virtio-9p: Security model for chown

mapped model changes the owner in the extended attributes.
passthrough model does the change through lchown() as the
server don't need to follow the link and client will send the
actual filesystem object.

Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

diff --git a/hw/file-op-9p.h b/hw/file-op-9p.h
index 1c8d89b59783a9ed1b2513cd29ce01a0c22d16a8..a53cd35094ace076f687a4f70b23e005a6c31299 100644 (file)
--- a/hw/file-op-9p.h
+++ b/hw/file-op-9p.h
@@ -50,7 +50,7 @@ typedef struct FileOperations
     int (*lstat)(FsContext *, const char *, struct stat *);
     ssize_t (*readlink)(FsContext *, const char *, char *, size_t);
     int (*chmod)(FsContext *, const char *, FsCred *);
-    int (*chown)(FsContext *, const char *, uid_t, gid_t);
+    int (*chown)(FsContext *, const char *, FsCred *);
     int (*mknod)(FsContext *, const char *, mode_t, dev_t);
     int (*mksock)(FsContext *, const char *);
     int (*utime)(FsContext *, const char *, const struct utimbuf *);

diff --git a/hw/virtio-9p-local.c b/hw/virtio-9p-local.c
index 9bdcf02b72b54102b6f25f05bc9d233db0271331..1d7cb32411d141b17f2f62618e53468a6c454381 100644 (file)
--- a/hw/virtio-9p-local.c
+++ b/hw/virtio-9p-local.c
@@ -240,9 +240,14 @@ static int local_rename(FsContext *ctx, const char *oldpath,
 
 }
 
-static int local_chown(FsContext *ctx, const char *path, uid_t uid, gid_t gid)
+static int local_chown(FsContext *fs_ctx, const char *path, FsCred *credp)
 {
-    return chown(rpath(ctx, path), uid, gid);
+    if (fs_ctx->fs_sm == SM_MAPPED) {
+        return local_set_xattr(rpath(fs_ctx, path), credp);
+    } else if (fs_ctx->fs_sm == SM_PASSTHROUGH) {
+        return lchown(rpath(fs_ctx, path), credp->fc_uid, credp->fc_gid);
+    }
+    return -1;
 }
 
 static int local_utime(FsContext *ctx, const char *path,

diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c
index 24291f486058308a888850f6b2854b93bd8cbae0..fa459c92607f66f77c52b4d26ab8bb657d12604d 100644 (file)
--- a/hw/virtio-9p.c
+++ b/hw/virtio-9p.c
@@ -209,7 +209,12 @@ static int v9fs_do_rename(V9fsState *s, V9fsString *oldpath,
 
 static int v9fs_do_chown(V9fsState *s, V9fsString *path, uid_t uid, gid_t gid)
 {
-    return s->ops->chown(&s->ctx, path->data, uid, gid);
+    FsCred cred;
+    cred_init(&cred);
+    cred.fc_uid = uid;
+    cred.fc_gid = gid;
+
+    return s->ops->chown(&s->ctx, path->data, &cred);
 }
 
 static int v9fs_do_utime(V9fsState *s, V9fsString *path,
@@ -2014,7 +2019,7 @@ static void v9fs_wstat_post_utime(V9fsState *s, V9fsWstatState *vs, int err)
         goto out;
     }
 
-    if (vs->v9stat.n_gid != -1) {
+    if (vs->v9stat.n_gid != -1 || vs->v9stat.n_uid != -1) {
         if (v9fs_do_chown(s, &vs->fidp->path, vs->v9stat.n_uid,
                     vs->v9stat.n_gid)) {
             err = -errno;