Re: [Qemu-devel] [PATCH] hw/9pfs: Handle Security model parsing

["Daniel P. Berrange" <berrange@redhat.com>]

On Wed, Oct 12, 2011 at 01:24:16PM +0530, M. Mohan Kumar wrote:
> Security model is needed only for 'local' fs driver.
> 
> Signed-off-by: M. Mohan Kumar <mohan@in.ibm.com>
> ---
>  fsdev/qemu-fsdev.c         |    6 +----
>  fsdev/qemu-fsdev.h         |    1 +
>  hw/9pfs/virtio-9p-device.c |   47 ++++++++++++++++++++++---------------------
>  vl.c                       |   20 +++++++++++++++--
>  4 files changed, 43 insertions(+), 31 deletions(-)
> 
> --- a/fsdev/qemu-fsdev.h
> +++ b/fsdev/qemu-fsdev.h
> @@ -40,6 +40,7 @@ typedef struct FsTypeTable {
>  typedef struct FsTypeEntry {
>      char *fsdev_id;
>      char *path;
> +    char *fsdriver;
>      char *security_model;
>      int cache_flags;
>      FileOperations *ops;
> diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c
> index aac58ad..1846e36 100644
> --- a/hw/9pfs/virtio-9p-device.c
> +++ b/hw/9pfs/virtio-9p-device.c
> @@ -83,29 +83,30 @@ VirtIODevice *virtio_9p_init(DeviceState *dev, V9fsConf *conf)
>          exit(1);
>      }
>  
> -    if (!strcmp(fse->security_model, "passthrough")) {
> -        /* Files on the Fileserver set to client user credentials */
> -        s->ctx.fs_sm = SM_PASSTHROUGH;
> -        s->ctx.xops = passthrough_xattr_ops;
> -    } else if (!strcmp(fse->security_model, "mapped")) {
> -        /* Files on the fileserver are set to QEMU credentials.
> -         * Client user credentials are saved in extended attributes.
> -         */
> -        s->ctx.fs_sm = SM_MAPPED;
> -        s->ctx.xops = mapped_xattr_ops;
> -    } else if (!strcmp(fse->security_model, "none")) {
> -        /*
> -         * Files on the fileserver are set to QEMU credentials.
> -         */
> -        s->ctx.fs_sm = SM_NONE;
> -        s->ctx.xops = none_xattr_ops;
> -    } else {
> -        fprintf(stderr, "Default to security_model=none. You may want"
> -                " enable advanced security model using "
> -                "security option:\n\t security_model=passthrough\n\t "
> -                "security_model=mapped\n");
> -        s->ctx.fs_sm = SM_NONE;
> -        s->ctx.xops = none_xattr_ops;
> +    /* security models is needed only for local fs driver */
> +    if (!strcmp(fse->fsdriver, "local")) {
> +        if (!strcmp(fse->security_model, "passthrough")) {
> +            /* Files on the Fileserver set to client user credentials */
> +            s->ctx.fs_sm = SM_PASSTHROUGH;
> +            s->ctx.xops = passthrough_xattr_ops;
> +        } else if (!strcmp(fse->security_model, "mapped")) {
> +            /* Files on the fileserver are set to QEMU credentials.
> +            * Client user credentials are saved in extended attributes.
> +            */
> +            s->ctx.fs_sm = SM_MAPPED;
> +            s->ctx.xops = mapped_xattr_ops;
> +        } else if (!strcmp(fse->security_model, "none")) {
> +            /*
> +            * Files on the fileserver are set to QEMU credentials.
> +            */
> +            s->ctx.fs_sm = SM_NONE;
> +            s->ctx.xops = none_xattr_ops;
> +        } else {
> +            fprintf(stderr, "Invalid security_model %s specified.\n"
> +                    "Available security models are:\t "
> +                    "passthrough,mapped or none\n", fse->security_model);
> +            exit(1);
> +        }

Are you sure there aren't use cases where people would like to
choose between  passthrough & mapped, even when using the 'proxy'
or 'handle' security drivers.

Both of the security models seem pretty generally useful to me,
regardless of the driver type.

Regards,
Daniel
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