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  1. Dec 28, 2023
  3. Dec 27, 2023
  5. Dec 25, 2023
    • David S. Miller's avatar
      Merge branch 'nfc-refcounting' · dff90e4a
      David S. Miller authored 
      

@ 2023-12-19 17:49 Siddh Raman Pant
  2023-12-19 17:49 ` [PATCH net-next v7 1/2] nfc: llcp_core: Hold a ref to llcp_local->dev when holding a ref to llcp_local Siddh Raman Pant
  2023-12-19 17:49 ` [PATCH net-next v7 2/2] nfc: Do not send datagram if socket state isn't LLCP_BOUND Siddh Raman Pant
  0 siblings, 2 replies; 4+ messages in thread
Siddh Raman Pant says:

====================
[PATCH net-next v7 0/2] nfc: Fix UAF during datagram sending caused by missing refcounting

Changes in v7:
- Stupidly reverted ordering in recv() too, fix that.
- Remove redundant call to nfc_llcp_sock_free().

Changes in v6:
- Revert label introduction from v4, and thus also v5 entirely.

Changes in v5:
- Move reason = LLCP_DM_REJ under the fail_put_sock label.
- Checkpatch now warns about == NULL check for new_sk, so fix that,
  and also at other similar places in the same function.

Changes in v4:
- Fix put ordering and comments.
- Separate freeing in recv() into end labels.
- Remove obvious comment and add reasoning.
- Picked up r-bs by Suman.

Changes in v3:
- Fix missing freeing statements.

Changes in v2:
- Add net-next in patch subject.
- Removed unnecessary extra lock and hold nfc_dev ref when holding llcp_sock.
- Remove last formatting patch.
- Picked up r-b from Krzysztof for LLCP_BOUND patch.

---

For connectionless transmission, llcp_sock_sendmsg() codepath will
eventually call nfc_alloc_send_skb() which takes in an nfc_dev as
an argument for calculating the total size for skb allocation.

virtual_ncidev_close() codepath eventually releases socket by calling
nfc_llcp_socket_release() (which sets the sk->sk_state to LLCP_CLOSED)
and afterwards the nfc_dev will be eventually freed.

When an ndev gets freed, llcp_sock_sendmsg() will result in an
use-after-free as it

(1) doesn't have any checks in place for avoiding the datagram sending.

(2) calls nfc_llcp_send_ui_frame(), which also has a do-while loop
    which can race with freeing. This loop contains the call to
    nfc_alloc_send_skb() where we dereference the nfc_dev pointer.

nfc_dev is being freed because we do not hold a reference to it when
we hold a reference to llcp_local. Thus, virtual_ncidev_close()
eventually calls nfc_release() due to refcount going to 0.

Since state has to be LLCP_BOUND for datagram sending, we can bail out
early in llcp_sock_sendmsg().

Please review and let me know if any errors are there, and hopefully
this gets accepted.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      dff90e4a
    • Siddh Raman Pant's avatar
      nfc: Do not send datagram if socket state isn't LLCP_BOUND · 6ec0d752
      Siddh Raman Pant authored 
      

As we know we cannot send the datagram (state can be set to LLCP_CLOSED
by nfc_llcp_socket_release()), there is no need to proceed further.

Thus, bail out early from llcp_sock_sendmsg().

Signed-off-by: default avatarSiddh Raman Pant <code@siddh.me>
Reviewed-by: default avatarKrzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: default avatarSuman Ghosh <sumang@marvell.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      6ec0d752
    • Siddh Raman Pant's avatar
      nfc: llcp_core: Hold a ref to llcp_local->dev when holding a ref to llcp_local · c95f9195
      Siddh Raman Pant authored 
      

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: default avatar <syzbot+bbe84a4010eeea00982d@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=bbe84a4010eeea00982d
Fixes: c7aa1225

 ("NFC: Take a reference on the LLCP local pointer when creating a socket")
Reviewed-by: default avatarSuman Ghosh <sumang@marvell.com>
Signed-off-by: default avatarSiddh Raman Pant <code@siddh.me>
Reviewed-by: default avatarKrzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      c95f9195
  7. Dec 22, 2023
    • Linus Torvalds's avatar
      Merge tag 'net-6.7-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net · 7c5e046b
      Linus Torvalds authored 
      Pull networking fixes from Paolo Abeni:
 "Including fixes from WiFi and bpf.

  Current release - regressions:

   - bpf: syzkaller found null ptr deref in unix_bpf proto add

   - eth: i40e: fix ST code value for clause 45

  Previous releases - regressions:

   - core: return error from sk_stream_wait_connect() if sk_wait_event()
     fails

   - ipv6: revert remove expired routes with a separated list of routes

   - wifi rfkill:
       - set GPIO direction
       - fix crash with WED rx support enabled

   - bluetooth:
       - fix deadlock in vhci_send_frame
       - fix use-after-free in bt_sock_recvmsg

   - eth: mlx5e: fix a race in command alloc flow

   - eth: ice: fix PF with enabled XDP going no-carrier after reset

   - eth: bnxt_en: do not map packet buffers twice

  Previous releases - always broken:

   - core:
       - check vlan filter feature in vlan_vids_add_by_dev() and
         vlan_vids_del_by_dev()
       - check dev->gso_max_size in gso_features_check()

   - mptcp: fix inconsistent state on fastopen race

   - phy: skip LED triggers on PHYs on SFP modules

   - eth: mlx5e:
       - fix double free of encap_header
       - fix slab-out-of-bounds in mlx5_query_nic_vport_mac_list()"

* tag 'net-6.7-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (69 commits)
  net: check dev->gso_max_size in gso_features_check()
  kselftest: rtnetlink.sh: use grep_fail when expecting the cmd fail
  net/ipv6: Revert remove expired routes with a separated list of routes
  net: avoid build bug in skb extension length calculation
  net: ethernet: mtk_wed: fix possible NULL pointer dereference in mtk_wed_wo_queue_tx_clean()
  net: stmmac: fix incorrect flag check in timestamp interrupt
  selftests: add vlan hw filter tests
  net: check vlan filter feature in vlan_vids_add_by_dev() and vlan_vids_del_by_dev()
  net: hns3: add new maintainer for the HNS3 ethernet driver
  net: mana: select PAGE_POOL
  net: ks8851: Fix TX stall caused by TX buffer overrun
  ice: Fix PF with enabled XDP going no-carrier after reset
  ice: alter feature support check for SRIOV and LAG
  ice: stop trashing VF VSI aggregator node ID information
  mailmap: add entries for Geliang Tang
  mptcp: fill in missing MODULE_DESCRIPTION()
  mptcp: fix inconsistent state on fastopen race
  selftests: mptcp: join: fix subflow_send_ack lookup
  net: phy: skip LED triggers on PHYs on SFP modules
  bpf: Add missing BPF_LINK_TYPE invocations
  ...
      7c5e046b
  9. Dec 21, 2023
  11. Dec 20, 2023