* [9fans] IOHDRSZ @ 2013-04-04 19:50 erik quanstrom 2013-04-04 20:14 ` Charles Forsyth 0 siblings, 1 reply; 3+ messages in thread From: erik quanstrom @ 2013-04-04 19:50 UTC (permalink / raw) To: 9fans i wonder if the typical use of IOHDRSZ is correct. many programs set msize = bufsize + IOHDRSIZE but Twrite has 2+4+8+4=18 bytes overhead, so i think this assumption is going to lead to 6-byte buffer overruns. - erik ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [9fans] IOHDRSZ 2013-04-04 19:50 [9fans] IOHDRSZ erik quanstrom @ 2013-04-04 20:14 ` Charles Forsyth 2013-04-04 20:49 ` erik quanstrom 0 siblings, 1 reply; 3+ messages in thread From: Charles Forsyth @ 2013-04-04 20:14 UTC (permalink / raw) To: Fans of the OS Plan 9 from Bell Labs [-- Attachment #1: Type: text/plain, Size: 346 bytes --] On 4 April 2013 20:50, erik quanstrom <quanstro@quanstro.net> wrote: > so > i think this assumption is going to lead to > 6-byte buffer overruns. > I don't follow the reasoning. bufsize + Rread or Twrite will always fit. bufsize is the limit for application data. The receiving 9P also trims the count to match the receiving buffer. [-- Attachment #2: Type: text/html, Size: 772 bytes --] ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [9fans] IOHDRSZ 2013-04-04 20:14 ` Charles Forsyth @ 2013-04-04 20:49 ` erik quanstrom 0 siblings, 0 replies; 3+ messages in thread From: erik quanstrom @ 2013-04-04 20:49 UTC (permalink / raw) To: 9fans > On 4 April 2013 20:50, erik quanstrom <quanstro@quanstro.net> wrote: > > > so > > i think this assumption is going to lead to > > 6-byte buffer overruns. > > > > I don't follow the reasoning. bufsize + Rread or Twrite will always fit. > bufsize is the limit for application data. The receiving 9P also trims the > count > to match the receiving buffer. i'm thinking of applications that have a seperate buffer for data. in this case, i can't think of a clean way of sizing that seperate buffer correctly. if msize=bufsize+IOHDRSZ, then incoming bytes would be too big. - erik ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2013-04-04 20:49 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2013-04-04 19:50 [9fans] IOHDRSZ erik quanstrom 2013-04-04 20:14 ` Charles Forsyth 2013-04-04 20:49 ` erik quanstrom
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