nfc: llcp: fix slab-out-of-bounds reads when logging service names

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nfc_llcp_wks_sap() and nfc_llcp_build_sdreq_tlv() pass non-null-
terminated strings to pr_debug() using the %s format specifier.
The buffers are allocated via kmemdup() or come from netlink
attributes and are not guaranteed to be null-terminated, causing
__dynamic_pr_debug() to read beyond the allocated region:

  KASAN: slab-out-of-bounds Read in __dynamic_pr_debug

Fix both call sites by using %.*s with the explicit length to limit
the output to the actual length of the string.

Fixes: d9b8d8e19b ("NFC: llcp: Service Name Lookup netlink interface")
Reported-by: syzbot+1e3df0852e82c21ca418@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=1e3df0852e82c21ca418
Signed-off-by: Ömer Mete Kaya <omermetekaya0@gmail.com>
Link: https://patch.msgid.link/20260908161952.731468-1-omermetekaya0@gmail.com
Signed-off-by: David Heidelberg <david@ixit.cz>

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Ömer Mete Kaya 2026-09-08 19:18:01 +03:00 • committed by David Heidelberg

parent 408cff6bd6

commit 7dcf371a35

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net/nfc/llcp_commands.c

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2

net/nfc/llcp_core.c

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