nfc: nci: fix uninit-value in the RF discover/activated NTF handlers

Overview

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

nfc: nci: fix uninit-value in the RF discover/activated NTF handlers

nci_rf_discover_ntf_packet() and nci_rf_intf_activated_ntf_packet() each parse a notification into an on-stack struct (nci_rf_discover_ntf / nci_rf_intf_activated_ntf) that is not initialised. The RF technology-specific parameters are only extracted when rf_tech_specific_params_len is non-zero, so a notification that reports a zero length leaves the rf_tech_specific_params union uninitialised - and both handlers then pass it to nci_add_new_protocol(), which reads it:

• discover: nci_add_new_target() -> nci_add_new_protocol();
• activated: nci_target_auto_activated() -> nci_add_new_protocol().

nci_add_new_protocol() uses nfca_poll->nfcid1_len as both a branch condition and a memcpy() length and copies nfcid1/sens_res/sel_res into ndev->targets, which is later exposed to user space via NFC_CMD_GET_TARGET.

BUG: KMSAN: uninit-value in nci_add_new_protocol+0x624/0x6c0 nci_add_new_protocol+0x624/0x6c0 nci_ntf_packet+0x25b2/0x3c30 nci_rx_work+0x318/0x5d0 process_scheduled_works+0x84b/0x17a0 worker_thread+0xc10/0x11b0 kthread+0x376/0x500 Local variable ntf.i created at: nci_ntf_packet+0xbc2/0x3c30

Zero-initialise both on-stack notifications so the union reads back as zero when no technology-specific parameters are present.

Affected

• Linux >= e8c0dacd9836dc2dcb28d236c9cc3cfaa9965a20 < 1007a6b429d756513abd25bd00290908f2e89a4a
• Linux >= e8c0dacd9836dc2dcb28d236c9cc3cfaa9965a20 < 4bda9ef8392710f21e99027467f3f4afdfb5c99a
• Linux >= e8c0dacd9836dc2dcb28d236c9cc3cfaa9965a20 < fe69fed3495f676578d49414a069ad7d8468e2ce
• Linux >= e8c0dacd9836dc2dcb28d236c9cc3cfaa9965a20 < 7489f59d1ea2d3298aa41de7baf193e5e6e132f6
• Linux >= e8c0dacd9836dc2dcb28d236c9cc3cfaa9965a20 < 7086dab72b3ed95df96842801e10e935cfeb27a3
• Linux >= e8c0dacd9836dc2dcb28d236c9cc3cfaa9965a20 < 0d4b5cfab6891a5ca0f6aef209beebba4bd7c095
• Linux >= e8c0dacd9836dc2dcb28d236c9cc3cfaa9965a20 < 5bd00c0e1470d90d77a7c60242854257ddf14e00
• Linux >= e8c0dacd9836dc2dcb28d236c9cc3cfaa9965a20 < d6f743d3d388913135681cde051c08823730194f
• Linux >= e8c0dacd9836dc2dcb28d236c9cc3cfaa9965a20 < 8cbe06c1e699c0a165dae5093a2550e65f914818
• Linux 3.3

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.