reviewed by me
On Wed, Sep 22, 2021 at 10:01 PM Namjae Jeon <linkinjeon@xxxxxxxxxx> wrote:
>
> When second smb2 pdu has invalid protocol id, ksmbd doesn't detect it
> and allow to process smb2 request. This patch add the check it in
> ksmbd_verify_smb_message() and don't use protocol id of smb2 request as
> protocol id of response.
>
> Cc: Ronnie Sahlberg <ronniesahlberg@xxxxxxxxx>
> Cc: Ralph Böhme <slow@xxxxxxxxx>
> Cc: Steve French <smfrench@xxxxxxxxx>
> Reported-by: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
> Signed-off-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
> ---
> fs/ksmbd/smb2pdu.c | 2 +-
> fs/ksmbd/smb_common.c | 13 +++++++++----
> fs/ksmbd/smb_common.h | 1 +
> 3 files changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
> index 3d250e2539e6..3be1493cb18d 100644
> --- a/fs/ksmbd/smb2pdu.c
> +++ b/fs/ksmbd/smb2pdu.c
> @@ -433,7 +433,7 @@ static void init_chained_smb2_rsp(struct ksmbd_work *work)
> work->compound_pfid = KSMBD_NO_FID;
> }
> memset((char *)rsp_hdr + 4, 0, sizeof(struct smb2_hdr) + 2);
> - rsp_hdr->ProtocolId = rcv_hdr->ProtocolId;
> + rsp_hdr->ProtocolId = SMB2_PROTO_NUMBER;
> rsp_hdr->StructureSize = SMB2_HEADER_STRUCTURE_SIZE;
> rsp_hdr->Command = rcv_hdr->Command;
>
> diff --git a/fs/ksmbd/smb_common.c b/fs/ksmbd/smb_common.c
> index da17b21ac685..ace8a1b02c81 100644
> --- a/fs/ksmbd/smb_common.c
> +++ b/fs/ksmbd/smb_common.c
> @@ -129,16 +129,22 @@ int ksmbd_lookup_protocol_idx(char *str)
> *
> * check for valid smb signature and packet direction(request/response)
> *
> - * Return: 0 on success, otherwise 1
> + * Return: 0 on success, otherwise -EINVAL
> */
> int ksmbd_verify_smb_message(struct ksmbd_work *work)
> {
> - struct smb2_hdr *smb2_hdr = work->request_buf;
> + struct smb2_hdr *smb2_hdr = work->request_buf + work->next_smb2_rcv_hdr_off;
> + struct smb_hdr *hdr;
>
> if (smb2_hdr->ProtocolId == SMB2_PROTO_NUMBER)
> return ksmbd_smb2_check_message(work);
>
> - return 0;
> + hdr = work->request_buf;
> + if (*(__le32 *)hdr->Protocol == SMB1_PROTO_NUMBER &&
> + hdr->Command == SMB_COM_NEGOTIATE)
> + return 0;
> +
> + return -EINVAL;
> }
>
> /**
> @@ -270,7 +276,6 @@ static int ksmbd_negotiate_smb_dialect(void *buf)
> return BAD_PROT_ID;
> }
>
> -#define SMB_COM_NEGOTIATE 0x72
> int ksmbd_init_smb_server(struct ksmbd_work *work)
> {
> struct ksmbd_conn *conn = work->conn;
> diff --git a/fs/ksmbd/smb_common.h b/fs/ksmbd/smb_common.h
> index d7df19c97c4c..994abede27e9 100644
> --- a/fs/ksmbd/smb_common.h
> +++ b/fs/ksmbd/smb_common.h
> @@ -202,6 +202,7 @@
> FILE_READ_ATTRIBUTES | FILE_WRITE_ATTRIBUTES)
>
> #define SMB1_PROTO_NUMBER cpu_to_le32(0x424d53ff)
> +#define SMB_COM_NEGOTIATE 0x72
>
> #define SMB1_CLIENT_GUID_SIZE (16)
> struct smb_hdr {
> --
> 2.25.1
>
