CookieContainer doesn't replace Cookie with same name

[adjgam]

Description

CookieContainer doesn't replace cookie which added using CookieContainer.Add(Uri uri, Cookie cookie)

Reproduction Steps

1. Add cookie to CookieContainer
2. Do http/s request
3. Receive cookie from web server with existing cookie name in CookieContainer

Expected behavior

New cookie received from web server must replace existing cookie with same name

Actual behavior

New cookie doesn't replace old cookie and we have two cookies with same name

Regression?

No response

Known Workarounds

No response

Configuration

Win 10 .Net 6.0.16 7.0.5 .Net Framework 4.7 4.8 4.8.1

Other information

static Task<HttpResponseMessage> HttpReq(CookieContainer cookieContainer)
{
    string url = "https://arduino.ua/";

    // Now create a client handler which uses that proxy
    var httpClientHandler = new HttpClientHandler
    {
        CookieContainer = cookieContainer,
        UseCookies = true
    };

    httpClientHandler.AllowAutoRedirect = true;

    var client = new HttpClient(
        handler: httpClientHandler,
        disposeHandler: true
        );


    client.Timeout = TimeSpan.FromSeconds(30);
    // add default headers
    client.DefaultRequestHeaders.TryAddWithoutValidation("Accept", "text/javascript, text/html, application/xml, text/xml, */*");
    client.DefaultRequestHeaders.TryAddWithoutValidation("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/109.0");
    client.DefaultRequestHeaders.TryAddWithoutValidation("Accept-Encoding", "gzip, deflate, br");
    client.DefaultRequestHeaders.TryAddWithoutValidation("Accept-Language", "uk-UA,uk;q=0.8,en-US;q=0.5,en;q=0.3");


    var response = client.GetAsync(url);
    return response;

}


var cookieContainer = new CookieContainer();

Uri uri = new Uri("https://arduino.ua");
System.DateTime today = System.DateTime.Now;
System.DateTime Expires = today.AddYears(1);

Cookie cookie = new Cookie();
cookie.Expires = Expires;
cookie.HttpOnly = false;
cookie.Value = "nnnnn";
cookie.Name = "FBeID";
cookie.Domain = "arduino.ua";

cookieContainer.Add(uri, cookie);

var response = HttpReq(cookieContainer);
response.Result.Content.ReadAsStringAsync().Wait();

IEnumerable<Cookie> responseCookies = cookieContainer.GetCookies(uri).Cast<Cookie>();
foreach (Cookie new_cookie in responseCookies)
{
    Console.WriteLine(new_cookie.Name + "=" +new_cookie.Value);
}

request cookies:
Cookie: FBeID=nnnnn

resonce cookies:
Set-Cookie: PHPSESSID=eljpt8ef572ulpqn6bkv6io93h; expires=Thu, 18-Jan-2024 02:33:24 GMT; Max-Age=24105600; path=/
Set-Cookie: FBeID=1423878233

CookieContainer content:
PHPSESSID=eljpt8ef572ulpqn6bkv6io93h
FBeID=1423878233
FBeID=nnnnn

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Issue Details

---

Description

CookieContainer doesn't replace cookie which added using CookieContainer.Add(Uri uri, Cookie cookie)

Reproduction Steps

1. Add cookie to CookieContainer
2. Do http/s request
3. Receive cookie from web server with existing cookie name in CookieContainer

Expected behavior

New cookie received from web server must replace existing cookie with same name

Actual behavior

New cookie doesn't replace old cookie and we have two cookies with same name

Regression?

No response

Known Workarounds

No response

Configuration

Win 10 .Net 6.0.16 7.0.5 .Net Framework 4.7 4.8 4.8.1

Other information

static Task<HttpResponseMessage> HttpReq(CookieContainer cookieContainer)
{
    string url = "https://arduino.ua/";

    // Now create a client handler which uses that proxy
    var httpClientHandler = new HttpClientHandler
    {
        CookieContainer = cookieContainer,
        UseCookies = true
    };

    httpClientHandler.AllowAutoRedirect = true;

    var client = new HttpClient(
        handler: httpClientHandler,
        disposeHandler: true
        );


    client.Timeout = TimeSpan.FromSeconds(30);
    // add default headers
    client.DefaultRequestHeaders.TryAddWithoutValidation("Accept", "text/javascript, text/html, application/xml, text/xml, */*");
    client.DefaultRequestHeaders.TryAddWithoutValidation("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/109.0");
    client.DefaultRequestHeaders.TryAddWithoutValidation("Accept-Encoding", "gzip, deflate, br");
    client.DefaultRequestHeaders.TryAddWithoutValidation("Accept-Language", "uk-UA,uk;q=0.8,en-US;q=0.5,en;q=0.3");


    var response = client.GetAsync(url);
    return response;

}


var cookieContainer = new CookieContainer();

Uri uri = new Uri("https://arduino.ua");
System.DateTime today = System.DateTime.Now;
System.DateTime Expires = today.AddYears(1);

Cookie cookie = new Cookie();
cookie.Expires = Expires;
cookie.HttpOnly = false;
cookie.Value = "nnnnn";
cookie.Name = "FBeID";
cookie.Domain = "arduino.ua";

cookieContainer.Add(uri, cookie);

var response = HttpReq(cookieContainer);
response.Result.Content.ReadAsStringAsync().Wait();

IEnumerable<Cookie> responseCookies = cookieContainer.GetCookies(uri).Cast<Cookie>();
foreach (Cookie new_cookie in responseCookies)
{
    Console.WriteLine(new_cookie.Name + "=" +new_cookie.Value);
}

request cookies:
Cookie: FBeID=nnnnn

resonce cookies:
Set-Cookie: PHPSESSID=eljpt8ef572ulpqn6bkv6io93h; expires=Thu, 18-Jan-2024 02:33:24 GMT; Max-Age=24105600; path=/
Set-Cookie: FBeID=1423878233

CookieContainer content:
PHPSESSID=eljpt8ef572ulpqn6bkv6io93h
FBeID=1423878233
FBeID=nnnnn

Author:	adjgam
Assignees:	-
Labels:	area-System.Net, untriaged
Milestone:	-

[ManickaP]

For some reason, the manually created cookie gets the DomainKey changed to contain a leading dot (the cookie gets cloned before inserting into the container). Then, the container has the cookies in different buckets and thus doesn't match them.

I'd say this belongs to the batch of cookie problems in #40328.

We also did some targeted fix for leading dot in #39781.

cc @CarnaViire @antonfirsov

[ManickaP]

Looking more into the history, seems like #64038 didn't catch all possibilities. We might also use:

runtime/src/libraries/Common/src/System/Net/CookieComparer.cs

Lines 25 to 30 in d0a287a

	internal static bool EqualDomains(ReadOnlySpan<char> left, ReadOnlySpan<char> right)
	{
	if (left.Length != 0 && left[0] == '.') left = left.Slice(1);
	if (right.Length != 0 && right[0] == '.') right = right.Slice(1);
	return left.Equals(right, StringComparison.OrdinalIgnoreCase);

As equality comparer for the hashtable:

runtime/src/libraries/System.Net.Primitives/src/System/Net/CookieContainer.cs

Line 103 in d0a287a

private readonly Hashtable m_domainTable = new Hashtable(); // Do not rename (binary serialization)

[antonfirsov]

A minimal repro to trigger this issue would be:

Uri uri = new Uri("https://arduino.ua");
CookieContainer container = new();
Cookie a = new()
{
    Domain= "arduino.ua",
    Name = "FBeID",
    Value = "0"
};
container.Add(uri, a);
container.SetCookies(uri, "FBeID=42");
Assert.Equal(1, container.Count);

For some reason, the manually created cookie gets the DomainKey changed to contain a leading dot

The manually created cookie has an explicitly set domain and CookieContainer is adding a leading dot when the domain is explicit. @adjgam a workaround to this issue is to remove the line setting the domain:

cookie.Domain = "arduino.ua";

According to RFC 6265 we should remove leading dots not add them, however I would be afraid to apply any naïve changes to the code without reviewing the bigger picture and the behavior of various browsers like for other cases described in #40328. Unfortunately, people may depend on the current behavior.

Moving to Future for now.