nfc: llcp: read llcp_sock->local under the socket lock in getsockopt

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nfc_llcp_getsockopt() read llcp_sock->local before lock_sock(sk) and
then dereferenced the cached pointer inside the locked region.
llcp_sock_bind() assigns and clears llcp_sock->local under the same
socket lock, dropping the last reference on its error path. A
getsockopt() racing an in-flight bind() can observe the pointer, block
on lock_sock(), and then dereference a freed nfc_llcp_local once bind()
has unwound.

Move the llcp_sock->local read and the NULL check inside the
lock_sock(sk) region so bind() cannot mutate or free the pointer between
the load and the use.

Fixes: 26fd76cab2 ("NFC: llcp: Implement socket options")
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260521-fix_llc-v2-2-ab44cc09179c@debian.org
Signed-off-by: David Heidelberg <david@ixit.cz>

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Breno Leitao 2026-05-21 07:32:10 -07:00 • committed by David Heidelberg

parent 99985bfa83

commit 3681252705

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1 changed files with 6 additions and 4 deletions

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net/nfc/llcp_sock.c

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