[PATCH net] nfc: llcp: fix UAF on socket in nfc_llcp_tx_work()
Eric Dumazet <[email protected]>
| Newsgroups | dev.linux.lists.oe-linux-nfc,org.kernel.vger.netdev |
|---|---|
| Message-ID | <[email protected]> |
Shuangpeng Bai reported a slab-use-after-free in nfc_llcp_tx_work():
BUG: KASAN: slab-use-after-free in _raw_spin_lock_irqsave
Write of size 4 at addr ffff88811da9cb94 by task kworker/0:0/9
Call Trace:
_raw_spin_lock_irqsave (kernel/locking/spinlock.c:166)
skb_queue_tail (net/core/skbuff.c:4114)
nfc_llcp_tx_work (net/nfc/llcp_core.c:848)
When transmitting an I-frame, nfc_llcp_tx_work() creates a copy via
skb_copy() to keep in tx_pending_queue. If the socket is closed
concurrently, freeing the original skb during nfc_data_exchange()
drops sk_wmem_alloc to 0 and destroys the socket before copy_skb is
queued to llcp_sock->tx_pending_queue.
Call skb_set_owner_w(copy_skb, sk) to keep the socket alive while
copy_skb is queued.
Fixes: be02b6b62400 ("NFC: Queue a copy of the transmitted LLCP skb")
Reported-by: Shuangpeng Bai <[email protected]>
Closes: https://lore.kernel.org/netdev/[email protected]/
Signed-off-by: Eric Dumazet <[email protected]>
---
Cc: David Heidelberg <[email protected]>
Cc: [email protected]
---
net/nfc/llcp_core.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/net/nfc/llcp_core.c b/net/nfc/llcp_core.c
index cac1b5487064d0c5b4966bb6a75aa26e67131049..49cb632268c0c2841e3b44dde124c7966267b709 100644
--- a/net/nfc/llcp_core.c
+++ b/net/nfc/llcp_core.c
@@ -786,8 +786,11 @@ static void nfc_llcp_tx_work(struct work_struct *work)
print_hex_dump_debug("LLCP Tx: ", DUMP_PREFIX_OFFSET,
16, 1, skb->data, skb->len, true);
- if (ptype == LLCP_PDU_I)
+ if (ptype == LLCP_PDU_I) {
copy_skb = skb_copy(skb, GFP_ATOMIC);
+ if (copy_skb)
+ skb_set_owner_w(copy_skb, sk);
+ }
__net_timestamp(skb);
--
2.55.0.766.g2966f0265a-goog