diff --git a/src/common/ieee802_11_defs.h b/src/common/ieee802_11_defs.h
index 2e51935b8..6e9c43cb2 100644
--- a/src/common/ieee802_11_defs.h
+++ b/src/common/ieee802_11_defs.h
@@ -470,35 +470,35 @@ struct ieee80211_mgmt {
 			le16 auth_transaction;
 			le16 status_code;
 			/* possibly followed by Challenge text */
-			u8 variable[0];
+			u8 variable[];
 		} STRUCT_PACKED auth;
 		struct {
 			le16 reason_code;
-			u8 variable[0];
+			u8 variable[];
 		} STRUCT_PACKED deauth;
 		struct {
 			le16 capab_info;
 			le16 listen_interval;
 			/* followed by SSID and Supported rates */
-			u8 variable[0];
+			u8 variable[];
 		} STRUCT_PACKED assoc_req;
 		struct {
 			le16 capab_info;
 			le16 status_code;
 			le16 aid;
 			/* followed by Supported rates */
-			u8 variable[0];
+			u8 variable[];
 		} STRUCT_PACKED assoc_resp, reassoc_resp;
 		struct {
 			le16 capab_info;
 			le16 listen_interval;
 			u8 current_ap[6];
 			/* followed by SSID and Supported rates */
-			u8 variable[0];
+			u8 variable[];
 		} STRUCT_PACKED reassoc_req;
 		struct {
 			le16 reason_code;
-			u8 variable[0];
+			u8 variable[];
 		} STRUCT_PACKED disassoc;
 		struct {
 			u8 timestamp[8];
@@ -506,7 +506,7 @@ struct ieee80211_mgmt {
 			le16 capab_info;
 			/* followed by some of SSID, Supported rates,
 			 * FH Params, DS Params, CF Params, IBSS Params, TIM */
-			u8 variable[0];
+			u8 variable[];
 		} STRUCT_PACKED beacon;
 		struct {
 			/* only variable items: SSID, Supported rates */
@@ -518,7 +518,7 @@ struct ieee80211_mgmt {
 			le16 capab_info;
 			/* followed by some of SSID, Supported rates,
 			 * FH Params, DS Params, CF Params, IBSS Params */
-			u8 variable[0];
+			u8 variable[];
 		} STRUCT_PACKED probe_resp;
 		struct {
 			u8 category;
@@ -527,7 +527,7 @@ struct ieee80211_mgmt {
 					u8 action_code;
 					u8 dialog_token;
 					u8 status_code;
-					u8 variable[0];
+					u8 variable[];
 				} STRUCT_PACKED wmm_action;
 				struct{
 					u8 action_code;
@@ -541,14 +541,14 @@ struct ieee80211_mgmt {
 					u8 action;
 					u8 sta_addr[ETH_ALEN];
 					u8 target_ap_addr[ETH_ALEN];
-					u8 variable[0]; /* FT Request */
+					u8 variable[]; /* FT Request */
 				} STRUCT_PACKED ft_action_req;
 				struct {
 					u8 action;
 					u8 sta_addr[ETH_ALEN];
 					u8 target_ap_addr[ETH_ALEN];
 					le16 status_code;
-					u8 variable[0]; /* FT Request */
+					u8 variable[]; /* FT Request */
 				} STRUCT_PACKED ft_action_resp;
 				struct {
 					u8 action;
@@ -561,23 +561,23 @@ struct ieee80211_mgmt {
 				struct {
 					u8 action;
 					u8 dialogtoken;
-					u8 variable[0];
+					u8 variable[];
 				} STRUCT_PACKED wnm_sleep_req;
 				struct {
 					u8 action;
 					u8 dialogtoken;
 					le16 keydata_len;
-					u8 variable[0];
+					u8 variable[];
 				} STRUCT_PACKED wnm_sleep_resp;
 				struct {
 					u8 action;
-					u8 variable[0];
+					u8 variable[];
 				} STRUCT_PACKED public_action;
 				struct {
 					u8 action; /* 9 */
 					u8 oui[3];
 					/* Vendor-specific content */
-					u8 variable[0];
+					u8 variable[];
 				} STRUCT_PACKED vs_public_action;
 				struct {
 					u8 action; /* 7 */
@@ -589,7 +589,7 @@ struct ieee80211_mgmt {
 					 * Session Information URL (optional),
 					 * BSS Transition Candidate List
 					 * Entries */
-					u8 variable[0];
+					u8 variable[];
 				} STRUCT_PACKED bss_tm_req;
 				struct {
 					u8 action; /* 8 */
@@ -599,7 +599,7 @@ struct ieee80211_mgmt {
 					/* Target BSSID (optional),
 					 * BSS Transition Candidate List
 					 * Entries (optional) */
-					u8 variable[0];
+					u8 variable[];
 				} STRUCT_PACKED bss_tm_resp;
 				struct {
 					u8 action; /* 6 */
@@ -607,11 +607,11 @@ struct ieee80211_mgmt {
 					u8 query_reason;
 					/* BSS Transition Candidate List
 					 * Entries (optional) */
-					u8 variable[0];
+					u8 variable[];
 				} STRUCT_PACKED bss_tm_query;
 				struct {
 					u8 action; /* 15 */
-					u8 variable[0];
+					u8 variable[];
 				} STRUCT_PACKED slf_prot_action;
 			} u;
 		} STRUCT_PACKED action;
diff --git a/src/crypto/fips_prf_openssl.c b/src/crypto/fips_prf_openssl.c
index d69eceabf..fb03efcd4 100644
--- a/src/crypto/fips_prf_openssl.c
+++ b/src/crypto/fips_prf_openssl.c
@@ -13,13 +13,21 @@
 #include "crypto.h"
 
 
-static void sha1_transform(u8 *state, const u8 data[64])
+static void sha1_transform(u32 *state, const u8 data[64])
 {
 	SHA_CTX context;
 	os_memset(&context, 0, sizeof(context));
-	os_memcpy(&context.h0, state, 5 * 4);
+	context.h0 = state[0];
+	context.h1 = state[1];
+	context.h2 = state[2];
+	context.h3 = state[3];
+	context.h4 = state[4];
 	SHA1_Transform(&context, data);
-	os_memcpy(state, &context.h0, 5 * 4);
+	state[0] = context.h0;
+	state[1] = context.h1;
+	state[2] = context.h2;
+	state[3] = context.h3;
+	state[4] = context.h4;
 }
 
 
@@ -53,7 +61,7 @@ int fips186_2_prf(const u8 *seed, size_t seed_len, u8 *x, size_t xlen)
 
 			/* w_i = G(t, XVAL) */
 			os_memcpy(_t, t, 20);
-			sha1_transform((u8 *) _t, xkey);
+			sha1_transform(_t, xkey);
 			_t[0] = host_to_be32(_t[0]);
 			_t[1] = host_to_be32(_t[1]);
 			_t[2] = host_to_be32(_t[2]);