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Re: [PATCH 5/6] remote-curl: error on incomplete packet

From
Jeff King <peff@peff.net>
Date
May 18, 2020, 15:49 UTC
Message-ID
<20200518154937.GB41356@coredump.intra.peff.net>
In-Reply-To
<20200518090857.GA24557@generichostname>
On Mon, May 18, 2020 at 05:08:57AM -0400, Denton Liu wrote:
Show 11 quoted lines
> > Hmm. Right now there's no assumption in rpc_in that we're writing
> > pktlines. Will this always be the case?
> > 
> > I think the answer is probably yes. If there's a case where it isn't, it
> > might be something like v0 git-over-http against a server which doesn't
> > have the sideband capability.
> 
> As far as I can tell from skimming the code, v0 uses always pktlines
> although I'm far from being an expert on Git's networking stuff. Perhaps
> we could implement this such that the line-length checking only happens
> for stateless_connect()?

Yeah, that would certainly limit the possibility of unintended side effects (and I don't think there's any benefit to this patch for the non-stateless-connect cases).

We'd still be locking stateless-connect into always using pktlines, but I think that's probably OK in practice. AFAICT it's the case now, and I doubt we'd have any desire to change it in the future (and if we do, this is all local-ish code that we could modify).

One unfortunate thing about the protocol (but not new to your patch) is that this will be a problem for _any_ remote-helper which claims to support stateless-connect. So they'd all need to carry similar code to deal with this issue. Right now remote-curl is the only one, but probably git-remote-ext and git-remote-fd could support this, too. Those are pretty exotic, though (I don't think anyone has even bothered to make them support v2 yet).

-Peff
Previous: Denton LiuNext: Denton Liu
Message 15 of 62 in “remote-curl: partial fix for a deadlock with stateless rpc”
  1. 0/6 remote-curl: partial fix for a deadlock with stateless rpcDenton Liu, May 13, 2020
  2. 1/6 remote-curl: fix typoDenton Liu, May 13, 2020
  3. 2/6 remote-curl: remove label indentationDenton Liu, May 13, 2020
  4. 3/6 transport: combine common cases with a fallthroughDenton Liu, May 13, 2020
  5. Eric SunshineMay 13, 2020
  6. Denton LiuMay 18, 2020
  7. Eric SunshineMay 18, 2020
  8. 4/6 pkt-line: extern packet_length()Denton Liu, May 13, 2020
  9. Eric SunshineMay 13, 2020
  10. Jeff KingMay 15, 2020
  11. Jeff KingMay 15, 2020
  12. 5/6 remote-curl: error on incomplete packetDenton Liu, May 13, 2020
  13. Jeff KingMay 15, 2020
  14. Denton LiuMay 18, 2020
  15. Jeff KingMay 18, 2020
  16. 6/6 remote-curl: ensure last packet is a flushDenton Liu, May 13, 2020
  17. Denton LiuMay 15, 2020
  18. Jeff KingMay 15, 2020
  19. Junio C HamanoMay 18, 2020
  20. Jeff KingMay 18, 2020
  21. Jeff KingMay 18, 2020
  22. 0/7 remote-curl: fix deadlocks when remote server disconnectsDenton Liu, May 18, 2020
  23. 1/7 remote-curl: fix typoDenton Liu, May 18, 2020
  24. 2/7 remote-curl: remove label indentationDenton Liu, May 18, 2020
  25. Junio C HamanoMay 18, 2020
  26. 4/7 pkt-line: extern packet_length()Denton Liu, May 18, 2020
  27. Jeff KingMay 18, 2020
  28. Eric SunshineMay 18, 2020
  29. Jeff KingMay 18, 2020
  30. Junio C HamanoMay 18, 2020
  31. 3/7 transport: extract common fetch_pack() callDenton Liu, May 18, 2020
  32. Junio C HamanoMay 18, 2020
  33. 6/7 pkt-line: PACKET_READ_RESPONSE_ENDDenton Liu, May 18, 2020
  34. 7/7 stateless-connect: send response end packetDenton Liu, May 18, 2020
  35. Jeff KingMay 18, 2020
  36. Denton LiuMay 18, 2020
  37. Jeff KingMay 18, 2020
  38. 5/7 remote-curl: error on incomplete packetDenton Liu, May 18, 2020
  39. Jeff KingMay 18, 2020
  40. Denton LiuMay 18, 2020
  41. Jeff KingMay 18, 2020
  42. Denton LiuMay 18, 2020
  43. Jeff KingMay 18, 2020
  44. Junio C HamanoMay 18, 2020
  45. Jeff KingMay 19, 2020
  46. Junio C HamanoMay 18, 2020
  47. 0/7 remote-curl: fix deadlocks when remote server disconnectsDenton Liu, May 19, 2020
  48. 1/7 remote-curl: fix typoDenton Liu, May 19, 2020
  49. 2/7 remote-curl: remove label indentationDenton Liu, May 19, 2020
  50. 3/7 transport: extract common fetch_pack() callDenton Liu, May 19, 2020
  51. 4/7 pkt-line: extern packet_length()Denton Liu, May 19, 2020
  52. Eric SunshineMay 19, 2020
  53. 6/7 pkt-line: define PACKET_READ_RESPONSE_ENDDenton Liu, May 19, 2020
  54. 5/7 remote-curl: error on incomplete packetDenton Liu, May 19, 2020
  55. 7/7 stateless-connect: send response end packetDenton Liu, May 19, 2020
  56. Jeff KingMay 19, 2020
  57. Denton LiuMay 19, 2020
  58. 8/7 fixup! pkt-line: extern packet_length()Denton Liu, May 19, 2020
  59. 9/9 fixup! remote-curl: error on incomplete packetDenton Liu, May 22, 2020
  60. Jeff KingMay 22, 2020
  61. Denton LiuMay 22, 2020
  62. Jeff KingMay 22, 2020

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