It might be a kernel disaster if one sysfs entry is freed but
still referenced by sysfs tree.
Recently Dave and Sasha reported one use-after-free problem on
sysfs entry, and the problem has been troubleshooted with help
of debug message added in this patch.
Given sysfs_get_dirent/sysfs_put are exported APIs, even inside
sysfs they are called in many contexts(kobject/attribe add/delete,
inode init/drop, dentry lookup/release, readdir, ...), it is healthful
to check the removed flag before freeing one entry and dump message
if it is freeing without being removed first.
Cc: Dave Jones <davej@redhat.com>
Cc: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The inode->i_mutex isn't hold when updating filp->f_pos
in read()/write(), so the filp->f_pos might be read as
0 or 1 in readdir() when there is concurrent read()/write()
on this same file, then may cause use after free in readdir().
The bug can be reproduced with Li Zefan's test code on the
link:
https://patchwork.kernel.org/patch/2160771/
This patch fixes the use after free under this situation.
Cc: stable <stable@vger.kernel.org>
Reported-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Here are two fixes for sysfs that resolve issues that have been found by the
Trinity fuzz tool, causing oopses in sysfs. They both have been in linux-next
for a while to ensure that they do not cause any other problems.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-3.9-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull sysfs fixes from Greg Kroah-Hartman:
"Here are two fixes for sysfs that resolve issues that have been found
by the Trinity fuzz tool, causing oopses in sysfs. They both have
been in linux-next for a while to ensure that they do not cause any
other problems."
* tag 'driver-core-3.9-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
sysfs: handle failure path correctly for readdir()
sysfs: fix race between readdir and lseek
Only allow unprivileged mounts of proc and sysfs if they are already
mounted when the user namespace is created.
proc and sysfs are interesting because they have content that is
per namespace, and so fresh mounts are needed when new namespaces
are created while at the same time proc and sysfs have content that
is shared between every instance.
Respect the policy of who may see the shared content of proc and sysfs
by only allowing new mounts if there was an existing mount at the time
the user namespace was created.
In practice there are only two interesting cases: proc and sysfs are
mounted at their usual places, proc and sysfs are not mounted at all
(some form of mount namespace jail).
Cc: stable@vger.kernel.org
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
It seems that sysfs has an interesting way of doing the same thing.
This removes the cpu_relax unfortunately, but if it's really needed,
it would be better to add this to include/linux/atomic.h to benefit
all atomic ops users.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In case of 'if (filp->f_pos == 0 or 1)' of sysfs_readdir(),
the failure from filldir() isn't handled, and the reference counter
of the sysfs_dirent object pointed by filp->private_data will be
released without clearing filp->private_data, so use after free
bug will be triggered later.
This patch returns immeadiately under the situation for fixing the bug,
and it is reasonable to return from readdir() when filldir() fails.
Reported-by: Dave Jones <davej@redhat.com>
Tested-by: Sasha Levin <levinsasha928@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
While readdir() is running, lseek() may set filp->f_pos as zero,
then may leave filp->private_data pointing to one sysfs_dirent
object without holding its reference counter, so the sysfs_dirent
object may be used after free in next readdir().
This patch holds inode->i_mutex to avoid the problem since
the lock is always held in readdir path.
Reported-by: Dave Jones <davej@redhat.com>
Tested-by: Sasha Levin <levinsasha928@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
I'm not sure why, but the hlist for each entry iterators were conceived
list_for_each_entry(pos, head, member)
The hlist ones were greedy and wanted an extra parameter:
hlist_for_each_entry(tpos, pos, head, member)
Why did they need an extra pos parameter? I'm not quite sure. Not only
they don't really need it, it also prevents the iterator from looking
exactly like the list iterator, which is unfortunate.
Besides the semantic patch, there was some manual work required:
- Fix up the actual hlist iterators in linux/list.h
- Fix up the declaration of other iterators based on the hlist ones.
- A very small amount of places were using the 'node' parameter, this
was modified to use 'obj->member' instead.
- Coccinelle didn't handle the hlist_for_each_entry_safe iterator
properly, so those had to be fixed up manually.
The semantic patch which is mostly the work of Peter Senna Tschudin is here:
@@
iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;
type T;
expression a,c,d,e;
identifier b;
statement S;
@@
-T b;
<+... when != b
(
hlist_for_each_entry(a,
- b,
c, d) S
|
hlist_for_each_entry_continue(a,
- b,
c) S
|
hlist_for_each_entry_from(a,
- b,
c) S
|
hlist_for_each_entry_rcu(a,
- b,
c, d) S
|
hlist_for_each_entry_rcu_bh(a,
- b,
c, d) S
|
hlist_for_each_entry_continue_rcu_bh(a,
- b,
c) S
|
for_each_busy_worker(a, c,
- b,
d) S
|
ax25_uid_for_each(a,
- b,
c) S
|
ax25_for_each(a,
- b,
c) S
|
inet_bind_bucket_for_each(a,
- b,
c) S
|
sctp_for_each_hentry(a,
- b,
c) S
|
sk_for_each(a,
- b,
c) S
|
sk_for_each_rcu(a,
- b,
c) S
|
sk_for_each_from
-(a, b)
+(a)
S
+ sk_for_each_from(a) S
|
sk_for_each_safe(a,
- b,
c, d) S
|
sk_for_each_bound(a,
- b,
c) S
|
hlist_for_each_entry_safe(a,
- b,
c, d, e) S
|
hlist_for_each_entry_continue_rcu(a,
- b,
c) S
|
nr_neigh_for_each(a,
- b,
c) S
|
nr_neigh_for_each_safe(a,
- b,
c, d) S
|
nr_node_for_each(a,
- b,
c) S
|
nr_node_for_each_safe(a,
- b,
c, d) S
|
- for_each_gfn_sp(a, c, d, b) S
+ for_each_gfn_sp(a, c, d) S
|
- for_each_gfn_indirect_valid_sp(a, c, d, b) S
+ for_each_gfn_indirect_valid_sp(a, c, d) S
|
for_each_host(a,
- b,
c) S
|
for_each_host_safe(a,
- b,
c, d) S
|
for_each_mesh_entry(a,
- b,
c, d) S
)
...+>
[akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
[akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foudnation.org: redo intrusive kvm changes]
Tested-by: Peter Senna Tschudin <peter.senna@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull vfs pile (part one) from Al Viro:
"Assorted stuff - cleaning namei.c up a bit, fixing ->d_name/->d_parent
locking violations, etc.
The most visible changes here are death of FS_REVAL_DOT (replaced with
"has ->d_weak_revalidate()") and a new helper getting from struct file
to inode. Some bits of preparation to xattr method interface changes.
Misc patches by various people sent this cycle *and* ocfs2 fixes from
several cycles ago that should've been upstream right then.
PS: the next vfs pile will be xattr stuff."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (46 commits)
saner proc_get_inode() calling conventions
proc: avoid extra pde_put() in proc_fill_super()
fs: change return values from -EACCES to -EPERM
fs/exec.c: make bprm_mm_init() static
ocfs2/dlm: use GFP_ATOMIC inside a spin_lock
ocfs2: fix possible use-after-free with AIO
ocfs2: Fix oops in ocfs2_fast_symlink_readpage() code path
get_empty_filp()/alloc_file() leave both ->f_pos and ->f_version zero
target: writev() on single-element vector is pointless
export kernel_write(), convert open-coded instances
fs: encode_fh: return FILEID_INVALID if invalid fid_type
kill f_vfsmnt
vfs: kill FS_REVAL_DOT by adding a d_weak_revalidate dentry op
nfsd: handle vfs_getattr errors in acl protocol
switch vfs_getattr() to struct path
default SET_PERSONALITY() in linux/elf.h
ceph: prepopulate inodes only when request is aborted
d_hash_and_lookup(): export, switch open-coded instances
9p: switch v9fs_set_create_acl() to inode+fid, do it before d_instantiate()
9p: split dropping the acls from v9fs_set_create_acl()
...
Here is the big driver core merge for 3.9-rc1
There are two major series here, both of which touch lots of drivers all
over the kernel, and will cause you some merge conflicts:
- add a new function called devm_ioremap_resource() to properly be
able to check return values.
- remove CONFIG_EXPERIMENTAL
If you need me to provide a merged tree to handle these resolutions,
please let me know.
Other than those patches, there's not much here, some minor fixes and
updates.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-3.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core patches from Greg Kroah-Hartman:
"Here is the big driver core merge for 3.9-rc1
There are two major series here, both of which touch lots of drivers
all over the kernel, and will cause you some merge conflicts:
- add a new function called devm_ioremap_resource() to properly be
able to check return values.
- remove CONFIG_EXPERIMENTAL
Other than those patches, there's not much here, some minor fixes and
updates"
Fix up trivial conflicts
* tag 'driver-core-3.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (221 commits)
base: memory: fix soft/hard_offline_page permissions
drivercore: Fix ordering between deferred_probe and exiting initcalls
backlight: fix class_find_device() arguments
TTY: mark tty_get_device call with the proper const values
driver-core: constify data for class_find_device()
firmware: Ignore abort check when no user-helper is used
firmware: Reduce ifdef CONFIG_FW_LOADER_USER_HELPER
firmware: Make user-mode helper optional
firmware: Refactoring for splitting user-mode helper code
Driver core: treat unregistered bus_types as having no devices
watchdog: Convert to devm_ioremap_resource()
thermal: Convert to devm_ioremap_resource()
spi: Convert to devm_ioremap_resource()
power: Convert to devm_ioremap_resource()
mtd: Convert to devm_ioremap_resource()
mmc: Convert to devm_ioremap_resource()
mfd: Convert to devm_ioremap_resource()
media: Convert to devm_ioremap_resource()
iommu: Convert to devm_ioremap_resource()
drm: Convert to devm_ioremap_resource()
...
The most convenient way to expose ACPI power resources lists of a
device is to put symbolic links to sysfs directories representing
those resources into special attribute groups in the device's sysfs
directory. For this purpose, it is necessary to be able to add
symbolic links to attribute groups.
For this reason, add sysfs helper functions for adding/removing
symbolic links to/from attribute groups, sysfs_add_link_to_group()
and sysfs_remove_link_from_group(), respectively.
This change set includes a build fix from David Rientjes.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 6ad58fa82d as %pSR
isn't in the tree yet.
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use the new vsprintf extension to avoid any possible
message interleaving.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch removes the trailing white space in fs/sysfs/mount.c.
Signed-off-by: Bin Wang <wbin00@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull user namespace changes from Eric Biederman:
"While small this set of changes is very significant with respect to
containers in general and user namespaces in particular. The user
space interface is now complete.
This set of changes adds support for unprivileged users to create user
namespaces and as a user namespace root to create other namespaces.
The tyranny of supporting suid root preventing unprivileged users from
using cool new kernel features is broken.
This set of changes completes the work on setns, adding support for
the pid, user, mount namespaces.
This set of changes includes a bunch of basic pid namespace
cleanups/simplifications. Of particular significance is the rework of
the pid namespace cleanup so it no longer requires sending out
tendrils into all kinds of unexpected cleanup paths for operation. At
least one case of broken error handling is fixed by this cleanup.
The files under /proc/<pid>/ns/ have been converted from regular files
to magic symlinks which prevents incorrect caching by the VFS,
ensuring the files always refer to the namespace the process is
currently using and ensuring that the ptrace_mayaccess permission
checks are always applied.
The files under /proc/<pid>/ns/ have been given stable inode numbers
so it is now possible to see if different processes share the same
namespaces.
Through the David Miller's net tree are changes to relax many of the
permission checks in the networking stack to allowing the user
namespace root to usefully use the networking stack. Similar changes
for the mount namespace and the pid namespace are coming through my
tree.
Two small changes to add user namespace support were commited here adn
in David Miller's -net tree so that I could complete the work on the
/proc/<pid>/ns/ files in this tree.
Work remains to make it safe to build user namespaces and 9p, afs,
ceph, cifs, coda, gfs2, ncpfs, nfs, nfsd, ocfs2, and xfs so the
Kconfig guard remains in place preventing that user namespaces from
being built when any of those filesystems are enabled.
Future design work remains to allow root users outside of the initial
user namespace to mount more than just /proc and /sys."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (38 commits)
proc: Usable inode numbers for the namespace file descriptors.
proc: Fix the namespace inode permission checks.
proc: Generalize proc inode allocation
userns: Allow unprivilged mounts of proc and sysfs
userns: For /proc/self/{uid,gid}_map derive the lower userns from the struct file
procfs: Print task uids and gids in the userns that opened the proc file
userns: Implement unshare of the user namespace
userns: Implent proc namespace operations
userns: Kill task_user_ns
userns: Make create_new_namespaces take a user_ns parameter
userns: Allow unprivileged use of setns.
userns: Allow unprivileged users to create new namespaces
userns: Allow setting a userns mapping to your current uid.
userns: Allow chown and setgid preservation
userns: Allow unprivileged users to create user namespaces.
userns: Ignore suid and sgid on binaries if the uid or gid can not be mapped
userns: fix return value on mntns_install() failure
vfs: Allow unprivileged manipulation of the mount namespace.
vfs: Only support slave subtrees across different user namespaces
vfs: Add a user namespace reference from struct mnt_namespace
...
Nothing outside of fs/sysfs/file.c references this function, so mark it static.
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
- The context in which proc and sysfs are mounted have no
effect on the the uid/gid of their files so no conversion is
needed except allowing the mount.
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
The warning check for duplicate sysfs entries can cause a buffer overflow
when printing the warning, as strcat() doesn't check buffer sizes.
Use strlcat() instead.
Since strlcat() doesn't return a pointer to the passed buffer, unlike
strcat(), I had to convert the nested concatenation in sysfs_add_one() to
an admittedly more obscure comma operator construct, to avoid emitting code
for the concatenation if CONFIG_BUG is disabled.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull second vfs pile from Al Viro:
"The stuff in there: fsfreeze deadlock fixes by Jan (essentially, the
deadlock reproduced by xfstests 068), symlink and hardlink restriction
patches, plus assorted cleanups and fixes.
Note that another fsfreeze deadlock (emergency thaw one) is *not*
dealt with - the series by Fernando conflicts a lot with Jan's, breaks
userland ABI (FIFREEZE semantics gets changed) and trades the deadlock
for massive vfsmount leak; this is going to be handled next cycle.
There probably will be another pull request, but that stuff won't be
in it."
Fix up trivial conflicts due to unrelated changes next to each other in
drivers/{staging/gdm72xx/usb_boot.c, usb/gadget/storage_common.c}
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (54 commits)
delousing target_core_file a bit
Documentation: Correct s_umount state for freeze_fs/unfreeze_fs
fs: Remove old freezing mechanism
ext2: Implement freezing
btrfs: Convert to new freezing mechanism
nilfs2: Convert to new freezing mechanism
ntfs: Convert to new freezing mechanism
fuse: Convert to new freezing mechanism
gfs2: Convert to new freezing mechanism
ocfs2: Convert to new freezing mechanism
xfs: Convert to new freezing code
ext4: Convert to new freezing mechanism
fs: Protect write paths by sb_start_write - sb_end_write
fs: Skip atime update on frozen filesystem
fs: Add freezing handling to mnt_want_write() / mnt_drop_write()
fs: Improve filesystem freezing handling
switch the protection of percpu_counter list to spinlock
nfsd: Push mnt_want_write() outside of i_mutex
btrfs: Push mnt_want_write() outside of i_mutex
fat: Push mnt_want_write() outside of i_mutex
...
Here's the big driver core pull request for 3.6-rc1.
Unlike 3.5, this kernel should be a lot tamer, with the printk changes now
settled down. All we have here is some extcon driver updates, w1 driver
updates, a few printk cleanups that weren't needed for 3.5, but are good to
have now, and some other minor fixes/changes in the driver core.
All of these have been in the linux-next releases for a while now.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-3.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core changes from Greg Kroah-Hartman:
"Here's the big driver core pull request for 3.6-rc1.
Unlike 3.5, this kernel should be a lot tamer, with the printk changes
now settled down. All we have here is some extcon driver updates, w1
driver updates, a few printk cleanups that weren't needed for 3.5, but
are good to have now, and some other minor fixes/changes in the driver
core.
All of these have been in the linux-next releases for a while now.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>"
* tag 'driver-core-3.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (38 commits)
printk: Export struct log size and member offsets through vmcoreinfo
Drivers: hv: Change the hex constant to a decimal constant
driver core: don't trigger uevent after failure
extcon: MAX77693: Add extcon-max77693 driver to support Maxim MAX77693 MUIC device
sysfs: fail dentry revalidation after namespace change fix
sysfs: fail dentry revalidation after namespace change
extcon: spelling of detach in function doc
extcon: arizona: Stop microphone detection if we give up on it
extcon: arizona: Update cable reporting calls and split headset
PM / Runtime: Do not increment device usage counts before probing
kmsg - do not flush partial lines when the console is busy
kmsg - export "continuation record" flag to /dev/kmsg
kmsg - avoid warning for CONFIG_PRINTK=n compilations
kmsg - properly print over-long continuation lines
driver-core: Use kobj_to_dev instead of re-implementing it
driver-core: Move kobj_to_dev from genhd.h to device.h
driver core: Move deferred devices to the end of dpm_list before probing
driver core: move uevent call to driver_register
driver core: fix shutdown races with probe/remove(v3)
Extcon: Arizona: Add driver for Wolfson Arizona class devices
...
don't assume that KOBJ_NS_TYPE_NONE==0. Also save a test-n-branch.
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When we change the namespace tag of a sysfs entry, the associated dentry
is still kept around. readdir() will work correctly and not display the
old entries, but open() will still succeed, so will reads and writes.
This will no longer happen if sysfs is remounted, hinting that this is a
cache-related problem.
I am using the following sequence to demonstrate that:
shell1:
ip link add type veth
unshare -nm
shell2:
ip link set veth1 <pid_of_shell_1>
cat /sys/devices/virtual/net/veth1/ifindex
Before that patch, this will succeed (fail to fail). After it, it will
correctly return an error. Differently from a normal rename, which we
handle fine, changing the object namespace will keep it's path intact.
So this check seems necessary as well.
[ v2: get type from parent, as suggested by Eric Biederman ]
Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Tejun Heo <tj@kernel.org>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pass mount flags to sget() so that it can use them in initialising a new
superblock before the set function is called. They could also be passed to the
compare function.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
a) ->d_iput() is wrong here - what we do to inode is completely usual, it's
dentry->d_fsdata that we want to drop. Just use ->d_release().
b) switch to ->s_d_op - no need to play with d_set_d_op()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Just the flags; only NFS cares even about that, but there are
legitimate uses for such argument. And getting rid of that
completely would require splitting ->lookup() into a couple
of methods (at least), so let's leave that alone for now...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'writeback' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux
Pull writeback tree from Wu Fengguang:
"Mainly from Jan Kara to avoid iput() in the flusher threads."
* tag 'writeback' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
writeback: Avoid iput() from flusher thread
vfs: Rename end_writeback() to clear_inode()
vfs: Move waiting for inode writeback from end_writeback() to evict_inode()
writeback: Refactor writeback_single_inode()
writeback: Remove wb->list_lock from writeback_single_inode()
writeback: Separate inode requeueing after writeback
writeback: Move I_DIRTY_PAGES handling
writeback: Move requeueing when I_SYNC set to writeback_sb_inodes()
writeback: Move clearing of I_SYNC into inode_sync_complete()
writeback: initialize global_dirty_limit
fs: remove 8 bytes of padding from struct writeback_control on 64 bit builds
mm: page-writeback.c: local functions should not be exposed globally
Pull user namespace enhancements from Eric Biederman:
"This is a course correction for the user namespace, so that we can
reach an inexpensive, maintainable, and reasonably complete
implementation.
Highlights:
- Config guards make it impossible to enable the user namespace and
code that has not been converted to be user namespace safe.
- Use of the new kuid_t type ensures the if you somehow get past the
config guards the kernel will encounter type errors if you enable
user namespaces and attempt to compile in code whose permission
checks have not been updated to be user namespace safe.
- All uids from child user namespaces are mapped into the initial
user namespace before they are processed. Removing the need to add
an additional check to see if the user namespace of the compared
uids remains the same.
- With the user namespaces compiled out the performance is as good or
better than it is today.
- For most operations absolutely nothing changes performance or
operationally with the user namespace enabled.
- The worst case performance I could come up with was timing 1
billion cache cold stat operations with the user namespace code
enabled. This went from 156s to 164s on my laptop (or 156ns to
164ns per stat operation).
- (uid_t)-1 and (gid_t)-1 are reserved as an internal error value.
Most uid/gid setting system calls treat these value specially
anyway so attempting to use -1 as a uid would likely cause
entertaining failures in userspace.
- If setuid is called with a uid that can not be mapped setuid fails.
I have looked at sendmail, login, ssh and every other program I
could think of that would call setuid and they all check for and
handle the case where setuid fails.
- If stat or a similar system call is called from a context in which
we can not map a uid we lie and return overflowuid. The LFS
experience suggests not lying and returning an error code might be
better, but the historical precedent with uids is different and I
can not think of anything that would break by lying about a uid we
can't map.
- Capabilities are localized to the current user namespace making it
safe to give the initial user in a user namespace all capabilities.
My git tree covers all of the modifications needed to convert the core
kernel and enough changes to make a system bootable to runlevel 1."
Fix up trivial conflicts due to nearby independent changes in fs/stat.c
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (46 commits)
userns: Silence silly gcc warning.
cred: use correct cred accessor with regards to rcu read lock
userns: Convert the move_pages, and migrate_pages permission checks to use uid_eq
userns: Convert cgroup permission checks to use uid_eq
userns: Convert tmpfs to use kuid and kgid where appropriate
userns: Convert sysfs to use kgid/kuid where appropriate
userns: Convert sysctl permission checks to use kuid and kgids.
userns: Convert proc to use kuid/kgid where appropriate
userns: Convert ext4 to user kuid/kgid where appropriate
userns: Convert ext3 to use kuid/kgid where appropriate
userns: Convert ext2 to use kuid/kgid where appropriate.
userns: Convert devpts to use kuid/kgid where appropriate
userns: Convert binary formats to use kuid/kgid where appropriate
userns: Add negative depends on entries to avoid building code that is userns unsafe
userns: signal remove unnecessary map_cred_ns
userns: Teach inode_capable to understand inodes whose uids map to other namespaces.
userns: Fail exec for suid and sgid binaries with ids outside our user namespace.
userns: Convert stat to return values mapped from kuids and kgids
userns: Convert user specfied uids and gids in chown into kuids and kgid
userns: Use uid_eq gid_eq helpers when comparing kuids and kgids in the vfs
...
This patch (as1554) fixes a lockdep false-positive report. The
problem arises because lockdep is unable to deal with the
tree-structured locks created by the device core and sysfs.
This particular problem involves a sysfs attribute method that
unregisters itself, not from the device it was called for, but from a
descendant device. Lockdep doesn't understand the distinction and
reports a possible deadlock, even though the operation is safe.
This is the sort of thing that would normally be handled by using a
nested lock annotation; unfortunately it's not feasible to do that
here. There's no sensible way to tell sysfs when attribute removal
occurs in the context of a parent attribute method.
As a workaround, the patch adds a new flag to struct attribute
telling sysfs not to inform lockdep when it acquires a readlock on a
sysfs_dirent instance for the attribute. The readlock is still
acquired, but lockdep doesn't know about it and hence does not
complain about impossible deadlock scenarios.
Also added are macros for static initialization of attribute
structures with the ignore_lockdep flag set. The three offending
attributes in the USB subsystem are converted to use the new macros.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Tejun Heo <tj@kernel.org>
CC: Eric W. Biederman <ebiederm@xmission.com>
CC: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
After we moved inode_sync_wait() from end_writeback() it doesn't make sense
to call the function end_writeback() anymore. Rename it to clear_inode()
which well says what the function really does - set I_CLEAR flag.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Since no one using "dup_name", removed it completely in sysfs_rename.
Signed-off-by: Sasikantha babu <sasikanth.v19@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In scsi at least two cases of the parent device being deleted before the
child is added have been observed.
1/ scsi is performing async scans and the device is removed prior to the
async can thread running (can happen with an in-opportune / unlikely
unplug during initial scan).
2/ libsas discovery event running after the parent port has been torn
down (this is a bug in libsas).
Result in crash signatures like:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000098
IP: [<ffffffff8115e100>] sysfs_create_dir+0x32/0xb6
...
Process scsi_scan_8 (pid: 5417, threadinfo ffff88080bd16000, task ffff880801b8a0b0)
Stack:
00000000fffffffe ffff880813470628 ffff88080bd17cd0 ffff88080614b7e8
ffff88080b45c108 00000000fffffffe ffff88080bd17d20 ffffffff8125e4a8
ffff88080bd17cf0 ffffffff81075149 ffff88080bd17d30 ffff88080614b7e8
Call Trace:
[<ffffffff8125e4a8>] kobject_add_internal+0x120/0x1e3
[<ffffffff81075149>] ? trace_hardirqs_on+0xd/0xf
[<ffffffff8125e641>] kobject_add_varg+0x41/0x50
[<ffffffff8125e70b>] kobject_add+0x64/0x66
[<ffffffff8131122b>] device_add+0x12d/0x63a
In this scenario the parent is still valid (because we have a
reference), but it has been device_del()'d which means its kobj->sd
pointer is NULL'd via:
device_del()->kobject_del()->sysfs_remove_dir()
...and then sysfs_create_dir() (without this fix) goes ahead and
de-references parent_sd via sysfs_ns_type():
return (sd->s_flags & SYSFS_NS_TYPE_MASK) >> SYSFS_NS_TYPE_SHIFT;
This scenario is being fixed in scsi/libsas, but if other subsystems
present the same ordering the system need not immediately crash.
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: James Bottomley <JBottomley@parallels.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is needed to allow renaming network devices that have been moved
to another network namespace.
Signed-off-by: Tom Goff <thomas.goff@boeing.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull vfs pile 1 from Al Viro:
"This is _not_ all; in particular, Miklos' and Jan's stuff is not there
yet."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (64 commits)
ext4: initialization of ext4_li_mtx needs to be done earlier
debugfs-related mode_t whack-a-mole
hfsplus: add an ioctl to bless files
hfsplus: change finder_info to u32
hfsplus: initialise userflags
qnx4: new helper - try_extent()
qnx4: get rid of qnx4_bread/qnx4_getblk
take removal of PF_FORKNOEXEC to flush_old_exec()
trim includes in inode.c
um: uml_dup_mmap() relies on ->mmap_sem being held, but activate_mm() doesn't hold it
um: embed ->stub_pages[] into mmu_context
gadgetfs: list_for_each_safe() misuse
ocfs2: fix leaks on failure exits in module_init
ecryptfs: make register_filesystem() the last potential failure exit
ntfs: forgets to unregister sysctls on register_filesystem() failure
logfs: missing cleanup on register_filesystem() failure
jfs: mising cleanup on register_filesystem() failure
make configfs_pin_fs() return root dentry on success
configfs: configfs_create_dir() has parent dentry in dentry->d_parent
configfs: sanitize configfs_create()
...
This reverts commit 524b6c5b39.
It has shown to break userspace tools, which is not acceptable.
Reported-by: Jiri Slaby <jslaby@suse.cz>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This was done to resolve a merge and build problem with the
drivers/acpi/processor_driver.c file.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This fixes a bug introduced with sysfs name hashes where renaming a
network device appears to succeed but silently makes the sysfs files for
that network device inaccessible.
In at least one configuration this bug has stopped networking from
coming up during boot.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Tested-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
There is a misleading difference between /proc and /sys permissions, /proc is 0555 and /sys is 0755. But
as it is impossible to create or unlink something in /sys it would be nice to have same permissions.
Signed-off-by: Vitaly Kuznetsov <vitty@altlinux.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Tracking the number of subdirectories requires an extra field that increases
the size of sysfs_dirent. nlinks are not particularly interesting for sysfs
and the nlink counts are wrong when network namespaces are involved so stop
counting them, and always return nlink == 1. Userspace already knows that
directories with nlink == 1 have an nlink count they can't use to count
subdirectories.
This reduces the size of sysfs_dirent by 8 bytes on 64bit platforms.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Store the sysfs inode number in an unsided int because
ida inode allocator can return at most a 31 bit number,
reducing the size of struct sysfs_dirent by 8 bytes
on 64bit platforms.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
