd_work
>> *work)
>>
>>   	hdr = ksmbd_req_buf_next(work);
>>   	if (le32_to_cpu(hdr->NextCommand) > 0) {
>> +		if ((u64)work->next_smb2_rcv_hdr_off + le32_to_cpu(hdr->NextCommand) +
>> 64 >
>> +		    get_rfc1002_len(work->request_buf)) {
>
> is this safe from overflows on 32 bit arch?
Okay, will fix it on next version.

Thanks for your review!
>
> Thanks!
> -slow
>
> --
> Ralph Boehme, Samba Team                 https://samba.org/
> SerNet Samba Team Lead      https://sernet.de/en/team-samba
>
>

      reply	other threads:[~2021-09-22 23:15 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-22 12:01 Namjae Jeon
2021-09-22 14:23 ` Ralph Boehme
2021-09-22 23:15   ` Namjae Jeon [this message]

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