nfc: fdp: bound the device-reported read length and fix an skb leak

fdp_nci_i2c_read() takes the next packet length from two device-supplied
bytes and never validates it. The value is a u16 used as the
i2c_master_recv() count into a 261-byte on-stack buffer: a malicious,
counterfeit or malfunctioning controller (or an i2c bus interposer) can
drive it far past the buffer for a stack out-of-bounds write that
clobbers the canary and return address, or below the minimum frame size
(directly, or by truncating the computed sum) so the header/LRC strip
and the next length read run past a short receive. Reject a length
outside [FDP_NCI_I2C_MIN_PAYLOAD, FDP_NCI_I2C_MAX_PAYLOAD], as a
corrupted packet already is, and force resynchronization.

The same loop allocates one data skb per iteration and assumes a length
packet followed by a data packet; a device that sends two data packets
in one call leaks the first skb when the second allocation overwrites
it. Free a previously allocated skb before allocating the next.

Fixes: a06347c04c13 ("NFC: Add Intel Fields Peak NFC solution driver")
Cc: stable@vger.kernel.org
Suggested-by: Simon Horman <horms@kernel.org>
Signed-off-by: Bryam Vargas <hexlabsecurity@proton.me>
Link: https://patch.msgid.link/20260616-b4-disp-b1f8ab4c-v2-1-2d1fe5955325@proton.me
Signed-off-by: David Heidelberg <david@ixit.cz>

0 files changed, 0 insertions, 0 deletions