[tor-bugs] #27367 [Core Tor/Tor]: Authorities should reject non-UTF-8 in relay descriptors

[Tor Bug Tracker & Wiki]

#27367: Authorities should reject non-UTF-8 in relay descriptors
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 Reporter:  teor                                 |          Owner:  (none)
     Type:  defect                               |         Status:
                                                 |  needs_revision
 Priority:  Medium                               |      Milestone:  Tor:
                                                 |  0.3.6.x-final
Component:  Core Tor/Tor                         |        Version:
 Severity:  Normal                               |     Resolution:
 Keywords:  rust-wants, prop285,                 |  Actual Points:
  034-triage-20180328, 034-removed-20180328      |
Parent ID:  #24033                               |         Points:
 Reviewer:                                       |        Sponsor:
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Comment (by teor):

 Replying to [comment:13 cyberpunks]:
 > Replying to [comment:7 teor]:
 > > Since the UTF-8 checking function accepts a length, we should probably
 also check for NUL. If we fail on the first NUL, this check becomes a
 last-ditch memory safety check, as most bytes in RAM are NUL.
 > >
 > > We should probably also log a bug warning if the function encounters a
 NUL byte:
 >
 > Receiving a NUL byte isn't a bug though. This function is processing
 untrusted input from `fetch_from_buf_http()` that might contain anything
 including NUL bytes.

 Right, it's not a bug in tor, but it is a protocol violation. (NUL bytes
 are ok in compressed content. But when it's uncompressed, it should all be
 UTF-8.)

 We probably don't need a separate check then.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/27367#comment:16>
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