[Qemu-devel] [PATCH -V4 1/7] virtio-9p: Introduces an option to specify the security model.

[Venkateswararao Jujjuri (JV)]

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 <address@hidden>
---
 fsdev/qemu-fsdev.c |   14 +++++++++++++-
 fsdev/qemu-fsdev.h |    1 +
 hw/virtio-9p.c     |   22 ++++++++++++++++++----
 qemu-config.c      |   12 +++++++++---
 qemu-options.hx    |   15 +++++++++++----
 vl.c               |   18 +++++++++++++++---
 6 files changed, 67 insertions(+), 15 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..a57562a 100644
--- a/hw/virtio-9p.c
+++ b/hw/virtio-9p.c
@@ -2402,7 +2402,7 @@ VirtIODevice *virtio_9p_init(DeviceState *dev, V9fsConf 
*conf)
         /* We don't have a fsdev identified by fsdev_id */
         fprintf(stderr, "Virtio-9p device couldn't find fsdev "
                     "with the id %s\n", conf->fsdev_id);
-        exit(1);
+        return NULL;
     }
 
     if (!fse->path || !conf->tag) {
@@ -2410,15 +2410,29 @@ VirtIODevice *virtio_9p_init(DeviceState *dev, V9fsConf 
*conf)
         fprintf(stderr, "fsdev with id %s needs path "
                 "and Virtio-9p device needs mount_tag arguments\n",
                 conf->fsdev_id);
-        exit(1);
+        return NULL;
+    }
+
+    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");
+        return NULL;
     }
 
     if (lstat(fse->path, &stat)) {
         fprintf(stderr, "share path %s does not exist\n", fse->path);
-        exit(1);
+        return NULL;
     } else if (!S_ISDIR(stat.st_mode)) {
         fprintf(stderr, "share path %s is not a directory \n", fse->path);
-        exit(1);
+        return NULL;
     }
 
     s->ctx.fs_root = qemu_strdup(fse->path);
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.
 
address@hidden -fsdev local ,address@hidden ,address@hidden
address@hidden -fsdev local ,address@hidden ,address@hidden ,address@hidden
 
 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.
 
address@hidden specifies the security model to be followed.
address@hidden 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.
 
address@hidden -virtfs local ,address@hidden ,address@hidden
address@hidden -virtfs local ,address@hidden ,address@hidden ,address@hidden
 
 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.
 
address@hidden specifies the security model to be followed.
address@hidden 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"));
-- 
1.6.5.2