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Siddh Raman Pant 65c6ef02ff nfc: llcp_core: Hold a ref to llcp_local->dev when holding a ref to llcp_local
[ Upstream commit c95f919567d6f1914f13350af61a1b044ac85014 ]

llcp_sock_sendmsg() calls nfc_llcp_send_ui_frame() which in turn calls
nfc_alloc_send_skb(), which accesses the nfc_dev from the llcp_sock for
getting the headroom and tailroom needed for skb allocation.

Parallelly the nfc_dev can be freed, as the refcount is decreased via
nfc_free_device(), leading to a UAF reported by Syzkaller, which can
be summarized as follows:

(1) llcp_sock_sendmsg() -> nfc_llcp_send_ui_frame()
	-> nfc_alloc_send_skb() -> Dereference *nfc_dev
(2) virtual_ncidev_close() -> nci_free_device() -> nfc_free_device()
	-> put_device() -> nfc_release() -> Free *nfc_dev

When a reference to llcp_local is acquired, we do not acquire the same
for the nfc_dev. This leads to freeing even when the llcp_local is in
use, and this is the case with the UAF described above too.

Thus, when we acquire a reference to llcp_local, we should acquire a
reference to nfc_dev, and release the references appropriately later.

References for llcp_local is initialized in nfc_llcp_register_device()
(which is called by nfc_register_device()). Thus, we should acquire a
reference to nfc_dev there.

nfc_unregister_device() calls nfc_llcp_unregister_device() which in
turn calls nfc_llcp_local_put(). Thus, the reference to nfc_dev is
appropriately released later.

Reported-and-tested-by: syzbot+bbe84a4010eeea00982d@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=bbe84a4010eeea00982d
Fixes: c7aa12252f ("NFC: Take a reference on the LLCP local pointer when creating a socket")
Reviewed-by: Suman Ghosh <sumang@marvell.com>
Signed-off-by: Siddh Raman Pant <code@siddh.me>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-01-15 18:25:25 +01:00
arch x86/alternatives: Sync core before enabling interrupts 2024-01-08 11:29:47 +01:00
block blk-throttle: fix lockdep warning of "cgroup_mutex or RCU read lock required!" 2023-12-20 15:41:20 +01:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:11:22 +02:00
crypto crypto: pcrypt - Fix hungtask for PADATA_RESET 2023-11-28 16:50:14 +00:00
Documentation firmware: ti_sci: Replace HTTP links with HTTPS ones 2023-11-20 10:30:12 +01:00
drivers usb: fotg210-hcd: delete an incorrect bounds test 2024-01-08 11:29:47 +01:00
fs block: Don't invalidate pagecache for invalid falloc modes 2024-01-08 11:29:48 +01:00
include asm-generic: qspinlock: fix queued_spin_value_unlocked() implementation 2023-12-20 15:41:22 +01:00
init x86/mm: Initialize text poking earlier 2023-08-08 19:56:36 +02:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:23:06 +01:00
kernel ring-buffer: Fix wake ups when buffer_percent is set to 100 2024-01-08 11:29:48 +01:00
lib kobject: Fix slab-out-of-bounds in fill_kobj_path() 2023-11-08 11:23:38 +01:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm/cma: use nth_page() in place of direct struct page manipulation 2023-11-28 16:50:19 +00:00
net nfc: llcp_core: Hold a ref to llcp_local->dev when holding a ref to llcp_local 2024-01-15 18:25:25 +01:00
samples samples/bpf: Fix buffer overflow in tcp_basertt 2023-07-27 08:37:07 +02:00
scripts sign-file: Fix incorrect return values check 2023-12-20 15:41:17 +01:00
security ima: detect changes to the backing overlay file 2023-12-08 08:44:27 +01:00
sound ALSA: hda/hdmi: add force-connect quirk for NUC5CPYB 2024-01-08 11:29:45 +01:00
tools tools headers UAPI: Sync linux/perf_event.h with the kernel sources 2023-12-13 18:18:17 +01:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: Destroy target device if coalesced MMIO unregistration fails 2023-03-11 16:44:01 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS iio: stx104: Move to addac subdirectory 2023-08-30 16:27:12 +02:00
Makefile Linux 5.4.266 2024-01-08 11:29:48 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.