cfg80211: make wmm_rule part of the reg_rule structure

Make wmm_rule be part of the reg_rule structure. This simplifies the
code a lot at the cost of having bigger memory usage. However in most
cases we have only few reg_rule's and when we do have many like in
iwlwifi we do not save memory as it allocates a separate wmm_rule for
each channel anyway.

This also fixes a bug reported in various places where somewhere the
pointers were corrupted and we ended up doing a null-dereference.

Fixes: 230ebaa189af ("cfg80211: read wmm rules from regulatory database")
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
[rephrase commit message slightly]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

2 files changed, 18 insertions, 82 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 80bc986c79e5..e3dcffd96919 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -667,13 +667,13 @@ static int nl80211_msg_put_wmm_rules(struct sk_buff *msg,
 			goto nla_put_failure;
 
 		if (nla_put_u16(msg, NL80211_WMMR_CW_MIN,
-				rule->wmm_rule->client[j].cw_min) ||
+				rule->wmm_rule.client[j].cw_min) ||
 		    nla_put_u16(msg, NL80211_WMMR_CW_MAX,
-				rule->wmm_rule->client[j].cw_max) ||
+				rule->wmm_rule.client[j].cw_max) ||
 		    nla_put_u8(msg, NL80211_WMMR_AIFSN,
-			       rule->wmm_rule->client[j].aifsn) ||
+			       rule->wmm_rule.client[j].aifsn) ||
 		    nla_put_u8(msg, NL80211_WMMR_TXOP,
-			       rule->wmm_rule->client[j].cot))
+			       rule->wmm_rule.client[j].cot))
 			goto nla_put_failure;
 
 		nla_nest_end(msg, nl_wmm_rule);
@@ -766,7 +766,7 @@ static int nl80211_msg_put_channel(struct sk_buff *msg, struct wiphy *wiphy,
 		const struct ieee80211_reg_rule *rule =
 			freq_reg_info(wiphy, chan->center_freq);
 
-		if (!IS_ERR(rule) && rule->wmm_rule) {
+		if (!IS_ERR_OR_NULL(rule) && rule->has_wmm) {
 			if (nl80211_msg_put_wmm_rules(msg, rule))
 				goto nla_put_failure;
 		}
diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index 283902974fbf..2f702adf2912 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -425,35 +425,23 @@ static const struct ieee80211_regdomain *
 reg_copy_regd(const struct ieee80211_regdomain *src_regd)
 {
 	struct ieee80211_regdomain *regd;
-	int size_of_regd, size_of_wmms;
+	int size_of_regd;
 	unsigned int i;
-	struct ieee80211_wmm_rule *d_wmm, *s_wmm;
 
 	size_of_regd =
 		sizeof(struct ieee80211_regdomain) +
 		src_regd->n_reg_rules * sizeof(struct ieee80211_reg_rule);
-	size_of_wmms = src_regd->n_wmm_rules *
-		sizeof(struct ieee80211_wmm_rule);
 
-	regd = kzalloc(size_of_regd + size_of_wmms, GFP_KERNEL);
+	regd = kzalloc(size_of_regd, GFP_KERNEL);
 	if (!regd)
 		return ERR_PTR(-ENOMEM);
 
 	memcpy(regd, src_regd, sizeof(struct ieee80211_regdomain));
 
-	d_wmm = (struct ieee80211_wmm_rule *)((u8 *)regd + size_of_regd);
-	s_wmm = (struct ieee80211_wmm_rule *)((u8 *)src_regd + size_of_regd);
-	memcpy(d_wmm, s_wmm, size_of_wmms);
-
-	for (i = 0; i < src_regd->n_reg_rules; i++) {
+	for (i = 0; i < src_regd->n_reg_rules; i++)
 		memcpy(&regd->reg_rules[i], &src_regd->reg_rules[i],
 		       sizeof(struct ieee80211_reg_rule));
-		if (!src_regd->reg_rules[i].wmm_rule)
-			continue;
 
-		regd->reg_rules[i].wmm_rule = d_wmm +
-			(src_regd->reg_rules[i].wmm_rule - s_wmm);
-	}
 	return regd;
 }
 
@@ -859,9 +847,10 @@ static bool valid_regdb(const u8 *data, unsigned int size)
 	return true;
 }
 
-static void set_wmm_rule(struct ieee80211_wmm_rule *rule,
+static void set_wmm_rule(struct ieee80211_reg_rule *rrule,
 			 struct fwdb_wmm_rule *wmm)
 {
+	struct ieee80211_wmm_rule *rule = &rrule->wmm_rule;
 	unsigned int i;
 
 	for (i = 0; i < IEEE80211_NUM_ACS; i++) {
@@ -875,11 +864,13 @@ static void set_wmm_rule(struct ieee80211_wmm_rule *rule,
 		rule->ap[i].aifsn = wmm->ap[i].aifsn;
 		rule->ap[i].cot = 1000 * be16_to_cpu(wmm->ap[i].cot);
 	}
+
+	rrule->has_wmm = true;
 }
 
 static int __regdb_query_wmm(const struct fwdb_header *db,
 			     const struct fwdb_country *country, int freq,
-			     u32 *dbptr, struct ieee80211_wmm_rule *rule)
+			     struct ieee80211_reg_rule *rule)
 {
 	unsigned int ptr = be16_to_cpu(country->coll_ptr) << 2;
 	struct fwdb_collection *coll = (void *)((u8 *)db + ptr);
@@ -900,8 +891,6 @@ static int __regdb_query_wmm(const struct fwdb_header *db,
 			wmm_ptr = be16_to_cpu(rrule->wmm_ptr) << 2;
 			wmm = (void *)((u8 *)db + wmm_ptr);
 			set_wmm_rule(rule, wmm);
-			if (dbptr)
-				*dbptr = wmm_ptr;
 			return 0;
 		}
 	}
@@ -909,8 +898,7 @@ static int __regdb_query_wmm(const struct fwdb_header *db,
 	return -ENODATA;
 }
 
-int reg_query_regdb_wmm(char *alpha2, int freq, u32 *dbptr,
-			struct ieee80211_wmm_rule *rule)
+int reg_query_regdb_wmm(char *alpha2, int freq, struct ieee80211_reg_rule *rule)
 {
 	const struct fwdb_header *hdr = regdb;
 	const struct fwdb_country *country;
@@ -924,8 +912,7 @@ int reg_query_regdb_wmm(char *alpha2, int freq, u32 *dbptr,
 	country = &hdr->country[0];
 	while (country->coll_ptr) {
 		if (alpha2_equal(alpha2, country->alpha2))
-			return __regdb_query_wmm(regdb, country, freq, dbptr,
-						 rule);
+			return __regdb_query_wmm(regdb, country, freq, rule);
 
 		country++;
 	}
@@ -934,32 +921,13 @@ int reg_query_regdb_wmm(char *alpha2, int freq, u32 *dbptr,
 }
 EXPORT_SYMBOL(reg_query_regdb_wmm);
 
-struct wmm_ptrs {
-	struct ieee80211_wmm_rule *rule;
-	u32 ptr;
-};
-
-static struct ieee80211_wmm_rule *find_wmm_ptr(struct wmm_ptrs *wmm_ptrs,
-					       u32 wmm_ptr, int n_wmms)
-{
-	int i;
-
-	for (i = 0; i < n_wmms; i++) {
-		if (wmm_ptrs[i].ptr == wmm_ptr)
-			return wmm_ptrs[i].rule;
-	}
-	return NULL;
-}
-
 static int regdb_query_country(const struct fwdb_header *db,
 			       const struct fwdb_country *country)
 {
 	unsigned int ptr = be16_to_cpu(country->coll_ptr) << 2;
 	struct fwdb_collection *coll = (void *)((u8 *)db + ptr);
 	struct ieee80211_regdomain *regdom;
-	struct ieee80211_regdomain *tmp_rd;
-	unsigned int size_of_regd, i, n_wmms = 0;
-	struct wmm_ptrs *wmm_ptrs;
+	unsigned int size_of_regd, i;
 
 	size_of_regd = sizeof(struct ieee80211_regdomain) +
 		coll->n_rules * sizeof(struct ieee80211_reg_rule);
@@ -968,12 +936,6 @@ static int regdb_query_country(const struct fwdb_header *db,
 	if (!regdom)
 		return -ENOMEM;
 
-	wmm_ptrs = kcalloc(coll->n_rules, sizeof(*wmm_ptrs), GFP_KERNEL);
-	if (!wmm_ptrs) {
-		kfree(regdom);
-		return -ENOMEM;
-	}
-
 	regdom->n_reg_rules = coll->n_rules;
 	regdom->alpha2[0] = country->alpha2[0];
 	regdom->alpha2[1] = country->alpha2[1];
@@ -1012,37 +974,11 @@ static int regdb_query_country(const struct fwdb_header *db,
 				1000 * be16_to_cpu(rule->cac_timeout);
 		if (rule->len >= offsetofend(struct fwdb_rule, wmm_ptr)) {
 			u32 wmm_ptr = be16_to_cpu(rule->wmm_ptr) << 2;
-			struct ieee80211_wmm_rule *wmm_pos =
-				find_wmm_ptr(wmm_ptrs, wmm_ptr, n_wmms);
-			struct fwdb_wmm_rule *wmm;
-			struct ieee80211_wmm_rule *wmm_rule;
-
-			if (wmm_pos) {
-				rrule->wmm_rule = wmm_pos;
-				continue;
-			}
-			wmm = (void *)((u8 *)db + wmm_ptr);
-			tmp_rd = krealloc(regdom, size_of_regd + (n_wmms + 1) *
-					  sizeof(struct ieee80211_wmm_rule),
-					  GFP_KERNEL);
-
-			if (!tmp_rd) {
-				kfree(regdom);
-				kfree(wmm_ptrs);
-				return -ENOMEM;
-			}
-			regdom = tmp_rd;
-
-			wmm_rule = (struct ieee80211_wmm_rule *)
-				((u8 *)regdom + size_of_regd + n_wmms *
-				sizeof(struct ieee80211_wmm_rule));
+			struct fwdb_wmm_rule *wmm = (void *)((u8 *)db + wmm_ptr);
 
-			set_wmm_rule(wmm_rule, wmm);
-			wmm_ptrs[n_wmms].ptr = wmm_ptr;
-			wmm_ptrs[n_wmms++].rule = wmm_rule;
+			set_wmm_rule(rrule, wmm);
 		}
 	}
-	kfree(wmm_ptrs);
 
 	return reg_schedule_apply(regdom);
 }