[PATCH 3/4] vdpa: Add max vqp attr to vdpa_nl_policy for nlattr length check

[Dragos Tatulea]

From: Lin Ma <linma@xxxxxxxxxx>

The vdpa_nl_policy structure is used to validate the nlattr when parsing
the incoming nlmsg. It will ensure the attribute being described produces
a valid nlattr pointer in info->attrs before entering into each handler
in vdpa_nl_ops.

That is to say, the missing part in vdpa_nl_policy may lead to illegal
nlattr after parsing, which could lead to OOB read just like CVE-2023-3773.

This patch adds the missing nla_policy for vdpa max vqp attr to avoid
such bugs.

Fixes: ad69dd0bf26b ("vdpa: Introduce query of device config layout")
Signed-off-by: Lin Ma <linma@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
 drivers/vdpa/vdpa.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index 75f1df2b9d2a..f2f654fd84e5 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -1247,6 +1247,7 @@ static const struct nla_policy vdpa_nl_policy[VDPA_ATTR_MAX + 1] = {
 	[VDPA_ATTR_MGMTDEV_DEV_NAME] = { .type = NLA_STRING },
 	[VDPA_ATTR_DEV_NAME] = { .type = NLA_STRING },
 	[VDPA_ATTR_DEV_NET_CFG_MACADDR] = NLA_POLICY_ETH_ADDR,
+	[VDPA_ATTR_DEV_NET_CFG_MAX_VQP] = { .type = NLA_U16 },
 	/* virtio spec 1.1 section 5.1.4.1 for valid MTU range */
 	[VDPA_ATTR_DEV_NET_CFG_MTU] = NLA_POLICY_MIN(NLA_U16, 68),
 	[VDPA_ATTR_DEV_QUEUE_INDEX] = { .type = NLA_U32 },
-- 
2.41.0