diff --git a/src/openvpn/crypto.c b/src/openvpn/crypto.c
index af7583ae..a63e543b 100644
--- a/src/openvpn/crypto.c
+++ b/src/openvpn/crypto.c
@@ -1901,7 +1901,7 @@ check_tls_prf_working(void)
     const char *seed = "tls1-prf-test";
     const char *secret = "tls1-prf-test-secret";
     uint8_t out[8];
-    uint8_t expected_out[] = { 'q', 'D', '\xfe', '%', '@', 's', 'u', '\x95' };
+    uint8_t expected_out[] = { 'q', 'D', 0xfe, '%', '@', 's', 'u', 0x95 };
 
     int ret = ssl_tls1_PRF((uint8_t *)seed, (int)strlen(seed), (uint8_t *)secret,
                            (int)strlen(secret), out, sizeof(out));
diff --git a/src/openvpn/init.c b/src/openvpn/init.c
index 40ae2c8c..55832745 100644
--- a/src/openvpn/init.c
+++ b/src/openvpn/init.c
@@ -343,7 +343,7 @@ management_callback_remote_entry_get(void *arg, unsigned int index, char **remot
         const char *status = (ce->flags & CE_DISABLED) ? "disabled" : "enabled";
 
         /* space for output including 3 commas and a nul */
-        int len =
+        size_t len =
             strlen(ce->remote) + strlen(ce->remote_port) + strlen(proto) + strlen(status) + 3 + 1;
         char *out = malloc(len);
         check_malloc_return(out);
diff --git a/src/openvpn/options.c b/src/openvpn/options.c
index c54032d8..5f9971cd 100644
--- a/src/openvpn/options.c
+++ b/src/openvpn/options.c
@@ -4957,7 +4957,7 @@ atou(const char *str)
 #endif
 
 static inline bool
-space(unsigned char c)
+space(char c)
 {
     return c == '\0' || isspace(c);
 }
diff --git a/src/openvpn/pool.c b/src/openvpn/pool.c
index 898a0452..a41364a5 100644
--- a/src/openvpn/pool.c
+++ b/src/openvpn/pool.c
@@ -158,7 +158,7 @@ ifconfig_pool_init(const bool ipv4_pool, enum pool_type type, in_addr_t start, i
         switch (pool->ipv4.type)
         {
             case IFCONFIG_POOL_30NET:
-                pool->ipv4.base = start & ~3;
+                pool->ipv4.base = start & ~3u;
                 pool_ipv4_size = (((end | 3) + 1) - pool->ipv4.base) >> 2;
                 break;