From: Philip McGrath <philip@philipmcgrath.com>
To: Mark H Weaver <mhw@netris.org>, Jack Hill <jackhill@jackhill.us>,
47064@debbugs.gnu.org
Subject: bug#47064: [racket-users] bytevector-uncompress: internal error uncompressing
Date: Wed, 14 Apr 2021 18:03:30 -0400 [thread overview]
Message-ID: <b669b5ff-2435-a956-5c1d-3cc28a345857@philipmcgrath.com> (raw)
In-Reply-To: <87o8ehquk6.fsf@netris.org>
Hi Mark and everyone,
On 4/14/21 1:54 AM, Mark H Weaver wrote:
> Recall that the grafting code performs a set of substitutions, replacing
> store item names (i.e. file names in /gnu/store) with replacement store
> items of the same length, with rules like:
> "fx3979c88s9yxdbchyf36qryawgzpwb5-libx11-1.6.10" =>
> "rwkqxykm91a75w9afhb41saj0dmf30hw-libx11-1.6.12".
>
> The grafting code currently only checks the first 33 bytes, consisting
> of the nix-base32 hash and the "-". It *assumes* that the remainder of
> the associated store item name immediately follows, and blindly writes
> the replacement string over whatever is there.
>
> In this case, I suspect that within a *.zo file, a Guix store item name
> was split into pieces, with the hash and "-" together in one piece but
> split somewhere between the "-" and the last byte of the store item.
> This results in corruption of the bytes following that piece.
>
> I've recently observed the splitting of store item names in *.zo files
> (see <https://bugs.gnu.org/47614>), but in that case the "-" was
> separated from the hash, and as a result the reference was _invisible_
> to the grafter.
Yes, I agree with this diagnosis.
It seems the discussion has become a bit fragmented, since Jack first
reported one set of symptoms in <https://issues.guix.gnu.org/47064> and
you then reported another in <https://issues.guix.gnu.org/47614> (with
much better forensics than I'd found on my own—thanks!).
Both issues should have been fixed (at least with respect to Racket) by
my patch in <https://issues.guix.gnu.org/47180>, which was applied on
Monday.
-Philip
next prev parent reply other threads:[~2021-04-14 22:04 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <alpine.DEB.2.21.2103150040230.8138@marsh.hcoop.net>
2021-03-15 21:38 ` bug#47064: [racket-users] bytevector-uncompress: internal error uncompressing Philip McGrath
2021-03-15 22:26 ` Philip McGrath
2021-03-15 22:38 ` Philip McGrath
2021-03-16 0:28 ` jackhill
2021-03-16 3:01 ` Philip McGrath
2021-04-14 5:54 ` Mark H Weaver
2021-04-14 22:03 ` Philip McGrath [this message]
2021-04-15 8:44 ` Mark H Weaver
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