commit 4f704d9a83 upstream.
We've aligned setgid behavior over multiple kernel releases. The details
can be found in the following two merge messages:
cf619f8919 ("Merge tag 'fs.ovl.setgid.v6.2')
426b4ca2d6 ("Merge tag 'fs.setgid.v6.0')
Consistent setgid stripping behavior is now encapsulated in the
setattr_should_drop_sgid() helper which is used by all filesystems that
strip setgid bits outside of vfs proper. Switch nfs to rely on this
helper as well. Without this patch the setgid stripping tests in
xfstests will fail.
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Message-Id: <20230313-fs-nfs-setgid-v2-1-9a59f436cfc0@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
[ Harshit: backport to 5.15.y]
fs/internal.h -- minor conflcit due to code change differences.
include/linux/fs.h -- Used struct user_namespace *mnt_userns
instead of struct mnt_idmap *idmap
fs/nfs/inode.c -- Used init_user_ns instead of nop_mnt_idmap ]
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 211db0ac9e ]
Since vfs_path_lookup is exported, It should not be internal.
Move vfs_path_lookup prototype in internal.h to linux/namei.h.
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Stable-dep-of: df9d70c186 ("cifs: if deferred close is disabled then close files immediately")
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit f23ce75718 upstream.
Currently the locking order of inode locks for directories that are not
in ancestor relationship is not defined because all operations that
needed to lock two directories like this were serialized by
sb->s_vfs_rename_mutex. However some filesystems need to lock two
subdirectories for RENAME_EXCHANGE operations and for this we need the
locking order established even for two tree-unrelated directories.
Provide a helper function lock_two_inodes() that establishes lock
ordering for any two inodes and use it in lock_two_directories().
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230601105830.13168-4-jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ed5a7047d2 upstream.
[backport to 5.15.y, prior to vfsgid_t]
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>
Tested-by: Leah Rumancik <leah.rumancik@gmail.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 72ae017c54 upstream.
[backport to 5.15.y, prior to vfsgid_t]
The current setgid stripping logic during write and ownership change
operations is inconsistent and strewn over multiple places. In order to
consolidate it and make more consistent we'll add a new helper
setattr_should_drop_sgid(). The function retains the old behavior where
we remove the S_ISGID bit unconditionally when S_IXGRP is set but also
when it isn't set and the caller is neither in the group of the inode
nor privileged over the inode.
We will use this helper both in write operation permission removal such
as file_remove_privs() as well as in ownership change operations.
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Tested-by: Leah Rumancik <leah.rumancik@gmail.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 11c2a8700c upstream.
[backport to 5.15.y, prior to vfsgid_t]
In setattr_{copy,prepare}() we need to perform the same permission
checks to determine whether we need to drop the setgid bit or not.
Instead of open-coding it twice add a simple helper the encapsulates the
logic. We will reuse this helpers to make dropping the setgid bit during
write operations more consistent in a follow up patch.
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Tested-by: Leah Rumancik <leah.rumancik@gmail.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit d6da19c9ca ]
Thread A trying to acquire a write lease checks the value of i_readcount
and i_writecount in check_conflicting_open() to verify that its own fd
is the only fd referencing the file.
Thread B trying to open the file for read will call break_lease() in
do_dentry_open() before incrementing i_readcount, which leaves a small
window where thread A can acquire the write lease and then thread B
completes the open of the file for read without breaking the write lease
that was acquired by thread A.
Fix this race by incrementing i_readcount before checking for existing
leases, same as the case with i_writecount.
Use a helper put_file_access() to decrement i_readcount or i_writecount
in do_dentry_open() and __fput().
Fixes: 387e3746d0 ("locks: eliminate false positive conflicts for write lease")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1a91794ce8 ]
This splits of the setup part of the function setxattr in its own
dedicated function called setxattr_copy. In addition it also exposes a new
function called do_setxattr for making the setxattr call.
This makes it possible to call these two functions from io_uring in the
processing of an xattr request.
Signed-off-by: Stefan Roesch <shr@fb.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20220323154420.3301504-2-shr@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Stable-dep-of: 06bbaa6dc5 ("[coredump] don't use __kernel_write() on kmap_local_page()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1e03a36bdf ]
Get rid of the indirections and just provide a sync_bdevs
helper for the generic sync code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211019062530.2174626-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 70164eb6cc ]
Instead offer a new sync_blockdev_nowait helper for the !wait case.
This new helper is exported as it will grow modular callers in a bit.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211019062530.2174626-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
- Simplify the bio_end_page usage in the buffered IO code.
- Support reading inline data at nonzero offsets for erofs.
- Fix some typos and bad grammar.
- Convert kmap_atomic usage in the inline data read path.
- Add some extra inline data input checking.
- Fix a memory corruption bug stemming from iomap_swapfile_activate
trying to activate more pages than mm was expecting.
- Pass errnos through the page writeback code so that writeback errors
are reported correctly instead of being munged to EIO.
- Replace iomap_apply with a open-coded iterator loops to reduce the
number of indirect calls by a third to a half.
- Refactor the fsdax code to use iomap iterators instead of the
open-coded iomap_apply code that it had before.
- Format file range iomap tracepoint data in hexadecimal and
standardize the names used in the pretty-print string.
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Merge tag 'iomap-5.15-merge-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull iomap updates from Darrick Wong:
"The most notable externally visible change for this cycle is the
addition of support for reads to inline tail fragments of files, which
was requested by the erofs developers; and a correction for a kernel
memory corruption bug if the sysadmin tries to activate a swapfile
with more pages than the swapfile header suggests.
We also now report writeback completion errors to the file mapping
correctly, instead of munging all errors into EIO.
Internally, the bulk of the changes are Christoph's patchset to reduce
the indirect function call count by a third to a half by converting
iomap iteration from a loop pattern to a generator/consumer pattern.
As an added bonus, fsdax no longer open-codes iomap apply loops.
Summary:
- Simplify the bio_end_page usage in the buffered IO code.
- Support reading inline data at nonzero offsets for erofs.
- Fix some typos and bad grammar.
- Convert kmap_atomic usage in the inline data read path.
- Add some extra inline data input checking.
- Fix a memory corruption bug stemming from iomap_swapfile_activate
trying to activate more pages than mm was expecting.
- Pass errnos through the page writeback code so that writeback
errors are reported correctly instead of being munged to EIO.
- Replace iomap_apply with a open-coded iterator loops to reduce the
number of indirect calls by a third to a half.
- Refactor the fsdax code to use iomap iterators instead of the
open-coded iomap_apply code that it had before.
- Format file range iomap tracepoint data in hexadecimal and
standardize the names used in the pretty-print string"
* tag 'iomap-5.15-merge-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (41 commits)
iomap: standardize tracepoint formatting and storage
mm/swap: consider max pages in iomap_swapfile_add_extent
iomap: move loop control code to iter.c
iomap: constify iomap_iter_srcmap
fsdax: switch the fault handlers to use iomap_iter
fsdax: factor out a dax_fault_actor() helper
fsdax: factor out helpers to simplify the dax fault code
iomap: rework unshare flag
iomap: pass an iomap_iter to various buffered I/O helpers
iomap: remove iomap_apply
fsdax: switch dax_iomap_rw to use iomap_iter
iomap: switch iomap_swapfile_activate to use iomap_iter
iomap: switch iomap_seek_data to use iomap_iter
iomap: switch iomap_seek_hole to use iomap_iter
iomap: switch iomap_bmap to use iomap_iter
iomap: switch iomap_fiemap to use iomap_iter
iomap: switch __iomap_dio_rw to use iomap_iter
iomap: switch iomap_page_mkwrite to use iomap_iter
iomap: switch iomap_zero_range to use iomap_iter
iomap: switch iomap_file_unshare to use iomap_iter
...
IORING_OP_LINKAT behaves like linkat(2) and takes the same flags and
arguments.
In some internal places 'hardlink' is used instead of 'link' to avoid
confusion with the SQE links. Name 'link' conflicts with the existing
'link' member of io_kiocb.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/io-uring/20210514145259.wtl4xcsp52woi6ab@wittgenstein/
Signed-off-by: Dmitry Kadashev <dkadashev@gmail.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20210708063447.3556403-12-dkadashev@gmail.com
[axboe: add splice_fd_in check]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Update the following to return int rather than long, for uniformity with
the rest of the do_* helpers in namei.c:
* do_rmdir()
* do_unlinkat()
* do_mkdirat()
* do_mknodat()
* do_symlinkat()
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/io-uring/20210514143202.dmzfcgz5hnauy7ze@wittgenstein/
Signed-off-by: Dmitry Kadashev <dkadashev@gmail.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20210708063447.3556403-9-dkadashev@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pass in the struct filename pointers instead of the user string, and
update the three callers to do the same. This is heavily based on
commit dbea8d345177 ("fs: make do_renameat2() take struct filename").
This behaves like do_unlinkat() and do_renameat2().
Cc: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dmitry Kadashev <dkadashev@gmail.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20210708063447.3556403-4-dkadashev@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
__block_write_begin_int never modifies the passed in iomap, so mark it
const.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Richard reported sporadic (roughly one in 10 or so) null dereferences and
other strange behaviour for a set of automated LTP tests. Things like:
BUG: kernel NULL pointer dereference, address: 0000000000000008
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 0 PID: 1516 Comm: umount Not tainted 5.10.0-yocto-standard #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-48-gd9c812dda519-prebuilt.qemu.org 04/01/2014
RIP: 0010:kernfs_sop_show_path+0x1b/0x60
...or these others:
RIP: 0010:do_mkdirat+0x6a/0xf0
RIP: 0010:d_alloc_parallel+0x98/0x510
RIP: 0010:do_readlinkat+0x86/0x120
There were other less common instances of some kind of a general scribble
but the common theme was mount and cgroup and a dubious dentry triggering
the NULL dereference. I was only able to reproduce it under qemu by
replicating Richard's setup as closely as possible - I never did get it
to happen on bare metal, even while keeping everything else the same.
In commit 71d883c37e ("cgroup_do_mount(): massage calling conventions")
we see this as a part of the overall change:
--------------
struct cgroup_subsys *ss;
- struct dentry *dentry;
[...]
- dentry = cgroup_do_mount(&cgroup_fs_type, fc->sb_flags, root,
- CGROUP_SUPER_MAGIC, ns);
[...]
- if (percpu_ref_is_dying(&root->cgrp.self.refcnt)) {
- struct super_block *sb = dentry->d_sb;
- dput(dentry);
+ ret = cgroup_do_mount(fc, CGROUP_SUPER_MAGIC, ns);
+ if (!ret && percpu_ref_is_dying(&root->cgrp.self.refcnt)) {
+ struct super_block *sb = fc->root->d_sb;
+ dput(fc->root);
deactivate_locked_super(sb);
msleep(10);
return restart_syscall();
}
--------------
In changing from the local "*dentry" variable to using fc->root, we now
export/leave that dentry pointer in the file context after doing the dput()
in the unlikely "is_dying" case. With LTP doing a crazy amount of back to
back mount/unmount [testcases/bin/cgroup_regression_5_1.sh] the unlikely
becomes slightly likely and then bad things happen.
A fix would be to not leave the stale reference in fc->root as follows:
--------------
dput(fc->root);
+ fc->root = NULL;
deactivate_locked_super(sb);
--------------
...but then we are just open-coding a duplicate of fc_drop_locked() so we
simply use that instead.
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: stable@vger.kernel.org # v5.1+
Reported-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Fixes: 71d883c37e ("cgroup_do_mount(): massage calling conventions")
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Merge tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull idmapped mounts from Christian Brauner:
"This introduces idmapped mounts which has been in the making for some
time. Simply put, different mounts can expose the same file or
directory with different ownership. This initial implementation comes
with ports for fat, ext4 and with Christoph's port for xfs with more
filesystems being actively worked on by independent people and
maintainers.
Idmapping mounts handle a wide range of long standing use-cases. Here
are just a few:
- Idmapped mounts make it possible to easily share files between
multiple users or multiple machines especially in complex
scenarios. For example, idmapped mounts will be used in the
implementation of portable home directories in
systemd-homed.service(8) where they allow users to move their home
directory to an external storage device and use it on multiple
computers where they are assigned different uids and gids. This
effectively makes it possible to assign random uids and gids at
login time.
- It is possible to share files from the host with unprivileged
containers without having to change ownership permanently through
chown(2).
- It is possible to idmap a container's rootfs and without having to
mangle every file. For example, Chromebooks use it to share the
user's Download folder with their unprivileged containers in their
Linux subsystem.
- It is possible to share files between containers with
non-overlapping idmappings.
- Filesystem that lack a proper concept of ownership such as fat can
use idmapped mounts to implement discretionary access (DAC)
permission checking.
- They allow users to efficiently changing ownership on a per-mount
basis without having to (recursively) chown(2) all files. In
contrast to chown (2) changing ownership of large sets of files is
instantenous with idmapped mounts. This is especially useful when
ownership of a whole root filesystem of a virtual machine or
container is changed. With idmapped mounts a single syscall
mount_setattr syscall will be sufficient to change the ownership of
all files.
- Idmapped mounts always take the current ownership into account as
idmappings specify what a given uid or gid is supposed to be mapped
to. This contrasts with the chown(2) syscall which cannot by itself
take the current ownership of the files it changes into account. It
simply changes the ownership to the specified uid and gid. This is
especially problematic when recursively chown(2)ing a large set of
files which is commong with the aforementioned portable home
directory and container and vm scenario.
- Idmapped mounts allow to change ownership locally, restricting it
to specific mounts, and temporarily as the ownership changes only
apply as long as the mount exists.
Several userspace projects have either already put up patches and
pull-requests for this feature or will do so should you decide to pull
this:
- systemd: In a wide variety of scenarios but especially right away
in their implementation of portable home directories.
https://systemd.io/HOME_DIRECTORY/
- container runtimes: containerd, runC, LXD:To share data between
host and unprivileged containers, unprivileged and privileged
containers, etc. The pull request for idmapped mounts support in
containerd, the default Kubernetes runtime is already up for quite
a while now: https://github.com/containerd/containerd/pull/4734
- The virtio-fs developers and several users have expressed interest
in using this feature with virtual machines once virtio-fs is
ported.
- ChromeOS: Sharing host-directories with unprivileged containers.
I've tightly synced with all those projects and all of those listed
here have also expressed their need/desire for this feature on the
mailing list. For more info on how people use this there's a bunch of
talks about this too. Here's just two recent ones:
https://www.cncf.io/wp-content/uploads/2020/12/Rootless-Containers-in-Gitpod.pdfhttps://fosdem.org/2021/schedule/event/containers_idmap/
This comes with an extensive xfstests suite covering both ext4 and
xfs:
https://git.kernel.org/brauner/xfstests-dev/h/idmapped_mounts
It covers truncation, creation, opening, xattrs, vfscaps, setid
execution, setgid inheritance and more both with idmapped and
non-idmapped mounts. It already helped to discover an unrelated xfs
setgid inheritance bug which has since been fixed in mainline. It will
be sent for inclusion with the xfstests project should you decide to
merge this.
In order to support per-mount idmappings vfsmounts are marked with
user namespaces. The idmapping of the user namespace will be used to
map the ids of vfs objects when they are accessed through that mount.
By default all vfsmounts are marked with the initial user namespace.
The initial user namespace is used to indicate that a mount is not
idmapped. All operations behave as before and this is verified in the
testsuite.
Based on prior discussions we want to attach the whole user namespace
and not just a dedicated idmapping struct. This allows us to reuse all
the helpers that already exist for dealing with idmappings instead of
introducing a whole new range of helpers. In addition, if we decide in
the future that we are confident enough to enable unprivileged users
to setup idmapped mounts the permission checking can take into account
whether the caller is privileged in the user namespace the mount is
currently marked with.
The user namespace the mount will be marked with can be specified by
passing a file descriptor refering to the user namespace as an
argument to the new mount_setattr() syscall together with the new
MOUNT_ATTR_IDMAP flag. The system call follows the openat2() pattern
of extensibility.
The following conditions must be met in order to create an idmapped
mount:
- The caller must currently have the CAP_SYS_ADMIN capability in the
user namespace the underlying filesystem has been mounted in.
- The underlying filesystem must support idmapped mounts.
- The mount must not already be idmapped. This also implies that the
idmapping of a mount cannot be altered once it has been idmapped.
- The mount must be a detached/anonymous mount, i.e. it must have
been created by calling open_tree() with the OPEN_TREE_CLONE flag
and it must not already have been visible in the filesystem.
The last two points guarantee easier semantics for userspace and the
kernel and make the implementation significantly simpler.
By default vfsmounts are marked with the initial user namespace and no
behavioral or performance changes are observed.
The manpage with a detailed description can be found here:
1d7b902e28
In order to support idmapped mounts, filesystems need to be changed
and mark themselves with the FS_ALLOW_IDMAP flag in fs_flags. The
patches to convert individual filesystem are not very large or
complicated overall as can be seen from the included fat, ext4, and
xfs ports. Patches for other filesystems are actively worked on and
will be sent out separately. The xfstestsuite can be used to verify
that port has been done correctly.
The mount_setattr() syscall is motivated independent of the idmapped
mounts patches and it's been around since July 2019. One of the most
valuable features of the new mount api is the ability to perform
mounts based on file descriptors only.
Together with the lookup restrictions available in the openat2()
RESOLVE_* flag namespace which we added in v5.6 this is the first time
we are close to hardened and race-free (e.g. symlinks) mounting and
path resolution.
While userspace has started porting to the new mount api to mount
proper filesystems and create new bind-mounts it is currently not
possible to change mount options of an already existing bind mount in
the new mount api since the mount_setattr() syscall is missing.
With the addition of the mount_setattr() syscall we remove this last
restriction and userspace can now fully port to the new mount api,
covering every use-case the old mount api could. We also add the
crucial ability to recursively change mount options for a whole mount
tree, both removing and adding mount options at the same time. This
syscall has been requested multiple times by various people and
projects.
There is a simple tool available at
https://github.com/brauner/mount-idmapped
that allows to create idmapped mounts so people can play with this
patch series. I'll add support for the regular mount binary should you
decide to pull this in the following weeks:
Here's an example to a simple idmapped mount of another user's home
directory:
u1001@f2-vm:/$ sudo ./mount --idmap both:1000:1001:1 /home/ubuntu/ /mnt
u1001@f2-vm:/$ ls -al /home/ubuntu/
total 28
drwxr-xr-x 2 ubuntu ubuntu 4096 Oct 28 22:07 .
drwxr-xr-x 4 root root 4096 Oct 28 04:00 ..
-rw------- 1 ubuntu ubuntu 3154 Oct 28 22:12 .bash_history
-rw-r--r-- 1 ubuntu ubuntu 220 Feb 25 2020 .bash_logout
-rw-r--r-- 1 ubuntu ubuntu 3771 Feb 25 2020 .bashrc
-rw-r--r-- 1 ubuntu ubuntu 807 Feb 25 2020 .profile
-rw-r--r-- 1 ubuntu ubuntu 0 Oct 16 16:11 .sudo_as_admin_successful
-rw------- 1 ubuntu ubuntu 1144 Oct 28 00:43 .viminfo
u1001@f2-vm:/$ ls -al /mnt/
total 28
drwxr-xr-x 2 u1001 u1001 4096 Oct 28 22:07 .
drwxr-xr-x 29 root root 4096 Oct 28 22:01 ..
-rw------- 1 u1001 u1001 3154 Oct 28 22:12 .bash_history
-rw-r--r-- 1 u1001 u1001 220 Feb 25 2020 .bash_logout
-rw-r--r-- 1 u1001 u1001 3771 Feb 25 2020 .bashrc
-rw-r--r-- 1 u1001 u1001 807 Feb 25 2020 .profile
-rw-r--r-- 1 u1001 u1001 0 Oct 16 16:11 .sudo_as_admin_successful
-rw------- 1 u1001 u1001 1144 Oct 28 00:43 .viminfo
u1001@f2-vm:/$ touch /mnt/my-file
u1001@f2-vm:/$ setfacl -m u:1001:rwx /mnt/my-file
u1001@f2-vm:/$ sudo setcap -n 1001 cap_net_raw+ep /mnt/my-file
u1001@f2-vm:/$ ls -al /mnt/my-file
-rw-rwxr--+ 1 u1001 u1001 0 Oct 28 22:14 /mnt/my-file
u1001@f2-vm:/$ ls -al /home/ubuntu/my-file
-rw-rwxr--+ 1 ubuntu ubuntu 0 Oct 28 22:14 /home/ubuntu/my-file
u1001@f2-vm:/$ getfacl /mnt/my-file
getfacl: Removing leading '/' from absolute path names
# file: mnt/my-file
# owner: u1001
# group: u1001
user::rw-
user:u1001:rwx
group::rw-
mask::rwx
other::r--
u1001@f2-vm:/$ getfacl /home/ubuntu/my-file
getfacl: Removing leading '/' from absolute path names
# file: home/ubuntu/my-file
# owner: ubuntu
# group: ubuntu
user::rw-
user:ubuntu:rwx
group::rw-
mask::rwx
other::r--"
* tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: (41 commits)
xfs: remove the possibly unused mp variable in xfs_file_compat_ioctl
xfs: support idmapped mounts
ext4: support idmapped mounts
fat: handle idmapped mounts
tests: add mount_setattr() selftests
fs: introduce MOUNT_ATTR_IDMAP
fs: add mount_setattr()
fs: add attr_flags_to_mnt_flags helper
fs: split out functions to hold writers
namespace: only take read lock in do_reconfigure_mnt()
mount: make {lock,unlock}_mount_hash() static
namespace: take lock_mount_hash() directly when changing flags
nfs: do not export idmapped mounts
overlayfs: do not mount on top of idmapped mounts
ecryptfs: do not mount on top of idmapped mounts
ima: handle idmapped mounts
apparmor: handle idmapped mounts
fs: make helpers idmap mount aware
exec: handle idmapped mounts
would_dump: handle idmapped mounts
...
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Merge tag 'for-5.12/io_uring-2021-02-17' of git://git.kernel.dk/linux-block
Pull io_uring updates from Jens Axboe:
"Highlights from this cycles are things like request recycling and
task_work optimizations, which net us anywhere from 10-20% of speedups
on workloads that mostly are inline.
This work was originally done to put io_uring under memcg, which adds
considerable overhead. But it's a really nice win as well. Also worth
highlighting is the LOOKUP_CACHED work in the VFS, and using it in
io_uring. Greatly speeds up the fast path for file opens.
Summary:
- Put io_uring under memcg protection. We accounted just the rings
themselves under rlimit memlock before, now we account everything.
- Request cache recycling, persistent across invocations (Pavel, me)
- First part of a cleanup/improvement to buffer registration (Bijan)
- SQPOLL fixes (Hao)
- File registration NULL pointer fixup (Dan)
- LOOKUP_CACHED support for io_uring
- Disable /proc/thread-self/ for io_uring, like we do for /proc/self
- Add Pavel to the io_uring MAINTAINERS entry
- Tons of code cleanups and optimizations (Pavel)
- Support for skip entries in file registration (Noah)"
* tag 'for-5.12/io_uring-2021-02-17' of git://git.kernel.dk/linux-block: (103 commits)
io_uring: tctx->task_lock should be IRQ safe
proc: don't allow async path resolution of /proc/thread-self components
io_uring: kill cached requests from exiting task closing the ring
io_uring: add helper to free all request caches
io_uring: allow task match to be passed to io_req_cache_free()
io-wq: clear out worker ->fs and ->files
io_uring: optimise io_init_req() flags setting
io_uring: clean io_req_find_next() fast check
io_uring: don't check PF_EXITING from syscall
io_uring: don't split out consume out of SQE get
io_uring: save ctx put/get for task_work submit
io_uring: don't duplicate io_req_task_queue()
io_uring: optimise SQPOLL mm/files grabbing
io_uring: optimise out unlikely link queue
io_uring: take compl state from submit state
io_uring: inline io_complete_rw_common()
io_uring: move res check out of io_rw_reissue()
io_uring: simplify iopoll reissuing
io_uring: clean up io_req_free_batch_finish()
io_uring: move submit side state closer in the ring
...
Assumes current->files->file_lock is already held on invocation. Helps
the caller check the file before removing the fd, if it needs to.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The may_follow_link(), may_linkat(), may_lookup(), may_open(),
may_o_create(), may_create_in_sticky(), may_delete(), and may_create()
helpers determine whether the caller is privileged enough to perform the
associated operations. Let them handle idmapped mounts by mapping the
inode or fsids according to the mount's user namespace. Afterwards the
checks are identical to non-idmapped inodes. The patch takes care to
retrieve the mount's user namespace right before performing permission
checks and passing it down into the fileystem so the user namespace
can't change in between by someone idmapping a mount that is currently
not idmapped. If the initial user namespace is passed nothing changes so
non-idmapped mounts will see identical behavior as before.
Link: https://lore.kernel.org/r/20210121131959.646623-13-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
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Merge tag 'for-5.11/block-2020-12-14' of git://git.kernel.dk/linux-block
Pull block updates from Jens Axboe:
"Another series of killing more code than what is being added, again
thanks to Christoph's relentless cleanups and tech debt tackling.
This contains:
- blk-iocost improvements (Baolin Wang)
- part0 iostat fix (Jeffle Xu)
- Disable iopoll for split bios (Jeffle Xu)
- block tracepoint cleanups (Christoph Hellwig)
- Merging of struct block_device and hd_struct (Christoph Hellwig)
- Rework/cleanup of how block device sizes are updated (Christoph
Hellwig)
- Simplification of gendisk lookup and removal of block device
aliasing (Christoph Hellwig)
- Block device ioctl cleanups (Christoph Hellwig)
- Removal of bdget()/blkdev_get() as exported API (Christoph Hellwig)
- Disk change rework, avoid ->revalidate_disk() (Christoph Hellwig)
- sbitmap improvements (Pavel Begunkov)
- Hybrid polling fix (Pavel Begunkov)
- bvec iteration improvements (Pavel Begunkov)
- Zone revalidation fixes (Damien Le Moal)
- blk-throttle limit fix (Yu Kuai)
- Various little fixes"
* tag 'for-5.11/block-2020-12-14' of git://git.kernel.dk/linux-block: (126 commits)
blk-mq: fix msec comment from micro to milli seconds
blk-mq: update arg in comment of blk_mq_map_queue
blk-mq: add helper allocating tagset->tags
Revert "block: Fix a lockdep complaint triggered by request queue flushing"
nvme-loop: use blk_mq_hctx_set_fq_lock_class to set loop's lock class
blk-mq: add new API of blk_mq_hctx_set_fq_lock_class
block: disable iopoll for split bio
block: Improve blk_revalidate_disk_zones() checks
sbitmap: simplify wrap check
sbitmap: replace CAS with atomic and
sbitmap: remove swap_lock
sbitmap: optimise sbitmap_deferred_clear()
blk-mq: skip hybrid polling if iopoll doesn't spin
blk-iocost: Factor out the base vrate change into a separate function
blk-iocost: Factor out the active iocgs' state check into a separate function
blk-iocost: Move the usage ratio calculation to the correct place
blk-iocost: Remove unnecessary advance declaration
blk-iocost: Fix some typos in comments
blktrace: fix up a kerneldoc comment
block: remove the request_queue to argument request based tracepoints
...
Pass in the struct filename pointers instead of the user string, and
update the three callers to do the same.
This behaves like do_unlinkat(), which also takes a filename struct and
puts it when it is done. Converting callers is then trivial.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Switch the block device lookup interfaces to directly work with a dev_t
so that struct block_device references are only acquired by the
blkdev_get variants (and the blk-cgroup special case). This means that
we now don't need an extra reference in the inode and can generally
simplify handling of struct block_device to keep the lookups contained
in the core block layer code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Coly Li <colyli@suse.de> [bcache]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Just open code the wait in the only caller of both functions.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
compat_sys_mount is identical to the regular sys_mount now, so remove it
and use the native version everywhere.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull init and set_fs() cleanups from Al Viro:
"Christoph's 'getting rid of ksys_...() uses under KERNEL_DS' series"
* 'hch.init_path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (50 commits)
init: add an init_dup helper
init: add an init_utimes helper
init: add an init_stat helper
init: add an init_mknod helper
init: add an init_mkdir helper
init: add an init_symlink helper
init: add an init_link helper
init: add an init_eaccess helper
init: add an init_chmod helper
init: add an init_chown helper
init: add an init_chroot helper
init: add an init_chdir helper
init: add an init_rmdir helper
init: add an init_unlink helper
init: add an init_umount helper
init: add an init_mount helper
init: mark create_dev as __init
init: mark console_on_rootfs as __init
init: initialize ramdisk_execute_command at compile time
devtmpfs: refactor devtmpfsd()
...
Add a simple helper to mknod with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_mknod.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Add a simple helper to mkdir with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_mkdir.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Add a simple helper to symlink with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_symlink.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Add a simple helper to link with a kernel space file name and switch
the early init code over to it. Remove the now unused ksys_link.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Like ksys_umount, but takes a kernel pointer for the destination path.
Switch over the umount in the init code, which just happen to work due to
the implicit set_fs(KERNEL_DS) during early init right now.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Like do_mount, but takes a kernel pointer for the destination path.
Switch over the mounts in the init code and devtmpfs to it, which
just happen to work due to the implicit set_fs(KERNEL_DS) during early
init right now.
Signed-off-by: Christoph Hellwig <hch@lst.de>
This mirrors do_unlinkat and will make life a little easier for
the init code to reuse the whole function with a kernel filename.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Move most of the block related definition out of fs.h into more suitable
headers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Fix performance problems found in dioread_nolock now that it is the
default, caused by transaction leaks.
* Clean up fiemap handling in ext4
* Clean up and refactor multiple block allocator (mballoc) code
* Fix a problem with mballoc with a smaller file systems running out
of blocks because they couldn't properly use blocks that had been
reserved by inode preallocation.
* Fixed a race in ext4_sync_parent() versus rename()
* Simplify the error handling in the extent manipulation code
* Make sure all metadata I/O errors are felected to ext4_ext_dirty()'s and
ext4_make_inode_dirty()'s callers.
* Avoid passing an error pointer to brelse in ext4_xattr_set()
* Fix race which could result to freeing an inode on the dirty last
in data=journal mode.
* Fix refcount handling if ext4_iget() fails
* Fix a crash in generic/019 caused by a corrupted extent node
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
"A lot of bug fixes and cleanups for ext4, including:
- Fix performance problems found in dioread_nolock now that it is the
default, caused by transaction leaks.
- Clean up fiemap handling in ext4
- Clean up and refactor multiple block allocator (mballoc) code
- Fix a problem with mballoc with a smaller file systems running out
of blocks because they couldn't properly use blocks that had been
reserved by inode preallocation.
- Fixed a race in ext4_sync_parent() versus rename()
- Simplify the error handling in the extent manipulation code
- Make sure all metadata I/O errors are felected to
ext4_ext_dirty()'s and ext4_make_inode_dirty()'s callers.
- Avoid passing an error pointer to brelse in ext4_xattr_set()
- Fix race which could result to freeing an inode on the dirty last
in data=journal mode.
- Fix refcount handling if ext4_iget() fails
- Fix a crash in generic/019 caused by a corrupted extent node"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (58 commits)
ext4: avoid unnecessary transaction starts during writeback
ext4: don't block for O_DIRECT if IOCB_NOWAIT is set
ext4: remove the access_ok() check in ext4_ioctl_get_es_cache
fs: remove the access_ok() check in ioctl_fiemap
fs: handle FIEMAP_FLAG_SYNC in fiemap_prep
fs: move fiemap range validation into the file systems instances
iomap: fix the iomap_fiemap prototype
fs: move the fiemap definitions out of fs.h
fs: mark __generic_block_fiemap static
ext4: remove the call to fiemap_check_flags in ext4_fiemap
ext4: split _ext4_fiemap
ext4: fix fiemap size checks for bitmap files
ext4: fix EXT4_MAX_LOGICAL_BLOCK macro
add comment for ext4_dir_entry_2 file_type member
jbd2: avoid leaking transaction credits when unreserving handle
ext4: drop ext4_journal_free_reserved()
ext4: mballoc: use lock for checking free blocks while retrying
ext4: mballoc: refactor ext4_mb_good_group()
ext4: mballoc: introduce pcpu seqcnt for freeing PA to improve ENOSPC handling
ext4: mballoc: refactor ext4_mb_discard_preallocations()
...
Ext4 needs to remove inode from writeback lists after it is out of
visibility of its journalling machinery (which can still dirty the
inode). Export inode_io_list_del() for it.
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200421085445.5731-3-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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Merge tag 'for-5.8/io_uring-2020-06-01' of git://git.kernel.dk/linux-block
Pull io_uring updates from Jens Axboe:
"A relatively quiet round, mostly just fixes and code improvements. In
particular:
- Make statx just use the generic statx handler, instead of open
coding it. We don't need that anymore, as we always call it async
safe (Bijan)
- Enable closing of the ring itself. Also fixes O_PATH closure (me)
- Properly name completion members (me)
- Batch reap of dead file registrations (me)
- Allow IORING_OP_POLL with double waitqueues (me)
- Add tee(2) support (Pavel)
- Remove double off read (Pavel)
- Fix overflow cancellations (Pavel)
- Improve CQ timeouts (Pavel)
- Async defer drain fixes (Pavel)
- Add support for enabling/disabling notifications on a registered
eventfd (Stefano)
- Remove dead state parameter (Xiaoguang)
- Disable SQPOLL submit on dying ctx (Xiaoguang)
- Various code cleanups"
* tag 'for-5.8/io_uring-2020-06-01' of git://git.kernel.dk/linux-block: (29 commits)
io_uring: fix overflowed reqs cancellation
io_uring: off timeouts based only on completions
io_uring: move timeouts flushing to a helper
statx: hide interfaces no longer used by io_uring
io_uring: call statx directly
statx: allow system call to be invoked from io_uring
io_uring: add io_statx structure
io_uring: get rid of manual punting in io_close
io_uring: separate DRAIN flushing into a cold path
io_uring: don't re-read sqe->off in timeout_prep()
io_uring: simplify io_timeout locking
io_uring: fix flush req->refs underflow
io_uring: don't submit sqes when ctx->refs is dying
io_uring: async task poll trigger cleanup
io_uring: add tee(2) support
splice: export do_tee()
io_uring: don't repeat valid flag list
io_uring: rename io_file_put()
io_uring: remove req->needs_fixed_files
io_uring: cleanup io_poll_remove_one() logic
...
The io_uring interfaces have been replaced by do_statx() and are no
longer needed.
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This is a prepatory patch to allow io_uring to invoke statx directly.
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
POSIX defines faccessat() as having a fourth "flags" argument, while the
linux syscall doesn't have it. Glibc tries to emulate AT_EACCESS and
AT_SYMLINK_NOFOLLOW, but AT_EACCESS emulation is broken.
Add a new faccessat(2) syscall with the added flags argument and implement
both flags.
The value of AT_EACCESS is defined in glibc headers to be the same as
AT_REMOVEDIR. Use this value for the kernel interface as well, together
with the explanatory comment.
Also add AT_EMPTY_PATH support, which is not documented by POSIX, but can
be useful and is trivial to implement.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Pull vfs pathwalk sanitizing from Al Viro:
"Massive pathwalk rewrite and cleanups.
Several iterations have been posted; hopefully this thing is getting
readable and understandable now. Pretty much all parts of pathname
resolutions are affected...
The branch is identical to what has sat in -next, except for commit
message in "lift all calls of step_into() out of follow_dotdot/
follow_dotdot_rcu", crediting Qian Cai for reporting the bug; only
commit message changed there."
* 'work.dotdot1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (69 commits)
lookup_open(): don't bother with fallbacks to lookup+create
atomic_open(): no need to pass struct open_flags anymore
open_last_lookups(): move complete_walk() into do_open()
open_last_lookups(): lift O_EXCL|O_CREAT handling into do_open()
open_last_lookups(): don't abuse complete_walk() when all we want is unlazy
open_last_lookups(): consolidate fsnotify_create() calls
take post-lookup part of do_last() out of loop
link_path_walk(): sample parent's i_uid and i_mode for the last component
__nd_alloc_stack(): make it return bool
reserve_stack(): switch to __nd_alloc_stack()
pick_link(): take reserving space on stack into a new helper
pick_link(): more straightforward handling of allocation failures
fold path_to_nameidata() into its only remaining caller
pick_link(): pass it struct path already with normal refcounting rules
fs/namei.c: kill follow_mount()
non-RCU analogue of the previous commit
helper for mount rootwards traversal
follow_dotdot(): be lazy about changing nd->path
follow_dotdot_rcu(): be lazy about changing nd->path
follow_dotdot{,_rcu}(): massage loops
...
This is bio layer functionality and not related to buffer heads.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
New LOOKUP flag, telling path_lookupat() to act as path_mountpointat().
IOW, traverse mounts at the final point and skip revalidation of the
location where it ends up.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'for-5.6/io_uring-vfs-2020-01-29' of git://git.kernel.dk/linux-block
Pull io_uring updates from Jens Axboe:
- Support for various new opcodes (fallocate, openat, close, statx,
fadvise, madvise, openat2, non-vectored read/write, send/recv, and
epoll_ctl)
- Faster ring quiesce for fileset updates
- Optimizations for overflow condition checking
- Support for max-sized clamping
- Support for probing what opcodes are supported
- Support for io-wq backend sharing between "sibling" rings
- Support for registering personalities
- Lots of little fixes and improvements
* tag 'for-5.6/io_uring-vfs-2020-01-29' of git://git.kernel.dk/linux-block: (64 commits)
io_uring: add support for epoll_ctl(2)
eventpoll: support non-blocking do_epoll_ctl() calls
eventpoll: abstract out epoll_ctl() handler
io_uring: fix linked command file table usage
io_uring: support using a registered personality for commands
io_uring: allow registering credentials
io_uring: add io-wq workqueue sharing
io-wq: allow grabbing existing io-wq
io_uring/io-wq: don't use static creds/mm assignments
io-wq: make the io_wq ref counted
io_uring: fix refcounting with batched allocations at OOM
io_uring: add comment for drain_next
io_uring: don't attempt to copy iovec for READ/WRITE
io_uring: honor IOSQE_ASYNC for linked reqs
io_uring: prep req when do IOSQE_ASYNC
io_uring: use labeled array init in io_op_defs
io_uring: optimise sqe-to-req flags translation
io_uring: remove REQ_F_IO_DRAINED
io_uring: file switch work needs to get flushed on exit
io_uring: hide uring_fd in ctx
...
Christian Brauner
Namjae Jeon
Jan Kara
Amir Goldstein
Stefan Roesch
Christoph Hellwig
Linus Torvalds
Dmitry Kadashev
Paul Gortmaker
Al Viro
Jens Axboe
Christian Brauner
Bijan Mottahedeh
Miklos Szeredi