[Bug 1916050] Re: Invalid base64 for high-bit characters

[Launchpad Bug Tracker]

This bug was fixed in the package apt - 2.0.5

---------------
apt (2.0.5) focal; urgency=medium

  [ Julian Andres Klode ]
  * private-search: Only use V.TranslatedDescription() if good (LP: #1877987)
  * Implement update --error-on=any (Closes: #594813) (LP: #1693900)
  * Include all translations when building the cache (LP: #1907850)
  * Add basic support for the Protected field, and do not require force-loopbreak
    on Protected/Important packages (Closes: #983014) (LP: #1916725)
  * Protect currently running kernel at run-time (LP: #1615381)
  * Make ADDARG{,C}() macros expand to single statements
  * Default Acquire::AllowReleaseInfoChange::Suite to "true" (Closes: #931566)
    (LP: #1918907)

  [ David Kalnischkies ]
  * Fix incorrect base64 encoding due to int promotion (LP: #1916050)
  * Harden test for no new acquires after transaction abort (Closes: #984966)
    (LP: #1918920)

 -- Julian Andres Klode <juliank at ubuntu.com>  Fri, 12 Mar 2021 12:47:30
+0100

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https://bugs.launchpad.net/bugs/1916050

Title:
  Invalid base64 for high-bit characters

Status in apt package in Ubuntu:
  Fix Released
Status in apt source package in Xenial:
  Confirmed
Status in apt source package in Bionic:
  Fix Released
Status in apt source package in Focal:
  Fix Released
Status in apt source package in Groovy:
  Fix Released
Status in apt source package in Hirsute:
  Fix Released

Bug description:
  [Impact]
  The Base64Encode function incorrectly encodes using char instead of uint8_t, leading to characters with the high bit set to be encoded wrongly. This function is used for base authentication, and high bits are set for UTF-8 character sequences, so it's likely affecting people with utf-8 user names and passwords and might cause them to be denied access to their https resources (though arguably they'd work around that).

  [Test case]
  A unit test has been added that checks that the encoding is correct.

  [Where problems could occur]
  This only affects the base64 encoding function, which is only used for quoting user names and passwords in basic auth in http, but it's also exposed to library users and like in python-apt, so problems could occur wherever they use that base64 encoding function as well.

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