diff --git a/src/rgw/rgw_asio_client.cc b/src/rgw/rgw_asio_client.cc
index ccafa3498b8..82d5d43f8b8 100644
--- a/src/rgw/rgw_asio_client.cc
+++ b/src/rgw/rgw_asio_client.cc
@@ -54,6 +54,8 @@ int ClientIO::init_env(CephContext *cct)
     for (auto src = name.begin(); src != name.end(); ++src, ++dest) {
       if (*src == '-') {
         *dest = '_';
+      } else if (*src == '_') {
+        *dest = '-';
       } else {
         *dest = std::toupper(*src);
       }
diff --git a/src/rgw/rgw_auth_s3.cc b/src/rgw/rgw_auth_s3.cc
index f59f3126344..629d1b9825b 100644
--- a/src/rgw/rgw_auth_s3.cc
+++ b/src/rgw/rgw_auth_s3.cc
@@ -635,7 +635,7 @@ get_v4_canonical_headers(const req_info& info,
 
     std::transform(std::begin(token), std::end(token),
                    std::back_inserter(token_env), [](const int c) {
-                     return c == '-' ? '_' : std::toupper(c);
+                     return c == '-' ? '_' : c == '_' ? '-' : std::toupper(c);
                    });
 
     if (token_env == "HTTP_CONTENT_LENGTH") {
diff --git a/src/rgw/rgw_common.cc b/src/rgw/rgw_common.cc
index 4f764c2cffd..9314331557a 100644
--- a/src/rgw/rgw_common.cc
+++ b/src/rgw/rgw_common.cc
@@ -410,10 +410,12 @@ void req_info::init_meta_info(const DoutPrefixProvider *dpp, bool *found_bad_met
         snprintf(name_low, meta_prefixes[0].len - 5 + name_len + 1, "%s%s", meta_prefixes[0].str + 5 /* skip HTTP_ */, name); // normalize meta prefix
         int j;
         for (j = 0; name_low[j]; j++) {
-          if (name_low[j] != '_')
-            name_low[j] = tolower(name_low[j]);
-          else
+          if (name_low[j] == '_')
             name_low[j] = '-';
+          else if (name_low[j] == '-')
+            name_low[j] = '_';
+          else
+            name_low[j] = tolower(name_low[j]);
         }
         name_low[j] = 0;