Both nfc_hci_recv_from_llc() and nci_hci_data_received_cb() read
packet->header from skb->data at function entry without first checking
that the buffer holds at least one byte. A malicious NFC peer can send
a 0-byte HCP frame that passes through the SHDLC layer and reaches
these functions, causing an out-of-bounds heap read of packet->header.
The same 0-byte frame, if queued as a non-final fragment, also causes
the reassembly loop to underflow msg_len to UINT_MAX, triggering
skb_over_panic() when the reassembled skb is written.
Fix this by adding a pskb_may_pull() check at the entry of each
function before packet->header is first accessed. The existing
pskb_may_pull() checks before the reassembled hcp_skb is cast to
struct hcp_packet remain in place to guard the 2-byte HCP message
header.
Fixes: 8b8d2e08bf ("NFC: HCI support")
Fixes: 11f54f2286 ("NFC: nci: Add HCI over NCI protocol support")
Cc: stable@vger.kernel.org
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Ashutosh Desai <ashutoshdesai993@gmail.com>
Link: https://patch.msgid.link/20260505170712.96560-1-ashutoshdesai993@gmail.com
Signed-off-by: David Heidelberg <david@ixit.cz>
A race condition exists in the NFC LLCP connection state machine where
the connection acceptance packet (CC) can be processed concurrently with
socket release. This can lead to a use-after-free of the socket object.
When nfc_llcp_recv_cc() moves the socket from the connecting_sockets
list to the sockets list, it does so without holding the socket lock.
If llcp_sock_release() is executing concurrently, it might have already
unlinked the socket and dropped its references, which can result in
nfc_llcp_recv_cc() linking a freed socket into the live list.
Fix this by holding lock_sock() during the state transition and list
movement in nfc_llcp_recv_cc(). After acquiring the lock, check if
the socket is still hashed to ensure it hasn't already been unlinked
and marked for destruction by the release path. This aligns the locking
pattern with recv_hdlc() and recv_disc().
Fixes: a69f32af86 ("NFC: Socket linked list")
Signed-off-by: Lee Jones <lee@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260429134115.3558604-2-lee@kernel.org
Signed-off-by: David Heidelberg <david@ixit.cz>
llcp_sock_release() unconditionally unlinks the socket from the local
sockets list. However, if the socket is still in connecting state, it
is on the connecting list.
Fix this by checking the socket state and unlinking from the correct list.
Fixes: b4011239a0 ("NFC: llcp: Fix non blocking sockets connections")
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://patch.msgid.link/20260429134115.3558604-1-lee@kernel.org
Signed-off-by: David Heidelberg <david@ixit.cz>
The NFC-A anti-collision cascade in digital_in_recv_sdd_res() appends 3
or 4 bytes to target->nfcid1 on each round, but the number of cascade
rounds is controlled entirely by the peer device. The peer sets the
cascade tag in the SDD_RES (deciding 3 vs 4 bytes) and the
cascade-incomplete bit in the SEL_RES (deciding whether another round
follows).
ISO 14443-3 limits NFC-A to three cascade levels and target->nfcid1 is
sized accordingly (NFC_NFCID1_MAXSIZE = 10), but nothing in the driver
actually enforces this. This means a malicious peer can keep the
cascade running, writing past the heap-allocated nfc_target with each
round.
Fix this by rejecting the response when the accumulated UID would exceed
the buffer.
Commit e329e71013 ("NFC: nci: Bounds check struct nfc_target arrays")
fixed similar missing checks against the same field on the NCI path.
Cc: Simon Horman <horms@kernel.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Thierry Escande <thierry.escande@linux.intel.com>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Fixes: 2c66daecc4 ("NFC Digital: Add NFC-A technology support")
Cc: stable <stable@kernel.org>
Assisted-by: gregkh_clanker_t1000
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/2026040913-figure-seducing-bd3f@gregkh
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
In nfc_llcp_recv_hdlc() and nfc_llcp_recv_disc(), when the socket
state is LLCP_CLOSED, the code correctly calls release_sock() and
nfc_llcp_sock_put() but fails to return. Execution falls through to
the remainder of the function, which calls release_sock() and
nfc_llcp_sock_put() again. This results in a double release_sock()
and a refcount underflow via double nfc_llcp_sock_put(), leading to
a use-after-free.
Add the missing return statements after the LLCP_CLOSED branches
in both functions to prevent the fall-through.
Fixes: d646960f79 ("NFC: Initial LLCP support")
Signed-off-by: Junxi Qian <qjx1298677004@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260408081006.3723-1-qjx1298677004@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
nci_close_device() flushes rx_wq and tx_wq while holding req_lock.
This causes a circular locking dependency because nci_rx_work()
running on rx_wq can end up taking req_lock too:
nci_rx_work -> nci_rx_data_packet -> nci_data_exchange_complete
-> __sk_destruct -> rawsock_destruct -> nfc_deactivate_target
-> nci_deactivate_target -> nci_request -> mutex_lock(&ndev->req_lock)
Move the flush of rx_wq after req_lock has been released.
This should safe (I think) because NCI_UP has already been cleared
and the transport is closed, so the work will see it and return
-ENETDOWN.
NIPA has been hitting this running the nci selftest with a debug
kernel on roughly 4% of the runs.
Fixes: 6a2968aaf5 ("NFC: basic NCI protocol implementation")
Reviewed-by: Ian Ray <ian.ray@gehealthcare.com>
Link: https://patch.msgid.link/20260317193334.988609-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
In rawsock_release(), cancel any pending tx_work and purge the write
queue before orphaning the socket. rawsock_tx_work runs on the system
workqueue and calls nfc_data_exchange which dereferences the NCI
device. Without synchronization, tx_work can race with socket and
device teardown when a process is killed (e.g. by SIGKILL), leading
to use-after-free or leaked references.
Set SEND_SHUTDOWN first so that if tx_work is already running it will
see the flag and skip transmitting, then use cancel_work_sync to wait
for any in-progress execution to finish, and finally purge any
remaining queued skbs.
Fixes: 23b7869c0f ("NFC: add the NFC socket raw protocol")
Reviewed-by: Joe Damato <joe@dama.to>
Link: https://patch.msgid.link/20260303162346.2071888-6-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Move clear_bit(NCI_DATA_EXCHANGE) before invoking the data exchange
callback in nci_data_exchange_complete().
The callback (e.g. rawsock_data_exchange_complete) may immediately
schedule another data exchange via schedule_work(tx_work). On a
multi-CPU system, tx_work can run and reach nci_transceive() before
the current nci_data_exchange_complete() clears the flag, causing
test_and_set_bit(NCI_DATA_EXCHANGE) to return -EBUSY and the new
transfer to fail.
This causes intermittent flakes in nci/nci_dev in NIPA:
# # RUN NCI.NCI1_0.t4t_tag_read ...
# # t4t_tag_read: Test terminated by timeout
# # FAIL NCI.NCI1_0.t4t_tag_read
# not ok 3 NCI.NCI1_0.t4t_tag_read
Fixes: 38f04c6b1b ("NFC: protect nci_data_exchange transactions")
Reviewed-by: Joe Damato <joe@dama.to>
Link: https://patch.msgid.link/20260303162346.2071888-5-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
digital_in_send() takes ownership of the skb passed by the caller
(nfc_data_exchange), make sure it's freed on all error paths.
Found looking around the real driver for similar bugs to the one
just fixed in nci.
Fixes: 2c66daecc4 ("NFC Digital: Add NFC-A technology support")
Reviewed-by: Joe Damato <joe@dama.to>
Link: https://patch.msgid.link/20260303162346.2071888-3-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
llc_shdlc_deinit() purges SHDLC skb queues and frees the llc_shdlc
structure while its timers and state machine work may still be active.
Timer callbacks can schedule sm_work, and sm_work accesses SHDLC state
and the skb queues. If teardown happens in parallel with a queued/running
work item, it can lead to UAF and other shutdown races.
Stop all SHDLC timers and cancel sm_work synchronously before purging the
queues and freeing the context.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: 4a61cd6687 ("NFC: Add an shdlc llc module to llc core")
Signed-off-by: Votokina Victoria <Victoria.Votokina@kaspersky.com>
Link: https://patch.msgid.link/20260203113158.2008723-1-Victoria.Votokina@kaspersky.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
A deadlock can occur between nfc_unregister_device() and rfkill_fop_write()
due to lock ordering inversion between device_lock and rfkill_global_mutex.
The problematic lock order is:
Thread A (rfkill_fop_write):
rfkill_fop_write()
mutex_lock(&rfkill_global_mutex)
rfkill_set_block()
nfc_rfkill_set_block()
nfc_dev_down()
device_lock(&dev->dev) <- waits for device_lock
Thread B (nfc_unregister_device):
nfc_unregister_device()
device_lock(&dev->dev)
rfkill_unregister()
mutex_lock(&rfkill_global_mutex) <- waits for rfkill_global_mutex
This creates a classic ABBA deadlock scenario.
Fix this by moving rfkill_unregister() and rfkill_destroy() outside the
device_lock critical section. Store the rfkill pointer in a local variable
before releasing the lock, then call rfkill_unregister() after releasing
device_lock.
This change is safe because rfkill_fop_write() holds rfkill_global_mutex
while calling the rfkill callbacks, and rfkill_unregister() also acquires
rfkill_global_mutex before cleanup. Therefore, rfkill_unregister() will
wait for any ongoing callback to complete before proceeding, and
device_del() is only called after rfkill_unregister() returns, preventing
any use-after-free.
The similar lock ordering in nfc_register_device() (device_lock ->
rfkill_global_mutex via rfkill_register) is safe because during
registration the device is not yet in rfkill_list, so no concurrent
rfkill operations can occur on this device.
Fixes: 3e3b5dfcd1 ("NFC: reorder the logic in nfc_{un,}register_device")
Cc: stable@vger.kernel.org
Reported-by: syzbot+4ef89409a235d804c6c2@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=4ef89409a235d804c6c2
Link: https://lore.kernel.org/all/20251217054908.178907-1-kartikey406@gmail.com/T/ [v1]
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Link: https://patch.msgid.link/20251218012355.279940-1-kartikey406@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Update all struct proto_ops connect() callback function prototypes from
"struct sockaddr *" to "struct sockaddr_unsized *" to avoid lying to the
compiler about object sizes. Calls into struct proto handlers gain casts
that will be removed in the struct proto conversion patch.
No binary changes expected.
Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20251104002617.2752303-3-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Update all struct proto_ops bind() callback function prototypes from
"struct sockaddr *" to "struct sockaddr_unsized *" to avoid lying to the
compiler about object sizes. Calls into struct proto handlers gain casts
that will be removed in the struct proto conversion patch.
No binary changes expected.
Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20251104002617.2752303-2-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Syzbot reported an uninitialized value bug in nci_init_req, which was
introduced by commit 5aca7966d2 ("Merge tag
'perf-tools-fixes-for-v6.17-2025-09-16' of
git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools").
This bug arises due to very limited and poor input validation
that was done at nic_valid_size(). This validation only
validates the skb->len (directly reflects size provided at the
userspace interface) with the length provided in the buffer
itself (interpreted as NCI_HEADER). This leads to the processing
of memory content at the address assuming the correct layout
per what opcode requires there. This leads to the accesses to
buffer of `skb_buff->data` which is not assigned anything yet.
Following the same silent drop of packets of invalid sizes at
`nic_valid_size()`, add validation of the data in the respective
handlers and return error values in case of failure. Release
the skb if error values are returned from handlers in
`nci_nft_packet` and effectively do a silent drop
Possible TODO: because we silently drop the packets, the
call to `nci_request` will be waiting for completion of request
and will face timeouts. These timeouts can get excessively logged
in the dmesg. A proper handling of them may require to export
`nci_request_cancel` (or propagate error handling from the
nft packets handlers).
Reported-by: syzbot+740e04c2a93467a0f8c8@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=740e04c2a93467a0f8c8
Fixes: 6a2968aaf5 ("NFC: basic NCI protocol implementation")
Tested-by: syzbot+740e04c2a93467a0f8c8@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Deepak Sharma <deepak.sharma.472935@gmail.com>
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Link: https://patch.msgid.link/20250925132846.213425-1-deepak.sharma.472935@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Setting tty->disc_data before opening the NCI device means we need to
clean it up on error paths. This also opens some short window if device
starts sending data, even before NCIUARTSETDRIVER IOCTL succeeded
(broken hardware?). Close the window by exposing tty->disc_data only on
the success path, when opening of the NCI device and try_module_get()
succeeds.
The code differs in error path in one aspect: tty->disc_data won't be
ever assigned thus NULL-ified. This however should not be relevant
difference, because of "tty->disc_data=NULL" in nci_uart_tty_open().
Cc: Linus Torvalds <torvalds@linuxfoundation.org>
Fixes: 9961127d4b ("NFC: nci: add generic uart support")
Cc: <stable@vger.kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20250618073649.25049-2-krzysztof.kozlowski@linaro.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The implementation of nla_data is as follows:
static inline void *nla_data(const struct nlattr *nla)
{
return (char *) nla + NLA_HDRLEN;
}
Excluding the case where nla is exactly -NLA_HDRLEN, it will not return
NULL. And it seems misleading to assume that it can, other than in this
corner case. So drop checks for this condition.
Flagged by Smatch.
Compile tested only.
Signed-off-by: Simon Horman <horms@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/20250617-nfc-null-data-v1-1-c7525ead2e95@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
