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So far, POSIX ACLs are using a canonical representation that keeps all ACL
entries in a strict order; the ACL_USER and ACL_GROUP entries for specific
users and groups are ordered by user and group identifier, respectively.
The user-space code provides ACL entries in this order; the kernel
verifies that the ACL entry order is correct in posix_acl_valid().
User namespaces allow to arbitrary map user and group identifiers which
can cause the ACL_USER and ACL_GROUP entry order to differ between user
space and the kernel; posix_acl_valid() would then fail.
Work around this by allowing ACL_USER and ACL_GROUP entries to be in any
order in the kernel. The effect is only minor: file permission checks
will pick the first matching ACL_USER entry, and check all matching
ACL_GROUP entries.
(The libacl user-space library and getfacl / setfacl tools will not create
ACLs with duplicate user or group idenfifiers; they will handle ACLs with
entries in an arbitrary order correctly.)
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Theodore Tso <tytso@mit.edu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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solution using repeated rb_erase()
Use rbtree_postorder_for_each_entry_safe() to destroy the rbtree instead
of using repeated rb_erase() calls
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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use do{}while - more efficient and it squishes a coccinelle warning
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Use rbtree_postorder_for_each_entry_safe() to destroy the rbtree instead
of opencoding an alternate postorder iteration that modifies the tree
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Use rbtree_postorder_for_each_entry_safe() to destroy the rbtree instead
of opencoding an alternate postorder iteration that modifies the tree
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Use rbtree_postorder_for_each_entry_safe() to destroy the rbtree instead
of opencoding an alternate postorder iteration that modifies the tree
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Michel Lespinasse <walken@google.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Use rbtree_postorder_for_each_entry_safe() to destroy the rbtree instead
of opencoding an alternate postorder iteration that modifies the tree
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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instead of opencoding
Use rbtree_postorder_for_each_entry_safe() to destroy the rbtree instead
of opencoding an alternate postorder iteration that modifies the tree
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Avoid making the rb_node the first entry to catch some bugs around NULL
checking the rb_node.
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Allow modular build option for RapidIO subsystem core in MIPS and PowerPC
architectural branches.
At this moment modular RapidIO subsystem build is enabled only for
platforms that use PCI/PCIe based RapidIO controllers (e.g. Tsi721).
Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Jean Delvare <jdelvare@suse.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The usage of the 'gpt' kernel parameter is twofold: (i) skip any mbr
integrity checks and (ii) enable the backup GPT header to be used in
situations where the primary one is corrupted. This last "feature" is not
obvious and needs to be properly documented in the kernel-parameters
document.
Addresses https://bugzilla.kernel.org/show_bug.cgi?id=63591
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Cc: Matt Domsch <Matt_Domsch@dell.com>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: "Chandramouleeswaran,Aswin" <aswin@hp.com>
Cc: Chris Murphy <bugzilla@colorremedies.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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/sys/kernel/vmcoreinfo was introduced long back but there is no ABI
documentation. This patch adds the documentation.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Ken'ichi Ohmichi <oomichi@mxs.nes.nec.co.jp>
Cc: Dan Aloni <da-x@monatomic.org>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Right now we seem to be exporting the max data size contained inside
vmcoreinfo note. But this does not include the size of meta data around
vmcore info data. Like name of the note and starting and ending elf_note.
I think user space expects total size and that size is put in PT_NOTE elf
header. Things seem to be fine so far because we are not using vmcoreinfo
note to the maximum capacity. But as it starts filling up, to capacity,
at some point of time, problem will be visible.
I don't think user space will be broken with this change. So there is no
need to introduce vmcoreinfo2. This change is safe and backward
compatible. More explanation on why this change is safe is below.
vmcoreinfo contains information about kernel which user space needs to
know to do things like filtering. For example, various kernel config
options or information about size or offset of some data structures etc.
All this information is commmunicated to user space with an ELF note
present in ELF /proc/vmcore file.
Currently vmcoreinfo data size is 4096. With some elf note meta data
around it, actual size is 4132 bytes. But we are using barely 25% of that
size. Rest is empty. So even if we tell user space that size of ELf note
is 4096 and not 4132, nothing will be broken becase after around 1000
bytes, everything is zero anyway.
But once we start filling up the note to the capacity, and not report the
full size of note, bad things will start happening. Either some data will
be lost or tools will be confused that they did not fine the zero note at
the end.
So I think this change is safe and should not break existing tools.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Ken'ichi Ohmichi <oomichi@mxs.nes.nec.co.jp>
Cc: Dan Aloni <da-x@monatomic.org>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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For general-purpose (i.e. distro) kernel builds it makes sense to build
with CONFIG_KEXEC to allow end users to choose what kind of things they
want to do with kexec. However, in the face of trying to lock down a
system with such a kernel, there needs to be a way to disable kexec_load
(much like module loading can be disabled). Without this, it is too easy
for the root user to modify kernel memory even when CONFIG_STRICT_DEVMEM
and modules_disabled are set. With this change, it is still possible to
load an image for use later, then disable kexec_load so the image (or lack
of image) can't be altered.
The intention is for using this in environments where "perfect"
enforcement is hard. Without a verified boot, along with verified
modules, and along with verified kexec, this is trying to give a system a
better chance to defend itself (or at least grow the window of
discoverability) against attack in the face of a privilege escalation.
In my mind, I consider several boot scenarios:
1) Verified boot of read-only verified root fs loading fd-based
verification of kexec images.
2) Secure boot of writable root fs loading signed kexec images.
3) Regular boot loading kexec (e.g. kcrash) image early and locking it.
4) Regular boot with no control of kexec image at all.
1 and 2 don't exist yet, but will soon once the verified kexec series has
landed. 4 is the state of things now. The gap between 2 and 4 is too
large, so this change creates scenario 3, a middle-ground above 4 when 2
and 1 are not possible for a system.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Currently both setup_new_exec() and flush_old_exec() issue a call to
arch_pick_mmap_layout(). As setup_new_exec() and flush_old_exec() are
always called pairwise arch_pick_mmap_layout() is called twice.
This patch removes one call from setup_new_exec() to have it only called
once.
Signed-off-by: Richard Weinberger <richard@nod.at>
Tested-by: Pat Erley <pat-lkml@erley.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Userspace process doesn't want the PF_NO_SETAFFINITY, but its parent may be
a kernel worker thread which has PF_NO_SETAFFINITY set, and this worker thread
can do kernel_thread() to create the child.
Clearing this flag in usersapce child to enable its migrating capability.
Signed-off-by: Zhang Yi <zhang.yi20@zte.com.cn>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Change do_signal_stop() and do_sigaction() to avoid next_thread() and use
while_each_thread() instead.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Reviewed-by: Sameer Nanda <snanda@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Change k_getrusage() to use while_each_thread(), no changes in the
compiled code.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Reviewed-by: Sameer Nanda <snanda@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Change the remaining next_thread (ab)users to use while_each_thread().
The last user which should be changed is next_tid(), but we can't do this
now.
__exit_signal() and complete_signal() are fine, they actually need
next_thread() logic.
This patch (of 3):
do_task_stat() can use while_each_thread(), no changes in
the compiled code.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Reviewed-by: Sameer Nanda <snanda@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We can kill either task->did_exec or PF_FORKNOEXEC, they are mutually
exclusive. The patch kills ->did_exec because it has a single user.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Both success/failure paths cleanup bprm->file, we can move this
code into free_bprm() to simlify and cleanup this logic.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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fs_struct->in_exec == T means that this ->fs is used by a single process
(thread group), and one of the treads does do_execve().
To avoid the mt-exec races this code has the following complications:
1. check_unsafe_exec() returns -EBUSY if ->in_exec was
already set by another thread.
2. do_execve_common() records "clear_in_exec" to ensure
that the error path can only clear ->in_exec if it was
set by current.
However, after 9b1bf12d5d51 "signals: move cred_guard_mutex from
task_struct to signal_struct" we do not need these complications:
1. We can't race with our sub-thread, this is called under
per-process ->cred_guard_mutex. And we can't race with
another CLONE_FS task, we already checked that this fs
is not shared.
We can remove the dead -EAGAIN logic.
2. "out_unmark:" in do_execve_common() is either called
under ->cred_guard_mutex, or after de_thread() which
kills other threads, so we can't race with sub-thread
which could set ->in_exec. And if ->fs is shared with
another process ->in_exec should be false anyway.
We can clear in_exec unconditionally.
This also means that check_unsafe_exec() can be void.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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next_thread() should be avoided, change check_unsafe_exec() to use
while_each_thread().
Nobody except signal->curr_target actually needs next_thread-like code,
and we need to change (fix) this interface. This particular code is fine,
p == current. But in general the code like this can loop forever if p
exits and next_thread(t) can't reach the unhashed thread.
This also saves 32 bytes.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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current->mm doesn't need a NULL check in dup_mm(). Becasue dup_mm() is
used only in copy_mm() and current->mm is checked whether it is NULL or
not in copy_mm() before calling dup_mm().
Signed-off-by: Daeseok Youn <daeseok.youn@gmail.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Fix errors reported by checkpatch.pl. One error is parentheses, the other
is a whitespace issue.
Signed-off-by: Daeseok Youn <daeseok.youn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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dup_mm() is used only in kernel/fork.c
Signed-off-by: Daeseok Youn <daeseok.youn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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PROC_FS is a bool, so this code is either present or absent. It will
never be modular, so using module_init as an alias for __initcall is
rather misleading.
Fix this up now, so that we can relocate module_init from init.h into
module.h in the future. If we don't do this, we'd have to add module.h to
obviously non-modular code, and that would be ugly at best.
Note that direct use of __initcall is discouraged, vs. one of the
priority categorized subgroups. As __initcall gets mapped onto
device_initcall, our use of fs_initcall (which makes sense for fs code)
will thus change these registrations from level 6-device to level 5-fs
(i.e. slightly earlier). However no observable impact of that small
difference has been observed during testing, or is expected.
Also note that this change uncovers a missing semicolon bug in the
registration of vmcore_init as an initcall.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Trivial cleanup to eliminate a goto.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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exists.
Distribution kernels might want to build in support for /proc/device-tree
for kernels that might end up running on hardware that doesn't support
openfirmware. This results in an empty /proc/device-tree existing.
Remove it if the OFW root node doesn't exist.
This situation actually confuses grub2, resulting in install failures.
grub2 sees the /proc/device-tree and picks the wrong install target cf.
http://bzr.savannah.gnu.org/lh/grub/trunk/grub/annotate/4300/util/grub-install.in#L311
grub should be more robust, but still, leaving an empty proc dir seems
pointless.
Addresses https://bugzilla.redhat.com/show_bug.cgi?id=818378.
Signed-off-by: Dave Jones <davej@redhat.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Josh Boyer <jwboyer@fedoraproject.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Use existing accessors proc_set_user() and proc_set_size() to set
attributes. Just a cleanup.
Signed-off-by: Rui Xiang <rui.xiang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1. proc_task_readdir()->first_tid() path truncates f_pos to int, this
is wrong even on 64bit.
We could check that f_pos < PID_MAX or even INT_MAX in
proc_task_readdir(), but this patch simply checks the potential
overflow in first_tid(), this check is nop on 64bit. We do not care if
it was negative and the new unsigned value is huge, all we need to
ensure is that we never wrongly return !NULL.
2. Remove the 2nd "nr != 0" check before get_nr_threads(),
nr_threads == 0 is not distinguishable from !pid_task() above.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Sameer Nanda <snanda@chromium.org>
Cc: Sergey Dyasly <dserrg@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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proc_task_readdir() does not really need "leader", first_tid() has to
revalidate it anyway. Just pass proc_pid(inode) to first_tid() instead,
it can do pid_task(PIDTYPE_PID) itself and read ->group_leader only if
necessary.
The patch also extracts the "inode is dead" code from
pid_delete_dentry(dentry) into the new trivial helper,
proc_inode_is_dead(inode), proc_task_readdir() uses it to return -ENOENT
if this dir was removed.
This is a bit racy, but the race is very inlikely and the getdents() after
openndir() can see the empty "." + ".." dir only once.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Sameer Nanda <snanda@chromium.org>
Cc: Sergey Dyasly <dserrg@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rerwrite the main loop to use while_each_thread() instead of
next_thread(). We are going to fix or replace while_each_thread(),
next_thread() should be avoided whenever possible.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Sameer Nanda <snanda@chromium.org>
Cc: Sergey Dyasly <dserrg@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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proc_task_readdir() verifies that the result of get_proc_task() is
pid_alive() and thus its ->group_leader is fine too. However this is not
necessarily true after rcu_read_unlock(), we need to recheck this again
after first_tid() does rcu_read_lock(). Otherwise
leader->thread_group.next (used by next_thread()) can be invalid if the
rcu grace period expires in between.
The race is subtle and unlikely, but still it is possible afaics. To
simplify lets ignore the "likely" case when tid != 0, f_version can be
cleared by proc_task_operations->llseek().
Suppose we have a main thread M and its subthread T. Suppose that f_pos
== 3, iow first_tid() should return T. Now suppose that the following
happens between rcu_read_unlock() and rcu_read_lock():
1. T execs and becomes the new leader. This removes M from
->thread_group but next_thread(M) is still T.
2. T creates another thread X which does exec as well, T
goes away.
3. X creates another subthread, this increments nr_threads.
4. first_tid() does next_thread(M) and returns the already
dead T.
Note also that we need 2. and 3. only because of get_nr_threads() check,
and this check was supposed to be optimization only.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Sameer Nanda <snanda@chromium.org>
Cc: Sergey Dyasly <dserrg@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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get_task_state() and task_state_array[] look confusing and suboptimal, it
is not clear what it can actually report to user-space and
task_state_array[] blows .data for no reason.
1. state = (tsk->state & TASK_REPORT) | tsk->exit_state is not
clear. TASK_REPORT is self-documenting but it is not clear
what ->exit_state can add.
Move the potential exit_state's (EXIT_ZOMBIE and EXIT_DEAD)
into TASK_REPORT and use it to calculate the final result.
2. With the change above it is obvious that task_state_array[]
has the unused entries just to make BUILD_BUG_ON() happy.
Change this BUILD_BUG_ON() to use TASK_REPORT rather than
TASK_STATE_MAX and shrink task_state_array[].
3. Turn the "while (state)" loop into fls(state).
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1. Remove fs/coredump.h. It is not clear why do we need it,
it only declares __get_dumpable(), signal.c includes it
for no reason.
2. Now that get_dumpable() and __get_dumpable() are really
trivial make them inline in linux/sched.h.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Alex Kelly <alex.page.kelly@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Petr Matousek <pmatouse@redhat.com>
Cc: Vasily Kulikov <segoon@openwall.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Nobody actually needs MMF_DUMPABLE/MMF_DUMP_SECURELY, they are only used
to enforce the encoding of SUID_DUMP_* enum in mm->flags &
MMF_DUMPABLE_MASK.
Now that set_dumpable() updates both bits atomically we can kill them and
simply store the value "as is" in 2 lower bits.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Alex Kelly <alex.page.kelly@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Petr Matousek <pmatouse@redhat.com>
Cc: Vasily Kulikov <segoon@openwall.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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set_dumpable() updates MMF_DUMPABLE_MASK in a non-trivial way to ensure
that get_dumpable() can't observe the intermediate state, but this all
can't help if multiple threads call set_dumpable() at the same time.
And in theory commit_creds()->set_dumpable(SUID_DUMP_ROOT) racing with
sys_prctl()->set_dumpable(SUID_DUMP_DISABLE) can result in SUID_DUMP_USER.
Change this code to update both bits atomically via cmpxchg().
Note: this assumes that it is safe to mix bitops and cmpxchg. IOW, if,
say, an architecture implements cmpxchg() using the locking (like
arch/parisc/lib/bitops.c does), then it should use the same locks for
set_bit/etc.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Alex Kelly <alex.page.kelly@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Petr Matousek <pmatouse@redhat.com>
Cc: Vasily Kulikov <segoon@openwall.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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As the notifier_block name (i.e. foobar_cpu_notifer) is different from
the parameter (i.e.foobar_cpu_notifier) of register function, that is
definitely error and it also makes readers confused.
Signed-off-by: Sangjung Woo <sangjung.woo@samsung.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Remove an outdated reference to "most personal computers" having only one
CPU, and change the use of "singleprocessor" and "single processor" in
CONFIG_SMP's documentation to "uniprocessor" across all arches where that
documentation is present.
Signed-off-by: Robert Graffham <psquid@psquid.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Add the following documentation-files with description :
-autofs4-mount-control.txt
-btrfs.txt
-debugfs.txt
-devpts.txt
-fiemap.txt
-gfs2-glocks.txt
-gfs2-uevents.txt
-omfs.txt
-path-lookup.txt
-qnx6.txt
-quota.txt
-squashfs.txt
-sysfs-tagging.txt
-ubifs.txt
-xfs-delayed-logging-design.txt
-xfs-self-describing-metadata.txt
Add the following documentation directories with description :
-caching
-cifs (replacing cifs.txt)
-pohmelfs
Remove the following documentation-files reference:
-dentry-locking.txt
-reiser4.txt
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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- ramdisk_blocksize doesn't exist anymore
- Module parameters added to documentation
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Fix a wrong device_attribute declaration example.
Signed-off-by: Andre Richter <andre.o.richter@gmail.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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HFS+ resource fork lookup breaks opendir() library function. Since
opendir first calls open() with O_DIRECTORY flag set. O_DIRECTORY means
"refuse to open if not a directory". The open system call in the kernel
does a check for inode->i_op->lookup and returns -ENOTDIR. So if
hfsplus_file_lookup is set it allows opendir() for plain files.
Also resource fork lookup in HFS+ does not work. Since it is never
invoked after VFS permission checking. It will always return with
-EACCES.
When we call opendir() on a file, it does not return NULL. opendir()
library call is based on open with O_DIRECTORY flag passed and then
layered on top of getdents() system call. O_DIRECTORY means "refuse to
open if not a directory".
The open() system call in the kernel does a check for: do_sys_open()
-->..--> can_lookup() i.e it only checks inode->i_op->lookup and returns
ENOTDIR if this function pointer is not set.
In OSX, we can open "file/rsrc" to get the resource fork of "file". This
behavior is emulated inside hfsplus on Linux, which means that to some
degree every file acts like a directory. That is the reason lookup()
inode operations is supported for files, and it is possible to do a lookup
on this specific name. As a result of this open succeeds without
returning ENOTDIR for HFS+
Please see the LKML discussion thread on this issue:
http://marc.info/?l=linux-fsdevel&m=122823343730412&w=2
I tried to test file/rsrc lookup in HFS+ driver and the feature does not
work. From OSX:
$ touch test
$ echo "1234" > test/..namedfork/rsrc
$ ls -l test..namedfork/rsrc
--rw-r--r-- 1 tuxera staff 5 10 dec 12:59 test/..namedfork/rsrc
[sougata@ultrabook tmp]$ id
uid=1000(sougata) gid=1000(sougata) groups=1000(sougata),5(tty),18(dialout),1001(vboxusers)
[sougata@ultrabook tmp]$ mount
/dev/sdb1 on /mnt/tmp type hfsplus (rw,relatime,umask=0,uid=1000,gid=1000,nls=utf8)
[sougata@ultrabook tmp]$ ls -l test/rsrc
ls: cannot access test/rsrc: Permission denied
According to this LKML thread it is expected behavior.
http://marc.info/?t=121139033800008&r=1&w=4
I guess now that permission checking happens in vfs generic_permission() ?
So it turns out that even though the lookup() inode_operation exists for
HFS+ files. It cannot really get invoked ?. So if we can disable this
feature to make opendir() work for HFS+.
Signed-off-by: Sougata Santra <sougata@tuxera.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Anton Altaparmakov <aia21@cam.ac.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Add comments for ioctls in fs/nilfs2/ioctl.c file and describe NILFS2
specific ioctls in Documentation/filesystems/nilfs2.txt.
Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Reviewed-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Wenliang Fan <fanwlexca@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The local variable 'pos' in nilfs_ioctl_wrap_copy function can overflow if
a large number was passed to argv->v_index from userspace and the sum of
argv->v_index and argv->v_nmembs exceeds the maximum value of __u64 type
integer (= ~(__u64)0 = 18446744073709551615).
Here, argv->v_index is a 64-bit width argument to specify the start
position of target data items (such as segment number, checkpoint number,
or virtual block address of nilfs), and argv->v_nmembs gives the total
number of the items that userland programs (such as lssu, lscp, or
cleanerd) want to get information about, which also gives the maximum
element count of argv->v_base[] array.
nilfs_ioctl_wrap_copy() calls dofunc() repeatedly and increments the
position variable 'pos' at the end of each iteration if dofunc() itself
didn't update 'pos':
if (pos == ppos)
pos += n;
This patch prevents the overflow here by rejecting pairs of a start
position (argv->v_index) and a total count (argv->v_nmembs) which leads to
the overflow.
[konishi.ryusuke@lab.ntt.co.jp: fix signedness issue]
Signed-off-by: Wenliang Fan <fanwlexca@gmail.com>
Cc: Vyacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Pipe has no data associated with fs so it is not good idea to block
pipe_write() if FS is frozen, but we can not update file's time on such
filesystem. Let's use same idea as we use in touch_time().
Addresses https://bugzilla.kernel.org/show_bug.cgi?id=65701
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Add support for SMBus-only adapters (e.g. i2c-piix4). The driver has
implemented only support for I2C adapters which implement the
I2C_FUNC_SMBUS_I2C_BLOCK functionality before.
With this patch it is possible to load and use the RTC driver with I2C and
SMBUS adapters like the rtc-ds1307 does.
Tested on AMD G Series Platform (i2c-piix4 adapter driver).
Signed-off-by: Andreas Werner <andreas.werner@men.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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CONFIG_PM_SLEEP
If CONFIG_PM_SLEEP=n:
drivers/rtc/rtc-s5m.c:643: warning: `s5m_rtc_resume' defined but not used
drivers/rtc/rtc-s5m.c:654: warning: `s5m_rtc_suspend' defined but not used
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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