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Reject control characters in IsLocalUrl check #25378

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Merged
merged 1 commit into from
Sep 3, 2020
Merged

Reject control characters in IsLocalUrl check #25378

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21 changes: 18 additions & 3 deletions src/Mvc/Mvc.Core/src/Routing/UrlHelperBase.cs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
// Copyright (c) .NET Foundation. All rights reserved.
// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
Expand Down Expand Up @@ -60,7 +60,7 @@ public virtual bool IsLocalUrl(string url)
// url doesn't start with "//" or "/\"
if (url[1] != '/' && url[1] != '\\')
{
return true;
return !HasControlCharacter(url.AsSpan(1));
}

return false;
Expand All @@ -78,15 +78,30 @@ public virtual bool IsLocalUrl(string url)
// url doesn't start with "~//" or "~/\"
if (url[2] != '/' && url[2] != '\\')
{
return true;
return !HasControlCharacter(url.AsSpan(2));
}

return false;
}

return false;

static bool HasControlCharacter(ReadOnlySpan<char> readOnlySpan)
{
// URLs may not contain ASCII control characters.
for (var i = 0; i < readOnlySpan.Length; i++)
{
if (char.IsControl(readOnlySpan[i]))
{
return true;
}
}

return false;
}
}


/// <inheritdoc />
public virtual string Content(string contentPath)
{
Expand Down
39 changes: 38 additions & 1 deletion src/Mvc/Mvc.Core/test/Routing/UrlHelperTestBase.cs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
// Copyright (c) .NET Foundation. All rights reserved.
// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
Expand Down Expand Up @@ -288,6 +288,43 @@ public void IsLocalUrl_RejectsInvalidTokenUrls(string url)
Assert.False(result);
}

[Theory]
[InlineData("\n")]
[InlineData("\\n")]
[InlineData("/\n")]
[InlineData("~\n")]
[InlineData("~/\n")]
public void IsLocalUrl_RejectsUrlWithNewLineAtStart(string url)
{
// Arrange
var helper = CreateUrlHelper(appRoot: string.Empty, host: "www.mysite.com", protocol: null);

// Act
var result = helper.IsLocalUrl(url);

// Assert
Assert.False(result);
}

[Theory]
[InlineData("/\r\nsomepath")]
[InlineData("~/\r\nsomepath")]
[InlineData("/some\npath")]
[InlineData("~/some\npath")]
[InlineData("\\path\b")]
[InlineData("~\\path\b")]
public void IsLocalUrl_RejectsUrlWithControlCharacters(string url)
{
// Arrange
var helper = CreateUrlHelper(appRoot: string.Empty, host: "www.mysite.com", protocol: null);

// Act
var result = helper.IsLocalUrl(url);

// Assert
Assert.False(result);
}

[Fact]
public void RouteUrlWithDictionary()
{
Expand Down