CVE-2026-80796: nfc: nci: add data_len bound checks to activation parameter extractors

CVE-2026-80796: nfc: nci: add data_len bound checks to activation parameter extractors

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

nfc: nci: add data_len bound checks to activation parameter extractors

nci_extract_activation_params_iso_dep() and
nci_extract_activation_params_nfc_dep() read an inner length byte from
the NCI RF_INTF_ACTIVATED_NTF payload and use it to memcpy() into fixed
kernel buffers, but neither function receives the caller-validated
activation_params_len.  A crafted NCI notification with
activation_params_len=1 and an inner length byte of up to 20 (NFC-A) or
50 (NFC-B) causes memcpy() to read that many bytes past the one valid
byte in the activation params region -- a slab out-of-bounds read of
kernel memory adjacent to the NCI skb.

The sibling nci_extract_rf_params_*() family was given equivalent
protection by commit 571dcbeb8e63 ("net: nfc: nci: Fix parameter
validation for packet data"), but the two activation parameter
extractors were not updated at that time.

Add a data_len parameter to both functions, guard against an empty
region before consuming the inner length byte, decrement the remaining
count after consuming it, and clamp the copy length to what is actually
available.  Update both call sites to pass ntf.activation_params_len,
which is already validated against the skb at ntf.c:801.

The Linux kernel CVE team has assigned CVE-2026-80796 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 3.3 with commit e8c0dacd9836dc2dcb28d236c9cc3cfaa9965a20 and fixed in 5.10.269 with commit 1168484fe2b3828bf24a46f3c42a8719fade679b
	Issue introduced in 3.3 with commit e8c0dacd9836dc2dcb28d236c9cc3cfaa9965a20 and fixed in 5.15.220 with commit be311c0cfeadfbe815ea22d2914a98d06e3fab0e
	Issue introduced in 3.3 with commit e8c0dacd9836dc2dcb28d236c9cc3cfaa9965a20 and fixed in 6.1.187 with commit 04e51353cb9fa321caaeeed8331d4cd041fbaca7
	Issue introduced in 3.3 with commit e8c0dacd9836dc2dcb28d236c9cc3cfaa9965a20 and fixed in 6.6.156 with commit e25b44bd8b8cc666b49a3fe0ef547e64d5b1e300
	Issue introduced in 3.3 with commit e8c0dacd9836dc2dcb28d236c9cc3cfaa9965a20 and fixed in 6.12.108 with commit 9b01f5af0dc59263b59391b148bc78d83c0354a9
	Issue introduced in 3.3 with commit e8c0dacd9836dc2dcb28d236c9cc3cfaa9965a20 and fixed in 6.18.47 with commit 9620a91f8d643b680f417a435db399a04d1e06d8
	Issue introduced in 3.3 with commit e8c0dacd9836dc2dcb28d236c9cc3cfaa9965a20 and fixed in 7.1.11 with commit cf9d44be50b9074a5abdc301b4a3ba3e283591df
	Issue introduced in 3.3 with commit e8c0dacd9836dc2dcb28d236c9cc3cfaa9965a20 and fixed in 7.2.1 with commit f5c534b53f8c424a8e7633c9b585475c4bf4ee18
	Issue introduced in 3.3 with commit e8c0dacd9836dc2dcb28d236c9cc3cfaa9965a20 and fixed in 7.3-rc1 with commit 0428fa2c22e2ba0cff766d3b80d461e149102045

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-80796
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	net/nfc/nci/ntf.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/1168484fe2b3828bf24a46f3c42a8719fade679b
	https://git.kernel.org/stable/c/be311c0cfeadfbe815ea22d2914a98d06e3fab0e
	https://git.kernel.org/stable/c/04e51353cb9fa321caaeeed8331d4cd041fbaca7
	https://git.kernel.org/stable/c/e25b44bd8b8cc666b49a3fe0ef547e64d5b1e300
	https://git.kernel.org/stable/c/9b01f5af0dc59263b59391b148bc78d83c0354a9
	https://git.kernel.org/stable/c/9620a91f8d643b680f417a435db399a04d1e06d8
	https://git.kernel.org/stable/c/cf9d44be50b9074a5abdc301b4a3ba3e283591df
	https://git.kernel.org/stable/c/f5c534b53f8c424a8e7633c9b585475c4bf4ee18
	https://git.kernel.org/stable/c/0428fa2c22e2ba0cff766d3b80d461e149102045