/vsicurl/: fix a redirect to a URL ending with a slash followed by a 403

Author: rouault

autotest/gcore/vsicurl.py

@@ -1742,3 +1742,27 @@ def test_VSIFOpenExL_CACHE_NO(server):
 
         with gdal.VSIFile(filename, "rb", False, {"CACHE": "NO"}) as f:
             assert f.read() == b"1234"
+
+
+###############################################################################
+# Test redirection to a URL ending with a slash, followed by a 403
+
+
+def test_vsicurl_test_redirect_301_to_url_ending_slash_and_then_403(server):
+
+    gdal.VSICurlClearCache()
+
+    handler = webserver.SequentialHandler()
+    handler.add(
+        "HEAD",
+        "/test_redirect",
+        301,
+        {"Location": "http://localhost:%d/test_redirect/" % server.port},
+    )
+    handler.add("HEAD", "/test_redirect/", 403)
+
+    with webserver.install_http_handler(handler), gdal.quiet_errors():
+        assert (
+            gdal.VSIStatL("/vsicurl/http://localhost:%d/test_redirect" % server.port)
+            is None
+        )

port/cpl_vsil_curl.cpp

@@ -1363,31 +1363,35 @@ vsi_l_offset VSICurlHandle::GetFileSizeOrHeaders(bool bSetError,
             }
         }
 
-        curl_off_t nSizeTmp = 0;
-        const CURLcode code = curl_easy_getinfo(
-            hCurlHandle, CURLINFO_CONTENT_LENGTH_DOWNLOAD_T, &nSizeTmp);
-        CPL_IGNORE_RET_VAL(dfSize);
-        dfSize = static_cast<double>(nSizeTmp);
-        if (code == 0)
+        if (response_code < 400)
         {
-            oFileProp.eExists = EXIST_YES;
-            if (dfSize < 0)
+            curl_off_t nSizeTmp = 0;
+            const CURLcode code = curl_easy_getinfo(
+                hCurlHandle, CURLINFO_CONTENT_LENGTH_DOWNLOAD_T, &nSizeTmp);
+            CPL_IGNORE_RET_VAL(dfSize);
+            dfSize = static_cast<double>(nSizeTmp);
+            if (code == 0)
             {
-                if (osVerb == "HEAD" && !bRetryWithGet && response_code == 200)
+                oFileProp.eExists = EXIST_YES;
+                if (dfSize < 0)
                 {
-                    CPLDebug(
-                        poFS->GetDebugKey(),
-                        "HEAD did not provide file size. Retrying with GET");
-                    bRetryWithGet = true;
-                    CPLFree(sWriteFuncData.pBuffer);
-                    CPLFree(sWriteFuncHeaderData.pBuffer);
-                    curl_easy_cleanup(hCurlHandle);
-                    goto retry;
+                    if (osVerb == "HEAD" && !bRetryWithGet &&
+                        response_code == 200)
+                    {
+                        CPLDebug(poFS->GetDebugKey(),
+                                 "HEAD did not provide file size. Retrying "
+                                 "with GET");
+                        bRetryWithGet = true;
+                        CPLFree(sWriteFuncData.pBuffer);
+                        CPLFree(sWriteFuncHeaderData.pBuffer);
+                        curl_easy_cleanup(hCurlHandle);
+                        goto retry;
+                    }
+                    oFileProp.fileSize = 0;
                 }
-                oFileProp.fileSize = 0;
+                else
+                    oFileProp.fileSize = static_cast<GUIntBig>(dfSize);
             }
-            else
-                oFileProp.fileSize = static_cast<GUIntBig>(dfSize);
         }
 
         if (sWriteFuncHeaderData.pBuffer != nullptr &&
@@ -1605,7 +1609,8 @@ vsi_l_offset VSICurlHandle::GetFileSizeOrHeaders(bool bSetError,
         // directory, curl will retry with an URL with slash added.
         if (!osEffectiveURL.empty() &&
             strncmp(osURL.c_str(), osEffectiveURL.c_str(), osURL.size()) == 0 &&
-            osEffectiveURL[osURL.size()] == '/')
+            osEffectiveURL[osURL.size()] == '/' &&
+            oFileProp.eExists != EXIST_NO)
         {
             oFileProp.eExists = EXIST_YES;
             oFileProp.fileSize = 0;