Unsafe handling of user-specified cookies in treq
### Impact
Treq's request methods (`treq.get`, `treq.post`, `HTTPClient.request`, `HTTPClient.get`, etc.) accept cookies as a dictionary, for example:
```py
treq.get('
https://example.com/', cookies={'session': '1234'})
```
Such cookies are not bound to a single domain, and are therefore sent to *every* domain ("supercookies"). This can potentially cause sensitive information to leak upon an HTTP redirect to a different domain., e.g. should `https://example.com` redirect to `http://cloudstorageprovider.com` the latter will receive the cookie `session`.
### Patches
Treq 2021.1.0 and later bind cookies given to request methods (`treq.request`, `treq.get`, `HTTPClient.request`, `HTTPClient.get`, etc.) to the origin of the *url* parameter.
### Workarounds
Instead of passing a dictionary as the *cookies* argument, pass a `http.cookiejar.CookieJar` instance with properly domain- and scheme-scoped cookies in it:
```py
from http.cookiejar import CookieJar
from requests.cookies import create_cookie
jar = CookieJar()
jar.add_cookie(
create_cookie(
name='session',
value='1234',
domain='
example.com',
secure=True,
),
)
client = HTTPClient(cookies=jar)
client.get('
https://example.com/')
```
### References
* Originally reported at huntr.dev
https://huntr.dev/bounties/3c9204fc-a3d1-4441-8599-924c5f57e7ae/?token=06d930e37046c914bcb037e85cc227dc7b510b475989fc69837566562ba899277d46b0fb4b1e21cdcb6ddc1b7d9b1ded632cf3a3551ecb89afca16a63b34641284b50479d5195bba2ac09b116f3dd4fad27f54404c2de922c05c8c8b744aec27bb4d4d198cb8b3abf479af0c2d5fbaa10412da7922594ac3eb39
* A related issue in the handling of HTTP basic authentication was addressed in Twisted 22.1 (GHSA-92x2-jw7w-xvvx
https://github.com/twisted/twisted/security/advisories/GHSA-92x2-jw7w-xvvx, CVE-2022-21712).