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.

Fixes: 54c28fab2fa5 ("bnxt_en: Set bp->max_tpa according to what the FW supports")
Reported-by: Raphael Cardoso Fernandes <raphaelcf@meta.com>
Suggested-by: Michael Chan <michael.chan@broadcom.com>
Cc: stable@vger.kernel.org
Signed-off-by: Joe Damato <joe@dama.to>
Link: https://patch.msgid.link/20260902015652.2421609-7-joe@dama.to
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

0 files changed, 0 insertions, 0 deletions