[PATCH 13/32] mac80211: Use mem_to_flex_dup() with several structs

[Kees Cook <keescook@xxxxxxxxxxxx>]

As part of the work to perform bounds checking on all memcpy() uses,
replace the open-coded a deserialization of bytes out of memory into a
trailing flexible array by using a flex_array.h helper to perform the
allocation, bounds checking, and copying:

    struct probe_resp
    struct fils_discovery_data
    struct unsol_bcast_probe_resp_data

Cc: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
Cc: linux-wireless@xxxxxxxxxxxxxxx
Cc: netdev@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
 net/mac80211/cfg.c         | 22 ++++++----------------
 net/mac80211/ieee80211_i.h | 12 ++++++------
 2 files changed, 12 insertions(+), 22 deletions(-)

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index f1d211e61e49..355edbf41707 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -867,20 +867,16 @@ ieee80211_set_probe_resp(struct ieee80211_sub_if_data 
*sdata,
                         const struct ieee80211_csa_settings *csa,
                         const struct ieee80211_color_change_settings *cca)
 {
-       struct probe_resp *new, *old;
+       struct probe_resp *new = NULL, *old;
 
        if (!resp || !resp_len)
                return 1;
 
        old = sdata_dereference(sdata->u.ap.probe_resp, sdata);
 
-       new = kzalloc(sizeof(struct probe_resp) + resp_len, GFP_KERNEL);
-       if (!new)
+       if (mem_to_flex_dup(&new, resp, resp_len, GFP_KERNEL))
                return -ENOMEM;
 
-       new->len = resp_len;
-       memcpy(new->data, resp, resp_len);
-
        if (csa)
                memcpy(new->cntdwn_counter_offsets, csa->counter_offsets_presp,
                       csa->n_counter_offsets_presp *
@@ -898,7 +894,7 @@ ieee80211_set_probe_resp(struct ieee80211_sub_if_data 
*sdata,
 static int ieee80211_set_fils_discovery(struct ieee80211_sub_if_data *sdata,
                                        struct cfg80211_fils_discovery *params)
 {
-       struct fils_discovery_data *new, *old = NULL;
+       struct fils_discovery_data *new = NULL, *old = NULL;
        struct ieee80211_fils_discovery *fd;
 
        if (!params->tmpl || !params->tmpl_len)
@@ -909,11 +905,8 @@ static int ieee80211_set_fils_discovery(struct 
ieee80211_sub_if_data *sdata,
        fd->max_interval = params->max_interval;
 
        old = sdata_dereference(sdata->u.ap.fils_discovery, sdata);
-       new = kzalloc(sizeof(*new) + params->tmpl_len, GFP_KERNEL);
-       if (!new)
+       if (mem_to_flex_dup(&new, params->tmpl, params->tmpl_len, GFP_KERNEL))
                return -ENOMEM;
-       new->len = params->tmpl_len;
-       memcpy(new->data, params->tmpl, params->tmpl_len);
        rcu_assign_pointer(sdata->u.ap.fils_discovery, new);
 
        if (old)
@@ -926,17 +919,14 @@ static int
 ieee80211_set_unsol_bcast_probe_resp(struct ieee80211_sub_if_data *sdata,
                                     struct cfg80211_unsol_bcast_probe_resp 
*params)
 {
-       struct unsol_bcast_probe_resp_data *new, *old = NULL;
+       struct unsol_bcast_probe_resp_data *new = NULL, *old = NULL;
 
        if (!params->tmpl || !params->tmpl_len)
                return -EINVAL;
 
        old = sdata_dereference(sdata->u.ap.unsol_bcast_probe_resp, sdata);
-       new = kzalloc(sizeof(*new) + params->tmpl_len, GFP_KERNEL);
-       if (!new)
+       if (mem_to_flex_dup(&new, params->tmpl, params->tmpl_len, GFP_KERNEL))
                return -ENOMEM;
-       new->len = params->tmpl_len;
-       memcpy(new->data, params->tmpl, params->tmpl_len);
        rcu_assign_pointer(sdata->u.ap.unsol_bcast_probe_resp, new);
 
        if (old)
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index d4a7ba4a8202..2e9bbfb12c0d 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -263,21 +263,21 @@ struct beacon_data {
 
 struct probe_resp {
        struct rcu_head rcu_head;
-       int len;
+       DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(int, len);
        u16 cntdwn_counter_offsets[IEEE80211_MAX_CNTDWN_COUNTERS_NUM];
-       u8 data[];
+       DECLARE_FLEX_ARRAY_ELEMENTS(u8, data);
 };
 
 struct fils_discovery_data {
        struct rcu_head rcu_head;
-       int len;
-       u8 data[];
+       DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(int, len);
+       DECLARE_FLEX_ARRAY_ELEMENTS(u8, data);
 };
 
 struct unsol_bcast_probe_resp_data {
        struct rcu_head rcu_head;
-       int len;
-       u8 data[];
+       DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(int, len);
+       DECLARE_FLEX_ARRAY_ELEMENTS(u8, data);
 };
 
 struct ps_data {
-- 
2.32.0