net: ethtool: avoid OOB accesses in PAUSE_SET

We now reuse .parse_request() from GET on SET, so we need to make sure
that the policies for both cover the attributes used for .parse_request().
genetlink will only allocate space in info->attrs for ARRAY_SIZE(policy).

Reported-by: [e-mail]
Fixes: 963781bdfe20 ("net: ethtool: call .parse_request for SET handlers")
Reviewed-by: Ido Schimmel <[e-mail]>
Tested-by: Ido Schimmel <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

net/ethtool/netlink.h

···
 extern const struct nla_policy ethnl_coalesce_get_policy[ETHTOOL_A_COALESCE_HEADER + 1];
 extern const struct nla_policy ethnl_coalesce_set_policy[ETHTOOL_A_COALESCE_MAX + 1];
 extern const struct nla_policy ethnl_pause_get_policy[ETHTOOL_A_PAUSE_STATS_SRC + 1];
-extern const struct nla_policy ethnl_pause_set_policy[ETHTOOL_A_PAUSE_TX + 1];
+extern const struct nla_policy ethnl_pause_set_policy[ETHTOOL_A_PAUSE_STATS_SRC + 1];
 extern const struct nla_policy ethnl_eee_get_policy[ETHTOOL_A_EEE_HEADER + 1];
 extern const struct nla_policy ethnl_eee_set_policy[ETHTOOL_A_EEE_TX_LPI_TIMER + 1];
 extern const struct nla_policy ethnl_tsinfo_get_policy[ETHTOOL_A_TSINFO_MAX + 1];

net/ethtool/pause.c

···
 	[ETHTOOL_A_PAUSE_AUTONEG]		= { .type = NLA_U8 },
 	[ETHTOOL_A_PAUSE_RX]			= { .type = NLA_U8 },
 	[ETHTOOL_A_PAUSE_TX]			= { .type = NLA_U8 },
+	[ETHTOOL_A_PAUSE_STATS_SRC]		= { .type = NLA_REJECT },
 };
 
 static int