30 May, 2018
1 commit
-
[ Upstream commit a0b0d1c345d0317efe594df268feb5ccc99f651e ]
proc_sys_link_fill_cache() does not take currently unregistering sysctl
tables into account, which might result into a page fault in
sysctl_follow_link() - add a check to fix it.This bug has been present since v3.4.
Link: http://lkml.kernel.org/r/20180228013506.4915-1-danilokrummrich@dk-develop.de
Fixes: 0e47c99d7fe25 ("sysctl: Replace root_list with links between sysctl_table_sets")
Signed-off-by: Danilo Krummrich
Acked-by: Kees Cook
Reviewed-by: Andrew Morton
Cc: "Luis R . Rodriguez"
Cc: "Eric W. Biederman"
Cc: Alexey Dobriyan
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
Signed-off-by: Sasha Levin
Signed-off-by: Greg Kroah-Hartman
02 Nov, 2017
1 commit
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Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.By default all files without license information are under the default
license of the kernel, which is GPL version 2.Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if
Reviewed-by: Philippe Ombredanne
Reviewed-by: Thomas Gleixner
Signed-off-by: Greg Kroah-Hartman
14 Jul, 2017
1 commit
-
Merge yet more updates from Andrew Morton:
- various misc things
- kexec updates
- sysctl core updates
- scripts/gdb udpates
- checkpoint-restart updates
- ipc updates
- kernel/watchdog updates
- Kees's "rough equivalent to the glibc _FORTIFY_SOURCE=1 feature"
- "stackprotector: ascii armor the stack canary"
- more MM bits
- checkpatch updates
* emailed patches from Andrew Morton : (96 commits)
writeback: rework wb_[dec|inc]_stat family of functions
ARM: samsung: usb-ohci: move inline before return type
video: fbdev: omap: move inline before return type
video: fbdev: intelfb: move inline before return type
USB: serial: safe_serial: move __inline__ before return type
drivers: tty: serial: move inline before return type
drivers: s390: move static and inline before return type
x86/efi: move asmlinkage before return type
sh: move inline before return type
MIPS: SMP: move asmlinkage before return type
m68k: coldfire: move inline before return type
ia64: sn: pci: move inline before type
ia64: move inline before return type
FRV: tlbflush: move asmlinkage before return type
CRIS: gpio: move inline before return type
ARM: HP Jornada 7XX: move inline before return type
ARM: KVM: move asmlinkage before type
checkpatch: improve the STORAGE_CLASS test
mm, migration: do not trigger OOM killer when migrating memory
drm/i915: use __GFP_RETRY_MAYFAIL
...
13 Jul, 2017
3 commits
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To keep parity with regular int interfaces provide the an unsigned int
proc_douintvec_minmax() which allows you to specify a range of allowed
valid numbers.Adding proc_douintvec_minmax_sysadmin() is easy but we can wait for an
actual user for that.Link: http://lkml.kernel.org/r/20170519033554.18592-6-mcgrof@kernel.org
Signed-off-by: Luis R. Rodriguez
Acked-by: Kees Cook
Cc: Subash Abhinov Kasiviswanathan
Cc: Heinrich Schuchardt
Cc: Kees Cook
Cc: "David S. Miller"
Cc: Ingo Molnar
Cc: Al Viro
Cc: "Eric W. Biederman"
Cc: Alexey Dobriyan
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Commit e7d316a02f68 ("sysctl: handle error writing UINT_MAX to u32
fields") added proc_douintvec() to start help adding support for
unsigned int, this however was only half the work needed. Two fixes
have come in since then for the following issues:o Printing the values shows a negative value, this happens since
do_proc_dointvec() and this uses proc_put_long()This was fixed by commit 5380e5644afbba9 ("sysctl: don't print negative
flag for proc_douintvec").o We can easily wrap around the int values: UINT_MAX is 4294967295, if
we echo in 4294967295 + 1 we end up with 0, using 4294967295 + 2 we
end up with 1.
o We echo negative values in and they are acceptedThis was fixed by commit 425fffd886ba ("sysctl: report EINVAL if value
is larger than UINT_MAX for proc_douintvec").It still also failed to be added to sysctl_check_table()... instead of
adding it with the current implementation just provide a proper and
simplified unsigned int support without any array unsigned int support
with no negative support at all.Historically sysctl proc helpers have supported arrays, due to the
complexity this adds though we've taken a step back to evaluate array
users to determine if its worth upkeeping for unsigned int. An
evaluation using Coccinelle has been done to perform a grammatical
search to ask ourselves:o How many sysctl proc_dointvec() (int) users exist which likely
should be moved over to proc_douintvec() (unsigned int) ?
Answer: about 8
- Of these how many are array users ?
Answer: Probably only 1
o How many sysctl array users exist ?
Answer: about 12This last question gives us an idea just how popular arrays: they are not.
Array support should probably just be kept for strings.The identified uint ports are:
drivers/infiniband/core/ucma.c - max_backlog
drivers/infiniband/core/iwcm.c - default_backlog
net/core/sysctl_net_core.c - rps_sock_flow_sysctl()
net/netfilter/nf_conntrack_timestamp.c - nf_conntrack_timestamp -- bool
net/netfilter/nf_conntrack_acct.c nf_conntrack_acct -- bool
net/netfilter/nf_conntrack_ecache.c - nf_conntrack_events -- bool
net/netfilter/nf_conntrack_helper.c - nf_conntrack_helper -- bool
net/phonet/sysctl.c proc_local_port_range()The only possible array users is proc_local_port_range() but it does not
seem worth it to add array support just for this given the range support
works just as well. Unsigned int support should be desirable more for
when you *need* more than INT_MAX or using int min/max support then does
not suffice for your ranges.If you forget and by mistake happen to register an unsigned int proc
entry with an array, the driver will fail and you will get something as
follows:sysctl table check failed: debug/test_sysctl//uint_0002 array now allowed
CPU: 2 PID: 1342 Comm: modprobe Tainted: G W E
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
Call Trace:
dump_stack+0x63/0x81
__register_sysctl_table+0x350/0x650
? kmem_cache_alloc_trace+0x107/0x240
__register_sysctl_paths+0x1b3/0x1e0
? 0xffffffffc005f000
register_sysctl_table+0x1f/0x30
test_sysctl_init+0x10/0x1000 [test_sysctl]
do_one_initcall+0x52/0x1a0
? kmem_cache_alloc_trace+0x107/0x240
do_init_module+0x5f/0x200
load_module+0x1867/0x1bd0
? __symbol_put+0x60/0x60
SYSC_finit_module+0xdf/0x110
SyS_finit_module+0xe/0x10
entry_SYSCALL_64_fastpath+0x1e/0xad
RIP: 0033:0x7f042b22d119Fixes: e7d316a02f68 ("sysctl: handle error writing UINT_MAX to u32 fields")
Link: http://lkml.kernel.org/r/20170519033554.18592-5-mcgrof@kernel.org
Signed-off-by: Luis R. Rodriguez
Suggested-by: Alexey Dobriyan
Cc: Subash Abhinov Kasiviswanathan
Cc: Liping Zhang
Cc: Alexey Dobriyan
Cc: Heinrich Schuchardt
Cc: Kees Cook
Cc: "David S. Miller"
Cc: Ingo Molnar
Cc: Al Viro
Cc: "Eric W. Biederman"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Patch series "sysctl: few fixes", v5.
I've been working on making kmod more deterministic, and as I did that I
couldn't help but notice a few issues with sysctl. My end goal was just
to fix unsigned int support, which back then was completely broken.
Liping Zhang has sent up small atomic fixes, however it still missed yet
one more fix and Alexey Dobriyan had also suggested to just drop array
support given its complexity.I have inspected array support using Coccinelle and indeed its not that
popular, so if in fact we can avoid it for new interfaces, I agree its
best.I did develop a sysctl stress driver but will hold that off for another
series.This patch (of 5):
Commit 7c60c48f58a7 ("sysctl: Improve the sysctl sanity checks")
improved sanity checks considerbly, however the enhancements on
sysctl_check_table() meant adding a functional change so that only the
last table entry's sanity error is propagated. It also changed the way
errors were propagated so that each new check reset the err value, this
means only last sanity check computed is used for an error. This has
been in the kernel since v3.4 days.Fix this by carrying on errors from previous checks and iterations as we
traverse the table and ensuring we keep any error from previous checks.
We keep iterating on the table even if an error is found so we can
complain for all errors found in one shot. This works as -EINVAL is
always returned on error anyway, and the check for error is any non-zero
value.Fixes: 7c60c48f58a7 ("sysctl: Improve the sysctl sanity checks")
Link: http://lkml.kernel.org/r/20170519033554.18592-2-mcgrof@kernel.org
Signed-off-by: Luis R. Rodriguez
Cc: Al Viro
Cc: "Eric W. Biederman"
Cc: Alexey Dobriyan
Cc: Kees Cook
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
12 Jul, 2017
1 commit
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Andrei Vagin writes:
FYI: This bug has been reproduced on 4.11.7
> BUG: Dentry ffff895a3dd01240{i=4e7c09a,n=lo} still in use (1) [unmount of proc proc]
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 13588 at fs/dcache.c:1445 umount_check+0x6e/0x80
> CPU: 1 PID: 13588 Comm: kworker/1:1 Not tainted 4.11.7-200.fc25.x86_64 #1
> Hardware name: CompuLab sbc-flt1/fitlet, BIOS SBCFLT_0.08.04 06/27/2015
> Workqueue: events proc_cleanup_work
> Call Trace:
> dump_stack+0x63/0x86
> __warn+0xcb/0xf0
> warn_slowpath_null+0x1d/0x20
> umount_check+0x6e/0x80
> d_walk+0xc6/0x270
> ? dentry_free+0x80/0x80
> do_one_tree+0x26/0x40
> shrink_dcache_for_umount+0x2d/0x90
> generic_shutdown_super+0x1f/0xf0
> kill_anon_super+0x12/0x20
> proc_kill_sb+0x40/0x50
> deactivate_locked_super+0x43/0x70
> deactivate_super+0x5a/0x60
> cleanup_mnt+0x3f/0x90
> mntput_no_expire+0x13b/0x190
> kern_unmount+0x3e/0x50
> pid_ns_release_proc+0x15/0x20
> proc_cleanup_work+0x15/0x20
> process_one_work+0x197/0x450
> worker_thread+0x4e/0x4a0
> kthread+0x109/0x140
> ? process_one_work+0x450/0x450
> ? kthread_park+0x90/0x90
> ret_from_fork+0x2c/0x40
> ---[ end trace e1c109611e5d0b41 ]---
> VFS: Busy inodes after unmount of proc. Self-destruct in 5 seconds. Have a nice day...
> BUG: unable to handle kernel NULL pointer dereference at (null)
> IP: _raw_spin_lock+0xc/0x30
> PGD 0Fix this by taking a reference to the super block in proc_sys_prune_dcache.
The superblock reference is the core of the fix however the sysctl_inodes
list is converted to a hlist so that hlist_del_init_rcu may be used. This
allows proc_sys_prune_dache to remove inodes the sysctl_inodes list, while
not causing problems for proc_sys_evict_inode when if it later choses to
remove the inode from the sysctl_inodes list. Removing inodes from the
sysctl_inodes list allows proc_sys_prune_dcache to have a progress
guarantee, while still being able to drop all locks. The fact that
head->unregistering is set in start_unregistering ensures that no more
inodes will be added to the the sysctl_inodes list.Previously the code did a dance where it delayed calling iput until the
next entry in the list was being considered to ensure the inode remained on
the sysctl_inodes list until the next entry was walked to. The structure
of the loop in this patch does not need that so is much easier to
understand and maintain.Cc: stable@vger.kernel.org
Reported-by: Andrei Vagin
Tested-by: Andrei Vagin
Fixes: ace0c791e6c3 ("proc/sysctl: Don't grab i_lock under sysctl_lock.")
Fixes: d6cffbbe9a7e ("proc/sysctl: prune stale dentries during unregistering")
Signed-off-by: "Eric W. Biederman"
06 May, 2017
1 commit
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Pull namespace updates from Eric Biederman:
"This is a set of small fixes that were mostly stumbled over during
more significant development. This proc fix and the fix to
posix-timers are the most significant of the lot.There is a lot of good development going on but unfortunately it
didn't quite make the merge window"* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
proc: Fix unbalanced hard link numbers
signal: Make kill_proc_info static
rlimit: Properly call security_task_setrlimit
signal: Remove unused definition of sig_user_definied
ia64: Remove unused IA64_TASK_SIGHAND_OFFSET and IA64_SIGHAND_SIGLOCK_OFFSET
ipc: Remove unused declaration of recompute_msgmni
posix-timers: Correct sanity check in posix_cpu_nsleep
sysctl: Remove dead register_sysctl_root
17 Apr, 2017
1 commit
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The function no longer does anything. The is only a single caller of
register_sysctl_root when semantically there should be two. Remove
this function so that if someone decides this functionality is needed
again it will be obvious all of the callers of setup_sysctl_set need
to be audited and modified appropriately.Signed-off-by: "Eric W. Biederman"
08 Apr, 2017
1 commit
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Commit e7d316a02f68 ("sysctl: handle error writing UINT_MAX to u32
fields") introduced the proc_douintvec helper function, but it forgot to
add the related sanity check when doing register_sysctl_table. So add
it now.Signed-off-by: Liping Zhang
Cc: Subash Abhinov Kasiviswanathan
Cc: Andrew Morton
Signed-off-by: Linus Torvalds
04 Mar, 2017
1 commit
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Pull vfs 'statx()' update from Al Viro.
This adds the new extended stat() interface that internally subsumes our
previous stat interfaces, and allows user mode to specify in more detail
what kind of information it wants.It also allows for some explicit synchronization information to be
passed to the filesystem, which can be relevant for network filesystems:
is the cached value ok, or do you need open/close consistency, or what?From David Howells.
Andreas Dilger points out that the first version of the extended statx
interface was posted June 29, 2010:https://www.spinics.net/lists/linux-fsdevel/msg33831.html
* 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
statx: Add a system call to make enhanced file info available
03 Mar, 2017
1 commit
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Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode. This change is propagated to the vfs_getattr*()
function.Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.========
OVERVIEW
========The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.A number of requests were gathered for features to be included. The
following have been included:(1) Make the fields a consistent size on all arches and make them large.
(2) Spare space, request flags and information flags are provided for
future expansion.(3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
__s64).(4) Creation time: The SMB protocol carries the creation time, which could
be exported by Samba, which will in turn help CIFS make use of
FS-Cache as that can be used for coherency data (stx_btime).This is also specified in NFSv4 as a recommended attribute and could
be exported by NFSD [Steve French].(5) Lightweight stat: Ask for just those details of interest, and allow a
netfs (such as NFS) to approximate anything not of interest, possibly
without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
Dilger] (AT_STATX_DONT_SYNC).(6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
its cached attributes are up to date [Trond Myklebust]
(AT_STATX_FORCE_SYNC).And the following have been left out for future extension:
(7) Data version number: Could be used by userspace NFS servers [Aneesh
Kumar].Can also be used to modify fill_post_wcc() in NFSD which retrieves
i_version directly, but has just called vfs_getattr(). It could get
it from the kstat struct if it used vfs_xgetattr() instead.(There's disagreement on the exact semantics of a single field, since
not all filesystems do this the same way).(8) BSD stat compatibility: Including more fields from the BSD stat such
as creation time (st_btime) and inode generation number (st_gen)
[Jeremy Allison, Bernd Schubert].(9) Inode generation number: Useful for FUSE and userspace NFS servers
[Bernd Schubert].(This was asked for but later deemed unnecessary with the
open-by-handle capability available and caused disagreement as to
whether it's a security hole or not).(10) Extra coherency data may be useful in making backups [Andreas Dilger].
(No particular data were offered, but things like last backup
timestamp, the data version number and the DOS archive bit would come
into this category).(11) Allow the filesystem to indicate what it can/cannot provide: A
filesystem can now say it doesn't support a standard stat feature if
that isn't available, so if, for instance, inode numbers or UIDs don't
exist or are fabricated locally...(This requires a separate system call - I have an fsinfo() call idea
for this).(12) Store a 16-byte volume ID in the superblock that can be returned in
struct xstat [Steve French].(Deferred to fsinfo).
(13) Include granularity fields in the time data to indicate the
granularity of each of the times (NFSv4 time_delta) [Steve French].(Deferred to fsinfo).
(14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags.
Note that the Linux IOC flags are a mess and filesystems such as Ext4
define flags that aren't in linux/fs.h, so translation in the kernel
may be a necessity (or, possibly, we provide the filesystem type too).(Some attributes are made available in stx_attributes, but the general
feeling was that the IOC flags were to ext[234]-specific and shouldn't
be exposed through statx this way).(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
Michael Kerrisk].(Deferred, probably to fsinfo. Finding out if there's an ACL or
seclabal might require extra filesystem operations).(16) Femtosecond-resolution timestamps [Dave Chinner].
(A __reserved field has been left in the statx_timestamp struct for
this - if there proves to be a need).(17) A set multiple attributes syscall to go with this.
===============
NEW SYSTEM CALL
===============The new system call is:
int ret = statx(int dfd,
const char *filename,
unsigned int flags,
unsigned int mask,
struct statx *buffer);The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat(). There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):(1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
respect.(2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
its attributes with the server - which might require data writeback to
occur to get the timestamps correct.(3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
network filesystem. The resulting values should be considered
approximate.mask is a bitmask indicating the fields in struct statx that are of
interest to the caller. The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat(). It should be noted that asking for
more information may entail extra I/O operations.buffer points to the destination for the data. This must be 256 bytes in
size.======================
MAIN ATTRIBUTES RECORD
======================The following structures are defined in which to return the main attribute
set:struct statx_timestamp {
__s64 tv_sec;
__s32 tv_nsec;
__s32 __reserved;
};struct statx {
__u32 stx_mask;
__u32 stx_blksize;
__u64 stx_attributes;
__u32 stx_nlink;
__u32 stx_uid;
__u32 stx_gid;
__u16 stx_mode;
__u16 __spare0[1];
__u64 stx_ino;
__u64 stx_size;
__u64 stx_blocks;
__u64 __spare1[1];
struct statx_timestamp stx_atime;
struct statx_timestamp stx_btime;
struct statx_timestamp stx_ctime;
struct statx_timestamp stx_mtime;
__u32 stx_rdev_major;
__u32 stx_rdev_minor;
__u32 stx_dev_major;
__u32 stx_dev_minor;
__u64 __spare2[14];
};The defined bits in request_mask and stx_mask are:
STATX_TYPE Want/got stx_mode & S_IFMT
STATX_MODE Want/got stx_mode & ~S_IFMT
STATX_NLINK Want/got stx_nlink
STATX_UID Want/got stx_uid
STATX_GID Want/got stx_gid
STATX_ATIME Want/got stx_atime{,_ns}
STATX_MTIME Want/got stx_mtime{,_ns}
STATX_CTIME Want/got stx_ctime{,_ns}
STATX_INO Want/got stx_ino
STATX_SIZE Want/got stx_size
STATX_BLOCKS Want/got stx_blocks
STATX_BASIC_STATS [The stuff in the normal stat struct]
STATX_BTIME Want/got stx_btime{,_ns}
STATX_ALL [All currently available stuff]stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution. Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does. The following
attributes map to FS_*_FL flags and are the same numerical value:STATX_ATTR_COMPRESSED File is compressed by the fs
STATX_ATTR_IMMUTABLE File is marked immutable
STATX_ATTR_APPEND File is append-only
STATX_ATTR_NODUMP File is not to be dumped
STATX_ATTR_ENCRYPTED File requires key to decrypt in fsWithin the kernel, the supported flags are listed by:
KSTAT_ATTR_FS_IOC_FLAGS
[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]New flags include:
STATX_ATTR_AUTOMOUNT Object is an automount trigger
These are for the use of GUI tools that might want to mark files specially,
depending on what they are.Fields in struct statx come in a number of classes:
(0) stx_dev_*, stx_blksize.
These are local system information and are always available.
(1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
stx_size, stx_blocks.These will be returned whether the caller asks for them or not. The
corresponding bits in stx_mask will be set to indicate whether they
actually have valid values.If the caller didn't ask for them, then they may be approximated. For
example, NFS won't waste any time updating them from the server,
unless as a byproduct of updating something requested.If the values don't actually exist for the underlying object (such as
UID or GID on a DOS file), then the bit won't be set in the stx_mask,
even if the caller asked for the value. In such a case, the returned
value will be a fabrication.Note that there are instances where the type might not be valid, for
instance Windows reparse points.(2) stx_rdev_*.
This will be set only if stx_mode indicates we're looking at a
blockdev or a chardev, otherwise will be 0.(3) stx_btime.
Similar to (1), except this will be set to 0 if it doesn't exist.
=======
TESTING
=======The following test program can be used to test the statx system call:
samples/statx/test-statx.c
Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.Here's some example output. Firstly, an NFS directory that crosses to
another FSID. Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.[root@andromeda ~]# /tmp/test-statx -A /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:26 Inode: 1703937 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)Secondly, the result of automounting on that directory.
[root@andromeda ~]# /tmp/test-statx /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:27 Inode: 2 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000Signed-off-by: David Howells
Signed-off-by: Al Viro
02 Mar, 2017
1 commit
-
Add #include dependencies to all .c files rely on sched.h
doing that for them.Note that even if the count where we need to add extra headers seems high,
it's still a net win, because is included in over
2,200 files ...Acked-by: Linus Torvalds
Cc: Mike Galbraith
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar
22 Feb, 2017
1 commit
-
Konstantin Khlebnikov writes:
> This patch has locking problem. I've got lockdep splat under LTP.
>
> [ 6633.115456] ======================================================
> [ 6633.115502] [ INFO: possible circular locking dependency detected ]
> [ 6633.115553] 4.9.10-debug+ #9 Tainted: G L
> [ 6633.115584] -------------------------------------------------------
> [ 6633.115627] ksm02/284980 is trying to acquire lock:
> [ 6633.115659] (&sb->s_type->i_lock_key#4){+.+...}, at: [] igrab+0x1e/0x80
> [ 6633.115834] but task is already holding lock:
> [ 6633.115882] (sysctl_lock){+.+...}, at: [] unregister_sysctl_table+0x6b/0x110
> [ 6633.116026] which lock already depends on the new lock.
> [ 6633.116026]
> [ 6633.116080]
> [ 6633.116080] the existing dependency chain (in reverse order) is:
> [ 6633.116117]
> -> #2 (sysctl_lock){+.+...}:
> -> #1 (&(&dentry->d_lockref.lock)->rlock){+.+...}:
> -> #0 (&sb->s_type->i_lock_key#4){+.+...}:
>
> d_lock nests inside i_lock
> sysctl_lock nests inside d_lock in d_compare
>
> This patch adds i_lock nesting inside sysctl_lock.Al Viro replied:
> Once ->unregistering is set, you can drop sysctl_lock just fine. So I'd
> try something like this - use rcu_read_lock() in proc_sys_prune_dcache(),
> drop sysctl_lock() before it and regain after. Make sure that no inodes
> are added to the list ones ->unregistering has been set and use RCU list
> primitives for modifying the inode list, with sysctl_lock still used to
> serialize its modifications.
>
> Freeing struct inode is RCU-delayed (see proc_destroy_inode()), so doing
> igrab() is safe there. Since we don't drop inode reference until after we'd
> passed beyond it in the list, list_for_each_entry_rcu() should be fine.I agree with Al Viro's analsysis of the situtation.
Fixes: d6cffbbe9a7e ("proc/sysctl: prune stale dentries during unregistering")
Reported-by: Konstantin Khlebnikov
Tested-by: Konstantin Khlebnikov
Suggested-by: Al Viro
Signed-off-by: "Eric W. Biederman"
13 Feb, 2017
1 commit
-
Currently unregistering sysctl table does not prune its dentries.
Stale dentries could slowdown sysctl operations significantly.For example, command:
# for i in {1..100000} ; do unshare -n -- sysctl -a &> /dev/null ; done
creates a millions of stale denties around sysctls of loopback interface:# sysctl fs.dentry-state
fs.dentry-state = 25812579 24724135 45 0 0 0All of them have matching names thus lookup have to scan though whole
hash chain and call d_compare (proc_sys_compare) which checks them
under system-wide spinlock (sysctl_lock).# time sysctl -a > /dev/null
real 1m12.806s
user 0m0.016s
sys 1m12.400sCurrently only memory reclaimer could remove this garbage.
But without significant memory pressure this never happens.This patch collects sysctl inodes into list on sysctl table header and
prunes all their dentries once that table unregisters.Konstantin Khlebnikov writes:
> On 10.02.2017 10:47, Al Viro wrote:
>> how about >> the matching stats *after* that patch?
>
> dcache size doesn't grow endlessly, so stats are fine
>
> # sysctl fs.dentry-state
> fs.dentry-state = 92712 58376 45 0 0 0
>
> # time sysctl -a &>/dev/null
>
> real 0m0.013s
> user 0m0.004s
> sys 0m0.008sSigned-off-by: Konstantin Khlebnikov
Suggested-by: Al Viro
Signed-off-by: Eric W. Biederman
10 Jan, 2017
1 commit
-
Fixes CVE-2016-9191, proc_sys_readdir doesn't drop reference
added by grab_header when return from !dir_emit_dots path.
It can cause any path called unregister_sysctl_table will
wait forever.The calltrace of CVE-2016-9191:
[ 5535.960522] Call Trace:
[ 5535.963265] [] schedule+0x3f/0xa0
[ 5535.968817] [] schedule_timeout+0x3db/0x6f0
[ 5535.975346] [] ? wait_for_completion+0x45/0x130
[ 5535.982256] [] wait_for_completion+0xc3/0x130
[ 5535.988972] [] ? wake_up_q+0x80/0x80
[ 5535.994804] [] drop_sysctl_table+0xc4/0xe0
[ 5536.001227] [] drop_sysctl_table+0x77/0xe0
[ 5536.007648] [] unregister_sysctl_table+0x4d/0xa0
[ 5536.014654] [] unregister_sysctl_table+0x7f/0xa0
[ 5536.021657] [] unregister_sched_domain_sysctl+0x15/0x40
[ 5536.029344] [] partition_sched_domains+0x44/0x450
[ 5536.036447] [] ? __mutex_unlock_slowpath+0x111/0x1f0
[ 5536.043844] [] rebuild_sched_domains_locked+0x64/0xb0
[ 5536.051336] [] update_flag+0x11d/0x210
[ 5536.057373] [] ? mutex_lock_nested+0x2df/0x450
[ 5536.064186] [] ? cpuset_css_offline+0x1b/0x60
[ 5536.070899] [] ? trace_hardirqs_on+0xd/0x10
[ 5536.077420] [] ? mutex_lock_nested+0x2df/0x450
[ 5536.084234] [] ? css_killed_work_fn+0x25/0x220
[ 5536.091049] [] cpuset_css_offline+0x35/0x60
[ 5536.097571] [] css_killed_work_fn+0x5c/0x220
[ 5536.104207] [] process_one_work+0x1df/0x710
[ 5536.110736] [] ? process_one_work+0x160/0x710
[ 5536.117461] [] worker_thread+0x12b/0x4a0
[ 5536.123697] [] ? process_one_work+0x710/0x710
[ 5536.130426] [] kthread+0xfe/0x120
[ 5536.135991] [] ret_from_fork+0x1f/0x40
[ 5536.142041] [] ? kthread_create_on_node+0x230/0x230One cgroup maintainer mentioned that "cgroup is trying to offline
a cpuset css, which takes place under cgroup_mutex. The offlining
ends up trying to drain active usages of a sysctl table which apprently
is not happening."
The real reason is that proc_sys_readdir doesn't drop reference added
by grab_header when return from !dir_emit_dots path. So this cpuset
offline path will wait here forever.See here for details: http://www.openwall.com/lists/oss-security/2016/11/04/13
Fixes: f0c3b5093add ("[readdir] convert procfs")
Cc: stable@vger.kernel.org
Reported-by: CAI Qian
Tested-by: Yang Shukui
Signed-off-by: Zhou Chengming
Acked-by: Al Viro
Signed-off-by: Eric W. Biederman
11 Oct, 2016
2 commits
-
Pull more vfs updates from Al Viro:
">rename2() work from Miklos + current_time() from Deepa"* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fs: Replace current_fs_time() with current_time()
fs: Replace CURRENT_TIME_SEC with current_time() for inode timestamps
fs: Replace CURRENT_TIME with current_time() for inode timestamps
fs: proc: Delete inode time initializations in proc_alloc_inode()
vfs: Add current_time() api
vfs: add note about i_op->rename changes to porting
fs: rename "rename2" i_op to "rename"
vfs: remove unused i_op->rename
fs: make remaining filesystems use .rename2
libfs: support RENAME_NOREPLACE in simple_rename()
fs: support RENAME_NOREPLACE for local filesystems
ncpfs: fix unused variable warning -
Pull misc vfs updates from Al Viro:
"Assorted misc bits and pieces.There are several single-topic branches left after this (rename2
series from Miklos, current_time series from Deepa Dinamani, xattr
series from Andreas, uaccess stuff from from me) and I'd prefer to
send those separately"* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (39 commits)
proc: switch auxv to use of __mem_open()
hpfs: support FIEMAP
cifs: get rid of unused arguments of CIFSSMBWrite()
posix_acl: uapi header split
posix_acl: xattr representation cleanups
fs/aio.c: eliminate redundant loads in put_aio_ring_file
fs/internal.h: add const to ns_dentry_operations declaration
compat: remove compat_printk()
fs/buffer.c: make __getblk_slow() static
proc: unsigned file descriptors
fs/file: more unsigned file descriptors
fs: compat: remove redundant check of nr_segs
cachefiles: Fix attempt to read i_blocks after deleting file [ver #2]
cifs: don't use memcpy() to copy struct iov_iter
get rid of separate multipage fault-in primitives
fs: Avoid premature clearing of capabilities
fs: Give dentry to inode_change_ok() instead of inode
fuse: Propagate dentry down to inode_change_ok()
ceph: Propagate dentry down to inode_change_ok()
xfs: Propagate dentry down to inode_change_ok()
...
07 Oct, 2016
1 commit
-
Pull namespace updates from Eric Biederman:
"This set of changes is a number of smaller things that have been
overlooked in other development cycles focused on more fundamental
change. The devpts changes are small things that were a distraction
until we managed to kill off DEVPTS_MULTPLE_INSTANCES. There is an
trivial regression fix to autofs for the unprivileged mount changes
that went in last cycle. A pair of ioctls has been added by Andrey
Vagin making it is possible to discover the relationships between
namespaces when referring to them through file descriptors.The big user visible change is starting to add simple resource limits
to catch programs that misbehave. With namespaces in general and user
namespaces in particular allowing users to use more kinds of
resources, it has become important to have something to limit errant
programs. Because the purpose of these limits is to catch errant
programs the code needs to be inexpensive to use as it always on, and
the default limits need to be high enough that well behaved programs
on well behaved systems don't encounter them.To this end, after some review I have implemented per user per user
namespace limits, and use them to limit the number of namespaces. The
limits being per user mean that one user can not exhause the limits of
another user. The limits being per user namespace allow contexts where
the limit is 0 and security conscious folks can remove from their
threat anlysis the code used to manage namespaces (as they have
historically done as it root only). At the same time the limits being
per user namespace allow other parts of the system to use namespaces.Namespaces are increasingly being used in application sand boxing
scenarios so an all or nothing disable for the entire system for the
security conscious folks makes increasing use of these sandboxes
impossible.There is also added a limit on the maximum number of mounts present in
a single mount namespace. It is nontrivial to guess what a reasonable
system wide limit on the number of mount structure in the kernel would
be, especially as it various based on how a system is using
containers. A limit on the number of mounts in a mount namespace
however is much easier to understand and set. In most cases in
practice only about 1000 mounts are used. Given that some autofs
scenarious have the potential to be 30,000 to 50,000 mounts I have set
the default limit for the number of mounts at 100,000 which is well
above every known set of users but low enough that the mount hash
tables don't degrade unreaonsably.These limits are a start. I expect this estabilishes a pattern that
other limits for resources that namespaces use will follow. There has
been interest in making inotify event limits per user per user
namespace as well as interest expressed in making details about what
is going on in the kernel more visible"* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (28 commits)
autofs: Fix automounts by using current_real_cred()->uid
mnt: Add a per mount namespace limit on the number of mounts
netns: move {inc,dec}_net_namespaces into #ifdef
nsfs: Simplify __ns_get_path
tools/testing: add a test to check nsfs ioctl-s
nsfs: add ioctl to get a parent namespace
nsfs: add ioctl to get an owning user namespace for ns file descriptor
kernel: add a helper to get an owning user namespace for a namespace
devpts: Change the owner of /dev/pts/ptmx to the mounter of /dev/pts
devpts: Remove sync_filesystems
devpts: Make devpts_kill_sb safe if fsi is NULL
devpts: Simplify devpts_mount by using mount_nodev
devpts: Move the creation of /dev/pts/ptmx into fill_super
devpts: Move parse_mount_options into fill_super
userns: When the per user per user namespace limit is reached return ENOSPC
userns; Document per user per user namespace limits.
mntns: Add a limit on the number of mount namespaces.
netns: Add a limit on the number of net namespaces
cgroupns: Add a limit on the number of cgroup namespaces
ipcns: Add a limit on the number of ipc namespaces
...
28 Sep, 2016
1 commit
-
CURRENT_TIME macro is not appropriate for filesystems as it
doesn't use the right granularity for filesystem timestamps.
Use current_time() instead.CURRENT_TIME is also not y2038 safe.
This is also in preparation for the patch that transitions
vfs timestamps to use 64 bit time and hence make them
y2038 safe. As part of the effort current_time() will be
extended to do range checks. Hence, it is necessary for all
file system timestamps to use current_time(). Also,
current_time() will be transitioned along with vfs to be
y2038 safe.Note that whenever a single call to current_time() is used
to change timestamps in different inodes, it is because they
share the same time granularity.Signed-off-by: Deepa Dinamani
Reviewed-by: Arnd Bergmann
Acked-by: Felipe Balbi
Acked-by: Steven Whitehouse
Acked-by: Ryusuke Konishi
Acked-by: David Sterba
Signed-off-by: Al Viro
22 Sep, 2016
1 commit
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inode_change_ok() will be resposible for clearing capabilities and IMA
extended attributes and as such will need dentry. Give it as an argument
to inode_change_ok() instead of an inode. Also rename inode_change_ok()
to setattr_prepare() to better relect that it does also some
modifications in addition to checks.Reviewed-by: Christoph Hellwig
Signed-off-by: Jan Kara
18 Aug, 2016
1 commit
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Minor overlapping changes for both merge conflicts.
Resolution work done by Stephen Rothwell was used
as a reference.Signed-off-by: David S. Miller
15 Aug, 2016
1 commit
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If net namespace is attached to a user namespace let's make container's
root owner of sysctls affecting said network namespace instead of global
root.This also allows us to clean up net_ctl_permissions() because we do not
need to fudge permissions anymore for the container's owner since it now
owns the objects in question.Acked-by: "Eric W. Biederman"
Signed-off-by: Dmitry Torokhov
Signed-off-by: David S. Miller
08 Aug, 2016
1 commit
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Passing nsproxy into sysctl_table_root.lookup was a premature
optimization in attempt to avoid depending on current. The
directory /proc/self/sys has not appeared and if and when
it does this code will need to be reviewed closely and reworked
anyway. So remove the premature optimization.Acked-by: Kees Cook
Acked-by: Serge Hallyn
Signed-off-by: "Eric W. Biederman"
07 Aug, 2016
1 commit
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Pull more vfs updates from Al Viro:
"Assorted cleanups and fixes.In the "trivial API change" department - ->d_compare() losing 'parent'
argument"* 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
cachefiles: Fix race between inactivating and culling a cache object
9p: use clone_fid()
9p: fix braino introduced in "9p: new helper - v9fs_parent_fid()"
vfs: make dentry_needs_remove_privs() internal
vfs: remove file_needs_remove_privs()
vfs: fix deadlock in file_remove_privs() on overlayfs
get rid of 'parent' argument of ->d_compare()
cifs, msdos, vfat, hfs+: don't bother with parent in ->d_compare()
affs ->d_compare(): don't bother with ->d_inode
fold _d_rehash() and __d_rehash() together
fold dentry_rcuwalk_invalidate() into its only remaining caller
06 Aug, 2016
1 commit
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Pull qstr constification updates from Al Viro:
"Fairly self-contained bunch - surprising lot of places passes struct
qstr * as an argument when const struct qstr * would suffice; it
complicates analysis for no good reason.I'd prefer to feed that separately from the assorted fixes (those are
in #for-linus and with somewhat trickier topology)"* 'work.const-qstr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
qstr: constify instances in adfs
qstr: constify instances in lustre
qstr: constify instances in f2fs
qstr: constify instances in ext2
qstr: constify instances in vfat
qstr: constify instances in procfs
qstr: constify instances in fuse
qstr constify instances in fs/dcache.c
qstr: constify instances in nfs
qstr: constify instances in ocfs2
qstr: constify instances in autofs4
qstr: constify instances in hfs
qstr: constify instances in hfsplus
qstr: constify instances in logfs
qstr: constify dentry_init_security
01 Aug, 2016
1 commit
-
Signed-off-by: Al Viro
31 Jul, 2016
1 commit
-
Signed-off-by: Al Viro
11 Jun, 2016
1 commit
-
We always mixed in the parent pointer into the dentry name hash, but we
did it late at lookup time. It turns out that we can simplify that
lookup-time action by salting the hash with the parent pointer early
instead of late.A few other users of our string hashes also wanted to mix in their own
pointers into the hash, and those are updated to use the same mechanism.Hash users that don't have any particular initial salt can just use the
NULL pointer as a no-salt.Cc: Vegard Nossum
Cc: George Spelvin
Cc: Al Viro
Signed-off-by: Linus Torvalds
03 May, 2016
2 commits
-
Signed-off-by: Al Viro
-
make it usable with directory locked shared
Signed-off-by: Al Viro
29 Sep, 2015
1 commit
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IS_ERR(_OR_NULL) already contain an 'unlikely' compiler flag and there
is no need to do that again from its callers. Drop it.Signed-off-by: Viresh Kumar
Reviewed-by: Jeff Layton
Reviewed-by: David Howells
Reviewed-by: Steve French
Signed-off-by: Jiri Kosina
01 Jul, 2015
1 commit
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Add a magic sysctl table sysctl_mount_point that when used to
create a directory forces that directory to be permanently empty.Update the code to use make_empty_dir_inode when accessing permanently
empty directories.Update the code to not allow adding to permanently empty directories.
Update /proc/sys/fs/binfmt_misc to be a permanently empty directory.
Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman"
16 Apr, 2015
1 commit
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that's the bulk of filesystem drivers dealing with inodes of their own
Signed-off-by: David Howells
Signed-off-by: Al Viro
09 Aug, 2014
1 commit
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Remove the final user, and the typedef itself.
Signed-off-by: Joe Perches
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
29 Jun, 2013
2 commits
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Instances either don't look at it at all (the majority of cases) or
only want it to find the superblock (which can be had as dentry->d_sb).
A few cases that want more are actually safe with dentry->d_inode -
the only precaution needed is the check that it hadn't been replaced with
NULL by rmdir() or by overwriting rename(), which case should be simply
treated as cache miss.Signed-off-by: Linus Torvalds
Signed-off-by: Al Viro -
Signed-off-by: Al Viro
28 Feb, 2013
1 commit
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- use pr_foo() throughout
- remove a couple of duplicated KERN_WARNINGs, via WARN(KERN_WARNING "...")
- nuke a few warnings which I've never seen happen, ever.
Cc: Joe Perches
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
23 Feb, 2013
1 commit
-
Signed-off-by: Al Viro
21 Dec, 2012
1 commit
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Removed vmtruncate
Signed-off-by: Marco Stornelli
Signed-off-by: Al Viro
