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Filename Latest commit message Latest commit date
Mikulas Patocka b545c0e1e4 dm ioctl: fix misbehavior if list_versions races with module loading
commit 4fe1ec995483737f3d2a14c3fe1d8fe634972979 upstream.

__list_versions will first estimate the required space using the
"dm_target_iterate(list_version_get_needed, &needed)" call and then will
fill the space using the "dm_target_iterate(list_version_get_info,
&iter_info)" call. Each of these calls locks the targets using the
"down_read(&_lock)" and "up_read(&_lock)" calls, however between the first
and second "dm_target_iterate" there is no lock held and the target
modules can be loaded at this point, so the second "dm_target_iterate"
call may need more space than what was the first "dm_target_iterate"
returned.

The code tries to handle this overflow (see the beginning of
list_version_get_info), however this handling is incorrect.

The code sets "param->data_size = param->data_start + needed" and
"iter_info.end = (char *)vers+len" - "needed" is the size returned by the
first dm_target_iterate call; "len" is the size of the buffer allocated by
userspace.

"len" may be greater than "needed"; in this case, the code will write up
to "len" bytes into the buffer, however param->data_size is set to
"needed", so it may write data past the param->data_size value. The ioctl
interface copies only up to param->data_size into userspace, thus part of
the result will be truncated.

Fix this bug by setting "iter_info.end = (char *)vers + needed;" - this
guarantees that the second "dm_target_iterate" call will write only up to
the "needed" buffer and it will exit with "DM_BUFFER_FULL_FLAG" if it
overflows the "needed" space - in this case, userspace will allocate a
larger buffer and retry.

Note that there is also a bug in list_version_get_needed - we need to add
"strlen(tt->name) + 1" to the needed size, not "strlen(tt->name)".

Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-11-25 17:42:19 +01:00
arch arm64: dts: imx8mn: Fix NAND controller size-cells 2022-11-25 17:42:15 +01:00
block block: sed-opal: kmalloc the cmd/resp buffers 2022-11-25 17:42:14 +01:00
certs
crypto
Documentation tracing/histogram: Update document for KEYS_MAX size 2022-11-10 17:57:55 +01:00
drivers dm ioctl: fix misbehavior if list_versions races with module loading 2022-11-25 17:42:19 +01:00
fs cifs: add check for returning value of SMB2_set_info_init 2022-11-25 17:42:16 +01:00
include vmlinux.lds.h: Fix placement of '.data..decrypted' section 2022-11-25 17:42:09 +01:00
init
ipc ipc: remove memcg accounting for sops objects in do_semtimedop() 2022-11-10 17:57:58 +01:00
kernel ring_buffer: Do not deactivate non-existant pages 2022-11-25 17:42:17 +01:00
lib
LICENSES
mm mm,hugetlb: take hugetlb_lock before decrementing h->resv_huge_pages 2022-11-03 23:56:54 +09:00
net net/x25: Fix skb leak in x25_lapb_receive_frame() 2022-11-25 17:42:16 +01:00
samples
scripts cert host tools: Stop complaining about deprecated OpenSSL functions 2022-11-25 17:42:10 +01:00
security capabilities: fix potential memleak on error path from vfs_getxattr_alloc() 2022-11-10 17:57:55 +01:00
sound ALSA: usb-audio: Drop snd_BUG_ON() from snd_usbmidi_output_open() 2022-11-25 17:42:17 +01:00
tools selftests/intel_pstate: fix build for ARCH=x86_64 2022-11-25 17:42:12 +01:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.224 2022-11-10 17:57:58 +01:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.