ibmvmc: replace deprecated strncpy with strscpy

`strncpy` is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.

A suitable replacement is `strscpy` [2] due to the fact that it
guarantees NUL-termination on the destination buffer without
unnecessarily NUL-padding.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230927-strncpy-drivers-misc-ibmvmc-c-v1-1-29f56cd3a269@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

misc: convert to new timestamp accessors

Convert to using the new inode timestamp accessor functions.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20231004185347.80880-7-jlayton@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

ibm: convert to ctime accessor functions

In later patches, we're going to change how the inode's ctime field is
used. Switch to using accessor functions instead of raw accesses of
inode->i_ctime.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Message-Id: <20230705190309.579783-17-jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

ibmvmc: update ctime in conjunction with mtime on write

POSIX says:

"Upon successful completion, where nbyte is greater than 0, write()
shall mark for update the last data modification and last file status
change timestamps of the file..."

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230705190309.579783-1-jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

ibmvmc: don't open-code file_inode()

badly, at that...

Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

vio: make remove callback return void

The driver core ignores the return value of struct bus_type::remove()
because there is only little that can be done. To simplify the quest to
make this function return void, let struct vio_driver::remove() return
void, too. All users already unconditionally return 0, this commit makes
it obvious that returning an error code is a bad idea.

Note there are two nominally different implementations for a vio bus:
one in arch/sparc/kernel/vio.c and the other in
arch/powerpc/platforms/pseries/vio.c. This patch only adapts the powerpc
one.

Before this patch for a device that was bound to a driver without a
remove callback vio_cmo_bus_remove(viodev) wasn't called. As the device
core still considers the device unbound after vio_bus_remove() returns
calling this unconditionally is the consistent behaviour which is
implemented here.

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Acked-by: Lijun Pan <ljp@linux.ibm.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[mpe: Drop unneeded hvcs_remove() forward declaration, squash in
change from sfr to drop ibmvnic_remove() forward declaration]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210225221834.160083-1-uwe@kleine-koenig.org

mm, treewide: rename kzfree() to kfree_sensitive()

As said by Linus:

A symmetric naming is only helpful if it implies symmetries in use.
Otherwise it's actively misleading.

In "kzalloc()", the z is meaningful and an important part of what the
caller wants.

In "kzfree()", the z is actively detrimental, because maybe in the
future we really _might_ want to use that "memfill(0xdeadbeef)" or
something. The "zero" part of the interface isn't even _relevant_.

The main reason that kzfree() exists is to clear sensitive information
that should not be leaked to other future users of the same memory
objects.

Rename kzfree() to kfree_sensitive() to follow the example of the recently
added kvfree_sensitive() and make the intention of the API more explicit.
In addition, memzero_explicit() is used to clear the memory to make sure
that it won't get optimized away by the compiler.

The renaming is done by using the command sequence:

git grep -w --name-only kzfree |\
xargs sed -i 's/kzfree/kfree_sensitive/'

followed by some editing of the kfree_sensitive() kerneldoc and adding
a kzfree backward compatibility macro in slab.h.

[akpm@linux-foundation.org: fs/crypto/inline_crypt.c needs linux/slab.h]
[akpm@linux-foundation.org: fix fs/crypto/inline_crypt.c some more]

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Joe Perches <joe@perches.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Jason A . Donenfeld" <Jason@zx2c4.com>
Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

misc: ibmvmc: Repair ill-named function argument descriptions

Formatting is correct and descriptions are all present, but some
of the argument names are not properly represented in the
documentation.

Fixes the following W=1 build warnings:

drivers/misc/ibmvmc.c:780: warning: Function parameter or member 'msg_len' not described in 'ibmvmc_send_msg'
drivers/misc/ibmvmc.c:780: warning: Excess function parameter 'msg_length' description in 'ibmvmc_send_msg'
drivers/misc/ibmvmc.c:1041: warning: Function parameter or member 'buffer' not described in 'ibmvmc_write'
drivers/misc/ibmvmc.c:1041: warning: Excess function parameter 'buf' description in 'ibmvmc_write'
drivers/misc/ibmvmc.c:1360: warning: Function parameter or member 'file' not described in 'ibmvmc_ioctl'
drivers/misc/ibmvmc.c:1360: warning: Excess function parameter 'session' description in 'ibmvmc_ioctl'

Cc: Steven Royer <seroyer@linux.ibm.com>
Cc: Adam Reznechek <adreznec@linux.vnet.ibm.com>
Cc: "Bryant G. Ly" <bryantly@linux.vnet.ibm.com>
Cc: Dave Engebretsen <engebret@us.ibm.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20200701083118.45744-30-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

misc: ibmvsm: Fix potential NULL pointer dereference

There is a potential NULL pointer dereference in case kzalloc()
fails and returns NULL.

Fix this by adding a NULL check on *session*

Also, update the function header with information about the
expected return on failure and remove unnecessary variable rc.

This issue was detected with the help of Coccinelle.

Fixes: 0eca353e7ae7 ("misc: IBM Virtual Management Channel Driver (VMC)")
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

misc: ibmvsm: Fix wrong assignment of return code

Currently the assignment is flipped and rc is always 0.

Signed-off-by: Bryant G. Ly <bryantly@linux.ibm.com>
Fixes: 0eca353e7ae7 ("misc: IBM Virtual Management Channel Driver (VMC)")
Reviewed-by: Bradley Warrum <bwarrum@us.ibm.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

misc: ibmvmc: Use GFP_ATOMIC under spin lock

The function alloc_dma_buffer() is called from ibmvmc_add_buffer(),
in which a spin lock be held here, so we should use GFP_ATOMIC when
a lock is held.

Fixes: 0eca353e7ae7 ("misc: IBM Virtual Management Channel Driver (VMC)")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

misc: IBM Virtual Management Channel Driver (VMC)

This driver is a logical device which provides an
interface between the hypervisor and a management
partition. This interface is like a message
passing interface. This management partition
is intended to provide an alternative to HMC-based
system management.

VMC enables the Management LPAR to provide basic
logical partition functions:
- Logical Partition Configuration
- Boot, start, and stop actions for individual
partitions
- Display of partition status
- Management of virtual Ethernet
- Management of virtual Storage
- Basic system management

This driver is to be used for the POWER Virtual
Management Channel Virtual Adapter on the PowerPC
platform. It provides a character device which
allows for both request/response and async message
support through the /dev/ibmvmc node.

Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Reviewed-by: Steven Royer <seroyer@linux.vnet.ibm.com>
Reviewed-by: Adam Reznechek <adreznec@linux.vnet.ibm.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Taylor Jakobson <tjakobs@us.ibm.com>
Tested-by: Brad Warrum <bwarrum@us.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>