Re: [PATCH 5/7] ksmbd: add the check to vaildate if stream protocol length exceeds maximum value

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2021년 9월 24일 (금) 오전 11:13, Namjae Jeon <linkinjeon@xxxxxxxxxx>님이 작성:
>
> This patch add MAX_STREAM_PROT_LEN macro and check if stream protocol
> length exceeds maximum value. opencode pdu size check in
> ksmbd_pdu_size_has_room().
>
> Cc: Tom Talpey <tom@xxxxxxxxxx>
> Cc: Ronnie Sahlberg <ronniesahlberg@xxxxxxxxx>
> Cc: Ralph Böhme <slow@xxxxxxxxx>
> Cc: Steve French <smfrench@xxxxxxxxx>
> Cc: Hyunchul Lee <hyc.lee@xxxxxxxxx>
> Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
> Signed-off-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
> ---
>  fs/ksmbd/connection.c | 10 ++++++----
>  fs/ksmbd/smb_common.c |  6 ------
>  fs/ksmbd/smb_common.h |  4 ++--
>  3 files changed, 8 insertions(+), 12 deletions(-)
>
> diff --git a/fs/ksmbd/connection.c b/fs/ksmbd/connection.c
> index af086d35398a..48b18b4ec117 100644
> --- a/fs/ksmbd/connection.c
> +++ b/fs/ksmbd/connection.c
> @@ -296,10 +296,12 @@ int ksmbd_conn_handler_loop(void *p)
>                 pdu_size = get_rfc1002_len(hdr_buf);
>                 ksmbd_debug(CONN, "RFC1002 header %u bytes\n", pdu_size);
>
> -               /* make sure we have enough to get to SMB header end */
> -               if (!ksmbd_pdu_size_has_room(pdu_size)) {
> -                       ksmbd_debug(CONN, "SMB request too short (%u bytes)\n",
> -                                   pdu_size);
> +               /*
> +                * Check if pdu size is valid (min : smb header size,
> +                * max : 0x00FFFFFF).
> +                */
> +               if (pdu_size < __SMB2_HEADER_STRUCTURE_SIZE ||
> +                   pdu_size > MAX_STREAM_PROT_LEN) {
>                         continue;
>                 }
>
> diff --git a/fs/ksmbd/smb_common.c b/fs/ksmbd/smb_common.c
> index 5901b2884c60..20bd5b8e3c0a 100644
> --- a/fs/ksmbd/smb_common.c
> +++ b/fs/ksmbd/smb_common.c
> @@ -21,7 +21,6 @@ static const char basechars[43] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_-!@#$%";
>  #define MAGIC_CHAR '~'
>  #define PERIOD '.'
>  #define mangle(V) ((char)(basechars[(V) % MANGLE_BASE]))
> -#define KSMBD_MIN_SUPPORTED_HEADER_SIZE        (sizeof(struct smb2_hdr))
>
>  struct smb_protocol {
>         int             index;
> @@ -272,11 +271,6 @@ int ksmbd_init_smb_server(struct ksmbd_work *work)
>         return 0;
>  }
>
> -bool ksmbd_pdu_size_has_room(unsigned int pdu)
> -{
> -       return (pdu >= KSMBD_MIN_SUPPORTED_HEADER_SIZE - 4);
> -}
> -
>  int ksmbd_populate_dot_dotdot_entries(struct ksmbd_work *work, int info_level,
>                                       struct ksmbd_file *dir,
>                                       struct ksmbd_dir_info *d_info,
> diff --git a/fs/ksmbd/smb_common.h b/fs/ksmbd/smb_common.h
> index 994abede27e9..6e79e7577f6b 100644
> --- a/fs/ksmbd/smb_common.h
> +++ b/fs/ksmbd/smb_common.h
> @@ -48,6 +48,8 @@
>  #define CIFS_DEFAULT_IOSIZE    (64 * 1024)
>  #define MAX_CIFS_SMALL_BUFFER_SIZE 448 /* big enough for most */
>
> +#define MAX_STREAM_PROT_LEN    0x00FFFFFF

Do we need to append "SMB" to this macro name?
Looks good to me.
Acked-by: Hyunchul Lee <hyc.lee@xxxxxxxxx>


> +
>  /* Responses when opening a file. */
>  #define F_SUPERSEDED   0
>  #define F_OPENED       1
> @@ -493,8 +495,6 @@ int ksmbd_lookup_dialect_by_id(__le16 *cli_dialects, __le16 dialects_count);
>
>  int ksmbd_init_smb_server(struct ksmbd_work *work);
>
> -bool ksmbd_pdu_size_has_room(unsigned int pdu);
> -
>  struct ksmbd_kstat;
>  int ksmbd_populate_dot_dotdot_entries(struct ksmbd_work *work,
>                                       int info_level,
> --
> 2.25.1
>


--
Thanks,
Hyunchul




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