Re: [PATCH 6/6] cifs: add separate cred_uid field to sesInfo

[Steve French <smfrench-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

I merged the first 5 of this series, but wanted to understand what
behavior this changes first (it is probably ok).  With current
userspace code - what changes would a user see with this?

On Sun, Jun 20, 2010 at 4:10 PM, Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:
> Right now, there's no clear separation between the uid that owns the
> credentials used to do the mount and the overriding owner of the files
> on that mount.
>
> Add a separate cred_uid field that is set to the real uid
> of the mount user. Unlike the linux_uid, the uid= option does not
> override this parameter. The parm is sent to cifs.upcall, which can then
> preferentially use the creduid= parm instead of the uid= parm for
> finding credentials.
>
> This is not the only way to solve this. We could try to do all of this
> in kernel instead by having a module parameter that affects what gets
> passed in the uid= field of the upcall. That said, we have a lot more
> flexibility to change things in userspace so I think it probably makes
> sense to do it this way.
>
> Signed-off-by: Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> ---
>  fs/cifs/cifs_spnego.c |    3 +++
>  fs/cifs/cifsglob.h    |    3 ++-
>  fs/cifs/connect.c     |    7 +++++--
>  3 files changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/fs/cifs/cifs_spnego.c b/fs/cifs/cifs_spnego.c
> index 379bd7d..6effccf 100644
> --- a/fs/cifs/cifs_spnego.c
> +++ b/fs/cifs/cifs_spnego.c
> @@ -144,6 +144,9 @@ cifs_get_spnego_key(struct cifsSesInfo *sesInfo)
>        sprintf(dp, ";uid=0x%x", sesInfo->linux_uid);
>
>        dp = description + strlen(description);
> +       sprintf(dp, ";creduid=0x%x", sesInfo->cred_uid);
> +
> +       dp = description + strlen(description);
>        sprintf(dp, ";user=%s", sesInfo->userName);
>
>        dp = description + strlen(description);
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index 415703b..e15d7a5 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -209,7 +209,8 @@ struct cifsSesInfo {
>        char *serverNOS;        /* name of network operating system of server */
>        char *serverDomain;     /* security realm of server */
>        int Suid;               /* remote smb uid  */
> -       uid_t linux_uid;        /* local Linux uid */
> +       uid_t linux_uid;        /* overriding owner of files on the mount */
> +       uid_t cred_uid;         /* owner of credentials */
>        int capabilities;
>        char serverName[SERVER_NAME_LEN_WITH_NULL * 2]; /* BB make bigger for
>                                TCP names - will ipv6 and sctp addresses fit? */
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index 58e0217..920d94e 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -66,6 +66,7 @@ struct smb_vol {
>        char *iocharset;  /* local code page for mapping to and from Unicode */
>        char source_rfc1001_name[16]; /* netbios name of client */
>        char target_rfc1001_name[16]; /* netbios name of server for Win9x/ME */
> +       uid_t cred_uid;
>        uid_t linux_uid;
>        gid_t linux_gid;
>        mode_t file_mode;
> @@ -830,7 +831,8 @@ cifs_parse_mount_options(char *options, const char *devname,
>        /* null target name indicates to use *SMBSERVR default called name
>           if we end up sending RFC1001 session initialize */
>        vol->target_rfc1001_name[0] = 0;
> -       vol->linux_uid = current_uid();  /* use current_euid() instead? */
> +       vol->cred_uid = current_uid();
> +       vol->linux_uid = current_uid();
>        vol->linux_gid = current_gid();
>
>        /* default to only allowing write access to owner of the mount */
> @@ -1647,7 +1649,7 @@ cifs_find_smb_ses(struct TCP_Server_Info *server, struct smb_vol *vol)
>        list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
>                switch (server->secType) {
>                case Kerberos:
> -                       if (vol->linux_uid != ses->linux_uid)
> +                       if (vol->cred_uid != ses->cred_uid)
>                                continue;
>                        break;
>                default:
> @@ -1764,6 +1766,7 @@ cifs_get_smb_ses(struct TCP_Server_Info *server, struct smb_vol *volume_info)
>                if (ses->domainName)
>                        strcpy(ses->domainName, volume_info->domainname);
>        }
> +       ses->cred_uid = volume_info->cred_uid;
>        ses->linux_uid = volume_info->linux_uid;
>        ses->overrideSecFlg = volume_info->secFlg;
>
> --
> 1.6.6.1
>
>



-- 
Thanks,

Steve