Re: [tor-bugs] #21134 [Core Tor/Tor]: Fail if file is too large to mmap.

["Tor Bug Tracker & Wiki" <blackhole@xxxxxxxxxxxxxx>]

#21134: Fail if file is too large to mmap.
---------------------------+------------------------------------
 Reporter:  junglefowl     |          Owner:
     Type:  defect         |         Status:  needs_information
 Priority:  Medium         |      Milestone:  Tor: 0.3.0.x-final
Component:  Core Tor/Tor   |        Version:  Tor: 0.2.9.8
 Severity:  Normal         |     Resolution:
 Keywords:  tor_mmap_file  |  Actual Points:
Parent ID:                 |         Points:
 Reviewer:                 |        Sponsor:
---------------------------+------------------------------------
Changes (by dgoulet):

 * status:  needs_review => needs_information


Comment:

 Hrm, both on 32 and 64 bit, don't `size_t` and `off_t` (st.st_size) are
 the same size? If so, that `SIZE_MAX` check is only useful with "==". I do
 think the `<` check is useful which would detect the overflow if the
 pagesize adjustment triggers it.

 {{{
 if (st.st_size >= SIZE_MAX || size < st.st_size) {
 }}}

 This snippet gives me the same size (on 64 bit and -m32):
 {{{
   size_t max = SIZE_MAX;
   off_t max2 = (~(off_t)0);
 }}}

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/21134#comment:2>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online
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