Fix snprintf/swnprintf related compiler warnings

When openvpn_snprintf is replaced by snprintf the GCC/MSVC compiler
will perform additional checks that the result is not truncated.

This warning can be avoid by either explicitly checking the return value
of snprintf (proxy) or ensuring that it is never truncated(tls crypt)

Change-Id: If23988a05dd53a519c5e57f2aa3b2d10bd29df1d
Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Frank Lichtenheld <frank@lichtenheld.com>
Message-Id: <20240326104101.531291-1-frank@lichtenheld.com>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg28475.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>

5 files changed, 25 insertions, 17 deletions

diff --git a/src/openvpn/proxy.c b/src/openvpn/proxy.c
index c904301..5c1cdcb 100644
--- a/src/openvpn/proxy.c
+++ b/src/openvpn/proxy.c
@@ -948,17 +948,21 @@ establish_http_proxy_passthru(struct http_proxy_info *p,
                 }
 
                 /* send digest response */
-                openvpn_snprintf(buf, sizeof(buf), "Proxy-Authorization: Digest username=\"%s\", realm=\"%s\", nonce=\"%s\", uri=\"%s\", qop=%s, nc=%s, cnonce=\"%s\", response=\"%s\"%s",
-                                 username,
-                                 realm,
-                                 nonce,
-                                 uri,
-                                 qop,
-                                 nonce_count,
-                                 cnonce,
-                                 response,
-                                 opaque_kv
-                                 );
+                int sret = openvpn_snprintf(buf, sizeof(buf), "Proxy-Authorization: Digest username=\"%s\", realm=\"%s\", nonce=\"%s\", uri=\"%s\", qop=%s, nc=%s, cnonce=\"%s\", response=\"%s\"%s",
+                                            username,
+                                            realm,
+                                            nonce,
+                                            uri,
+                                            qop,
+                                            nonce_count,
+                                            cnonce,
+                                            response,
+                                            opaque_kv
+                                            );
+                if (sret >= sizeof(buf))
+                {
+                    goto error;
+                }
                 msg(D_PROXY, "Send to HTTP proxy: '%s'", buf);
                 if (!send_line_crlf(sd, buf))
                 {
diff --git a/src/openvpn/socks.c b/src/openvpn/socks.c
index d842666..b046910 100644
--- a/src/openvpn/socks.c
+++ b/src/openvpn/socks.c
@@ -109,8 +109,11 @@ socks_username_password_auth(struct socks_proxy_info *p,
             "Authentication not possible.");
         goto cleanup;
     }
-    openvpn_snprintf(to_send, sizeof(to_send), "\x01%c%s%c%s", (int) strlen(creds.username),
-                     creds.username, (int) strlen(creds.password), creds.password);
+    int sret = openvpn_snprintf(to_send, sizeof(to_send), "\x01%c%s%c%s",
+                                (int) strlen(creds.username), creds.username,
+                                (int) strlen(creds.password), creds.password);
+    ASSERT(sret <= sizeof(to_send));
+
     size = send(sd, to_send, strlen(to_send), MSG_NOSIGNAL);
 
     if (size != strlen(to_send))
diff --git a/src/openvpn/ssl_openssl.c b/src/openvpn/ssl_openssl.c
index 4383e98..6f29c3d 100644
--- a/src/openvpn/ssl_openssl.c
+++ b/src/openvpn/ssl_openssl.c
@@ -2069,7 +2069,7 @@ print_pkey_details(EVP_PKEY *pkey, char *buf, size_t buflen)
 #endif
 
 #ifndef OPENSSL_NO_EC
-    char groupname[256];
+    char groupname[64];
     if (is_ec)
     {
         size_t len;
@@ -2130,7 +2130,7 @@ static void
 print_cert_details(X509 *cert, char *buf, size_t buflen)
 {
     EVP_PKEY *pkey = X509_get_pubkey(cert);
-    char pkeybuf[128] = { 0 };
+    char pkeybuf[64] = { 0 };
     print_pkey_details(pkey, pkeybuf, sizeof(pkeybuf));
 
     char sig[128] = { 0 };
diff --git a/src/openvpn/tls_crypt.c b/src/openvpn/tls_crypt.c
index 975d31f..6ef1c7d 100644
--- a/src/openvpn/tls_crypt.c
+++ b/src/openvpn/tls_crypt.c
@@ -575,7 +575,7 @@ tls_crypt_v2_verify_metadata(const struct tls_wrap_ctx *ctx,
 
     char metadata_type_str[4] = { 0 }; /* Max value: 255 */
     openvpn_snprintf(metadata_type_str, sizeof(metadata_type_str),
-                     "%i", metadata_type);
+                     "%i", (uint8_t) metadata_type);
     struct env_set *es = env_set_create(NULL);
     setenv_str(es, "script_type", "tls-crypt-v2-verify");
     setenv_str(es, "metadata_type", metadata_type_str);
diff --git a/src/openvpnserv/interactive.c b/src/openvpnserv/interactive.c
index 452633c..d32223c 100644
--- a/src/openvpnserv/interactive.c
+++ b/src/openvpnserv/interactive.c
@@ -33,6 +33,7 @@
 #include <sddl.h>
 #include <shellapi.h>
 #include <mstcpip.h>
+#include <inttypes.h>
 
 #include <versionhelpers.h>
 
@@ -2002,7 +2003,7 @@ RunOpenvpn(LPVOID p)
         ReturnLastError(pipe, L"malloc");
         goto out;
     }
-    openvpn_swprintf(cmdline, cmdline_size, L"openvpn %ls --msg-channel %lu",
+    openvpn_swprintf(cmdline, cmdline_size, L"openvpn %ls --msg-channel %" PRIuPTR,
                      sud.options, svc_pipe);
 
     if (!CreateEnvironmentBlock(&user_env, imp_token, FALSE))