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fix(remix): Correctly parse X-Forwarded-For Http header #7329

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merged 3 commits into from
Mar 6, 2023
Merged

fix(remix): Correctly parse X-Forwarded-For Http header #7329

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0b520ee
fix(remix): Correctly parse `X-Forwarded-For` Http header
Lms24 Mar 3, 2023
4218dae
fix linter error
Lms24 Mar 3, 2023
bc62629
add more tests
Lms24 Mar 6, 2023
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2 changes: 1 addition & 1 deletion packages/remix/src/utils/getIpAddress.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -52,7 +52,7 @@ export function getClientIPAddress(headers: Headers): string | null {
return parseForwardedHeader(value);
}

return value?.split(', ');
return value?.split(',').map((v: string) => v.trim());
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Super-l: This may be slightly more efficient as:

return value ? value.replace(/\s*/gm, '').split(',') : null;

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@Lms24 Lms24 Mar 6, 2023 •
edited

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Generally good idea (and I definitely didn't think of this initially) but my only concern here is that we're potentially rewriting individual IP addresses in the header value, very potentially making an invalid IP address appear valid:

'2b01:cb19:8350:ed00:d0 dd:fa5b:de31:8be5, 141.101.69.35' would first be rewritten to
'2b01:cb19:8350:ed00:d0dd:fa5b:de31:8be5,141.101.69.35' before it's split, resulting in the function returning 2b01:cb19:8350:ed00:d0dd:fa5b:de31:8be5 when it would otherwise have returned 141.101.69.35.

Of course, that's a super unlikely edge case but I'd rather avoid it. Wdyt?

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Wouldn't both code snippets (so the regex and the trim variants) return the same thing in this scenario? 😅 But maybe I am missing something here :) really it probably doesn't matter at all, so let's just go with what you wrote 👍

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Since trim only looks at trailing/leading white spaces it'd not touch the whitespace in the middle of the originally invalid IP address. (I double checked this with a test, just to be sure because I was also confused 😅 ).

But yeah, I'll go with the original version.

});

// Flatten the array and filter out any falsy entries
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37 changes: 37 additions & 0 deletions packages/remix/test/utils/getIpAddress.test.ts
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@@ -0,0 +1,37 @@
import { getClientIPAddress } from '../../src/utils/getIpAddress';

class Headers {
private _headers: Record<string, string> = {};

get(key: string): string | null {
return this._headers[key] ?? null;
}

set(key: string, value: string): void {
this._headers[key] = value;
}
}

describe('getClientIPAddress', () => {
it.each([
[
'2b01:cb19:8350:ed00:d0dd:fa5b:de31:8be5,2b01:cb19:8350:ed00:d0dd:fa5b:de31:8be5, 141.101.69.35',
'2b01:cb19:8350:ed00:d0dd:fa5b:de31:8be5',
Comment on lines +17 to +19
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@Lms24 Lms24 Mar 3, 2023 •
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This test failed before the fix, returning 141.101.69.35 instead of 2b01:cb19:8350:ed00:d0dd:fa5b:de31:8be5, due to a missing space after the first comma.

],
[
'2b01:cb19:8350:ed00:d0dd:fa5b:de31:8be5, 2b01:cb19:8350:ed00:d0dd:fa5b:de31:8be5, 141.101.69.35',
'2b01:cb19:8350:ed00:d0dd:fa5b:de31:8be5',
],
[
'2a01:cb19:8350:ed00:d0dd:INVALID_IP_ADDR:8be5,141.101.69.35,2a01:cb19:8350:ed00:d0dd:fa5b:de31:8be5',
'141.101.69.35',
],
])('should parse the IP from the X-Forwarded-For header %s', (headerValue, expectedIP) => {
const headers = new Headers();
headers.set('X-Forwarded-For', headerValue);

const ip = getClientIPAddress(headers as any);

expect(ip).toEqual(expectedIP);
});
});