linux/fs/fuse, branch v3.9

fs: Limit sys_mount to only request filesystem modules.

2013-03-04T03:36:31Z

Modify the request_module to prefix the file system type with "fs-" and add aliases to all of the filesystems that can be built as modules to match. A common practice is to build all of the kernel code and leave code that is not commonly needed as modules, with the result that many users are exposed to any bug anywhere in the kernel. Looking for filesystems with a fs- prefix limits the pool of possible modules that can be loaded by mount to just filesystems trivially making things safer with no real cost. Using aliases means user space can control the policy of which filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf with blacklist and alias directives. Allowing simple, safe, well understood work-arounds to known problematic software. This also addresses a rare but unfortunate problem where the filesystem name is not the same as it's module name and module auto-loading would not work. While writing this patch I saw a handful of such cases. The most significant being autofs that lives in the module autofs4. This is relevant to user namespaces because we can reach the request module in get_fs_type() without having any special permissions, and people get uncomfortable when a user specified string (in this case the filesystem type) goes all of the way to request_module. After having looked at this issue I don't think there is any particular reason to perform any filtering or permission checks beyond making it clear in the module request that we want a filesystem module. The common pattern in the kernel is to call request_module() without regards to the users permissions. In general all a filesystem module does once loaded is call register_filesystem() and go to sleep. Which means there is not much attack surface exposed by loading a filesytem module unless the filesystem is mounted. In a user namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT, which most filesystems do not set today. Acked-by: Serge Hallyn Acked-by: Kees Cook Reported-by: Kees Cook Signed-off-by: "Eric W. Biederman"

more file_inode() open-coded instances

2013-02-27T21:59:05Z

Signed-off-by: Al Viro

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2013-02-27T04:16:07Z

Pull vfs pile (part one) from Al Viro: "Assorted stuff - cleaning namei.c up a bit, fixing ->d_name/->d_parent locking violations, etc. The most visible changes here are death of FS_REVAL_DOT (replaced with "has ->d_weak_revalidate()") and a new helper getting from struct file to inode. Some bits of preparation to xattr method interface changes. Misc patches by various people sent this cycle *and* ocfs2 fixes from several cycles ago that should've been upstream right then. PS: the next vfs pile will be xattr stuff." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (46 commits) saner proc_get_inode() calling conventions proc: avoid extra pde_put() in proc_fill_super() fs: change return values from -EACCES to -EPERM fs/exec.c: make bprm_mm_init() static ocfs2/dlm: use GFP_ATOMIC inside a spin_lock ocfs2: fix possible use-after-free with AIO ocfs2: Fix oops in ocfs2_fast_symlink_readpage() code path get_empty_filp()/alloc_file() leave both ->f_pos and ->f_version zero target: writev() on single-element vector is pointless export kernel_write(), convert open-coded instances fs: encode_fh: return FILEID_INVALID if invalid fid_type kill f_vfsmnt vfs: kill FS_REVAL_DOT by adding a d_weak_revalidate dentry op nfsd: handle vfs_getattr errors in acl protocol switch vfs_getattr() to struct path default SET_PERSONALITY() in linux/elf.h ceph: prepopulate inodes only when request is aborted d_hash_and_lookup(): export, switch open-coded instances 9p: switch v9fs_set_create_acl() to inode+fid, do it before d_instantiate() 9p: split dropping the acls from v9fs_set_create_acl() ...

fs: encode_fh: return FILEID_INVALID if invalid fid_type

2013-02-26T07:46:10Z

This patch is a follow up on below patch: [PATCH] exportfs: add FILEID_INVALID to indicate invalid fid_type commit: 216b6cbdcbd86b1db0754d58886b466ae31f5a63 Signed-off-by: Namjae Jeon Signed-off-by: Vivek Trivedi Acked-by: Steven Whitehouse Acked-by: Sage Weil Signed-off-by: Al Viro

new helper: file_inode(file)

2013-02-23T04:31:31Z

Signed-off-by: Al Viro

fuse: allow control of adaptive readdirplus use

2013-02-07T13:25:44Z

For some filesystems (e.g. GlusterFS), the cost of performing a normal readdir and readdirplus are identical. Since adaptively using readdirplus has no benefit for those systems, give users/filesystems the option to control adaptive readdirplus use. v2 of this patch incorporates Miklos's suggestion to simplify the code, as well as improving consistency of macro names and documentation. Signed-off-by: Eric Wong Signed-off-by: Miklos Szeredi

fuse: send poll events

2013-02-04T15:14:32Z

commit 626cf23660 "poll: add poll_requested_events()..." enabled us to send the requested events to the filesystem. Signed-off-by: Miklos Szeredi

fuse: don't WARN when nlink is zero

2013-02-04T14:57:42Z

drop_nlink() warns if nlink is already zero. This is triggerable by a buggy userspace filesystem. The cure, I think, is worse than the disease so disable the warning. Reported-by: Tero Roponen Signed-off-by: Miklos Szeredi

fuse: avoid out-of-scope stack access

2013-02-04T14:22:23Z

The all pointers within fuse_req must point to valid memory once fuse_force_forget() returns. This bug appeared in "fuse: implement NFS-like readdirplus support" and was never in any official Linux release. I tested the fuse_force_forget() code path by injecting to fake -ENOMEM and verified the FORGET operation was called properly in userspace. Signed-off-by: Eric Wong Signed-off-by: Miklos Szeredi

FUSE: Adapt readdirplus to application usage patterns

2013-01-31T16:08:11Z

Use the same adaptive readdirplus mechanism as NFS: http://permalink.gmane.org/gmane.linux.nfs/49299 If the user space implementation wants to disable readdirplus temporarily, it could just return ENOTSUPP. Then kernel will recall it with readdir. Signed-off-by: Feng Shuo Signed-off-by: Miklos Szeredi