From 44b125f77e59be00a263f5f6e40911ff6367e970 Mon Sep 17 00:00:00 2001
From: Soner Tari <sonertari@gmail.com>
Date: Mon, 25 Mar 2019 03:39:15 +0300
Subject: [PATCH] Avoid malloc/free for vars of known sizes

---
 privsep.c | 23 +++--------------------
 pxyconn.c | 27 ++++++++++++---------------
 2 files changed, 15 insertions(+), 35 deletions(-)

diff --git a/privsep.c b/privsep.c
index d657932..6ebd70e 100644
--- a/privsep.c
+++ b/privsep.c
@@ -583,7 +583,7 @@ privsep_server_handle_req(opts_t *opts, int srvsock)
 		break;
 	}
 	case PRIVSEP_REQ_UPDATE_ATIME: {
-		userdbkeys_t *arg;
+		userdbkeys_t arg;
 
 		if (n != sizeof(char) + sizeof(userdbkeys_t)) {
 			ans[0] = PRIVSEP_ANS_INVALID;
@@ -594,24 +594,8 @@ privsep_server_handle_req(opts_t *opts, int srvsock)
 			}
 			return 0;
 		}
-
-		// @attention Do not typecast, but malloc and memcpy
-		//arg = *(userdbkeys_t**)(&req[1]);
-		if (!(arg = malloc(n))) {
-			ans[0] = PRIVSEP_ANS_SYS_ERR;
-			*((int*)&ans[1]) = errno;
-			if (sys_sendmsgfd(srvsock, ans, 1 + sizeof(int),
-			                  -1) == -1) {
-				log_err_level_printf(LOG_CRIT, "Sending message failed: %s (%i"
-				               ")\n", strerror(errno), errno);
-				return -1;
-			}
-			return 0;
-		}
-		memcpy(arg, req + 1, n - 1);
-
-		if (privsep_server_update_atime(opts, arg) == -1) {
-			free(arg);
+		arg = *(userdbkeys_t*)(&req[1]);
+		if (privsep_server_update_atime(opts, &arg) == -1) {
 			ans[0] = PRIVSEP_ANS_SYS_ERR;
 			*((int*)&ans[1]) = errno;
 			if (sys_sendmsgfd(srvsock, ans, 1 + sizeof(int),
@@ -622,7 +606,6 @@ privsep_server_handle_req(opts_t *opts, int srvsock)
 			}
 			return 0;
 		} else {
-			free(arg);
 			ans[0] = PRIVSEP_ANS_SUCCESS;
 			// @attention Pass -1 as arg 4, otherwise passing 0 opens an stdin (fd 0), causing fd leak
 			if (sys_sendmsgfd(srvsock, ans, 1, -1) == -1) {
diff --git a/pxyconn.c b/pxyconn.c
index 2649232..c3978d4 100644
--- a/pxyconn.c
+++ b/pxyconn.c
@@ -391,25 +391,22 @@ pxy_conn_ctx_free(pxy_conn_ctx_t *ctx, int by_requestor)
 		// Update userdb atime if idle time is more than 50% of user timeout, which is expected to reduce update frequency
 		unsigned int idletime = ctx->idletime + (time(NULL) - ctx->ctime);
 		if (idletime > (ctx->opts->user_timeout / 2)) {
-			struct userdbkeys *keys = malloc(sizeof(userdbkeys_t));
-			if (keys) {
-				// Zero out for NULL termination
-				memset(keys, 0, sizeof(userdbkeys_t));
-				// Leave room for NULL to make sure the strings are always NULL terminated
-				strncpy(keys->ip, ctx->srchost_str, sizeof(keys->ip) - 1);
-				strncpy(keys->user, ctx->user, sizeof(keys->user) - 1);
-				strncpy(keys->ether, ctx->ether, sizeof(keys->ether) - 1);
-
-				if (privsep_client_update_atime(ctx->clisock, keys) == -1) {
+			userdbkeys_t keys;
+			// Zero out for NULL termination
+			memset(&keys, 0, sizeof(userdbkeys_t));
+			// Leave room for NULL to make sure the strings are always NULL terminated
+			strncpy(keys.ip, ctx->srchost_str, sizeof(keys.ip) - 1);
+			strncpy(keys.user, ctx->user, sizeof(keys.user) - 1);
+			strncpy(keys.ether, ctx->ether, sizeof(keys.ether) - 1);
+
+			if (privsep_client_update_atime(ctx->clisock, &keys) == -1) {
 #ifdef DEBUG_PROXY
-					log_dbg_level_printf(LOG_DBG_MODE_FINEST, "pxy_conn_ctx_free: Error updating user atime: %s, ctx->fd=%d\n", sqlite3_errmsg(ctx->opts->userdb), ctx->fd);
+				log_dbg_level_printf(LOG_DBG_MODE_FINEST, "pxy_conn_ctx_free: Error updating user atime: %s, ctx->fd=%d\n", sqlite3_errmsg(ctx->opts->userdb), ctx->fd);
 #endif /* DEBUG_PROXY */
-				} else {
+			} else {
 #ifdef DEBUG_PROXY
-					log_dbg_level_printf(LOG_DBG_MODE_FINEST, "pxy_conn_ctx_free: Successfully updated user atime, ctx->fd=%d\n", ctx->fd);
+				log_dbg_level_printf(LOG_DBG_MODE_FINEST, "pxy_conn_ctx_free: Successfully updated user atime, ctx->fd=%d\n", ctx->fd);
 #endif /* DEBUG_PROXY */
-				}
-				free(keys);
 			}
 		} else {
 #ifdef DEBUG_PROXY