bnxt_en: Bound SW TPA IDs to prevent crashes

Summary

In the Linux kernel, the following vulnerability has been resolved: bnxt_en: Bound SW TPA IDs to prevent crashes FW supports up to 1024 concurrent TPAs, so the FW TPA ID is in the range 0..1023 (see commit ec4d8e7cf024 ("bnxt_en: Add TPA ID mapping logic for 57500 chips.")). bnxt_alloc_agg_idx is intended to wrap the FW ID down to a software ID which is used to index rxr->rx_tpa, and to generate a mapping between FW IDs and the wrapped software ID. On a 57608 with firmware version 233, the firmware advertises 32 concurrent TPAs. As of the commit under fixes, bp->max_tpa on this NIC is set to 32. If the software ID from bnxt_alloc_agg_idx is above 31, this results in an invalid address being loaded on this line: tpa_info = &rxr->rx_tpa[agg_id]; because rx_tpa is allocated with only bp->max_tpa (32) entries. Writes to tpa_info later in the code are out of bounds. This bug results in a crash at boot: Oops: general protection fault, kernel NULL pointer dereference 0x8: 0000 [#1] SMP NOPTI RIP: 0010:bnxt_rx_pkt+0xc0/0x1560 RSP: 0018:ffffc900009b8c78 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000048 RCX: 0000000206682516 RDX: ffffc900009b8db4 RSI: 0000000000000000 RDI: 01ffffff038fe1c0 RBP: ffffc9006e687480 R08: ffffc9006e687000 R09: 0000000000003048 R10: 0000000000000480 R11: ffff8881c6083900 R12: 0000000006682516 R13: ffff8881c6095400 R14: 0000000000000016 R15: ffff8881c6b66680 FS: 0000000000000000(0000) GS:ffff88fef3c77000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc8bda40584 CR3: 000000807c812001 CR4: 0000000008772ef0 PKRU: 55555554 Call Trace: <IRQ> ? __netif_receive_skb_list_core+0x1ca/0x250 __bnxt_poll_work+0x152/0x280 bnxt_poll_p5+0x1cd/0x480 __napi_poll+0x30/0x180 net_rx_action+0x20b/0x3b0 ? note_gp_changes+0x53/0xe0 ? tick_setup_sched_timer+0x180/0x180 ? __napi_schedule+0x9a/0xb0 ? bnxt_msix+0x24/0x30 handle_softirqs+0xdd/0x2c0 __irq_exit_rcu.llvm.3171231171502365008+0x47/0xf0 common_interrupt+0x85/0x90 </IRQ> <TASK> asm_common_interrupt+0x22/0x40 This stack trace is from a crash triggered when an out of bounds rx_tpa is dereferenced. The invalid write mentioned above is silent in this particular crash. Fix this by allocating rx_tpa with bp->max_tpa rounded up to the next power of 2 (bp->max_tpa_roundup_size) entries and masking the FW TPA ID with that size, so the wrapped ID can never index past the end of the array.