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From:   Ilya Dryomov <idryomov@gmail.com>
Date:   Tue, 4 Dec 2018 13:06:40 +0100
Message-ID: <CAOi1vP_uNBXySo4yNOjcSBUgqDRjo2abm41UZCXazUG7ygRVcA@mail.gmail.com>
Subject: Re: [PATCH 4.14 018/146] libceph: implement CEPHX_V2 calculation mode
To:     Greg KH <gregkh@linuxfoundation.org>
Cc:     linux-kernel@vger.kernel.org, stable@vger.kernel.org,
        Sage Weil <sage@redhat.com>, ben.hutchings@codethink.co.uk,
        sashal@kernel.org
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On Tue, Dec 4, 2018 at 12:01 PM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> 4.14-stable review patch.  If anyone has any objections, please let me know.
>
> ------------------
>
> commit cc255c76c70f7a87d97939621eae04b600d9f4a1 upstream.
>
> Derive the signature from the entire buffer (both AES cipher blocks)
> instead of using just the first half of the first block, leaving out
> data_crc entirely.
>
> This addresses CVE-2018-1129.
>
> Link: http://tracker.ceph.com/issues/24837
> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
> Reviewed-by: Sage Weil <sage@redhat.com>
> Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
>  include/linux/ceph/ceph_features.h |  7 +--
>  net/ceph/auth_x.c                  | 73 +++++++++++++++++++++++-------
>  2 files changed, 60 insertions(+), 20 deletions(-)
>
> diff --git a/include/linux/ceph/ceph_features.h b/include/linux/ceph/ceph_features.h
> index 59042d5ac520..70f42eef813b 100644
> --- a/include/linux/ceph/ceph_features.h
> +++ b/include/linux/ceph/ceph_features.h
> @@ -165,9 +165,9 @@ DEFINE_CEPH_FEATURE(58, 1, FS_FILE_LAYOUT_V2) // overlap
>  DEFINE_CEPH_FEATURE(59, 1, FS_BTIME)
>  DEFINE_CEPH_FEATURE(59, 1, FS_CHANGE_ATTR) // overlap
>  DEFINE_CEPH_FEATURE(59, 1, MSG_ADDR2) // overlap
> -DEFINE_CEPH_FEATURE(60, 1, BLKIN_TRACING)  // *do not share this bit*
> +DEFINE_CEPH_FEATURE(60, 1, OSD_RECOVERY_DELETES) // *do not share this bit*
> +DEFINE_CEPH_FEATURE(61, 1, CEPHX_V2)             // *do not share this bit*
>
> -DEFINE_CEPH_FEATURE(61, 1, RESERVED2)          // unused, but slow down!
>  DEFINE_CEPH_FEATURE(62, 1, RESERVED)           // do not use; used as a sentinal
>  DEFINE_CEPH_FEATURE_DEPRECATED(63, 1, RESERVED_BROKEN, LUMINOUS) // client-facing
>
> @@ -209,7 +209,8 @@ DEFINE_CEPH_FEATURE_DEPRECATED(63, 1, RESERVED_BROKEN, LUMINOUS) // client-facin
>          CEPH_FEATURE_SERVER_JEWEL |            \
>          CEPH_FEATURE_MON_STATEFUL_SUB |        \
>          CEPH_FEATURE_CRUSH_TUNABLES5 |         \
> -        CEPH_FEATURE_NEW_OSDOPREPLY_ENCODING)
> +        CEPH_FEATURE_NEW_OSDOPREPLY_ENCODING | \
> +        CEPH_FEATURE_CEPHX_V2)
>
>  #define CEPH_FEATURES_REQUIRED_DEFAULT   \
>         (CEPH_FEATURE_NOSRCADDR |        \
> diff --git a/net/ceph/auth_x.c b/net/ceph/auth_x.c
> index ce28bb07d8fd..10eb759bbcb4 100644
> --- a/net/ceph/auth_x.c
> +++ b/net/ceph/auth_x.c
> @@ -9,6 +9,7 @@
>
>  #include <linux/ceph/decode.h>
>  #include <linux/ceph/auth.h>
> +#include <linux/ceph/ceph_features.h>
>  #include <linux/ceph/libceph.h>
>  #include <linux/ceph/messenger.h>
>
> @@ -803,26 +804,64 @@ static int calc_signature(struct ceph_x_authorizer *au, struct ceph_msg *msg,
>                           __le64 *psig)
>  {
>         void *enc_buf = au->enc_buf;
> -       struct {
> -               __le32 len;
> -               __le32 header_crc;
> -               __le32 front_crc;
> -               __le32 middle_crc;
> -               __le32 data_crc;
> -       } __packed *sigblock = enc_buf + ceph_x_encrypt_offset();
>         int ret;
>
> -       sigblock->len = cpu_to_le32(4*sizeof(u32));
> -       sigblock->header_crc = msg->hdr.crc;
> -       sigblock->front_crc = msg->footer.front_crc;
> -       sigblock->middle_crc = msg->footer.middle_crc;
> -       sigblock->data_crc =  msg->footer.data_crc;
> -       ret = ceph_x_encrypt(&au->session_key, enc_buf, CEPHX_AU_ENC_BUF_LEN,
> -                            sizeof(*sigblock));
> -       if (ret < 0)
> -               return ret;
> +       if (!CEPH_HAVE_FEATURE(msg->con->peer_features, CEPHX_V2)) {
> +               struct {
> +                       __le32 len;
> +                       __le32 header_crc;
> +                       __le32 front_crc;
> +                       __le32 middle_crc;
> +                       __le32 data_crc;
> +               } __packed *sigblock = enc_buf + ceph_x_encrypt_offset();
> +
> +               sigblock->len = cpu_to_le32(4*sizeof(u32));
> +               sigblock->header_crc = msg->hdr.crc;
> +               sigblock->front_crc = msg->footer.front_crc;
> +               sigblock->middle_crc = msg->footer.middle_crc;
> +               sigblock->data_crc =  msg->footer.data_crc;
> +
> +               ret = ceph_x_encrypt(&au->session_key, enc_buf,
> +                                    CEPHX_AU_ENC_BUF_LEN, sizeof(*sigblock));
> +               if (ret < 0)
> +                       return ret;
> +
> +               *psig = *(__le64 *)(enc_buf + sizeof(u32));
> +       } else {
> +               struct {
> +                       __le32 header_crc;
> +                       __le32 front_crc;
> +                       __le32 front_len;
> +                       __le32 middle_crc;
> +                       __le32 middle_len;
> +                       __le32 data_crc;
> +                       __le32 data_len;
> +                       __le32 seq_lower_word;
> +               } __packed *sigblock = enc_buf;
> +               struct {
> +                       __le64 a, b, c, d;
> +               } __packed *penc = enc_buf;
> +               int ciphertext_len;
> +
> +               sigblock->header_crc = msg->hdr.crc;
> +               sigblock->front_crc = msg->footer.front_crc;
> +               sigblock->front_len = msg->hdr.front_len;
> +               sigblock->middle_crc = msg->footer.middle_crc;
> +               sigblock->middle_len = msg->hdr.middle_len;
> +               sigblock->data_crc =  msg->footer.data_crc;
> +               sigblock->data_len = msg->hdr.data_len;
> +               sigblock->seq_lower_word = *(__le32 *)&msg->hdr.seq;
> +
> +               /* no leading len, no ceph_x_encrypt_header */
> +               ret = ceph_crypt(&au->session_key, true, enc_buf,
> +                                CEPHX_AU_ENC_BUF_LEN, sizeof(*sigblock),
> +                                &ciphertext_len);
> +               if (ret)
> +                       return ret;
> +
> +               *psig = penc->a ^ penc->b ^ penc->c ^ penc->d;
> +       }
>
> -       *psig = *(__le64 *)(enc_buf + sizeof(u32));
>         return 0;
>  }

Hi Greg,

I thought this series (patches 13 - 18) was dropped from the 4.14 queue.
If it wasn't, you also need to pick up the following:

f1d10e046379 libceph: weaken sizeof check in ceph_x_verify_authorizer_reply()
130f52f2b203 libceph: check authorizer reply/challenge length before reading

See our discussion with Sasha:

  https://www.spinics.net/lists/stable/msg272462.html

Thanks,

                Ilya