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authorEric W. Biederman <ebiederm@xmission.com>2018-05-04 11:47:28 -0500
committerMiklos Szeredi <mszeredi@redhat.com>2018-05-31 12:26:10 +0200
commite45b2546e23c2d10f8585063a15c745a7603fac9 (patch)
tree6203c459f681766f6e073d3a3ffbf9766e77ec91 /fs/fuse
parent5ba24197b94d4070d8c2a17fa4944a55cc39ef03 (diff)
downloadlinux-e45b2546e23c2d10f8585063a15c745a7603fac9.tar.bz2
fuse: Ensure posix acls are translated outside of init_user_ns
Ensure the translation happens by failing to read or write posix acls when the filesystem has not indicated it supports posix acls. This ensures that modern cached posix acl support is available and used when dealing with posix acls. This is important because only that path has the code to convernt the uids and gids in posix acls into the user namespace of a fuse filesystem. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/fuse')
-rw-r--r--fs/fuse/fuse_i.h1
-rw-r--r--fs/fuse/inode.c7
-rw-r--r--fs/fuse/xattr.c43
3 files changed, 51 insertions, 0 deletions
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index f630951df8dc..5256ad333b05 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -985,6 +985,7 @@ ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size);
int fuse_removexattr(struct inode *inode, const char *name);
extern const struct xattr_handler *fuse_xattr_handlers[];
extern const struct xattr_handler *fuse_acl_xattr_handlers[];
+extern const struct xattr_handler *fuse_no_acl_xattr_handlers[];
struct posix_acl;
struct posix_acl *fuse_get_acl(struct inode *inode, int type);
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 1643043d4fe5..22c76cf8c2e3 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -1100,6 +1100,13 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
file->f_cred->user_ns != sb->s_user_ns)
goto err_fput;
+ /*
+ * If we are not in the initial user namespace posix
+ * acls must be translated.
+ */
+ if (sb->s_user_ns != &init_user_ns)
+ sb->s_xattr = fuse_no_acl_xattr_handlers;
+
fc = kmalloc(sizeof(*fc), GFP_KERNEL);
err = -ENOMEM;
if (!fc)
diff --git a/fs/fuse/xattr.c b/fs/fuse/xattr.c
index 3caac46b08b0..433717640f78 100644
--- a/fs/fuse/xattr.c
+++ b/fs/fuse/xattr.c
@@ -192,6 +192,26 @@ static int fuse_xattr_set(const struct xattr_handler *handler,
return fuse_setxattr(inode, name, value, size, flags);
}
+static bool no_xattr_list(struct dentry *dentry)
+{
+ return false;
+}
+
+static int no_xattr_get(const struct xattr_handler *handler,
+ struct dentry *dentry, struct inode *inode,
+ const char *name, void *value, size_t size)
+{
+ return -EOPNOTSUPP;
+}
+
+static int no_xattr_set(const struct xattr_handler *handler,
+ struct dentry *dentry, struct inode *nodee,
+ const char *name, const void *value,
+ size_t size, int flags)
+{
+ return -EOPNOTSUPP;
+}
+
static const struct xattr_handler fuse_xattr_handler = {
.prefix = "",
.get = fuse_xattr_get,
@@ -209,3 +229,26 @@ const struct xattr_handler *fuse_acl_xattr_handlers[] = {
&fuse_xattr_handler,
NULL
};
+
+static const struct xattr_handler fuse_no_acl_access_xattr_handler = {
+ .name = XATTR_NAME_POSIX_ACL_ACCESS,
+ .flags = ACL_TYPE_ACCESS,
+ .list = no_xattr_list,
+ .get = no_xattr_get,
+ .set = no_xattr_set,
+};
+
+static const struct xattr_handler fuse_no_acl_default_xattr_handler = {
+ .name = XATTR_NAME_POSIX_ACL_DEFAULT,
+ .flags = ACL_TYPE_ACCESS,
+ .list = no_xattr_list,
+ .get = no_xattr_get,
+ .set = no_xattr_set,
+};
+
+const struct xattr_handler *fuse_no_acl_xattr_handlers[] = {
+ &fuse_no_acl_access_xattr_handler,
+ &fuse_no_acl_default_xattr_handler,
+ &fuse_xattr_handler,
+ NULL
+};