From: Erni Sri Satya Vennela <ernis@linux•microsoft.com>
To: kys@microsoft•com, haiyangz@microsoft•com, wei.liu@kernel•org,
decui@microsoft•com, longli@microsoft•com, andrew+netdev@lunn•ch,
davem@davemloft•net, edumazet@google•com, kuba@kernel•org,
pabeni@redhat•com, ernis@linux•microsoft.com,
ssengar@linux•microsoft.com, dipayanroy@linux•microsoft.com,
gargaditya@linux•microsoft.com, shirazsaleem@microsoft•com,
kees@kernel•org, linux-hyperv@vger•kernel.org,
netdev@vger•kernel.org, linux-kernel@vger•kernel.org
Subject: [PATCH net-next] net: mana: hardening: Validate adapter_mtu from MANA_QUERY_DEV_CONFIG
Date: Thu, 26 Mar 2026 10:30:56 -0700 [thread overview]
Message-ID: <20260326173101.2010514-1-ernis@linux.microsoft.com> (raw)
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>
---
drivers/net/ethernet/microsoft/mana/mana_en.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
index b39e8b920791..bd07d17a6017 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_en.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
@@ -1207,10 +1207,16 @@ static int mana_query_device_cfg(struct mana_context *ac, u32 proto_major_ver,
*max_num_vports = resp.max_num_vports;
- if (resp.hdr.response.msg_version >= GDMA_MESSAGE_V2)
+ if (resp.hdr.response.msg_version >= GDMA_MESSAGE_V2) {
+ if (resp.adapter_mtu < ETH_MIN_MTU + ETH_HLEN) {
+ dev_err(dev, "Adapter MTU too small: %u\n",
+ resp.adapter_mtu);
+ return -EPROTO;
+ }
gc->adapter_mtu = resp.adapter_mtu;
- else
+ } else {
gc->adapter_mtu = ETH_FRAME_LEN;
+ }
if (resp.hdr.response.msg_version >= GDMA_MESSAGE_V3)
*bm_hostmode = resp.bm_hostmode;
--
2.34.1
next reply other threads:[~2026-03-26 17:31 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-26 17:30 Erni Sri Satya Vennela [this message]
2026-03-31 9:28 ` [PATCH net-next] net: mana: hardening: Validate adapter_mtu from MANA_QUERY_DEV_CONFIG Paolo Abeni
2026-03-31 18:00 ` Erni Sri Satya Vennela
2026-04-01 3:20 ` patchwork-bot+netdevbpf
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260326173101.2010514-1-ernis@linux.microsoft.com \
--to=ernis@linux$(echo .)microsoft.com \
--cc=andrew+netdev@lunn$(echo .)ch \
--cc=davem@davemloft$(echo .)net \
--cc=decui@microsoft$(echo .)com \
--cc=dipayanroy@linux$(echo .)microsoft.com \
--cc=edumazet@google$(echo .)com \
--cc=gargaditya@linux$(echo .)microsoft.com \
--cc=haiyangz@microsoft$(echo .)com \
--cc=kees@kernel$(echo .)org \
--cc=kuba@kernel$(echo .)org \
--cc=kys@microsoft$(echo .)com \
--cc=linux-hyperv@vger$(echo .)kernel.org \
--cc=linux-kernel@vger$(echo .)kernel.org \
--cc=longli@microsoft$(echo .)com \
--cc=netdev@vger$(echo .)kernel.org \
--cc=pabeni@redhat$(echo .)com \
--cc=shirazsaleem@microsoft$(echo .)com \
--cc=ssengar@linux$(echo .)microsoft.com \
--cc=wei.liu@kernel$(echo .)org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox