Re: [PATCH net-next] ethtool: plca: fix plca enable data type while parsing the value
From: Jakub Kicinski
Date: Tue Sep 05 2023 - 18:15:14 EST
On Thu, 31 Aug 2023 16:15:23 +0530 Parthiban Veerasooran wrote:
> Subject: [PATCH net-next] ethtool: plca: fix plca enable data type while parsing the value
Since this is a fix the subject should say net instead of net-next.
[PATCH net v2] for the next revision.
> The ETHTOOL_A_PLCA_ENABLED data type is u8. But while parsing the
> value from the attribute, nla_get_u32() is used in the plca_update_sint()
> function instead of nla_get_u8(). So plca_cfg.enabled variable is updated
> with some garbage value instead of 0 or 1 and always enables plca even
> though plca is disabled through ethtool application. This bug has been
> fixed by implementing plca_update_sint_from_u8() function which uses
> nla_get_u8() function to extract the plca_cfg.enabled value and the
> function plca_update_sint_from_u32() is used for extracting the other
> values using nla_get_u32() function.
Hm, yes, that seems like the best of the available options.
> Fixes: 8580e16c28f3 ("net/ethtool: add netlink interface for the PLCA RS")
Please make sure you CC all the people who signed off the commit under
Fixes. You missed pabeni@xxxxxxxxxx and andrew@xxxxxxx
> Signed-off-by: Parthiban Veerasooran <Parthiban.Veerasooran@xxxxxxxxxxxxx>
> ---
> net/ethtool/plca.c | 34 ++++++++++++++++++++++++----------
> 1 file changed, 24 insertions(+), 10 deletions(-)
>
> diff --git a/net/ethtool/plca.c b/net/ethtool/plca.c
> index b238a1afe9ae..b4e80dd33590 100644
> --- a/net/ethtool/plca.c
> +++ b/net/ethtool/plca.c
> @@ -21,8 +21,8 @@ struct plca_reply_data {
> #define PLCA_REPDATA(__reply_base) \
> container_of(__reply_base, struct plca_reply_data, base)
>
> -static void plca_update_sint(int *dst, const struct nlattr *attr,
> - bool *mod)
> +static void plca_update_sint_from_u32(int *dst, const struct nlattr *attr,
> + bool *mod)
> {
> if (!attr)
> return;
> @@ -31,6 +31,16 @@ static void plca_update_sint(int *dst, const struct nlattr *attr,
> *mod = true;
> }
>
> +static void plca_update_sint_from_u8(int *dst, const struct nlattr *attr,
> + bool *mod)
> +{
> + if (!attr)
> + return;
> +
> + *dst = nla_get_u8(attr);
> + *mod = true;
> +}
> +
> // PLCA get configuration message ------------------------------------------- //
>
> const struct nla_policy ethnl_plca_get_cfg_policy[] = {
> @@ -144,14 +154,18 @@ ethnl_set_plca(struct ethnl_req_info *req_info, struct genl_info *info)
> return -EOPNOTSUPP;
>
> memset(&plca_cfg, 0xff, sizeof(plca_cfg));
> - plca_update_sint(&plca_cfg.enabled, tb[ETHTOOL_A_PLCA_ENABLED], &mod);
> - plca_update_sint(&plca_cfg.node_id, tb[ETHTOOL_A_PLCA_NODE_ID], &mod);
> - plca_update_sint(&plca_cfg.node_cnt, tb[ETHTOOL_A_PLCA_NODE_CNT], &mod);
> - plca_update_sint(&plca_cfg.to_tmr, tb[ETHTOOL_A_PLCA_TO_TMR], &mod);
> - plca_update_sint(&plca_cfg.burst_cnt, tb[ETHTOOL_A_PLCA_BURST_CNT],
> - &mod);
> - plca_update_sint(&plca_cfg.burst_tmr, tb[ETHTOOL_A_PLCA_BURST_TMR],
> - &mod);
> + plca_update_sint_from_u8(&plca_cfg.enabled, tb[ETHTOOL_A_PLCA_ENABLED],
> + &mod);
> + plca_update_sint_from_u32(&plca_cfg.node_id, tb[ETHTOOL_A_PLCA_NODE_ID],
> + &mod);
> + plca_update_sint_from_u32(&plca_cfg.node_cnt,
> + tb[ETHTOOL_A_PLCA_NODE_CNT], &mod);
> + plca_update_sint_from_u32(&plca_cfg.to_tmr, tb[ETHTOOL_A_PLCA_TO_TMR],
> + &mod);
> + plca_update_sint_from_u32(&plca_cfg.burst_cnt,
> + tb[ETHTOOL_A_PLCA_BURST_CNT], &mod);
> + plca_update_sint_from_u32(&plca_cfg.burst_tmr,
> + tb[ETHTOOL_A_PLCA_BURST_TMR], &mod);
This looks error prone. We still need to maintain the types in multiple
places. How about we use the policy to decide the type? Something along
the lines of (untested):
diff --git a/net/ethtool/plca.c b/net/ethtool/plca.c
index b238a1afe9ae..aed30665e9c0 100644
--- a/net/ethtool/plca.c
+++ b/net/ethtool/plca.c
@@ -21,16 +21,6 @@ struct plca_reply_data {
#define PLCA_REPDATA(__reply_base) \
container_of(__reply_base, struct plca_reply_data, base)
-static void plca_update_sint(int *dst, const struct nlattr *attr,
- bool *mod)
-{
- if (!attr)
- return;
-
- *dst = nla_get_u32(attr);
- *mod = true;
-}
-
// PLCA get configuration message ------------------------------------------- //
const struct nla_policy ethnl_plca_get_cfg_policy[] = {
@@ -125,6 +115,29 @@ const struct nla_policy ethnl_plca_set_cfg_policy[] = {
[ETHTOOL_A_PLCA_BURST_TMR] = NLA_POLICY_MAX(NLA_U32, 255),
};
+static void
+plca_update_sint(int *dst, const struct nlattr **tb, u32 attrid, bool *mod)
+{
+ const struct nlattr *attr = tb[attrid];
+
+ if (!attr ||
+ WARN_ON_ONCE(attrid >= ARRAY_SIZE(ethnl_plca_set_cfg_policy)))
+ return;
+
+ switch (ethnl_plca_set_cfg_policy[attrid].type) {
+ case NLA_U8:
+ *dst = nla_get_u8(attr);
+ break;
+ case NLA_U32:
+ *dst = nla_get_u32(attr);
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ }
+
+ *mod = true;
+}
+
static int
ethnl_set_plca(struct ethnl_req_info *req_info, struct genl_info *info)
{
@@ -144,13 +157,13 @@ ethnl_set_plca(struct ethnl_req_info *req_info, struct genl_info *info)
return -EOPNOTSUPP;
memset(&plca_cfg, 0xff, sizeof(plca_cfg));
- plca_update_sint(&plca_cfg.enabled, tb[ETHTOOL_A_PLCA_ENABLED], &mod);
- plca_update_sint(&plca_cfg.node_id, tb[ETHTOOL_A_PLCA_NODE_ID], &mod);
- plca_update_sint(&plca_cfg.node_cnt, tb[ETHTOOL_A_PLCA_NODE_CNT], &mod);
- plca_update_sint(&plca_cfg.to_tmr, tb[ETHTOOL_A_PLCA_TO_TMR], &mod);
- plca_update_sint(&plca_cfg.burst_cnt, tb[ETHTOOL_A_PLCA_BURST_CNT],
+ plca_update_sint(&plca_cfg.enabled, tb, ETHTOOL_A_PLCA_ENABLED, &mod);
+ plca_update_sint(&plca_cfg.node_id, tb, ETHTOOL_A_PLCA_NODE_ID, &mod);
+ plca_update_sint(&plca_cfg.node_cnt, tb, ETHTOOL_A_PLCA_NODE_CNT, &mod);
+ plca_update_sint(&plca_cfg.to_tmr, tb, ETHTOOL_A_PLCA_TO_TMR, &mod);
+ plca_update_sint(&plca_cfg.burst_cnt, tb, ETHTOOL_A_PLCA_BURST_CNT,
&mod);
- plca_update_sint(&plca_cfg.burst_tmr, tb[ETHTOOL_A_PLCA_BURST_TMR],
+ plca_update_sint(&plca_cfg.burst_tmr, tb, ETHTOOL_A_PLCA_BURST_TMR,
&mod);
if (!mod)
return 0;