./ paths relative on page.

src/Microsoft.AspNetCore.Mvc.Core/Internal/ViewEnginePath.cs

@@ -11,6 +11,7 @@ namespace Microsoft.AspNetCore.Mvc.Core.Internal
 {
     public static class ViewEnginePath
     {
+        private const string CurrentDirectoryToken = ".";
         private const string ParentDirectoryToken = "..";
         private static readonly char[] _pathSeparators = new[] { '/', '\\' };
 
@@ -70,6 +71,11 @@ namespace Microsoft.AspNetCore.Mvc.Core.Internal
                     }
                     pathSegments.RemoveAt(pathSegments.Count - 1);
                 }
+                else if (segment.Equals(CurrentDirectoryToken, StringComparison.Ordinal))
+                {
+                    // We already have the current directory
+                    continue;
+                }
                 else
                 {
                     pathSegments.Add(segment);
@@ -89,7 +95,8 @@ namespace Microsoft.AspNetCore.Mvc.Core.Internal
 
         private static bool RequiresPathResolution(string path)
         {
-            return path.IndexOf(ParentDirectoryToken, StringComparison.Ordinal) != -1;
+            return path.IndexOf(ParentDirectoryToken, StringComparison.Ordinal) != -1 ||
+                path.IndexOf(CurrentDirectoryToken, StringComparison.Ordinal) != -1;
         }
     }
 }

src/Microsoft.AspNetCore.Mvc.Core/Resources.resx

@@ -404,6 +404,6 @@
     <value>No page named '{0}' matches the supplied values.</value>
   </data>
   <data name="UrlHelper_RelativePagePathIsNotSupported" xml:space="preserve">
-    <value>The relative page path '{0}' can only can only be used while executing a Razor Page. Specify a root relative path with a leading '/' to generate a URL outside of a Razor Page.</value>
+    <value>The relative page path '{0}' can only be used while executing a Razor Page. Specify a root relative path with a leading '/' to generate a URL outside of a Razor Page.</value>
   </data>
 </root>

test/Microsoft.AspNetCore.Mvc.Core.Test/RedirectToPageResultTest.cs

@@ -77,6 +77,63 @@ namespace Microsoft.AspNetCore.Mvc
             httpResponse.Verify(r => r.Redirect(expectedUrl, permanentRedirect), Times.Exactly(1));
         }
 
+        [Fact]
+        public async Task ExecuteResultAsync_LocalRelativePaths()
+        {
+            // Arrange
+            var httpContext = new DefaultHttpContext
+            {
+                RequestServices = CreateServices(),
+            };
+
+            var pageContext = new PageContext
+            {
+                HttpContext = httpContext,
+                RouteData = new RouteData(),
+                ActionDescriptor = new CompiledPageActionDescriptor(),
+            };
+
+            pageContext.RouteData.Values.Add("page", "/A/Redirecting/Page");
+
+            UrlRouteContext context = null;
+            var urlHelper = new Mock<IUrlHelper>();
+            urlHelper.SetupGet(h => h.ActionContext).Returns(pageContext);
+            urlHelper.Setup(h => h.RouteUrl(It.IsAny<UrlRouteContext>()))
+                .Callback((UrlRouteContext c) => context = c)
+                .Returns("some-value");
+            var values = new { test = "test-value" };
+            var result = new RedirectToPageResult("./", "page-handler", values, true, "test-fragment")
+            {
+                UrlHelper = urlHelper.Object,
+                Protocol = "ftp",
+            };
+
+            // Act
+            await result.ExecuteResultAsync(pageContext);
+
+            // Assert
+            Assert.NotNull(context);
+            Assert.Null(context.RouteName);
+            Assert.Collection(Assert.IsType<RouteValueDictionary>(context.Values),
+                value =>
+                {
+                    Assert.Equal("test", value.Key);
+                    Assert.Equal("test-value", value.Value);
+                },
+                value =>
+                {
+                    Assert.Equal("page", value.Key);
+                    Assert.Equal("/A/Redirecting", value.Value);
+                },
+                value =>
+                {
+                    Assert.Equal("handler", value.Key);
+                    Assert.Equal("page-handler", value.Value);
+                });
+            Assert.Equal("ftp", context.Protocol);
+            Assert.Equal("test-fragment", context.Fragment);
+        }
+
         [Fact]
         public async Task ExecuteResultAsync_WithAllParameters()
         {

test/Microsoft.AspNetCore.Mvc.Core.Test/Routing/UrlHelperTest.cs

@@ -1518,7 +1518,7 @@ namespace Microsoft.AspNetCore.Mvc.Routing
 
             // Act & Assert
             var ex = Assert.Throws<InvalidOperationException>(() => urlHelper.Object.Page(expected));
-            Assert.Equal($"The relative page path '{expected}' can only can only be used while executing a Razor Page. " +
+            Assert.Equal($"The relative page path '{expected}' can only be used while executing a Razor Page. " +
                 "Specify a root relative path with a leading '/' to generate a URL outside of a Razor Page.", ex.Message);
         }
 

test/Microsoft.AspNetCore.Mvc.FunctionalTests/RazorPagesTest.cs

@@ -924,6 +924,20 @@ Microsoft.AspNetCore.Mvc.ViewFeatures.ViewDataDictionary`1[AspNetCore._InjectedP
             Assert.Equal(expected, response.Headers.Location.ToString());
         }
 
+        [Fact]
+        public async Task RedirectToSibling_RedirectsToDotSlash()
+        {
+            // Arrange
+            var expected = "/Pages/Redirects/SubDir/SubDirPage";
+
+            // Act
+            var response = await Client.GetAsync("/Pages/Redirects/RedirectToSibling/RedirectToDotSlash");
+
+            // Assert
+            Assert.Equal(HttpStatusCode.Redirect, response.StatusCode);
+            Assert.Equal(expected, response.Headers.Location.ToString());
+        }
+
         [Fact]
         public async Task RedirectToSibling_RedirectsToParentDirectory()
         {
@@ -940,8 +954,8 @@ Microsoft.AspNetCore.Mvc.ViewFeatures.ViewDataDictionary`1[AspNetCore._InjectedP
         public async Task TagHelpers_SupportSiblingRoutes()
         {
             // Arrange
-var expected = 
-@"<form method=""post"" action=""/Pages/TagHelper/CrossPost""></form>
+            var expected =
+            @"<form method=""post"" action=""/Pages/TagHelper/CrossPost""></form>
 <a href=""/Pages/TagHelper/SelfPost/12"" />
 <input type=""image"" formaction=""/Pages/TagHelper/CrossPost#my-fragment"" />";
 
@@ -956,8 +970,8 @@ var expected =
         public async Task TagHelpers_SupportSubDirectoryRoutes()
         {
             // Arrange
-var expected = 
-@"<form method=""post"" action=""/Pages/TagHelper/SubDir/SubDirPage""></form>
+            var expected =
+            @"<form method=""post"" action=""/Pages/TagHelper/SubDir/SubDirPage""></form>
 <a href=""/Pages/TagHelper/SubDir/SubDirPage/12"" />
 <input type=""image"" formaction=""/Pages/TagHelper/SubDir/SubDirPage#my-fragment"" />";
 
@@ -972,8 +986,8 @@ var expected =
         public async Task TagHelpers_SupportsPathNavigation()
         {
             // Arrange
-var expected = 
-@"<form method=""post"" action=""/HelloWorld""></form>
+            var expected =
+            @"<form method=""post"" action=""/HelloWorld""></form>
 <a href=""/Pages/Redirects/RedirectToIndex"" />
 <input type=""image"" formaction=""/Pages/Admin#my-fragment"" />";
 
@@ -981,7 +995,20 @@ var expected =
             var response = await Client.GetStringAsync("/Pages/TagHelper/PathTraversalLinks");
 
             // Assert
-            Assert.Equal(expected, response.Trim());
+            Assert.EndsWith(expected, response.Trim());
+        }
+
+        [Fact]
+        public async Task TagHelpers_SupportsRelativeNavigation()
+        {
+            // Arrange
+            var expected = @"<form method=""post"" action=""/Pages/TagHelper/SubDirectoryLinks""></form>";
+
+            // Act
+            var response = await Client.GetStringAsync("/Pages/TagHelper/PathTraversalLinks");
+
+            // Assert
+            Assert.StartsWith(expected, response.Trim());
         }
 
         private async Task AddAntiforgeryHeaders(HttpRequestMessage request)

test/Microsoft.AspNetCore.Mvc.Razor.Test/RazorViewEngineTest.cs

@@ -1472,6 +1472,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor.Test
         [InlineData("/Views/Home/Index.cshtml", "..\\Shared\\_Partial.cshtml")]
         [InlineData("/Areas/MyArea/Views/Home/Index.cshtml", "../../../../Views/Shared/_Partial.cshtml")]
         [InlineData("/Views/Accounts/Users.cshtml", "../Test/../Shared/_Partial.cshtml")]
+        [InlineData("Views/Accounts/Users.cshtml", "./../Shared/./_Partial.cshtml")]
         public void GetAbsolutePath_ResolvesPathTraversals(string executingFilePath, string pagePath)
         {
             // Arrange

test/WebSites/RazorPagesWebSite/Pages/Redirects/RedirectToSibling.cshtml

@@ -8,4 +8,6 @@
     public IActionResult OnGetRedirectToSubDir() => RedirectToPage("SubDir/SubDirPage");
 
     public IActionResult OnGetRedirectToParent() => RedirectToPage("../Conventions/AuthFolder/Index");
+
+    public IActionResult OnGetRedirectToDotSlash() => RedirectToPage("./SubDir/SubDirPage");
 }

test/WebSites/RazorPagesWebSite/Pages/TagHelper/PathTraversalLinks.cshtml

@@ -1,5 +1,6 @@
 @page
 
+<form method="post" asp-page="./SubDirectoryLinks" asp-antiforgery="false"></form>
 <form method="post" asp-page="../../HelloWorld" asp-antiforgery="false"></form>
 <a asp-page="../Redirects/Index" asp-route-handler="RedirectToIndex" />
-<input type="image" asp-page="../Admin/Index" asp-fragment="my-fragment" />
+<input type="image" asp-page="../Admin/Index" asp-fragment="my-fragment" />