Bluetooth: qca: fix NVM tag length underflow in TLV parser

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: qca: fix NVM tag length underflow in TLV parser In the TLV_TYPE_NVM branch of qca_tlv_check_data() the tag loop bound is "while (idx < length - sizeof(struct tlv_type_nvm))". "length" is a signed int from the firmware TLV header and sizeof(struct tlv_type_nvm) is a size_t (12), so "length" is converted to size_t and any firmware-supplied "length" < 12 makes the subtraction wrap to a huge value. The loop body then reads a 12-byte struct tlv_type_nvm past the end of the short vmalloc'd firmware buffer (and the EDL_TAG_ID_* handlers can write past it). Rewrite the bound as "idx + sizeof(struct tlv_type_nvm) <= length"; both operands are non-negative, so it no longer underflows and a "length" too small for one record correctly skips the loop. BUG: KASAN: vmalloc-out-of-bounds in qca_download_firmware.isra.0 (drivers/bluetooth/btqca.c:421) Read of size 2 at addr ffffc900000e5004 by task kworker/u9:0/52 Workqueue: hci0 hci_power_on Call Trace: ... kasan_report (mm/kasan/report.c:595) qca_download_firmware.isra.0 (drivers/bluetooth/btqca.c:421 drivers/bluetooth/btqca.c:617) qca_uart_setup (drivers/bluetooth/btqca.c:948) qca_setup (drivers/bluetooth/hci_qca.c:2029) hci_uart_setup (drivers/bluetooth/hci_ldisc.c:438) hci_dev_open_sync (net/bluetooth/hci_sync.c:5227) hci_power_on (net/bluetooth/hci_core.c:920) process_one_work (kernel/workqueue.c:3322) worker_thread (kernel/workqueue.c:3486) kthread (kernel/kthread.c:436) ret_from_fork (arch/x86/kernel/process.c:158) ret_from_fork_asm (arch/x86/entry/entry_64.S:245)

Where it's fixed