commit 5cadfbd5a11e5495cac217534c5f788168b1afd7 upstream.
Add an init flag idicating whether the FUSE_EXPIRE_ONLY flag of
FUSE_NOTIFY_INVAL_ENTRY is effective.
This is needed for backports of this feature, otherwise the server could
just check the protocol version.
Fixes: 4f8d37020e1f ("fuse: add "expire only" mode to FUSE_NOTIFY_INVAL_ENTRY")
Cc: <stable@vger.kernel.org> # v6.2
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 15d937d7ca8c55d2b0ce9116e20c780fdd0b67cc ]
Will need to add supplementary groups to create messages, so add the
general concept of a request extension. A request extension is appended to
the end of the main request. It has a header indicating the size and type
of the extension.
The create security context (fuse_secctx_*) is similar to the generic
request extension, so include that as well in a backward compatible manner.
Add the total extension length to the request header. The offset of the
extension block within the request can be calculated by:
inh->len - inh->total_extlen * 8
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Stable-dep-of: 3002240d1649 ("fuse: fix memory leak in fuse_create_open")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 153524053bbb0d27bb2e0be36d1b46862e9ce74c ]
In general, as of now, in FUSE, direct writes on the same file are
serialized over inode lock i.e we hold inode lock for the full duration of
the write request. I could not find in fuse code and git history a comment
which clearly explains why this exclusive lock is taken for direct writes.
Following might be the reasons for acquiring an exclusive lock but not be
limited to
1) Our guess is some USER space fuse implementations might be relying on
this lock for serialization.
2) The lock protects against file read/write size races.
3) Ruling out any issues arising from partial write failures.
This patch relaxes the exclusive lock for direct non-extending writes only.
File size extending writes might not need the lock either, but we are not
entirely sure if there is a risk to introduce any kind of regression.
Furthermore, benchmarking with fio does not show a difference between patch
versions that take on file size extension a) an exclusive lock and b) a
shared lock.
A possible example of an issue with i_size extending writes are write error
cases. Some writes might succeed and others might fail for file system
internal reasons - for example ENOSPACE. With parallel file size extending
writes it _might_ be difficult to revert the action of the failing write,
especially to restore the right i_size.
With these changes, we allow non-extending parallel direct writes on the
same file with the help of a flag called FOPEN_PARALLEL_DIRECT_WRITES. If
this flag is set on the file (flag is passed from libfuse to fuse kernel as
part of file open/create), we do not take exclusive lock anymore, but
instead use a shared lock that allows non-extending writes to run in
parallel. FUSE implementations which rely on this inode lock for
serialization can continue to do so and serialized direct writes are still
the default. Implementations that do not do write serialization need to be
updated and need to set the FOPEN_PARALLEL_DIRECT_WRITES flag in their file
open/create reply.
On patch review there were concerns that network file systems (or vfs
multiple mounts of the same file system) might have issues with parallel
writes. We believe this is not the case, as this is just a local lock,
which network file systems could not rely on anyway. I.e. this lock is
just for local consistency.
Signed-off-by: Dharmendra Singh <dsingh@ddn.com>
Signed-off-by: Bernd Schubert <bschubert@ddn.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Stable-dep-of: 3002240d1649 ("fuse: fix memory leak in fuse_create_open")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 4f8d37020e1fd0bf6ee9381ba918135ef3712efd ]
Add a flag to entry expiration that lets the filesystem expire a dentry
without kicking it out from the cache immediately.
This makes a difference for overmounted dentries, where plain invalidation
would detach all submounts before dropping the dentry from the cache. If
only expiry is set on the dentry, then any overmounts are left alone and
until ->d_revalidate() is called.
Note: ->d_revalidate() is not called for the case of following a submount,
so invalidation will only be triggered for the non-overmounted case. The
dentry could also be mounted in a different mount instance, in which case
any submounts will still be detached.
Suggested-by: Jakob Blomer <jblomer@cern.ch>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Stable-dep-of: 3002240d1649 ("fuse: fix memory leak in fuse_create_open")
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit b18915248a15eae7d901262f108d6ff0ffb4ffc1 upstream.
The existing code uses min_t(ssize_t, outarg.size, XATTR_LIST_MAX) when
parsing the FUSE daemon's response to a zero-length getxattr/listxattr
request.
On 32-bit kernels, where ssize_t and outarg.size are the same size, this is
wrong: The min_t() will pass through any size values that are negative when
interpreted as signed.
fuse_listxattr() will then return this userspace-supplied negative value,
which callers will treat as an error value.
This kind of bug pattern can lead to fairly bad security bugs because of
how error codes are used in the Linux kernel. If a caller were to convert
the numeric error into an error pointer, like so:
struct foo *func(...) {
int len = fuse_getxattr(..., NULL, 0);
if (len < 0)
return ERR_PTR(len);
...
}
then it would end up returning this userspace-supplied negative value cast
to a pointer - but the caller of this function wouldn't recognize it as an
error pointer (IS_ERR_VALUE() only detects values in the narrow range in
which legitimate errno values are), and so it would just be treated as a
kernel pointer.
I think there is at least one theoretical codepath where this could happen,
but that path would involve virtio-fs with submounts plus some weird
SELinux configuration, so I think it's probably not a concern in practice.
Cc: stable@vger.kernel.org # v4.9
Fixes: 63401ccdb2 ("fuse: limit xattr returned size")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f7790d67785302b3116bbbfda62a5a44524601a3 upstream.
In the case where the aux writeback list is dropped (e.g. the pages
have been truncated or the connection is broken), the stats for
its pages and backing device info need to be updated as well.
Fixes: e2653bd53a ("fuse: fix leaked aux requests")
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Cc: <stable@vger.kernel.org> # v5.1
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 053fc4f755ad43cf35210677bcba798ccdc48d0c ]
->permission(), ->get_link() and ->inode_get_acl() might dereference
->s_fs_info (and, in case of ->permission(), ->s_fs_info->fc->user_ns
as well) when called from rcu pathwalk.
Freeing ->s_fs_info->fc is rcu-delayed; we need to make freeing ->s_fs_info
and dropping ->user_ns rcu-delayed too.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 3c0da3d163eb32f1f91891efaade027fa9b245b9 upstream.
fuse_notify_store(), unlike fuse_do_readpage(), does not enable page
zeroing (because it can be used to change partial page contents).
So fuse_notify_store() must be more careful to fully initialize page
contents (including parts of the page that are beyond end-of-file)
before marking the page uptodate.
The current code can leave beyond-EOF page contents uninitialized, which
makes these uninitialized page contents visible to userspace via mmap().
This is an information leak, but only affects systems which do not
enable init-on-alloc (via CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y or the
corresponding kernel command line parameter).
Link: https://bugs.chromium.org/p/project-zero/issues/detail?id=2574
Cc: stable@kernel.org
Fixes: a1d75f2582 ("fuse: add store request")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 525bd65aa759ec320af1dc06e114ed69733e9e23 upstream.
As was done in
0200679fc795 ("tmpfs: verify {g,u}id mount options correctly")
we need to validate that the requested uid and/or gid is representable in
the filesystem's idmapping.
Cribbing from the above commit log,
The contract for {g,u}id mount options and {g,u}id values in general set
from userspace has always been that they are translated according to the
caller's idmapping. In so far, fuse has been doing the correct thing.
But since fuse is mountable in unprivileged contexts it is also
necessary to verify that the resulting {k,g}uid is representable in the
namespace of the superblock.
Fixes: c30da2e981 ("fuse: convert to use the new mount API")
Cc: stable@vger.kernel.org # 5.4+
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Link: https://lore.kernel.org/r/8f07d45d-c806-484d-a2e3-7a2199df1cd2@redhat.com
Reviewed-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit b1fe686a765e6c0d71811d825b5a1585a202b777 ]
The root inode is assumed to be always hashed. Do not unhash the root
inode even if it is marked BAD.
Fixes: 5d069dbe8a ("fuse: fix bad inode")
Cc: <stable@vger.kernel.org> # v5.11
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 68ca1b49e430f6534d0774a94147a823e3b8b26e ]
The root inode has a fixed nodeid and generation (1, 0).
Prior to the commit 15db16837a ("fuse: fix illegal access to inode with
reused nodeid") generation number on lookup was ignored. After this commit
lookup with the wrong generation number resulted in the inode being
unhashed. This is correct for non-root inodes, but replacing the root
inode is wrong and results in weird behavior.
Fix by reverting to the old behavior if ignoring the generation for the
root inode, but issuing a warning in dmesg.
Reported-by: Antonio SJ Musumeci <trapexit@spawn.link>
Closes: https://lore.kernel.org/all/CAOQ4uxhek5ytdN8Yz2tNEOg5ea4NkBb4nk0FGPjPk_9nz-VG3g@mail.gmail.com/
Fixes: 15db16837a ("fuse: fix illegal access to inode with reused nodeid")
Cc: <stable@vger.kernel.org> # v5.14
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit c4d361f66ac91db8fc65061a9671682f61f4ca9d upstream.
Fuse submounts do not perform a lookup for the nodeid that they inherit
from their parent. Instead, the code decrements the nlookup on the
submount's fuse_inode when it is instantiated, and no forget is
performed when a submount root is evicted.
Trouble arises when the submount's parent is evicted despite the
submount itself being in use. In this author's case, the submount was
in a container and deatched from the initial mount namespace via a
MNT_DEATCH operation. When memory pressure triggered the shrinker, the
inode from the parent was evicted, which triggered enough forgets to
render the submount's nodeid invalid.
Since submounts should still function, even if their parent goes away,
solve this problem by sharing refcounted state between the parent and
its submount. When all of the references on this shared state reach
zero, it's safe to forget the final lookup of the fuse nodeid.
Signed-off-by: Krister Johansen <kjlx@templeofstupid.com>
Cc: stable@vger.kernel.org
Fixes: 1866d779d5 ("fuse: Allow fuse_fill_super_common() for submounts")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Krister Johansen <kjlx@templeofstupid.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7f8ed28d1401320bcb02dda81b3c23ab2dc5a6d8 upstream.
fuse_dax_conn_free() will be called when fuse_fill_super_common() fails
after fuse_dax_conn_alloc(). Then deactivate_locked_super() in
virtio_fs_get_tree() will call virtio_kill_sb() to release the discarded
superblock. This will call fuse_dax_conn_free() again in fuse_conn_put(),
resulting in a possible double free.
Fixes: 1dd539577c ("virtiofs: add a mount option to enable dax")
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Cc: <stable@vger.kernel.org> # v5.10
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b8bd342d50cbf606666488488f9fea374aceb2d5 upstream.
During our debugging of glusterfs, we found an Assertion failed error:
inode_lookup >= nlookup, which was caused by the nlookup value in the
kernel being greater than that in the FUSE file system.
The issue was introduced by fuse_direntplus_link, where in the function,
fuse_iget increments nlookup, and if d_splice_alias returns failure,
fuse_direntplus_link returns failure without decrementing nlookup
https://github.com/gluster/glusterfs/pull/4081
Signed-off-by: ruanmeisi <ruan.meisi@zte.com.cn>
Fixes: 0b05b18381 ("fuse: implement NFS-like readdirplus support")
Cc: <stable@vger.kernel.org> # v3.9
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6a567e920fd0451bf29abc418df96c3365925770 upstream.
Fuse shouldn't return ENOSYS from its ioctl implementation. If userspace
responds with ENOSYS it should be translated to ENOTTY.
There are two ways to return an error from the IOCTL request:
- fuse_out_header.error
- fuse_ioctl_out.result
Commit 02c0cab8e7 ("fuse: ioctl: translate ENOSYS") already fixed this
issue for the first case, but missed the second case. This patch fixes the
second case.
Reported-by: Jonathan Katz <jkatz@eitmlabs.org>
Closes: https://lore.kernel.org/all/CALKgVmcC1VUV_gJVq70n--omMJZUb4HSh_FqvLTHgNBc+HCLFQ@mail.gmail.com/
Fixes: 02c0cab8e7 ("fuse: ioctl: translate ENOSYS")
Cc: <stable@vger.kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3066ff93476c35679cb07a97cce37d9bb07632ff upstream.
This is just a safety precaution to avoid checking flags on memory that was
initialized on the user space side. libfuse zeroes struct fuse_init_out
outarg, but this is not guranteed to be done in all implementations.
Better is to act on flags and to only apply flags2 when FUSE_INIT_EXT is
set.
There is a risk with this change, though - it might break existing user
space libraries, which are already using flags2 without setting
FUSE_INIT_EXT.
The corresponding libfuse patch is here
https://github.com/libfuse/libfuse/pull/662
Signed-off-by: Bernd Schubert <bschubert@ddn.com>
Fixes: 53db28933e ("fuse: extend init flags")
Cc: <stable@vger.kernel.org> # v5.17
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ccc031e26afe60d2a5a3d93dabd9c978210825fb upstream.
The previous commit df8629af29 ("fuse: always revalidate if exclusive
create") ensures that the dentries are revalidated on O_EXCL creates. This
commit complements it by also performing revalidation for rename target
dentries. Otherwise, a rename target file that only exists in kernel
dentry cache but not in the filesystem will result in EEXIST if
RENAME_NOREPLACE flag is used.
Signed-off-by: Jiachen Zhang <zhangjiachen.jaycee@bytedance.com>
Signed-off-by: Zhang Tianci <zhangtianci.1997@bytedance.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Yang Bo <yb203166@antfin.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ed5a7047d2011cb6b2bf84ceb6680124cc6a7d95 upstream.
Currently setgid stripping in file_remove_privs()'s should_remove_suid()
helper is inconsistent with other parts of the vfs. Specifically, it only
raises ATTR_KILL_SGID if the inode is S_ISGID and S_IXGRP but not if the
inode isn't in the caller's groups and the caller isn't privileged over the
inode although we require this already in setattr_prepare() and
setattr_copy() and so all filesystem implement this requirement implicitly
because they have to use setattr_{prepare,copy}() anyway.
But the inconsistency shows up in setgid stripping bugs for overlayfs in
xfstests (e.g., generic/673, generic/683, generic/685, generic/686,
generic/687). For example, we test whether suid and setgid stripping works
correctly when performing various write-like operations as an unprivileged
user (fallocate, reflink, write, etc.):
echo "Test 1 - qa_user, non-exec file $verb"
setup_testfile
chmod a+rws $junk_file
commit_and_check "$qa_user" "$verb" 64k 64k
The test basically creates a file with 6666 permissions. While the file has
the S_ISUID and S_ISGID bits set it does not have the S_IXGRP set. On a
regular filesystem like xfs what will happen is:
sys_fallocate()
-> vfs_fallocate()
-> xfs_file_fallocate()
-> file_modified()
-> __file_remove_privs()
-> dentry_needs_remove_privs()
-> should_remove_suid()
-> __remove_privs()
newattrs.ia_valid = ATTR_FORCE | kill;
-> notify_change()
-> setattr_copy()
In should_remove_suid() we can see that ATTR_KILL_SUID is raised
unconditionally because the file in the test has S_ISUID set.
But we also see that ATTR_KILL_SGID won't be set because while the file
is S_ISGID it is not S_IXGRP (see above) which is a condition for
ATTR_KILL_SGID being raised.
So by the time we call notify_change() we have attr->ia_valid set to
ATTR_KILL_SUID | ATTR_FORCE. Now notify_change() sees that
ATTR_KILL_SUID is set and does:
ia_valid = attr->ia_valid |= ATTR_MODE
attr->ia_mode = (inode->i_mode & ~S_ISUID);
which means that when we call setattr_copy() later we will definitely
update inode->i_mode. Note that attr->ia_mode still contains S_ISGID.
Now we call into the filesystem's ->setattr() inode operation which will
end up calling setattr_copy(). Since ATTR_MODE is set we will hit:
if (ia_valid & ATTR_MODE) {
umode_t mode = attr->ia_mode;
vfsgid_t vfsgid = i_gid_into_vfsgid(mnt_userns, inode);
if (!vfsgid_in_group_p(vfsgid) &&
!capable_wrt_inode_uidgid(mnt_userns, inode, CAP_FSETID))
mode &= ~S_ISGID;
inode->i_mode = mode;
}
and since the caller in the test is neither capable nor in the group of the
inode the S_ISGID bit is stripped.
But assume the file isn't suid then ATTR_KILL_SUID won't be raised which
has the consequence that neither the setgid nor the suid bits are stripped
even though it should be stripped because the inode isn't in the caller's
groups and the caller isn't privileged over the inode.
If overlayfs is in the mix things become a bit more complicated and the bug
shows up more clearly. When e.g., ovl_setattr() is hit from
ovl_fallocate()'s call to file_remove_privs() then ATTR_KILL_SUID and
ATTR_KILL_SGID might be raised but because the check in notify_change() is
questioning the ATTR_KILL_SGID flag again by requiring S_IXGRP for it to be
stripped the S_ISGID bit isn't removed even though it should be stripped:
sys_fallocate()
-> vfs_fallocate()
-> ovl_fallocate()
-> file_remove_privs()
-> dentry_needs_remove_privs()
-> should_remove_suid()
-> __remove_privs()
newattrs.ia_valid = ATTR_FORCE | kill;
-> notify_change()
-> ovl_setattr()
// TAKE ON MOUNTER'S CREDS
-> ovl_do_notify_change()
-> notify_change()
// GIVE UP MOUNTER'S CREDS
// TAKE ON MOUNTER'S CREDS
-> vfs_fallocate()
-> xfs_file_fallocate()
-> file_modified()
-> __file_remove_privs()
-> dentry_needs_remove_privs()
-> should_remove_suid()
-> __remove_privs()
newattrs.ia_valid = attr_force | kill;
-> notify_change()
The fix for all of this is to make file_remove_privs()'s
should_remove_suid() helper to perform the same checks as we already
require in setattr_prepare() and setattr_copy() and have notify_change()
not pointlessly requiring S_IXGRP again. It doesn't make any sense in the
first place because the caller must calculate the flags via
should_remove_suid() anyway which would raise ATTR_KILL_SGID.
While we're at it we move should_remove_suid() from inode.c to attr.c
where it belongs with the rest of the iattr helpers. Especially since it
returns ATTR_KILL_S{G,U}ID flags. We also rename it to
setattr_should_drop_suidgid() to better reflect that it indicates both
setuid and setgid bit removal and also that it returns attr flags.
Running xfstests with this doesn't report any regressions. We should really
try and use consistent checks.
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit de4eda9de2d957ef2d6a8365a01e26a435e958cb ]
READ/WRITE proved to be actively confusing - the meanings are
"data destination, as used with read(2)" and "data source, as
used with write(2)", but people keep interpreting those as
"we read data from it" and "we write data to it", i.e. exactly
the wrong way.
Call them ITER_DEST and ITER_SOURCE - at least that is harder
to misinterpret...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Stable-dep-of: 6dd88fd59da8 ("vhost-scsi: unbreak any layout for response")
Signed-off-by: Sasha Levin <sashal@kernel.org>
file_modified() must be called with inode lock held. fuse_fallocate()
didn't lock the inode in case of just FALLOC_KEEP_SIZE flags value, which
resulted in a kernel Warning in notify_change().
Lock the inode unconditionally, like all other fallocate implementations
do.
Reported-by: Pengfei Xu <pengfei.xu@intel.com>
Reported-and-tested-by: syzbot+462da39f0667b357c4b6@syzkaller.appspotmail.com
Fixes: 4a6f278d48 ("fuse: add file_modified() to fallocate")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
