From: Stefan Eissing <stefan@eissing.org>
Date: Thu, 27 Nov 2025 14:13:11 +0000 (+0100)
Subject: cfilter: send uint8_t bytes
X-Git-Tag: rc-8_18_0-1~118
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=56e88e7c14dd1a529f9a4f23db5f791302bba6e7;p=thirdparty%2Fcurl.git

cfilter: send uint8_t bytes

Change the send parameter from `const void *` to `const uint8_t *` and
adapt calling code. Several had already unsigned chars and were casting.

Closes #19729
---

diff --git a/lib/cf-h1-proxy.c b/lib/cf-h1-proxy.c
index e496d7634d..417b4df67e 100644
--- a/lib/cf-h1-proxy.c
+++ b/lib/cf-h1-proxy.c
@@ -246,7 +246,7 @@ static CURLcode send_CONNECT(struct Curl_cfilter *cf,
                              struct h1_tunnel_state *ts,
                              bool *done)
 {
-  char *buf = curlx_dyn_ptr(&ts->request_data);
+  uint8_t *buf = curlx_dyn_uptr(&ts->request_data);
   size_t request_len = curlx_dyn_len(&ts->request_data);
   size_t blen = request_len;
   CURLcode result = CURLE_OK;
@@ -267,7 +267,7 @@ static CURLcode send_CONNECT(struct Curl_cfilter *cf,
 
   DEBUGASSERT(blen >= nwritten);
   ts->nsent += nwritten;
-  Curl_debug(data, CURLINFO_HEADER_OUT, buf, nwritten);
+  Curl_debug(data, CURLINFO_HEADER_OUT, (char *)buf, nwritten);
 
 out:
   if(result)
diff --git a/lib/cf-h2-proxy.c b/lib/cf-h2-proxy.c
index 89bc7cc23f..fca916a2c2 100644
--- a/lib/cf-h2-proxy.c
+++ b/lib/cf-h2-proxy.c
@@ -225,7 +225,7 @@ static void drain_tunnel(struct Curl_cfilter *cf,
 }
 
 static CURLcode proxy_h2_nw_out_writer(void *writer_ctx,
-                                       const unsigned char *buf, size_t buflen,
+                                       const uint8_t *buf, size_t buflen,
                                        size_t *pnwritten)
 {
   struct Curl_cfilter *cf = writer_ctx;
@@ -233,7 +233,7 @@ static CURLcode proxy_h2_nw_out_writer(void *writer_ctx,
   if(cf) {
     struct Curl_easy *data = CF_DATA_CURRENT(cf);
     CURLcode result;
-    result = Curl_conn_cf_send(cf->next, data, (const char *)buf, buflen,
+    result = Curl_conn_cf_send(cf->next, data, buf, buflen,
                                FALSE, pnwritten);
     CURL_TRC_CF(data, cf, "[0] nw_out_writer(len=%zu) -> %d, %zu",
                 buflen, result, *pnwritten);
@@ -1356,7 +1356,7 @@ out:
 
 static CURLcode cf_h2_proxy_send(struct Curl_cfilter *cf,
                                  struct Curl_easy *data,
-                                 const void *buf, size_t len, bool eos,
+                                 const uint8_t *buf, size_t len, bool eos,
                                  size_t *pnwritten)
 {
   struct cf_h2_proxy_ctx *ctx = cf->ctx;
diff --git a/lib/cf-haproxy.c b/lib/cf-haproxy.c
index 3231791097..8912604504 100644
--- a/lib/cf-haproxy.c
+++ b/lib/cf-haproxy.c
@@ -133,7 +133,7 @@ static CURLcode cf_haproxy_connect(struct Curl_cfilter *cf,
     if(len > 0) {
       size_t nwritten;
       result = Curl_conn_cf_send(cf->next, data,
-                                 curlx_dyn_ptr(&ctx->data_out), len, FALSE,
+                                 curlx_dyn_uptr(&ctx->data_out), len, FALSE,
                                  &nwritten);
       if(result) {
         if(result != CURLE_AGAIN)
diff --git a/lib/cf-socket.c b/lib/cf-socket.c
index c657330ec6..6e5333602c 100644
--- a/lib/cf-socket.c
+++ b/lib/cf-socket.c
@@ -1428,7 +1428,7 @@ static void win_update_sndbuf_size(struct cf_socket_ctx *ctx)
 #endif /* USE_WINSOCK */
 
 static CURLcode cf_socket_send(struct Curl_cfilter *cf, struct Curl_easy *data,
-                               const void *buf, size_t len, bool eos,
+                               const uint8_t *buf, size_t len, bool eos,
                                size_t *pnwritten)
 {
   struct cf_socket_ctx *ctx = cf->ctx;
diff --git a/lib/cfilters.c b/lib/cfilters.c
index 31c7b07747..7cb10f3928 100644
--- a/lib/cfilters.c
+++ b/lib/cfilters.c
@@ -85,7 +85,7 @@ bool Curl_cf_def_data_pending(struct Curl_cfilter *cf,
 }
 
 CURLcode Curl_cf_def_send(struct Curl_cfilter *cf, struct Curl_easy *data,
-                          const void *buf, size_t len, bool eos,
+                          const uint8_t *buf, size_t len, bool eos,
                           size_t *pnwritten)
 {
   if(cf->next)
@@ -296,12 +296,11 @@ CURLcode Curl_cf_recv_bufq(struct Curl_cfilter *cf,
 }
 
 static CURLcode cf_bufq_writer(void *writer_ctx,
-                               const unsigned char *buf, size_t buflen,
+                               const uint8_t *buf, size_t buflen,
                                size_t *pnwritten)
 {
   struct cf_io_ctx *io = writer_ctx;
-  return Curl_conn_cf_send(io->cf, io->data, (const char *)buf,
-                           buflen, FALSE, pnwritten);
+  return Curl_conn_cf_send(io->cf, io->data, buf, buflen, FALSE, pnwritten);
 }
 
 CURLcode Curl_cf_send_bufq(struct Curl_cfilter *cf,
@@ -422,7 +421,7 @@ void Curl_conn_cf_close(struct Curl_cfilter *cf, struct Curl_easy *data)
 }
 
 CURLcode Curl_conn_cf_send(struct Curl_cfilter *cf, struct Curl_easy *data,
-                           const void *buf, size_t len, bool eos,
+                           const uint8_t *buf, size_t len, bool eos,
                            size_t *pnwritten)
 {
   if(cf)
diff --git a/lib/cfilters.h b/lib/cfilters.h
index 6cb4a6909c..5d39725088 100644
--- a/lib/cfilters.h
+++ b/lib/cfilters.h
@@ -89,7 +89,7 @@ typedef bool     Curl_cft_data_pending(struct Curl_cfilter *cf,
 
 typedef CURLcode Curl_cft_send(struct Curl_cfilter *cf,
                                struct Curl_easy *data, /* transfer */
-                               const void *buf,        /* data to write */
+                               const uint8_t *buf,     /* data to write */
                                size_t len,             /* amount to write */
                                bool eos,               /* last chunk */
                                size_t *pnwritten);     /* how much sent */
@@ -250,7 +250,7 @@ CURLcode Curl_cf_def_adjust_pollset(struct Curl_cfilter *cf,
 bool     Curl_cf_def_data_pending(struct Curl_cfilter *cf,
                                   const struct Curl_easy *data);
 CURLcode Curl_cf_def_send(struct Curl_cfilter *cf, struct Curl_easy *data,
-                          const void *buf, size_t len, bool eos,
+                          const uint8_t *buf, size_t len, bool eos,
                           size_t *pnwritten);
 CURLcode Curl_cf_def_recv(struct Curl_cfilter *cf, struct Curl_easy *data,
                           char *buf, size_t len, size_t *pnread);
@@ -323,7 +323,7 @@ CURLcode Curl_conn_cf_connect(struct Curl_cfilter *cf,
                               bool *done);
 void Curl_conn_cf_close(struct Curl_cfilter *cf, struct Curl_easy *data);
 CURLcode Curl_conn_cf_send(struct Curl_cfilter *cf, struct Curl_easy *data,
-                           const void *buf, size_t len, bool eos,
+                           const uint8_t *buf, size_t len, bool eos,
                            size_t *pnwritten);
 CURLcode Curl_conn_cf_recv(struct Curl_cfilter *cf, struct Curl_easy *data,
                            char *buf, size_t len, size_t *pnread);
diff --git a/lib/http2.c b/lib/http2.c
index 4f49efe768..2e8649c105 100644
--- a/lib/http2.c
+++ b/lib/http2.c
@@ -2258,7 +2258,7 @@ static CURLcode cf_h2_body_send(struct Curl_cfilter *cf,
 
 static CURLcode h2_submit(struct h2_stream_ctx **pstream,
                           struct Curl_cfilter *cf, struct Curl_easy *data,
-                          const void *buf, size_t len,
+                          const uint8_t *buf, size_t len,
                           bool eos, size_t *pnwritten)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
@@ -2281,7 +2281,7 @@ static CURLcode h2_submit(struct h2_stream_ctx **pstream,
   if(result)
     goto out;
 
-  result = Curl_h1_req_parse_read(&stream->h1, buf, len, NULL,
+  result = Curl_h1_req_parse_read(&stream->h1, (const char *)buf, len, NULL,
                                   !data->state.http_ignorecustom ?
                                   data->set.str[STRING_CUSTOMREQUEST] : NULL,
                                   0, &nwritten);
@@ -2391,7 +2391,7 @@ out:
 }
 
 static CURLcode cf_h2_send(struct Curl_cfilter *cf, struct Curl_easy *data,
-                           const void *buf, size_t len, bool eos,
+                           const uint8_t *buf, size_t len, bool eos,
                            size_t *pnwritten)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
diff --git a/lib/socks_gssapi.c b/lib/socks_gssapi.c
index 30fefa5a6d..61c88be605 100644
--- a/lib/socks_gssapi.c
+++ b/lib/socks_gssapi.c
@@ -211,7 +211,7 @@ CURLcode Curl_SOCKS5_gssapi_negotiate(struct Curl_cfilter *cf,
       us_length = htons((unsigned short)gss_send_token.length);
       memcpy(socksreq + 2, &us_length, sizeof(short));
 
-      code = Curl_conn_cf_send(cf->next, data, (char *)socksreq, 4,
+      code = Curl_conn_cf_send(cf->next, data, socksreq, 4,
                                FALSE, &nwritten);
       if(code || (nwritten != 4)) {
         failf(data, "Failed to send GSS-API authentication request.");
@@ -222,7 +222,7 @@ CURLcode Curl_SOCKS5_gssapi_negotiate(struct Curl_cfilter *cf,
       }
 
       code = Curl_conn_cf_send(cf->next, data,
-                               (char *)gss_send_token.value,
+                               gss_send_token.value,
                                gss_send_token.length, FALSE, &nwritten);
       if(code || (gss_send_token.length != nwritten)) {
         failf(data, "Failed to send GSS-API authentication token.");
@@ -409,8 +409,7 @@ CURLcode Curl_SOCKS5_gssapi_negotiate(struct Curl_cfilter *cf,
     memcpy(socksreq + 2, &us_length, sizeof(short));
   }
 
-  code = Curl_conn_cf_send(cf->next, data, (char *)socksreq, 4, FALSE,
-                           &nwritten);
+  code = Curl_conn_cf_send(cf->next, data, socksreq, 4, FALSE, &nwritten);
   if(code || (nwritten != 4)) {
     failf(data, "Failed to send GSS-API encryption request.");
     gss_release_buffer(&gss_status, &gss_w_token);
@@ -420,8 +419,7 @@ CURLcode Curl_SOCKS5_gssapi_negotiate(struct Curl_cfilter *cf,
 
   if(data->set.socks5_gssapi_nec) {
     memcpy(socksreq, &gss_enc, 1);
-    code = Curl_conn_cf_send(cf->next, data, (char *)socksreq, 1, FALSE,
-                             &nwritten);
+    code = Curl_conn_cf_send(cf->next, data, socksreq, 1, FALSE, &nwritten);
     if(code || (nwritten != 1)) {
       failf(data, "Failed to send GSS-API encryption type.");
       Curl_gss_delete_sec_context(&gss_status, &gss_context, NULL);
@@ -429,7 +427,7 @@ CURLcode Curl_SOCKS5_gssapi_negotiate(struct Curl_cfilter *cf,
     }
   }
   else {
-    code = Curl_conn_cf_send(cf->next, data, (char *)gss_w_token.value,
+    code = Curl_conn_cf_send(cf->next, data, gss_w_token.value,
                              gss_w_token.length, FALSE, &nwritten);
     if(code || (gss_w_token.length != nwritten)) {
       failf(data, "Failed to send GSS-API encryption type.");
diff --git a/lib/socks_sspi.c b/lib/socks_sspi.c
index 975172576c..14025371ce 100644
--- a/lib/socks_sspi.c
+++ b/lib/socks_sspi.c
@@ -88,7 +88,7 @@ CURLcode Curl_SOCKS5_gssapi_negotiate(struct Curl_cfilter *cf,
   unsigned char socksreq[4]; /* room for GSS-API exchange header only */
   const char *service = data->set.str[STRING_PROXY_SERVICE_NAME] ?
                         data->set.str[STRING_PROXY_SERVICE_NAME] : "rcmd";
-  char *etbuf;
+  uint8_t *etbuf;
   size_t etbuf_size;
 
   /*   GSS-API request looks like
@@ -201,8 +201,7 @@ CURLcode Curl_SOCKS5_gssapi_negotiate(struct Curl_cfilter *cf,
       us_length = htons((unsigned short)sspi_send_token.cbBuffer);
       memcpy(socksreq + 2, &us_length, sizeof(short));
 
-      code = Curl_conn_cf_send(cf->next, data, (char *)socksreq, 4, FALSE,
-                               &written);
+      code = Curl_conn_cf_send(cf->next, data, socksreq, 4, FALSE, &written);
       if(code || (written != 4)) {
         failf(data, "Failed to send SSPI authentication request.");
         result = CURLE_COULDNT_CONNECT;
@@ -210,7 +209,7 @@ CURLcode Curl_SOCKS5_gssapi_negotiate(struct Curl_cfilter *cf,
       }
 
       code = Curl_conn_cf_send(cf->next, data,
-                               (char *)sspi_send_token.pvBuffer,
+                               sspi_send_token.pvBuffer,
                                sspi_send_token.cbBuffer, FALSE, &written);
       if(code || (sspi_send_token.cbBuffer != written)) {
         failf(data, "Failed to send SSPI authentication token.");
@@ -433,8 +432,7 @@ CURLcode Curl_SOCKS5_gssapi_negotiate(struct Curl_cfilter *cf,
     memcpy(socksreq + 2, &us_length, sizeof(short));
   }
 
-  code = Curl_conn_cf_send(cf->next, data, (char *)socksreq, 4, FALSE,
-                           &written);
+  code = Curl_conn_cf_send(cf->next, data, socksreq, 4, FALSE, &written);
   if(code || (written != 4)) {
     failf(data, "Failed to send SSPI encryption request.");
     result = CURLE_COULDNT_CONNECT;
@@ -443,8 +441,7 @@ CURLcode Curl_SOCKS5_gssapi_negotiate(struct Curl_cfilter *cf,
 
   if(data->set.socks5_gssapi_nec) {
     memcpy(socksreq, &gss_enc, 1);
-    code = Curl_conn_cf_send(cf->next, data, (char *)socksreq, 1, FALSE,
-                             &written);
+    code = Curl_conn_cf_send(cf->next, data, socksreq, 1, FALSE, &written);
     if(code || (written != 1)) {
       failf(data, "Failed to send SSPI encryption type.");
       result = CURLE_COULDNT_CONNECT;
diff --git a/lib/vquic/curl_ngtcp2.c b/lib/vquic/curl_ngtcp2.c
index 22ea0e3ef4..86f7428048 100644
--- a/lib/vquic/curl_ngtcp2.c
+++ b/lib/vquic/curl_ngtcp2.c
@@ -1524,7 +1524,7 @@ cb_h3_read_req_body(nghttp3_conn *conn, int64_t stream_id,
 
 static CURLcode h3_stream_open(struct Curl_cfilter *cf,
                                struct Curl_easy *data,
-                               const void *buf, size_t len,
+                               const uint8_t *buf, size_t len,
                                size_t *pnwritten)
 {
   struct cf_ngtcp2_ctx *ctx = cf->ctx;
@@ -1552,7 +1552,7 @@ static CURLcode h3_stream_open(struct Curl_cfilter *cf,
     goto out;
   }
 
-  result = Curl_h1_req_parse_read(&stream->h1, buf, len, NULL,
+  result = Curl_h1_req_parse_read(&stream->h1, (const char *)buf, len, NULL,
                                   !data->state.http_ignorecustom ?
                                   data->set.str[STRING_CUSTOMREQUEST] : NULL,
                                   0, pnwritten);
@@ -1656,7 +1656,7 @@ out:
 }
 
 static CURLcode cf_ngtcp2_send(struct Curl_cfilter *cf, struct Curl_easy *data,
-                               const void *buf, size_t len, bool eos,
+                               const uint8_t *buf, size_t len, bool eos,
                                size_t *pnwritten)
 {
   struct cf_ngtcp2_ctx *ctx = cf->ctx;
diff --git a/lib/vquic/curl_osslq.c b/lib/vquic/curl_osslq.c
index 376705e516..d6672ce132 100644
--- a/lib/vquic/curl_osslq.c
+++ b/lib/vquic/curl_osslq.c
@@ -1877,7 +1877,7 @@ out:
 
 static CURLcode h3_stream_open(struct Curl_cfilter *cf,
                                struct Curl_easy *data,
-                               const void *buf, size_t len,
+                               const uint8_t *buf, size_t len,
                                size_t *pnwritten)
 {
   struct cf_osslq_ctx *ctx = cf->ctx;
@@ -1903,7 +1903,7 @@ static CURLcode h3_stream_open(struct Curl_cfilter *cf,
     goto out;
   }
 
-  result = Curl_h1_req_parse_read(&stream->h1, buf, len, NULL,
+  result = Curl_h1_req_parse_read(&stream->h1, (const char *)buf, len, NULL,
                                   !data->state.http_ignorecustom ?
                                   data->set.str[STRING_CUSTOMREQUEST] : NULL,
                                   0, pnwritten);
@@ -2005,7 +2005,7 @@ out:
 }
 
 static CURLcode cf_osslq_send(struct Curl_cfilter *cf, struct Curl_easy *data,
-                              const void *buf, size_t len, bool eos,
+                              const uint8_t *buf, size_t len, bool eos,
                               size_t *pnwritten)
 {
   struct cf_osslq_ctx *ctx = cf->ctx;
diff --git a/lib/vquic/curl_quiche.c b/lib/vquic/curl_quiche.c
index 9274929790..f8fbadeebb 100644
--- a/lib/vquic/curl_quiche.c
+++ b/lib/vquic/curl_quiche.c
@@ -911,7 +911,7 @@ out:
 static CURLcode cf_quiche_send_body(struct Curl_cfilter *cf,
                                     struct Curl_easy *data,
                                     struct h3_stream_ctx *stream,
-                                    const void *buf, size_t len, bool eos,
+                                    const uint8_t *buf, size_t len, bool eos,
                                     size_t *pnwritten)
 {
   struct cf_quiche_ctx *ctx = cf->ctx;
@@ -956,7 +956,7 @@ static CURLcode cf_quiche_send_body(struct Curl_cfilter *cf,
 
 static CURLcode h3_open_stream(struct Curl_cfilter *cf,
                                struct Curl_easy *data,
-                               const char *buf, size_t blen, bool eos,
+                               const uint8_t *buf, size_t blen, bool eos,
                                size_t *pnwritten)
 {
   struct cf_quiche_ctx *ctx = cf->ctx;
@@ -980,7 +980,7 @@ static CURLcode h3_open_stream(struct Curl_cfilter *cf,
 
   DEBUGASSERT(stream);
 
-  result = Curl_h1_req_parse_read(&stream->h1, buf, blen, NULL,
+  result = Curl_h1_req_parse_read(&stream->h1, (const char *)buf, blen, NULL,
                                     !data->state.http_ignorecustom ?
                                     data->set.str[STRING_CUSTOMREQUEST] : NULL,
                                     0, pnwritten);
@@ -1076,7 +1076,7 @@ out:
 }
 
 static CURLcode cf_quiche_send(struct Curl_cfilter *cf, struct Curl_easy *data,
-                               const void *buf, size_t len, bool eos,
+                               const uint8_t *buf, size_t len, bool eos,
                                size_t *pnwritten)
 {
   struct cf_quiche_ctx *ctx = cf->ctx;
diff --git a/lib/vtls/mbedtls.c b/lib/vtls/mbedtls.c
index 9a30749959..2ea3670c1b 100644
--- a/lib/vtls/mbedtls.c
+++ b/lib/vtls/mbedtls.c
@@ -187,8 +187,7 @@ static int mbedtls_bio_cf_write(void *bio,
   if(!data)
     return 0;
 
-  result = Curl_conn_cf_send(cf->next, data, (const char *)buf, blen, FALSE,
-                             &nwritten);
+  result = Curl_conn_cf_send(cf->next, data, buf, blen, FALSE, &nwritten);
   CURL_TRC_CF(data, cf, "mbedtls_bio_cf_out_write(len=%zu) -> %d, %zu",
               blen, result, nwritten);
   if(CURLE_AGAIN == result)
diff --git a/lib/vtls/openssl.c b/lib/vtls/openssl.c
index 7ff5698e7c..d8f99b21c3 100644
--- a/lib/vtls/openssl.c
+++ b/lib/vtls/openssl.c
@@ -597,7 +597,8 @@ static int ossl_bio_cf_out_write(BIO *bio, const char *buf, int blen)
   if(blen < 0)
     return 0;
 
-  result = Curl_conn_cf_send(cf->next, data, buf, (size_t)blen, FALSE,
+  result = Curl_conn_cf_send(cf->next, data,
+                             (const uint8_t *)buf, (size_t)blen, FALSE,
                              &nwritten);
   CURL_TRC_CF(data, cf, "ossl_bio_cf_out_write(len=%d) -> %d, %zu",
               blen, result, nwritten);
diff --git a/lib/vtls/rustls.c b/lib/vtls/rustls.c
index 3b5bea2c6f..cc19a328ed 100644
--- a/lib/vtls/rustls.c
+++ b/lib/vtls/rustls.c
@@ -133,7 +133,7 @@ write_cb(void *userdata, const uint8_t *buf, uintptr_t len, uintptr_t *out_n)
   size_t nwritten;
 
   result = Curl_conn_cf_send(io_ctx->cf->next, io_ctx->data,
-                             (const char *)buf, len, FALSE, &nwritten);
+                             buf, len, FALSE, &nwritten);
   if(result) {
     nwritten = 0;
     if(CURLE_AGAIN == result)
diff --git a/lib/vtls/schannel.c b/lib/vtls/schannel.c
index f7e831f002..e5fbe40a8c 100644
--- a/lib/vtls/schannel.c
+++ b/lib/vtls/schannel.c
@@ -1074,7 +1074,8 @@ schannel_connect_step1(struct Curl_cfilter *cf, struct Curl_easy *data)
 
   /* send initial handshake data which is now stored in output buffer */
   result = Curl_conn_cf_send(cf->next, data,
-                             outbuf.pvBuffer, outbuf.cbBuffer, FALSE,
+                             (const uint8_t *)outbuf.pvBuffer,
+                             outbuf.cbBuffer, FALSE,
                              &written);
   Curl_pSecFn->FreeContextBuffer(outbuf.pvBuffer);
   if(result || (outbuf.cbBuffer != written)) {
@@ -1307,7 +1308,8 @@ schannel_connect_step2(struct Curl_cfilter *cf, struct Curl_easy *data)
 
           /* send handshake token to server */
           result = Curl_conn_cf_send(cf->next, data,
-                                     outbuf[i].pvBuffer, outbuf[i].cbBuffer,
+                                     (const uint8_t *)outbuf[i].pvBuffer,
+                                     outbuf[i].cbBuffer,
                                      FALSE, &written);
           if(result || (outbuf[i].cbBuffer != written)) {
             failf(data, "schannel: failed to send next handshake data: "
@@ -2004,7 +2006,8 @@ schannel_send(struct Curl_cfilter *cf, struct Curl_easy *data,
       /* socket is writable */
 
        result = Curl_conn_cf_send(cf->next, data,
-                                  ptr + *pnwritten, len - *pnwritten,
+                                  (const uint8_t *)ptr + *pnwritten,
+                                  len - *pnwritten,
                                   FALSE, &this_write);
       if(result == CURLE_AGAIN)
         continue;
@@ -2450,7 +2453,8 @@ static CURLcode schannel_shutdown(struct Curl_cfilter *cf,
       size_t written;
 
       result = Curl_conn_cf_send(cf->next, data,
-                                 outbuf.pvBuffer, outbuf.cbBuffer,
+                                 (const uint8_t *)outbuf.pvBuffer,
+                                 outbuf.cbBuffer,
                                  FALSE, &written);
       Curl_pSecFn->FreeContextBuffer(outbuf.pvBuffer);
       if(!result) {
diff --git a/lib/vtls/vtls.c b/lib/vtls/vtls.c
index 9c76ca7ed3..3b242fd485 100644
--- a/lib/vtls/vtls.c
+++ b/lib/vtls/vtls.c
@@ -1477,7 +1477,7 @@ static bool ssl_cf_data_pending(struct Curl_cfilter *cf,
 
 static CURLcode ssl_cf_send(struct Curl_cfilter *cf,
                             struct Curl_easy *data,
-                            const void *buf, size_t blen,
+                            const uint8_t *buf, size_t blen,
                             bool eos, size_t *pnwritten)
 {
   struct ssl_connect_data *connssl = cf->ctx;
@@ -1509,7 +1509,7 @@ static CURLcode ssl_cf_send(struct Curl_cfilter *cf,
     }
     else {
       *pnwritten = connssl->earlydata_skip;
-      buf = ((const char *)buf) + connssl->earlydata_skip;
+      buf = buf + connssl->earlydata_skip;
       blen -= connssl->earlydata_skip;
       connssl->earlydata_skip = 0;
     }
diff --git a/lib/vtls/wolfssl.c b/lib/vtls/wolfssl.c
index e622f909e5..2ad033f988 100644
--- a/lib/vtls/wolfssl.c
+++ b/lib/vtls/wolfssl.c
@@ -334,7 +334,8 @@ static int wssl_bio_cf_out_write(WOLFSSL_BIO *bio,
     skiplen = (ssize_t)(blen - wssl->io_send_blocked_len);
     blen = wssl->io_send_blocked_len;
   }
-  result = Curl_conn_cf_send(cf->next, data, buf, blen, FALSE, &nwritten);
+  result = Curl_conn_cf_send(cf->next, data,
+                             (const uint8_t *)buf, blen, FALSE, &nwritten);
   wssl->io_result = result;
   CURL_TRC_CF(data, cf, "bio_write(len=%d) -> %d, %zu",
               blen, result, nwritten);