diff --git a/libssh/channels1.c b/libssh/channels1.c
index 611c99b7..914cd386 100644
--- a/libssh/channels1.c
+++ b/libssh/channels1.c
@@ -282,7 +282,7 @@ int channel_write1(ssh_channel channel, const void *data, int len) {
   SSH_SESSION *session = channel->session;
   int origlen = len;
   int effectivelen;
-
+  const unsigned char *ptr=data;
   while (len > 0) {
     if (buffer_add_u8(session->out_buffer, SSH_CMSG_STDIN_DATA) < 0) {
       return -1;
@@ -291,11 +291,11 @@ int channel_write1(ssh_channel channel, const void *data, int len) {
     effectivelen = len > 32000 ? 32000 : len;
 
     if (buffer_add_u32(session->out_buffer, htonl(effectivelen)) < 0 ||
-        buffer_add_data(session->out_buffer, data, effectivelen) < 0) {
+        buffer_add_data(session->out_buffer, ptr, effectivelen) < 0) {
       return -1;
     }
 
-    data += effectivelen;
+    ptr += effectivelen;
     len -= effectivelen;
 
     if (packet_send(session) != SSH_OK) {
diff --git a/libssh/packet.c b/libssh/packet.c
index 4aadf56e..f0a56b17 100644
--- a/libssh/packet.c
+++ b/libssh/packet.c
@@ -318,7 +318,7 @@ static int packet_read1(SSH_SESSION *session) {
       }
 
       memcpy(&crc,
-          buffer_get_rest(session->in_buffer) + (len+padding) - sizeof(uint32_t),
+          (unsigned char *)buffer_get_rest(session->in_buffer) + (len+padding) - sizeof(uint32_t),
           sizeof(uint32_t));
       buffer_pass_bytes_end(session->in_buffer, sizeof(uint32_t));
       crc = ntohl(crc);
@@ -544,7 +544,7 @@ static int packet_send1(SSH_SESSION *session) {
     goto error;
   }
 
-  crc = ssh_crc32(buffer_get(session->out_buffer) + sizeof(uint32_t),
+  crc = ssh_crc32((char *)buffer_get(session->out_buffer) + sizeof(uint32_t),
       buffer_get_len(session->out_buffer) - sizeof(uint32_t));
 
   if (buffer_add_u32(session->out_buffer, ntohl(crc)) < 0) {
@@ -556,7 +556,7 @@ static int packet_send1(SSH_SESSION *session) {
       buffer_get_len(session->out_buffer));
 #endif
 
-  packet_encrypt(session, buffer_get(session->out_buffer) + sizeof(uint32_t),
+  packet_encrypt(session, (unsigned char *)buffer_get(session->out_buffer) + sizeof(uint32_t),
       buffer_get_len(session->out_buffer) - sizeof(uint32_t));
 
 #ifdef DEBUG_CRYPTO