treewide: const qualify ctl_tables where applicable

Add the const qualifier to all the ctl_tables in the tree except for
watchdog_hardlockup_sysctl, memory_allocation_profiling_sysctls,
loadpin_sysc

treewide: const qualify ctl_tables where applicable

Add the const qualifier to all the ctl_tables in the tree except for
watchdog_hardlockup_sysctl, memory_allocation_profiling_sysctls,
loadpin_sysctl_table and the ones calling register_net_sysctl (./net,
drivers/inifiniband dirs). These are special cases as they use a
registration function with a non-const qualified ctl_table argument or
modify the arrays before passing them on to the registration function.

Constifying ctl_table structs will prevent the modification of
proc_handler function pointers as the arrays would reside in .rodata.
This is made possible after commit 78eb4ea25cd5 ("sysctl: treewide:
constify the ctl_table argument of proc_handlers") constified all the
proc_handlers.

Created this by running an spatch followed by a sed command:
Spatch:
virtual patch

@
depends on !(file in "net")
disable optional_qualifier
@

identifier table_name != {
watchdog_hardlockup_sysctl,
iwcm_ctl_table,
ucma_ctl_table,
memory_allocation_profiling_sysctls,
loadpin_sysctl_table
};
@@

+ const
struct ctl_table table_name [] = { ... };

sed:
sed --in-place \
-e "s/struct ctl_table .table = &uts_kern/const struct ctl_table *table = \&uts_kern/" \
kernel/utsname_sysctl.c

Reviewed-by: Song Liu <[email protected]>
Acked-by: Steven Rostedt (Google) <[email protected]> # for kernel/trace/
Reviewed-by: Martin K. Petersen <[email protected]> # SCSI
Reviewed-by: Darrick J. Wong <[email protected]> # xfs
Acked-by: Jani Nikula <[email protected]>
Acked-by: Corey Minyard <[email protected]>
Acked-by: Wei Liu <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
Reviewed-by: Bill O'Donnell <[email protected]>
Acked-by: Baoquan He <[email protected]>
Acked-by: Ashutosh Dixit <[email protected]>
Acked-by: Anna Schumaker <[email protected]>
Signed-off-by: Joel Granados <[email protected]>

show more ...

remove pointless includes of <linux/fdtable.h>

some of those used to be needed, some had been cargo-culted for
no reason...

Reviewed-by: Christian Brauner <[email protected]>
Signed-off-by: Al Vir

remove pointless includes of <linux/fdtable.h>

some of those used to be needed, some had been cargo-culted for
no reason...

Reviewed-by: Christian Brauner <[email protected]>
Signed-off-by: Al Viro <[email protected]>

show more ...

sysctl: treewide: constify the ctl_table argument of proc_handlers

const qualify the struct ctl_table argument in the proc_handler function
signatures. This is a prerequisite to moving the static ct

sysctl: treewide: constify the ctl_table argument of proc_handlers

const qualify the struct ctl_table argument in the proc_handler function
signatures. This is a prerequisite to moving the static ctl_table
structs into .rodata data which will ensure that proc_handler function
pointers cannot be modified.

This patch has been generated by the following coccinelle script:

```
virtual patch

@r1@
identifier ctl, write, buffer, lenp, ppos;
identifier func !~ "appldata_(timer|interval)_handler|sched_(rt|rr)_handler|rds_tcp_skbuf_handler|proc_sctp_do_(hmac_alg|rto_min|rto_max|udp_port|alpha_beta|auth|probe_interval)";
@@

int func(
- struct ctl_table *ctl
+ const struct ctl_table *ctl
,int write, void *buffer, size_t *lenp, loff_t *ppos);

@r2@
identifier func, ctl, write, buffer, lenp, ppos;
@@

int func(
- struct ctl_table *ctl
+ const struct ctl_table *ctl
,int write, void *buffer, size_t *lenp, loff_t *ppos)
{ ... }

@r3@
identifier func;
@@

int func(
- struct ctl_table *
+ const struct ctl_table *
,int , void *, size_t *, loff_t *);

@r4@
identifier func, ctl;
@@

int func(
- struct ctl_table *ctl
+ const struct ctl_table *ctl
,int , void *, size_t *, loff_t *);

@r5@
identifier func, write, buffer, lenp, ppos;
@@

int func(
- struct ctl_table *
+ const struct ctl_table *
,int write, void *buffer, size_t *lenp, loff_t *ppos);

```

* Code formatting was adjusted in xfs_sysctl.c to comply with code
conventions. The xfs_stats_clear_proc_handler,
xfs_panic_mask_proc_handler and xfs_deprecated_dointvec_minmax where
adjusted.

* The ctl_table argument in proc_watchdog_common was const qualified.
This is called from a proc_handler itself and is calling back into
another proc_handler, making it necessary to change it as part of the
proc_handler migration.

Co-developed-by: Thomas Weißschuh <[email protected]>
Signed-off-by: Thomas Weißschuh <[email protected]>
Co-developed-by: Joel Granados <[email protected]>
Signed-off-by: Joel Granados <[email protected]>

show more ...

umh: Remove the now superfluous sentinel elements from ctl_table array

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinel

umh: Remove the now superfluous sentinel elements from ctl_table array

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which
will reduce the overall build time size of the kernel and run time
memory bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%[email protected]/)

Remove sentinel element from usermodehelper_table

Signed-off-by: Joel Granados <[email protected]>

show more ...

sysctl: fix unused proc_cap_handler() function warning

Since usermodehelper_table() is marked static now, we get a
warning about it being unused when SYSCTL is disabled:

kernel/umh.c:497:12: error:

sysctl: fix unused proc_cap_handler() function warning

Since usermodehelper_table() is marked static now, we get a
warning about it being unused when SYSCTL is disabled:

kernel/umh.c:497:12: error: 'proc_cap_handler' defined but not used [-Werror=unused-function]

Just move it inside of the same #ifdef.

Signed-off-by: Arnd Bergmann <[email protected]>
Tested-by: Matthieu Baerts <[email protected]>
Fixes: 861dc0b46432 ("sysctl: move umh sysctl registration to its own file")
Acked-by: Randy Dunlap <[email protected]>
Tested-by: Randy Dunlap <[email protected]> # build-tested
[mcgrof: adjust new commit ID for Fixes tag]
Signed-off-by: Luis Chamberlain <[email protected]>

show more ...

sysctl: move umh sysctl registration to its own file

Move the umh sysctl registration to its own file, the array is
already there. We do this to remove the clutter out of kernel/sysctl.c
to avoid me

sysctl: move umh sysctl registration to its own file

Move the umh sysctl registration to its own file, the array is
already there. We do this to remove the clutter out of kernel/sysctl.c
to avoid merge conflicts.

This also lets the sysctls not be built at all now when CONFIG_SYSCTL
is not enabled.

This has a small penalty of 23 bytes but soon we'll be removing
all the empty entries on sysctl arrays so just do this cleanup
now:

./scripts/bloat-o-meter vmlinux.base vmlinux.1
add/remove: 2/0 grow/shrink: 0/1 up/down: 49/-26 (23)
Function old new delta
init_umh_sysctls - 33 +33
__pfx_init_umh_sysctls - 16 +16
sysctl_init_bases 111 85 -26
Total: Before=21256914, After=21256937, chg +0.00%

Acked-by: Jarkko Sakkinen <[email protected]>
Signed-off-by: Luis Chamberlain <[email protected]>

show more ...

umh: simplify the capability pointer logic

The usermodehelper code uses two fake pointers for the two capability
cases: CAP_BSET for reading and writing 'usermodehelper_bset', and
CAP_PI to read and

umh: simplify the capability pointer logic

The usermodehelper code uses two fake pointers for the two capability
cases: CAP_BSET for reading and writing 'usermodehelper_bset', and
CAP_PI to read and write 'usermodehelper_inheritable'.

This seems to be a completely unnecessary indirection, since we could
instead just use the pointers themselves, and never have to do any "if
this then that" kind of logic.

So just get rid of the fake pointer values, and use the real pointer
values instead.

Reviewed-by: Luis Chamberlain <[email protected]>
Cc: Eric Biederman <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Iurii Zaikin <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

capability: just use a 'u64' instead of a 'u32[2]' array

Back in 2008 we extended the capability bits from 32 to 64, and we did
it by extending the single 32-bit capability word from one word to an

capability: just use a 'u64' instead of a 'u32[2]' array

Back in 2008 we extended the capability bits from 32 to 64, and we did
it by extending the single 32-bit capability word from one word to an
array of two words. It was then obfuscated by hiding the "2" behind two
macro expansions, with the reasoning being that maybe it gets extended
further some day.

That reasoning may have been valid at the time, but the last thing we
want to do is to extend the capability set any more. And the array of
values not only causes source code oddities (with loops to deal with
it), but also results in worse code generation. It's a lose-lose
situation.

So just change the 'u32[2]' into a 'u64' and be done with it.

We still have to deal with the fact that the user space interface is
designed around an array of these 32-bit values, but that was the case
before too, since the array layouts were different (ie user space
doesn't use an array of 32-bit values for individual capability masks,
but an array of 32-bit slices of multiple masks).

So that marshalling of data is actually simplified too, even if it does
remain somewhat obscure and odd.

This was all triggered by my reaction to the new "cap_isidentical()"
introduced recently. By just using a saner data structure, it went from

unsigned __capi;
CAP_FOR_EACH_U32(__capi) {
if (a.cap[__capi] != b.cap[__capi])
return false;
}
return true;

to just being

return a.val == b.val;

instead. Which is rather more obvious both to humans and to compilers.

Cc: Mateusz Guzik <[email protected]>
Cc: Casey Schaufler <[email protected]>
Cc: Serge Hallyn <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Paul Moore <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

freezer,umh: Fix call_usermode_helper_exec() vs SIGKILL

Tetsuo-San noted that commit f5d39b020809 ("freezer,sched: Rewrite
core freezer logic") broke call_usermodehelper_exec() for the KILLABLE
case

freezer,umh: Fix call_usermode_helper_exec() vs SIGKILL

Tetsuo-San noted that commit f5d39b020809 ("freezer,sched: Rewrite
core freezer logic") broke call_usermodehelper_exec() for the KILLABLE
case.

Specifically it was missed that the second, unconditional,
wait_for_completion() was not optional and ensures the on-stack
completion is unused before going out-of-scope.

Fixes: f5d39b020809 ("freezer,sched: Rewrite core freezer logic")
Reported-by: [email protected]
Reported-by: Tetsuo Handa <[email protected]>
Debugged-by: Tetsuo Handa <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

show more ...

freezer,sched: Rewrite core freezer logic

Rewrite the core freezer to behave better wrt thawing and be simpler
in general.

By replacing PF_FROZEN with TASK_FROZEN, a special block state, it is
ensu

freezer,sched: Rewrite core freezer logic

Rewrite the core freezer to behave better wrt thawing and be simpler
in general.

By replacing PF_FROZEN with TASK_FROZEN, a special block state, it is
ensured frozen tasks stay frozen until thawed and don't randomly wake
up early, as is currently possible.

As such, it does away with PF_FROZEN and PF_FREEZER_SKIP, freeing up
two PF_flags (yay!).

Specifically; the current scheme works a little like:

freezer_do_not_count();
schedule();
freezer_count();

And either the task is blocked, or it lands in try_to_freezer()
through freezer_count(). Now, when it is blocked, the freezer
considers it frozen and continues.

However, on thawing, once pm_freezing is cleared, freezer_count()
stops working, and any random/spurious wakeup will let a task run
before its time.

That is, thawing tries to thaw things in explicit order; kernel
threads and workqueues before doing bringing SMP back before userspace
etc.. However due to the above mentioned races it is entirely possible
for userspace tasks to thaw (by accident) before SMP is back.

This can be a fatal problem in asymmetric ISA architectures (eg ARMv9)
where the userspace task requires a special CPU to run.

As said; replace this with a special task state TASK_FROZEN and add
the following state transitions:

TASK_FREEZABLE -> TASK_FROZEN
__TASK_STOPPED -> TASK_FROZEN
__TASK_TRACED -> TASK_FROZEN

The new TASK_FREEZABLE can be set on any state part of TASK_NORMAL
(IOW. TASK_INTERRUPTIBLE and TASK_UNINTERRUPTIBLE) -- any such state
is already required to deal with spurious wakeups and the freezer
causes one such when thawing the task (since the original state is
lost).

The special __TASK_{STOPPED,TRACED} states *can* be restored since
their canonical state is in ->jobctl.

With this, frozen tasks need an explicit TASK_FROZEN wakeup and are
free of undue (early / spurious) wakeups.

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Ingo Molnar <[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

show more ...

freezer,umh: Clean up freezer/initrd interaction

handle_initrd() marks itself as PF_FREEZER_SKIP in order to ensure
that the UMH, which is going to freeze the system, doesn't
indefinitely wait for i

freezer,umh: Clean up freezer/initrd interaction

handle_initrd() marks itself as PF_FREEZER_SKIP in order to ensure
that the UMH, which is going to freeze the system, doesn't
indefinitely wait for it's caller.

Rework things by adding UMH_FREEZABLE to indicate the completion is
freezable.

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

show more ...

kthread: Don't allocate kthread_struct for init and umh

If kthread_is_per_cpu runs concurrently with free_kthread_struct the
kthread_struct that was just freed may be read from.

This bug was introd

kthread: Don't allocate kthread_struct for init and umh

If kthread_is_per_cpu runs concurrently with free_kthread_struct the
kthread_struct that was just freed may be read from.

This bug was introduced by commit 40966e316f86 ("kthread: Ensure
struct kthread is present for all kthreads"). When kthread_struct
started to be allocated for all tasks that have PF_KTHREAD set. This
in turn required the kthread_struct to be freed in kernel_execve and
violated the assumption that kthread_struct will have the same
lifetime as the task.

Looking a bit deeper this only applies to callers of kernel_execve
which is just the init process and the user mode helper processes.
These processes really don't want to be kernel threads but are for
historical reasons. Mostly that copy_thread does not know how to take
a kernel mode function to the process with for processes without
PF_KTHREAD or PF_IO_WORKER set.

Solve this by not allocating kthread_struct for the init process and
the user mode helper processes.

This is done by adding a kthread member to struct kernel_clone_args.
Setting kthread in fork_idle and kernel_thread. Adding
user_mode_thread that works like kernel_thread except it does not set
kthread. In fork only allocating the kthread_struct if .kthread is set.

I have looked at kernel/kthread.c and since commit 40966e316f86
("kthread: Ensure struct kthread is present for all kthreads") there
have been no assumptions added that to_kthread or __to_kthread will
not return NULL.

There are a few callers of to_kthread or __to_kthread that assume a
non-NULL struct kthread pointer will be returned. These functions are
kthread_data(), kthread_parmme(), kthread_exit(), kthread(),
kthread_park(), kthread_unpark(), kthread_stop(). All of those functions
can reasonably expected to be called when it is know that a task is a
kthread so that assumption seems reasonable.

Cc: [email protected]
Fixes: 40966e316f86 ("kthread: Ensure struct kthread is present for all kthreads")
Reported-by: Максим Кутявин <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: "Eric W. Biederman" <[email protected]>

show more ...

kernel/umh.c: fix some spelling mistakes

Fix some spelling mistakes, and modify the order of the parameter comments
to be consistent with the order of the parameters passed to the function.

Link: h

kernel/umh.c: fix some spelling mistakes

Fix some spelling mistakes, and modify the order of the parameter comments
to be consistent with the order of the parameters passed to the function.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: zhouchuangao <[email protected]>
Acked-by: Luis Chamberlain <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

init/initramfs.c: do unpacking asynchronously

Patch series "background initramfs unpacking, and CONFIG_MODPROBE_PATH", v3.

These two patches are independent, but better-together.

The second is a r

init/initramfs.c: do unpacking asynchronously

Patch series "background initramfs unpacking, and CONFIG_MODPROBE_PATH", v3.

These two patches are independent, but better-together.

The second is a rather trivial patch that simply allows the developer to
change "/sbin/modprobe" to something else - e.g. the empty string, so
that all request_module() during early boot return -ENOENT early, without
even spawning a usermode helper, needlessly synchronizing with the
initramfs unpacking.

The first patch delegates decompressing the initramfs to a worker thread,
allowing do_initcalls() in main.c to proceed to the device_ and late_
initcalls without waiting for that decompression (and populating of
rootfs) to finish. Obviously, some of those later calls may rely on the
initramfs being available, so I've added synchronization points in the
firmware loader and usermodehelper paths - there might be other places
that would need this, but so far no one has been able to think of any
places I have missed.

There's not much to win if most of the functionality needed during boot is
only available as modules. But systems with a custom-made .config and
initramfs can boot faster, partly due to utilizing more than one cpu
earlier, partly by avoiding known-futile modprobe calls (which would still
trigger synchronization with the initramfs unpacking, thus eliminating
most of the first benefit).

This patch (of 2):

Most of the boot process doesn't actually need anything from the
initramfs, until of course PID1 is to be executed. So instead of doing
the decompressing and populating of the initramfs synchronously in
populate_rootfs() itself, push that off to a worker thread.

This is primarily motivated by an embedded ppc target, where unpacking
even the rather modest sized initramfs takes 0.6 seconds, which is long
enough that the external watchdog becomes unhappy that it doesn't get
attention soon enough. By doing the initramfs decompression in a worker
thread, we get to do the device_initcalls and hence start petting the
watchdog much sooner.

Normal desktops might benefit as well. On my mostly stock Ubuntu kernel,
my initramfs is a 26M xz-compressed blob, decompressing to around 126M.
That takes almost two seconds:

[ 0.201454] Trying to unpack rootfs image as initramfs...
[ 1.976633] Freeing initrd memory: 29416K

Before this patch, these lines occur consecutively in dmesg. With this
patch, the timestamps on these two lines is roughly the same as above, but
with 172 lines inbetween - so more than one cpu has been kept busy doing
work that would otherwise only happen after the populate_rootfs()
finished.

Should one of the initcalls done after rootfs_initcall time (i.e., device_
and late_ initcalls) need something from the initramfs (say, a kernel
module or a firmware blob), it will simply wait for the initramfs
unpacking to be done before proceeding, which should in theory make this
completely safe.

But if some driver pokes around in the filesystem directly and not via one
of the official kernel interfaces (i.e. request_firmware*(),
call_usermodehelper*) that theory may not hold - also, I certainly might
have missed a spot when sprinkling wait_for_initramfs(). So there is an
escape hatch in the form of an initramfs_async= command line parameter.

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Rasmus Villemoes <[email protected]>
Reviewed-by: Luis Chamberlain <[email protected]>
Cc: Jessica Yu <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Nick Desaulniers <[email protected]>
Cc: Takashi Iwai <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

usermodehelper: reset umask to default before executing user process

Kernel threads intentionally do CLONE_FS in order to follow any changes
that 'init' does to set up the root directory (or cwd).

usermodehelper: reset umask to default before executing user process

Kernel threads intentionally do CLONE_FS in order to follow any changes
that 'init' does to set up the root directory (or cwd).

It is admittedly a bit odd, but it avoids the situation where 'init'
does some extensive setup to initialize the system environment, and then
we execute a usermode helper program, and it uses the original FS setup
from boot time that may be very limited and incomplete.

[ Both Al Viro and Eric Biederman point out that 'pivot_root()' will
follow the root regardless, since it fixes up other users of root (see
chroot_fs_refs() for details), but overmounting root and doing a
chroot() would not. ]

However, Vegard Nossum noticed that the CLONE_FS not only means that we
follow the root and current working directories, it also means we share
umask with whatever init changed it to. That wasn't intentional.

Just reset umask to the original default (0022) before actually starting
the usermode helper program.

Reported-by: Vegard Nossum <[email protected]>
Cc: Al Viro <[email protected]>
Acked-by: Eric W. Biederman <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

kernel: add a kernel_wait helper

Add a helper that waits for a pid and stores the status in the passed in
kernel pointer. Use it to fix the usage of kernel_wait4 in
call_usermodehelper_exec_sync th

kernel: add a kernel_wait helper

Add a helper that waits for a pid and stores the status in the passed in
kernel pointer. Use it to fix the usage of kernel_wait4 in
call_usermodehelper_exec_sync that only happens to work due to the
implicit set_fs(KERNEL_DS) for kernel threads.

Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Acked-by: "Eric W. Biederman" <[email protected]>
Cc: Luis Chamberlain <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

exec: Implement kernel_execve

To allow the kernel not to play games with set_fs to call exec
implement kernel_execve. The function kernel_execve takes pointers
into kernel memory and copies the val

exec: Implement kernel_execve

To allow the kernel not to play games with set_fs to call exec
implement kernel_execve. The function kernel_execve takes pointers
into kernel memory and copies the values pointed to onto the new
userspace stack.

The calls with arguments from kernel space of do_execve are replaced
with calls to kernel_execve.

The calls do_execve and do_execveat are made static as there are now
no callers outside of exec.

The comments that mention do_execve are updated to refer to
kernel_execve or execve depending on the circumstances. In addition
to correcting the comments, this makes it easy to grep for do_execve
and verify it is not used.

Inspired-by: https://lkml.kernel.org/r/[email protected]
Reviewed-by: Kees Cook <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: "Eric W. Biederman" <[email protected]>

show more ...

umh: Stop calling do_execve_file

With the user mode driver code changed to not set subprocess_info.file
there are no more users of subproces_info.file. Remove this field
from struct subprocess_info

umh: Stop calling do_execve_file

With the user mode driver code changed to not set subprocess_info.file
there are no more users of subproces_info.file. Remove this field
from struct subprocess_info and remove the only user in
call_usermodehelper_exec_async that would call do_execve_file instead
of do_execve if file was set.

v1: https://lkml.kernel.org/r/[email protected]
v2: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Acked-by: Alexei Starovoitov <[email protected]>
Tested-by: Alexei Starovoitov <[email protected]>
Signed-off-by: "Eric W. Biederman" <[email protected]>

show more ...

umh: Separate the user mode driver and the user mode helper support

This makes it clear which code is part of the core user mode
helper support and which code is needed to implement user mode
driver

umh: Separate the user mode driver and the user mode helper support

This makes it clear which code is part of the core user mode
helper support and which code is needed to implement user mode
drivers.

This makes the kernel smaller for everyone who does not use a usermode
driver.

v1: https://lkml.kernel.org/r/[email protected]
v2: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Acked-by: Alexei Starovoitov <[email protected]>
Tested-by: Alexei Starovoitov <[email protected]>
Signed-off-by: "Eric W. Biederman" <[email protected]>

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umh: Remove call_usermodehelper_setup_file.

The only caller of call_usermodehelper_setup_file is fork_usermode_blob.
In fork_usermode_blob replace call_usermodehelper_setup_file with
call_usermodehe

umh: Remove call_usermodehelper_setup_file.

The only caller of call_usermodehelper_setup_file is fork_usermode_blob.
In fork_usermode_blob replace call_usermodehelper_setup_file with
call_usermodehelper_setup and delete fork_usermodehelper_setup_file.

For this to work the argv_free is moved from umh_clean_and_save_pid
to fork_usermode_blob.

v1: https://lkml.kernel.org/r/[email protected]
v2: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Acked-by: Alexei Starovoitov <[email protected]>
Tested-by: Alexei Starovoitov <[email protected]>
Signed-off-by: "Eric W. Biederman" <[email protected]>

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umh: Rename the user mode driver helpers for clarity

Now that the functionality of umh_setup_pipe and
umh_clean_and_save_pid has changed their names are too specific and
don't make much sense. Inst

umh: Rename the user mode driver helpers for clarity

Now that the functionality of umh_setup_pipe and
umh_clean_and_save_pid has changed their names are too specific and
don't make much sense. Instead name them umd_setup and umd_cleanup
for the functional role in setting up user mode drivers.

v1: https://lkml.kernel.org/r/[email protected]
v2: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Acked-by: Alexei Starovoitov <[email protected]>
Tested-by: Alexei Starovoitov <[email protected]>
Signed-off-by: "Eric W. Biederman" <[email protected]>

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umh: Move setting PF_UMH into umh_pipe_setup

I am separating the code specific to user mode drivers from the code
for ordinary user space helpers. Move setting of PF_UMH from
call_usermodehelper_ex

umh: Move setting PF_UMH into umh_pipe_setup

I am separating the code specific to user mode drivers from the code
for ordinary user space helpers. Move setting of PF_UMH from
call_usermodehelper_exec_async which is core user mode helper code
into umh_pipe_setup which is user mode driver code.

The code is equally as easy to write in one location as the other and
the movement minimizes the impact of the user mode driver code on the
core of the user mode helper code.

Setting PF_UMH unconditionally is harmless as an action will only
happen if it is paired with an entry on umh_list.

v1: https://lkml.kernel.org/r/[email protected]
v2: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Acked-by: Alexei Starovoitov <[email protected]>
Tested-by: Alexei Starovoitov <[email protected]>
Signed-off-by: "Eric W. Biederman" <[email protected]>

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umh: Capture the pid in umh_pipe_setup

The pid in struct subprocess_info is only used by umh_clean_and_save_pid to
write the pid into umh_info.

Instead always capture the pid on struct umh_info in

umh: Capture the pid in umh_pipe_setup

The pid in struct subprocess_info is only used by umh_clean_and_save_pid to
write the pid into umh_info.

Instead always capture the pid on struct umh_info in umh_pipe_setup, removing
code that is specific to user mode drivers from the common user path of
user mode helpers.

v1: https://lkml.kernel.org/r/[email protected]
v2: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Acked-by: Alexei Starovoitov <[email protected]>
Tested-by: Alexei Starovoitov <[email protected]>
Signed-off-by: "Eric W. Biederman" <[email protected]>

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umh: fix memory leak on execve failure

If a UMH process created by fork_usermode_blob() fails to execute,
a pair of struct file allocated by umh_pipe_setup() will leak.

Under normal conditions, the

umh: fix memory leak on execve failure

If a UMH process created by fork_usermode_blob() fails to execute,
a pair of struct file allocated by umh_pipe_setup() will leak.

Under normal conditions, the caller (like bpfilter) needs to manage the
lifetime of the UMH and its two pipes. But when fork_usermode_blob()
fails, the caller doesn't really have a way to know what needs to be
done. It seems better to do the cleanup ourselves in this case.

Fixes: 449325b52b7a ("umh: introduce fork_usermode_blob() helper")
Signed-off-by: Vincent Minet <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>

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coredump: fix crash when umh is disabled

Commit 64e90a8acb859 ("Introduce STATIC_USERMODEHELPER to mediate
call_usermodehelper()") added the optiont to disable all
call_usermodehelper() calls by set

coredump: fix crash when umh is disabled

Commit 64e90a8acb859 ("Introduce STATIC_USERMODEHELPER to mediate
call_usermodehelper()") added the optiont to disable all
call_usermodehelper() calls by setting STATIC_USERMODEHELPER_PATH to
an empty string. When this is done, and crashdump is triggered, it
will crash on null pointer dereference, since we make assumptions
over what call_usermodehelper_exec() did.

This has been reported by Sergey when one triggers a a coredump
with the following configuration:

```
CONFIG_STATIC_USERMODEHELPER=y
CONFIG_STATIC_USERMODEHELPER_PATH=""
kernel.core_pattern = |/usr/lib/systemd/systemd-coredump %P %u %g %s %t %c %h %e
```

The way disabling the umh was designed was that call_usermodehelper_exec()
would just return early, without an error. But coredump assumes
certain variables are set up for us when this happens, and calls
ile_start_write(cprm.file) with a NULL file.

[ 2.819676] BUG: kernel NULL pointer dereference, address: 0000000000000020
[ 2.819859] #PF: supervisor read access in kernel mode
[ 2.820035] #PF: error_code(0x0000) - not-present page
[ 2.820188] PGD 0 P4D 0
[ 2.820305] Oops: 0000 [#1] SMP PTI
[ 2.820436] CPU: 2 PID: 89 Comm: a Not tainted 5.7.0-rc1+ #7
[ 2.820680] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190711_202441-buildvm-armv7-10.arm.fedoraproject.org-2.fc31 04/01/2014
[ 2.821150] RIP: 0010:do_coredump+0xd80/0x1060
[ 2.821385] Code: e8 95 11 ed ff 48 c7 c6 cc a7 b4 81 48 8d bd 28 ff
ff ff 89 c2 e8 70 f1 ff ff 41 89 c2 85 c0 0f 84 72 f7 ff ff e9 b4 fe ff
ff <48> 8b 57 20 0f b7 02 66 25 00 f0 66 3d 00 8
0 0f 84 9c 01 00 00 44
[ 2.822014] RSP: 0000:ffffc9000029bcb8 EFLAGS: 00010246
[ 2.822339] RAX: 0000000000000000 RBX: ffff88803f860000 RCX: 000000000000000a
[ 2.822746] RDX: 0000000000000009 RSI: 0000000000000282 RDI: 0000000000000000
[ 2.823141] RBP: ffffc9000029bde8 R08: 0000000000000000 R09: ffffc9000029bc00
[ 2.823508] R10: 0000000000000001 R11: ffff88803dec90be R12: ffffffff81c39da0
[ 2.823902] R13: ffff88803de84400 R14: 0000000000000000 R15: 0000000000000000
[ 2.824285] FS: 00007fee08183540(0000) GS:ffff88803e480000(0000) knlGS:0000000000000000
[ 2.824767] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 2.825111] CR2: 0000000000000020 CR3: 000000003f856005 CR4: 0000000000060ea0
[ 2.825479] Call Trace:
[ 2.825790] get_signal+0x11e/0x720
[ 2.826087] do_signal+0x1d/0x670
[ 2.826361] ? force_sig_info_to_task+0xc1/0xf0
[ 2.826691] ? force_sig_fault+0x3c/0x40
[ 2.826996] ? do_trap+0xc9/0x100
[ 2.827179] exit_to_usermode_loop+0x49/0x90
[ 2.827359] prepare_exit_to_usermode+0x77/0xb0
[ 2.827559] ? invalid_op+0xa/0x30
[ 2.827747] ret_from_intr+0x20/0x20
[ 2.827921] RIP: 0033:0x55e2c76d2129
[ 2.828107] Code: 2d ff ff ff e8 68 ff ff ff 5d c6 05 18 2f 00 00 01
c3 0f 1f 80 00 00 00 00 c3 0f 1f 80 00 00 00 00 e9 7b ff ff ff 55 48 89
e5 <0f> 0b b8 00 00 00 00 5d c3 66 2e 0f 1f 84 0
0 00 00 00 00 0f 1f 40
[ 2.828603] RSP: 002b:00007fffeba5e080 EFLAGS: 00010246
[ 2.828801] RAX: 000055e2c76d2125 RBX: 0000000000000000 RCX: 00007fee0817c718
[ 2.829034] RDX: 00007fffeba5e188 RSI: 00007fffeba5e178 RDI: 0000000000000001
[ 2.829257] RBP: 00007fffeba5e080 R08: 0000000000000000 R09: 00007fee08193c00
[ 2.829482] R10: 0000000000000009 R11: 0000000000000000 R12: 000055e2c76d2040
[ 2.829727] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 2.829964] CR2: 0000000000000020
[ 2.830149] ---[ end trace ceed83d8c68a1bf1 ]---
```

Cc: <[email protected]> # v4.11+
Fixes: 64e90a8acb85 ("Introduce STATIC_USERMODEHELPER to mediate call_usermodehelper()")
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=199795
Reported-by: Tony Vroon <[email protected]>
Reported-by: Sergey Kvachonok <[email protected]>
Tested-by: Sergei Trofimovich <[email protected]>
Signed-off-by: Luis Chamberlain <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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