net: mana: hardening: Validate adapter_mtu from MANA_QUERY_DEV_CONFIG

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As a part of MANA hardening for CVM, validate the adapter_mtu value
returned from the MANA_QUERY_DEV_CONFIG HWC command.

The adapter_mtu value is used to compute ndev->max_mtu via:
gc->adapter_mtu - ETH_HLEN. If hardware returns a bogus adapter_mtu
smaller than ETH_HLEN (e.g. 0), the unsigned subtraction wraps to a
huge value, silently allowing oversized MTU settings.

Add a validation check to reject adapter_mtu values below
ETH_MIN_MTU + ETH_HLEN, returning -EPROTO to fail the device
configuration early with a clear error message.

Signed-off-by: Erni Sri Satya Vennela <ernis@linux.microsoft.com>
Link: https://patch.msgid.link/20260326173101.2010514-1-ernis@linux.microsoft.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

...

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Erni Sri Satya Vennela 2026-03-26 10:30:56 -07:00 • committed by Jakub Kicinski

parent e5a3f10ed7

commit d7709812e1

1 changed files with 8 additions and 2 deletions

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10

drivers/net/ethernet/microsoft/mana/mana_en.c

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