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Re: [PATCH] Set hard limit on delta chain depth

From
Junio C Hamano <gitster@pobox.com>
Date
Dec 6, 2011, 15:06 UTC
Message-ID
<7vvcpthh97.fsf@alter.siamese.dyndns.org>
In-Reply-To
<1323068688-31481-1-git-send-email-pclouds@gmail.com>
Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:
Show 12 quoted lines
> Too deep delta chains can cause stack overflow in get_base_data(). Set
> a hard limit so that index-pack does not run out of stack. Also stop
> people from producing such a long delta chains using "pack-object
> --depth=<too large>"
>
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  I used to make very long delta chains and triggered this in index-pack.
>  I did not care reporting because it's my fault anyway. Think again,
>  index-pack is called at server side and a malicious client can
>  trigger this. This patch does not improve the situation much, but at
>  least we won't get sigsegv at server side.

Why should we treat this condition any differently from the case where the sender of a pack used beefier machine than you have and stuffed a huge object that the index-pack running on your box cannot hold in core, causing xmalloc() to die on your machine?

I do not think this is the right way to handle the issue. Your other patch to flatten the recursion to iteration looked a lot saner approach.

Previous: Jeff KingNext: Nguyen Thai Ngoc Duy
Message 10 of 19 in “Set hard limit on delta chain depth”
  1. Set hard limit on delta chain depthNguyễn Thái Ngọc Duy, Dec 5, 2011
  2. Erik Faye-LundDec 6, 2011
  3. Nguyen Thai Ngoc DuyDec 6, 2011
  4. Erik Faye-LundDec 6, 2011
  5. Nguyen Thai Ngoc DuyDec 6, 2011
  6. Michael HaggertyDec 6, 2011
  7. Nguyen Thai Ngoc DuyDec 6, 2011
  8. Shawn PearceDec 6, 2011
  9. Jeff KingDec 6, 2011
  10. Junio C HamanoDec 6, 2011
  11. Nguyen Thai Ngoc DuyDec 6, 2011
  12. Junio C HamanoDec 10, 2011
  13. index-pack: eliminate unlimited recursion in get_delta_base()Nguyễn Thái Ngọc Duy, Dec 7, 2011
  14. Shawn PearceDec 8, 2011
  15. Nguyen Thai Ngoc DuyDec 8, 2011
  16. 1/2 index_pack: indent find_unresolved_detals one levelpclouds@gmail.com, Dec 8, 2011
  17. Junio C HamanoDec 9, 2011
  18. 2/2 index-pack: a naive attempt to flatten find_unresolved_deltaspclouds@gmail.com, Dec 8, 2011
  19. Shawn PearceDec 8, 2011

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