[tor-bugs] #21278 [Core Tor/Tor]: Avoid signed integer underflow when comparing versions (Fix TROVE-2017-001)

[Tor Bug Tracker & Wiki]

#21278: Avoid signed integer underflow when comparing versions (Fix TROVE-2017-001)
--------------------------+------------------------------------
 Reporter:  nickm         |          Owner:  nickm
     Type:  defect        |         Status:  needs_revision
 Priority:  Medium        |      Milestone:  Tor: 0.3.0.x-final
Component:  Core Tor/Tor  |        Version:
 Severity:  Normal        |     Resolution:
 Keywords:  029-backport  |  Actual Points:
Parent ID:                |         Points:
 Reviewer:                |        Sponsor:
--------------------------+------------------------------------
Changes (by teor):

 * status:  needs_review => needs_revision


Comment:

 Replying to [comment:11 nickm]:
 > Okay.  So here's where we stand:
 >   * I have a `bug21278_024_v4` that has only the minimal fix for the
 integer issue.  I propose that it go into 0.2.4.

 This is ok, as anyone on a private network can stop their own relays
 misbehaving.
 `make check` passes for me on macOS 10.12 i386 and x86_64.

 >   * I have a `bug21278_redux_029` that blocks the bogus versions at the
 directory level, and includes a changes file and roger's function
 documentation.  I propose that it go into 0.2.9.

 This refuses to compile for me with:
 {{{
 src/or/routerparse.c:5555:32: error: comparison of unsigned enum
 expression < 0
       is always false [-Werror,-Wtautological-compare]
         router_version->status < 0 ||
 }}}
 on:
 {{{
 clang -arch i386 --version >&5
 clang version 3.9.1 (tags/RELEASE_391/final)
 Target: i386-apple-darwin16.4.0
 Thread model: posix
 }}}

 The 64-bit arch compiles and passes `make check test-network-all`.

 I don't know what the extra newline is doing in f1c2cea165, but that's a
 nitpick.

 The changes file in 1ff289a745 includes trailing whitespace.

 >   * I agree that it's okay to merge bug21278_024_v2_extra to 0.2.9. I
 have a `bug21278_extra_029` branch to port those forward.  I'm okay with
 taking that in 0.2.9 or 0.3.0.

 I think 029, in case there is a security issue here.

 `make check test-network-all` passes for me on macOS 10.12 i386 and
 x86_64.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/21278#comment:12>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online