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>
Parsing "silent" and clearing SB_SILENT makes zero sense.
Parsing "silent" and setting SB_SILENT would make a bit more sense, but
apparently nobody cares.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Unlike the others, this is _not_ a standard option accepted by mount(8).
In fact SB_POSIXACL is an internal flag, and accepting MS_POSIXACL on the
mount(2) interface is possibly a bug.
The only filesystem that apparently wants to handle the "posixacl" option
is 9p, but it has special handling of that option besides setting
SB_POSIXACL.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Makes little sense to keep this blacklist synced with what mount(8) parses
and what it doesn't. E.g. it has various forms of "*atime" options, but
not "atime"...
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Determining whether a path or file descriptor refers to a mountpoint (or
more precisely a mount root) is not trivial using current tools.
Add a flag to statx that indicates whether the path or fd refers to the
root of a mount or not.
Cc: linux-api@vger.kernel.org
Cc: linux-man@vger.kernel.org
Reported-by: Lennart Poettering <mzxreary@0pointer.de>
Reported-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
IS_NOATIME(inode) is defined as __IS_FLG(inode, SB_RDONLY|SB_NOATIME), so
generic_fillattr() will clear STATX_ATIME from the result_mask if the super
block is marked read only.
This was probably not the intention, so fix to only clear STATX_ATIME if
the fs doesn't support atime at all.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Constants of the *_ALL type can be actively harmful due to the fact that
developers will usually fail to consider the possible effects of future
changes to the definition.
Deprecate STATX_ALL in the uapi, while no damage has been done yet.
We could keep something like this around in the kernel, but there's
actually no point, since all filesystems should be explicitly checking
flags that they support and not rely on the VFS masking unknown ones out: a
flag could be known to the VFS, yet not known to the filesystem.
Cc: David Howells <dhowells@redhat.com>
Cc: linux-api@vger.kernel.org
Cc: linux-man@vger.kernel.org
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Split out a helper that overrides the credentials in preparation for
actually doing the access check.
This prepares for the next patch that optionally disables the creds
override.
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
If mounts are deleted after a read(2) call on /proc/self/mounts (or its
kin), the subsequent read(2) could miss a mount that comes after the
deleted one in the list. This is because the file position is interpreted
as the number mount entries from the start of the list.
E.g. first read gets entries #0 to #9; the seq file index will be 10. Then
entry #5 is deleted, resulting in #10 becoming #9 and #11 becoming #10,
etc... The next read will continue from entry #10, and #9 is missed.
Solve this by adding a cursor entry for each open instance. Taking the
global namespace_sem for write seems excessive, since we are only dealing
with a per-namespace list. Instead add a per-namespace spinlock and use
that together with namespace_sem taken for read to protect against
concurrent modification of the mount list. This may reduce parallelism of
is_local_mountpoint(), but it's hardly a big contention point. We could
also use RCU freeing of cursors to make traversal not need additional
locks, if that turns out to be neceesary.
Only move the cursor once for each read (cursor is not added on open) to
minimize cacheline invalidation. When EOF is reached, the cursor is taken
off the list, in order to prevent an excessive number of cursors due to
inactive open file descriptors.
Reported-by: Karel Zak <kzak@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Avi Kivity reports that on fuse filesystems running in a user namespace
asyncronous fsync fails with EOVERFLOW.
The reason is that f_ops->fsync() is called with the creds of the kthread
performing aio work instead of the creds of the process originally
submitting IOCB_CMD_FSYNC.
Fuse sends the creds of the caller in the request header and it needs to
translate the uid and gid into the server's user namespace. Since the
kthread is running in init_user_ns, the translation will fail and the
operation returns an error.
It can be argued that fsync doesn't actually need any creds, but just
zeroing out those fields in the header (as with requests that currently
don't take creds) is a backward compatibility risk.
Instead of working around this issue in fuse, solve the core of the problem
by calling the filesystem with the proper creds.
Reported-by: Avi Kivity <avi@scylladb.com>
Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
Fixes: c9582eb0ff ("fuse: Fail all requests with invalid uids or gids")
Cc: stable@vger.kernel.org # 4.18+
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Whiteouts, unlike real device node should not require privileges to create.
The general concern with device nodes is that opening them can have side
effects. The kernel already avoids zero major (see
Documentation/admin-guide/devices.txt). To be on the safe side the patch
explicitly forbids registering a char device with 0/0 number (see
cdev_add()).
This guarantees that a non-O_PATH open on a whiteout will fail with ENODEV;
i.e. it won't have any side effect.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Pull more btrfs fixes from David Sterba:
"A few more stability fixes, minor build warning fixes and git url
fixup:
- fix partial loss of prealloc extent past i_size after fsync
- fix potential deadlock due to wrong transaction handle passing via
journal_info
- fix gcc 4.8 struct intialization warning
- update git URL in MAINTAINERS entry"
* tag 'for-5.7-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
MAINTAINERS: btrfs: fix git repo URL
btrfs: fix gcc-4.8 build warning for struct initializer
btrfs: transaction: Avoid deadlock due to bad initialization timing of fs_info::journal_info
btrfs: fix partial loss of prealloc extent past i_size after fsync
Pull IOMMU fixes from Joerg Roedel:
- Fix a memory leak when dev_iommu gets freed and a sub-pointer does
not
- Build dependency fixes for Mediatek, spapr_tce, and Intel IOMMU
driver
- Export iommu_group_get_for_dev() only for GPLed modules
- Fix AMD IOMMU interrupt remapping when x2apic is enabled
- Fix error path in the QCOM IOMMU driver probe function
* tag 'iommu-fixes-v5.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
iommu/qcom: Fix local_base status check
iommu: Properly export iommu_group_get_for_dev()
iommu/vt-d: Use right Kconfig option name
iommu/amd: Fix legacy interrupt remapping for x2APIC-enabled system
iommu: spapr_tce: Disable compile testing to fix build on book3s_32 config
iommu/mediatek: Fix MTK_IOMMU dependencies
iommu: Fix the memory leak in dev_iommu_free()
The git repo listed for btrfs hasn't been updated in over a year.
List the current one instead.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pull power management fixes from Rafael Wysocki:
- prevent the intel_pstate driver from printing excessive diagnostic
messages in some cases (Chris Wilson)
- make the hibernation restore kernel freeze kernel threads as well as
user space tasks (Dexuan Cui)
- fix the ACPI device PM disagnostic messages to include the correct
power state name (Kai-Heng Feng).
* tag 'pm-5.7-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
PM: ACPI: Output correct message on target power state
PM: hibernate: Freeze kernel threads in software_resume()
cpufreq: intel_pstate: Only mention the BIOS disabling turbo mode once
Pull iomap fix from Darrick Wong:
"Hoist the check for an unrepresentable FIBMAP return value into
ioctl_fibmap.
The internal kernel function can handle 64-bit values (and is needed
to fix a regression on ext4 + jbd2). It is only the userspace ioctl
that is so old that it cannot deal"
* tag 'iomap-5.7-fixes-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
fibmap: Warn and return an error in case of block > INT_MAX
Pull NFS client bugfixes from Trond Myklebust:
"Highlights include:
Stable fixes:
- fix handling of backchannel binding in BIND_CONN_TO_SESSION
Bugfixes:
- Fix a credential use-after-free issue in pnfs_roc()
- Fix potential posix_acl refcnt leak in nfs3_set_acl
- defer slow parts of rpc_free_client() to a workqueue
- Fix an Oopsable race in __nfs_list_for_each_server()
- Fix trace point use-after-free race
- Regression: the RDMA client no longer responds to server disconnect
requests
- Fix return values of xdr_stream_encode_item_{present, absent}
- _pnfs_return_layout() must always wait for layoutreturn completion
Cleanups:
- Remove unreachable error conditions"
* tag 'nfs-for-5.7-4' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
NFS: Fix a race in __nfs_list_for_each_server()
NFSv4.1: fix handling of backchannel binding in BIND_CONN_TO_SESSION
SUNRPC: defer slow parts of rpc_free_client() to a workqueue.
NFSv4: Remove unreachable error condition due to rpc_run_task()
SUNRPC: Remove unreachable error condition
xprtrdma: Fix use of xdr_stream_encode_item_{present, absent}
xprtrdma: Fix trace point use-after-free race
xprtrdma: Restore wake-up-all to rpcrdma_cm_event_handler()
nfs: Fix potential posix_acl refcnt leak in nfs3_set_acl
NFS/pnfs: Fix a credential use-after-free issue in pnfs_roc()
NFS/pnfs: Ensure that _pnfs_return_layout() waits for layoutreturn completion
Pull dmaengine fixes from Vinod Koul:
"Core:
- Documentation typo fixes
- fix the channel indexes
- dmatest: fixes for process hang and iterations
Drivers:
- hisilicon: build error fix without PCI_MSI
- ti-k3: deadlock fix
- uniphier-xdmac: fix for reg region
- pch: fix data race
- tegra: fix clock state"
* tag 'dmaengine-fix-5.7-rc4' of git://git.infradead.org/users/vkoul/slave-dma:
dmaengine: dmatest: Fix process hang when reading 'wait' parameter
dmaengine: dmatest: Fix iteration non-stop logic
dmaengine: tegra-apb: Ensure that clock is enabled during of DMA synchronization
dmaengine: fix channel index enumeration
dmaengine: mmp_tdma: Reset channel error on release
dmaengine: mmp_tdma: Do not ignore slave config validation errors
dmaengine: pch_dma.c: Avoid data race between probe and irq handler
dt-bindings: dma: uniphier-xdmac: switch to single reg region
include/linux/dmaengine: Typos fixes in API documentation
dmaengine: xilinx_dma: Add missing check for empty list
dmaengine: ti: k3-psil: fix deadlock on error path
dmaengine: hisilicon: Fix build error without PCI_MSI
Pull VFIO fixes from Alex Williamson:
- copy_*_user validity check for new vfio_dma_rw interface (Yan Zhao)
- Fix a potential math overflow (Yan Zhao)
- Use follow_pfn() for calculating PFNMAPs (Sean Christopherson)
* tag 'vfio-v5.7-rc4' of git://github.com/awilliam/linux-vfio:
vfio/type1: Fix VA->PA translation for PFNMAP VMAs in vaddr_get_pfn()
vfio: avoid possible overflow in vfio_iommu_type1_pin_pages
vfio: checking of validity of user vaddr in vfio_dma_rw
Pull arm64 fix from Catalin Marinas:
"Add -fasynchronous-unwind-tables to the vDSO CFLAGS"
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: vdso: Add -fasynchronous-unwind-tables to cflags
Pull io_uring fixes from Jens Axboe:
- Fix for statx not grabbing the file table, making AT_EMPTY_PATH fail
- Cover a few cases where async poll can handle retry, eliminating the
need for an async thread
- fallback request busy/free fix (Bijan)
- syzbot reported SQPOLL thread exit fix for non-preempt (Xiaoguang)
- Fix extra put of req for sync_file_range (Pavel)
- Always punt splice async. We'll improve this for 5.8, but wanted to
eliminate the inode mutex lock from the non-blocking path for 5.7
(Pavel)
* tag 'io_uring-5.7-2020-05-01' of git://git.kernel.dk/linux-block:
io_uring: punt splice async because of inode mutex
io_uring: check non-sync defer_list carefully
io_uring: fix extra put in sync_file_range()
io_uring: use cond_resched() in io_ring_ctx_wait_and_kill()
io_uring: use proper references for fallback_req locking
io_uring: only force async punt if poll based retry can't handle it
io_uring: enable poll retry for any file with ->read_iter / ->write_iter
io_uring: statx must grab the file table for valid fd
Miklos Szeredi
Linus Torvalds
Eric Biggers
Rafael J. Wysocki