There is no backing store to ramfs and file creation
rules are the same as for any other filesystem so
it is semantically safe to allow unprivileged users
to mount it.
The memory control group successfully limits how much
memory ramfs can consume on any system that cares about
a user namespace root using ramfs to exhaust memory
the memory control group can be deployed.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
- The context in which devpts is mounted has no effect on the creation
of ptys as the /dev/ptmx interface has been used by unprivileged
users for many years.
- Only support unprivileged mounts in combination with the newinstance
option to ensure that mounting of /dev/pts in a user namespace will
not allow the options of an existing mount of devpts to be modified.
- Create /dev/pts/ptmx as the root user in the user namespace that
mounts devpts so that it's permissions to be changed.
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
With user namespaces enabled building f2fs fails with:
CC fs/f2fs/acl.o
fs/f2fs/acl.c: In function ‘f2fs_acl_from_disk’:
fs/f2fs/acl.c:85:21: error: ‘struct posix_acl_entry’ has no member named ‘e_id’
make[2]: *** [fs/f2fs/acl.o] Error 1
make[2]: Target `__build' not remade because of errors.
e_id is a backwards compatibility field only used for file systems
that haven't been converted to use kuids and kgids. When the posix
acl tag field is neither ACL_USER nor ACL_GROUP assigning e_id is
unnecessary. Remove the assignment so f2fs will build with user
namespaces enabled.
Cc: Namjae Jeon <namjae.jeon@samsung.com>
Cc: Amit Sahrawat <a.sahrawat@samsung.com>
Acked-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Pull CIFS fixes from Steve French:
"Misc small cifs fixes"
* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
cifs: eliminate cifsERROR variable
cifs: don't compare uniqueids in cifs_prime_dcache unless server inode numbers are in use
cifs: fix double-free of "string" in cifs_parse_mount_options
This reverts commit 79f77bf9a4.
This is obviously wrong, and I have no idea how I missed seeing the
warning in testing: I must just not have looked at the right logs. The
caller bumps rq_resused/rq_next_page, so it will always be hit on a
large enough read.
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The fscache code will currently bleat a "non-unique superblock keys"
warning even if the user is mounting without the 'fsc' option.
There should be no reason to even initialise the superblock cache cookie
unless we're planning on using fscache for something, so ensure that we
check for the NFS_OPTION_FSCACHE flag before calling into the fscache
code.
Reported-by: Paweł Sikora <pawel.sikora@agmk.net>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: David Howells <dhowells@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Provide a stub nfs_fscache_wait_on_invalidate() function for when
CONFIG_NFS_FSCACHE=n lest the following error appear:
fs/nfs/inode.c: In function 'nfs_invalidate_mapping':
fs/nfs/inode.c:887:2: error: implicit declaration of function 'nfs_fscache_wait_on_invalidate' [-Werror=implicit-function-declaration]
cc1: some warnings being treated as errors
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Reported-by: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull filesystem notification updates from Eric Paris:
"This pull mostly is about locking changes in the fsnotify system. By
switching the group lock from a spin_lock() to a mutex() we can now
hold the lock across things like iput(). This fixes a problem
involving unmounting a fs and having inodes be busy, first pointed out
by FAT, but reproducible with tmpfs.
This also restores signal driven I/O for inotify, which has been
broken since about 2.6.32."
Ugh. I *hate* the timing of this. It was rebased after the merge
window opened, and then left to sit with the pull request coming the day
before the merge window closes. That's just crap. But apparently the
patches themselves have been around for over a year, just gathering
dust, so now it's suddenly critical.
Fixed up semantic conflict in fs/notify/fdinfo.c as per Stephen
Rothwell's fixes from -next.
* 'for-next' of git://git.infradead.org/users/eparis/notify:
inotify: automatically restart syscalls
inotify: dont skip removal of watch descriptor if creation of ignored event failed
fanotify: dont merge permission events
fsnotify: make fasync generic for both inotify and fanotify
fsnotify: change locking order
fsnotify: dont put marks on temporary list when clearing marks by group
fsnotify: introduce locked versions of fsnotify_add_mark() and fsnotify_remove_mark()
fsnotify: pass group to fsnotify_destroy_mark()
fsnotify: use a mutex instead of a spinlock to protect a groups mark list
fanotify: add an extra flag to mark_remove_from_mask that indicates wheather a mark should be destroyed
fsnotify: take groups mark_lock before mark lock
fsnotify: use reference counting for groups
fsnotify: introduce fsnotify_get_group()
inotify, fanotify: replace fsnotify_put_group() with fsnotify_destroy_group()
Merge the rest of Andrew's patches for -rc1:
"A bunch of fixes and misc missed-out-on things.
That'll do for -rc1. I still have a batch of IPC patches which still
have a possible bug report which I'm chasing down."
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (25 commits)
keys: use keyring_alloc() to create module signing keyring
keys: fix unreachable code
sendfile: allows bypassing of notifier events
SGI-XP: handle non-fatal traps
fat: fix incorrect function comment
Documentation: ABI: remove testing/sysfs-devices-node
proc: fix inconsistent lock state
linux/kernel.h: fix DIV_ROUND_CLOSEST with unsigned divisors
memcg: don't register hotcpu notifier from ->css_alloc()
checkpatch: warn on uapi #includes that #include <uapi/...
revert "rtc: recycle id when unloading a rtc driver"
mm: clean up transparent hugepage sysfs error messages
hfsplus: add error message for the case of failure of sync fs in delayed_sync_fs() method
hfsplus: rework processing of hfs_btree_write() returned error
hfsplus: rework processing errors in hfsplus_free_extents()
hfsplus: avoid crash on failed block map free
kcmp: include linux/ptrace.h
drivers/rtc/rtc-imxdi.c: must include <linux/spinlock.h>
mm: cma: WARN if freed memory is still in use
exec: do not leave bprm->interp on stack
...
Pull VFS update from Al Viro:
"fscache fixes, ESTALE patchset, vmtruncate removal series, assorted
misc stuff."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (79 commits)
vfs: make lremovexattr retry once on ESTALE error
vfs: make removexattr retry once on ESTALE
vfs: make llistxattr retry once on ESTALE error
vfs: make listxattr retry once on ESTALE error
vfs: make lgetxattr retry once on ESTALE
vfs: make getxattr retry once on an ESTALE error
vfs: allow lsetxattr() to retry once on ESTALE errors
vfs: allow setxattr to retry once on ESTALE errors
vfs: allow utimensat() calls to retry once on an ESTALE error
vfs: fix user_statfs to retry once on ESTALE errors
vfs: make fchownat retry once on ESTALE errors
vfs: make fchmodat retry once on ESTALE errors
vfs: have chroot retry once on ESTALE error
vfs: have chdir retry lookup and call once on ESTALE error
vfs: have faccessat retry once on an ESTALE error
vfs: have do_sys_truncate retry once on an ESTALE error
vfs: fix renameat to retry on ESTALE errors
vfs: make do_unlinkat retry once on ESTALE errors
vfs: make do_rmdir retry once on ESTALE errors
vfs: add a flags argument to user_path_parent
...
Pull signal handling cleanups from Al Viro:
"sigaltstack infrastructure + conversion for x86, alpha and um,
COMPAT_SYSCALL_DEFINE infrastructure.
Note that there are several conflicts between "unify
SS_ONSTACK/SS_DISABLE definitions" and UAPI patches in mainline;
resolution is trivial - just remove definitions of SS_ONSTACK and
SS_DISABLED from arch/*/uapi/asm/signal.h; they are all identical and
include/uapi/linux/signal.h contains the unified variant."
Fixed up conflicts as per Al.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
alpha: switch to generic sigaltstack
new helpers: __save_altstack/__compat_save_altstack, switch x86 and um to those
generic compat_sys_sigaltstack()
introduce generic sys_sigaltstack(), switch x86 and um to it
new helper: compat_user_stack_pointer()
new helper: restore_altstack()
unify SS_ONSTACK/SS_DISABLE definitions
new helper: current_user_stack_pointer()
missing user_stack_pointer() instances
Bury the conditionals from kernel_thread/kernel_execve series
COMPAT_SYSCALL_DEFINE: infrastructure
do_sendfile() in fs/read_write.c does not call the fsnotify functions,
unlike its neighbors. This manifests as a lack of inotify ACCESS events
when a file is sent using sendfile(2).
Addresses
https://bugzilla.kernel.org/show_bug.cgi?id=12812
[akpm@linux-foundation.org: use fsnotify_modify(out.file), not fsnotify_access(), per Dave]
Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Scott Wolchok <swolchok@umich.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fat_search_long() returns 0 on success, -ENOENT/ENOMEM on failure.
Change the function comment accordingly.
While at it, fix some trivial typos.
Signed-off-by: Ravishankar N <cyberax82@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@gmail.com>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Lockdep found an inconsistent lock state when rcu is processing delayed
work in softirq. Currently, kernel is using spin_lock/spin_unlock to
protect proc_inum_ida, but proc_free_inum is called by rcu in softirq
context.
Use spin_lock_bh/spin_unlock_bh fix following lockdep warning.
=================================
[ INFO: inconsistent lock state ]
3.7.0 #36 Not tainted
---------------------------------
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
swapper/1/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
(proc_inum_lock){+.?...}, at: proc_free_inum+0x1c/0x50
{SOFTIRQ-ON-W} state was registered at:
__lock_acquire+0x8ae/0xca0
lock_acquire+0x199/0x200
_raw_spin_lock+0x41/0x50
proc_alloc_inum+0x4c/0xd0
alloc_mnt_ns+0x49/0xc0
create_mnt_ns+0x25/0x70
mnt_init+0x161/0x1c7
vfs_caches_init+0x107/0x11a
start_kernel+0x348/0x38c
x86_64_start_reservations+0x131/0x136
x86_64_start_kernel+0x103/0x112
irq event stamp: 2993422
hardirqs last enabled at (2993422): _raw_spin_unlock_irqrestore+0x55/0x80
hardirqs last disabled at (2993421): _raw_spin_lock_irqsave+0x29/0x70
softirqs last enabled at (2993394): _local_bh_enable+0x13/0x20
softirqs last disabled at (2993395): call_softirq+0x1c/0x30
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(proc_inum_lock);
<Interrupt>
lock(proc_inum_lock);
*** DEADLOCK ***
no locks held by swapper/1/0.
stack backtrace:
Pid: 0, comm: swapper/1 Not tainted 3.7.0 #36
Call Trace:
<IRQ> [<ffffffff810a40f1>] ? vprintk_emit+0x471/0x510
print_usage_bug+0x2a5/0x2c0
mark_lock+0x33b/0x5e0
__lock_acquire+0x813/0xca0
lock_acquire+0x199/0x200
_raw_spin_lock+0x41/0x50
proc_free_inum+0x1c/0x50
free_pid_ns+0x1c/0x50
put_pid_ns+0x2e/0x50
put_pid+0x4a/0x60
delayed_put_pid+0x12/0x20
rcu_process_callbacks+0x462/0x790
__do_softirq+0x1b4/0x3b0
call_softirq+0x1c/0x30
do_softirq+0x59/0xd0
irq_exit+0x54/0xd0
smp_apic_timer_interrupt+0x95/0xa3
apic_timer_interrupt+0x72/0x80
cpuidle_enter_tk+0x10/0x20
cpuidle_enter_state+0x17/0x50
cpuidle_idle_call+0x287/0x520
cpu_idle+0xba/0x130
start_secondary+0x2b3/0x2bc
Signed-off-by: Xiaotian Feng <dannyfeng@tencent.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add an error message for the case of failure of sync fs in
delayed_sync_fs() method.
Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Hin-Tak Leung <htl10@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add to hfs_btree_write() a return of -EIO on failure of b-tree node
searching. Also add logic ofor processing errors from hfs_btree_write()
in hfsplus_system_write_inode() with a message about b-tree writing
failure.
[akpm@linux-foundation.org: reduce scope of `err', print errno on error]
Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Hin-Tak Leung <htl10@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, it doesn't process error codes from the hfsplus_block_free()
call in hfsplus_free_extents() method. Add some error code processing.
Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Hin-Tak Leung <htl10@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If the read fails we kmap an error code. This doesn't end well. Instead
print a critical error and pray. This mirrors the rest of the fs
behaviour with critical error cases.
Acked-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jan Kara <jack@suse.cz>
Acked-by: Hin-Tak Leung <htl10@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If a series of scripts are executed, each triggering module loading via
unprintable bytes in the script header, kernel stack contents can leak
into the command line.
Normally execution of binfmt_script and binfmt_misc happens recursively.
However, when modules are enabled, and unprintable bytes exist in the
bprm->buf, execution will restart after attempting to load matching
binfmt modules. Unfortunately, the logic in binfmt_script and
binfmt_misc does not expect to get restarted. They leave bprm->interp
pointing to their local stack. This means on restart bprm->interp is
left pointing into unused stack memory which can then be copied into the
userspace argv areas.
After additional study, it seems that both recursion and restart remains
the desirable way to handle exec with scripts, misc, and modules. As
such, we need to protect the changes to interp.
This changes the logic to require allocation for any changes to the
bprm->interp. To avoid adding a new kmalloc to every exec, the default
value is left as-is. Only when passing through binfmt_script or
binfmt_misc does an allocation take place.
For a proof of concept, see DoTest.sh from:
http://www.halfdog.net/Security/2012/LinuxKernelBinfmtScriptStackDataDisclosure/
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: halfdog <me@halfdog.net>
Cc: P J P <ppandit@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Clearly, we can't handle the NULL filename case, but we can deal with
the case where there's a real pathname.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
...as always, rename is the messiest of the bunch. We have to track
whether to retry or not via a separate flag since the error handling
is already quite complex.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
...so we can pass in LOOKUP_REVAL. For now, nothing does yet.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Where we can pass in LOOKUP_DIRECTORY or LOOKUP_REVAL. Any other flags
passed in here are currently ignored.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
NFS appears to use d_obtain_alias() to create the root dentry rather than
d_make_root. This can cause 'prepend_path()' to complain that the root
has a weird name if an NFS filesystem is lazily unmounted. e.g. if
"/mnt" is an NFS mount then
{ cd /mnt; umount -l /mnt ; ls -l /proc/self/cwd; }
will cause a WARN message like
WARNING: at /home/git/linux/fs/dcache.c:2624 prepend_path+0x1d7/0x1e0()
...
Root dentry has weird name <>
to appear in kernel logs.
So change d_obtain_alias() to use "/" rather than "" as the anonymous
name.
Signed-off-by: NeilBrown <neilb@suse.de>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
