Re: [Qemu-devel] [PATCH -V3 1/7] virtio-9p: Introduces an option to specify the security model.

[Anthony Liguori <aliguori@linux.vnet.ibm.com>]

On 05/21/2010 04:26 PM, Venkateswararao Jujjuri (JV) wrote:
> The new option is:
>
> -fsdev fstype,id=myid,path=/share_path/,security_model=[mapped|passthrough]
> -virtfs fstype,path=/share_path/,security_model=[mapped|passthrough],mnt_tag=tag
>
> In the case of mapped security model, files are created with QEMU user
> credentials and the client-user's credentials are saved in extended attributes.
> Whereas in the case of passthrough security model, files on the
> filesystem are directly created with client-user's credentials.
>
> Signed-off-by: Venkateswararao Jujjuri<jvrao@linux.vnet.ibm.com>
> ---
>   fsdev/qemu-fsdev.c |   14 +++++++++++++-
>   fsdev/qemu-fsdev.h |    1 +
>   hw/virtio-9p.c     |   14 ++++++++++++++
>   qemu-config.c      |   12 +++++++++---
>   qemu-options.hx    |   15 +++++++++++----
>   vl.c               |   18 +++++++++++++++---
>   6 files changed, 63 insertions(+), 11 deletions(-)
>
> diff --git a/fsdev/qemu-fsdev.c b/fsdev/qemu-fsdev.c
> index 813e1f7..7d7a153 100644
> --- a/fsdev/qemu-fsdev.c
> +++ b/fsdev/qemu-fsdev.c
> @@ -34,7 +34,7 @@ int qemu_fsdev_add(QemuOpts *opts)
>           return -1;
>       }
>
> -     for (i = 0; i<  ARRAY_SIZE(FsTypes); i++) {
> +    for (i = 0; i<  ARRAY_SIZE(FsTypes); i++) {
>           if (strcmp(FsTypes[i].name, qemu_opt_get(opts, "fstype")) == 0) {
>               break;
>           }
> @@ -46,10 +46,22 @@ int qemu_fsdev_add(QemuOpts *opts)
>           return -1;
>       }
>
> +    if (qemu_opt_get(opts, "path") == NULL) {
> +        fprintf(stderr, "fsdev: No path specified.\n");
> +        return -1;
> +    }
> +
> +    if (qemu_opt_get(opts, "security_model") == NULL) {
> +        fprintf(stderr, "fsdev: No security_model specified.\n");
> +        return -1;
> +    }
> +
>       fsle = qemu_malloc(sizeof(*fsle));
>
>       fsle->fse.fsdev_id = qemu_strdup(qemu_opts_id(opts));
>       fsle->fse.path = qemu_strdup(qemu_opt_get(opts, "path"));
> +    fsle->fse.security_model = qemu_strdup(qemu_opt_get(opts,
> +                "security_model"));
>       fsle->fse.ops = FsTypes[i].ops;
>
>       QTAILQ_INSERT_TAIL(&fstype_entries, fsle, next);
> diff --git a/fsdev/qemu-fsdev.h b/fsdev/qemu-fsdev.h
> index b50fbe0..6c27881 100644
> --- 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 *security_model;
>       FileOperations *ops;
>   } FsTypeEntry;
>
> diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c
> index 687abc0..8ecd39c 100644
> --- a/hw/virtio-9p.c
> +++ b/hw/virtio-9p.c
> @@ -2413,6 +2413,20 @@ 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 */
> +    } else if (!strcmp(fse->security_model, "mapped")) {
> +        /* Files on the fileserver are set to QEMU credentials.
> +         * Client user credentials are saved in extended attributes.
> +         */
> +    } else {
> +        /* user haven't specified a correct security option */
> +        fprintf(stderr, "one of the following must be specified as the"
> +                "security option:\n\t security_model=passthrough \n\t "
> +                "security_model=mapped\n");
> +        exit(1);
> +    }
>    

error_report and a return NULL would be more appropriate than an exit(1).

Regards,

Anthony Liguori

> +
>       if (lstat(fse->path,&stat)) {
>           fprintf(stderr, "share path %s does not exist\n", fse->path);
>           exit(1);
> diff --git a/qemu-config.c b/qemu-config.c
> index d500885..e1e3aa1 100644
> --- a/qemu-config.c
> +++ b/qemu-config.c
> @@ -160,9 +160,12 @@ QemuOptsList qemu_fsdev_opts = {
>           {
>               .name = "fstype",
>               .type = QEMU_OPT_STRING,
> -        }, {
> +        },{
>               .name = "path",
>               .type = QEMU_OPT_STRING,
> +        },{
> +            .name = "security_model",
> +            .type = QEMU_OPT_STRING,
>           },
>           { /*End of list */ }
>       },
> @@ -178,12 +181,15 @@ QemuOptsList qemu_virtfs_opts = {
>           {
>               .name = "fstype",
>               .type = QEMU_OPT_STRING,
> -        }, {
> +        },{
>               .name = "path",
>               .type = QEMU_OPT_STRING,
> -        }, {
> +        },{
>               .name = "mount_tag",
>               .type = QEMU_OPT_STRING,
> +        },{
> +            .name = "security_model",
> +            .type = QEMU_OPT_STRING,
>           },
>
>           { /*End of list */ }
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 12f6b51..d557c92 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -482,7 +482,7 @@ ETEXI
>   DEFHEADING(File system options:)
>
>   DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev,
> -    "-fsdev local,id=id,path=path\n",
> +    "-fsdev local,id=id,path=path,security_model=[mapped|passthrough]\n",
>       QEMU_ARCH_ALL)
>
>   STEXI
> @@ -498,7 +498,7 @@ The specific Fstype will determine the applicable options.
>
>   Options to each backend are described below.
>
> -@item -fsdev local ,id=@var{id} ,path=@var{path}
> +@item -fsdev local ,id=@var{id} ,path=@var{path} ,security_model=@var{security_model}
>
>   Create a file-system-"device" for local-filesystem.
>
> @@ -506,6 +506,9 @@ Create a file-system-"device" for local-filesystem.
>
>   @option{path} specifies the path to be exported. @option{path} is required.
>
> +@option{security_model} specifies the security model to be followed.
> +@option{security_model} is required.
> +
>   @end table
>   ETEXI
>   #endif
> @@ -514,7 +517,7 @@ ETEXI
>   DEFHEADING(Virtual File system pass-through options:)
>
>   DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs,
> -    "-virtfs local,path=path,mount_tag=tag\n",
> +    "-virtfs local,path=path,mount_tag=tag,security_model=[mapped|passthrough]\n",
>       QEMU_ARCH_ALL)
>
>   STEXI
> @@ -530,7 +533,7 @@ The specific Fstype will determine the applicable options.
>
>   Options to each backend are described below.
>
> -@item -virtfs local ,path=@var{path} ,mount_tag=@var{mount_tag}
> +@item -virtfs local ,path=@var{path} ,mount_tag=@var{mount_tag} ,security_model=@var{security_model}
>
>   Create a Virtual file-system-pass through for local-filesystem.
>
> @@ -538,6 +541,10 @@ Create a Virtual file-system-pass through for local-filesystem.
>
>   @option{path} specifies the path to be exported. @option{path} is required.
>
> +@option{security_model} specifies the security model to be followed.
> +@option{security_model} is required.
> +
> +
>   @option{mount_tag} specifies the tag with which the exported file is mounted.
>   @option{mount_tag} is required.
>
> diff --git a/vl.c b/vl.c
> index 85bcc84..a341781 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -3109,10 +3109,21 @@ int main(int argc, char **argv, char **envp)
>                       exit(1);
>                   }
>
> -                len = strlen(",id=,path=");
> +                if (qemu_opt_get(opts, "fstype") == NULL ||
> +                        qemu_opt_get(opts, "mount_tag") == NULL ||
> +                        qemu_opt_get(opts, "path") == NULL ||
> +                        qemu_opt_get(opts, "security_model") == NULL) {
> +                    fprintf(stderr, "Usage: -virtfs fstype,path=/share_path/,"
> +                            "security_model=[mapped|passthrough],"
> +                            "mnt_tag=tag.\n");
> +                    exit(1);
> +                }
> +
> +                len = strlen(",id=,path=,security_model=");
>                   len += strlen(qemu_opt_get(opts, "fstype"));
>                   len += strlen(qemu_opt_get(opts, "mount_tag"));
>                   len += strlen(qemu_opt_get(opts, "path"));
> +                len += strlen(qemu_opt_get(opts, "security_model"));
>                   arg_fsdev = qemu_malloc((len + 1) * sizeof(*arg_fsdev));
>
>                   if (!arg_fsdev) {
> @@ -3121,10 +3132,11 @@ int main(int argc, char **argv, char **envp)
>                       exit(1);
>                   }
>
> -                sprintf(arg_fsdev, "%s,id=%s,path=%s",
> +                sprintf(arg_fsdev, "%s,id=%s,path=%s,security_model=%s",
>                                   qemu_opt_get(opts, "fstype"),
>                                   qemu_opt_get(opts, "mount_tag"),
> -                                qemu_opt_get(opts, "path"));
> +                                qemu_opt_get(opts, "path"),
> +                                qemu_opt_get(opts, "security_model"));
>
>                   len = strlen("virtio-9p-pci,fsdev=,mount_tag=");
>                   len += 2*strlen(qemu_opt_get(opts, "mount_tag"));
>