CVE-2024-44933

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

bnxt_en : Fix memory out-of-bounds in bnxt_fill_hw_rss_tbl()

A recent commit has modified the code in __bnxt_reserve_rings() to

set the default RSS indirection table to default only when the number

of RX rings is changing. While this works for newer firmware that

requires RX ring reservations, it causes the regression on older

firmware not requiring RX ring resrvations (BNXT_NEW_RM() returns

false).

With older firmware, RX ring reservations are not required and so

hw_resc->resv_rx_rings is not always set to the proper value. The

comparison:

if (old_rx_rings != bp->hw_resc.resv_rx_rings)

in __bnxt_reserve_rings() may be false even when the RX rings are

changing. This will cause __bnxt_reserve_rings() to skip setting

the default RSS indirection table to default to match the current

number of RX rings. This may later cause bnxt_fill_hw_rss_tbl() to

use an out-of-range index.

We already have bnxt_check_rss_tbl_no_rmgr() to handle exactly this

scenario. We just need to move it up in bnxt_need_reserve_rings()

to be called unconditionally when using older firmware. Without the

fix, if the TX rings are changing, we'll skip the

bnxt_check_rss_tbl_no_rmgr() call and __bnxt_reserve_rings() may also

skip the bnxt_set_dflt_rss_indir_tbl() call for the reason explained

in the last paragraph. Without setting the default RSS indirection

table to default, it causes the regression:

BUG: KASAN: slab-out-of-bounds in __bnxt_hwrm_vnic_set_rss+0xb79/0xe40

Read of size 2 at addr ffff8881c5809618 by task ethtool/31525

Call Trace:

__bnxt_hwrm_vnic_set_rss+0xb79/0xe40

bnxt_hwrm_vnic_rss_cfg_p5+0xf7/0x460

__bnxt_setup_vnic_p5+0x12e/0x270

__bnxt_open_nic+0x2262/0x2f30

bnxt_open_nic+0x5d/0xf0

ethnl_set_channels+0x5d4/0xb30

ethnl_default_set_doit+0x2f1/0x620