Bug 457678

Summary: It's possible to include a different spec in the srpm than the one used in build
Product: [Fedora] Fedora Reporter: Vasile Gaburici <gaburici>
Component: rpmAssignee: Panu Matilainen <pmatilai>
Status: CLOSED WONTFIX QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: low Docs Contact:
Priority: medium    
Version: 9CC: jnovy, n3npq, pnasrat
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OS: Linux   
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Last Closed: 2009-07-14 14:34:17 UTC Type: ---
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Description Vasile Gaburici 2008-08-03 12:14:02 UTC
Description of problem:
There's a race condition when the srpm is packaged: the spec file included in the srpm need not be the same file that was used to start the build process. This can  actually be useful in that one can build a rpm and continue editing the spec at the same time, but the srpm built that way is not reproducible, which make this race a low security threat.

IMHO a warning should be issued if the checksum of the spec started the build differs from the one just before the srpm is packaged.

Version-Release number of selected component (if applicable):
rpm-4.4.2.3-2.fc9.i386

How reproducible:
Always.

Steps to Reproduce:
1. Start building a rpm
2. While the build part is taking place, which can take a while, edit the spec

Actual results:
The spec included in the srpm is not the one that was used to start the build but the edited version.

Expected results:
Ideally, the spec included in the srpm should be the one that started the build, not the one at the end of the build. At least a warning should be issued when the two differ.

Comment 1 Jeff Johnson 2008-08-03 20:58:02 UTC
Sure. recursion at N+1 is different than recursion at N in general. IOTW, the
recipe used to produce a SRPM at stage N is not (in general) the same as
the included spec file at N+1.

Furthermore, even if the spec files were identical, recursion (as in rebuilding)
is not guaranteed because of the large amount of additional configure information.
Checking digest (or other content verifier) on spec files will never guarantee that the
N -> N+1 build succeeds.

But yes, I understand your expectations.

Comment 2 Vasile Gaburici 2008-08-03 22:27:49 UTC
(In reply to comment #1)
> Sure. recursion at N+1 is different than recursion at N in general. IOTW, the
> recipe used to produce a SRPM at stage N is not (in general) the same as
> the included spec file at N+1.
> 
> Furthermore, even if the spec files were identical, recursion (as in
> rebuilding)
> is not guaranteed because of the large amount of additional configure
> information.
> Checking digest (or other content verifier) on spec files will never guarantee
> that the
> N -> N+1 build succeeds.
> 
> But yes, I understand your expectations.

I'm afraid you misunderstood them a bit. I'm not expecting a guaranteed rebuild. What I'm arguing for is (a bit more) atomicity of the build process w.r.t. to the files that get included in the srpm: {sources, patches, spec}.

On a snapshotting file system you could easily fetch exactly the {sources, patches, spec} file versions that started the build and include those in srpm if/after the build succeeds. Since you don't normally have the luxury of snapshotting file system, the fallback (that doesn't involve changes to build process) is to print some stern warning if the {sources, patches, spec} differ at the end. An alternative that does alter the build process would be (for -ba) to create the srpm before initiating the build process, then to unpack it in some temp dir, and build the binaries from what was in the srpm. YMMV.

Comment 3 Vasile Gaburici 2008-08-03 22:36:20 UTC
(In reply to comment #2)

Forgot to add that checking anything but the spec at the end is overkill since the other stuff not likely to get changed, which is why I didn't mention it in the initial report. Checking the spec at the end is similar to a rpmlint check; it won't guarantee that stuff won't break, but will flag some accidental edit while the build is in progress. Besides, computing a hash on the spec file hardly takes any time...

Comment 4 Jeff Johnson 2008-08-03 23:17:38 UTC
Sure hashes are easy to generate.

The issue is when/how the "reference" and the "produced" spec file
digest gets compared.

You could already build from a *.src.rpm (which verifies the digest),
and look at the produced *.src.rpm (which would verify the included
spec file).

Note that a snapshot file system is not an available solution to rpm.

Note also that its not just spec files that can change. If preload runs
against just built libraries, then the libraries will be changed from
what was built, and can/will cause binary rpm packaging issues.

There's certainly no reason not to attempt to solve all these problems,
but I'm not sure that rpm is the place to do it, and the incidence is
small enough that "Don't modify the spec file while building the package."
is perhaps gud enough (once you understand the issue).

Comment 5 Bug Zapper 2009-06-10 02:21:45 UTC
This message is a reminder that Fedora 9 is nearing its end of life.
Approximately 30 (thirty) days from now Fedora will stop maintaining
and issuing updates for Fedora 9.  It is Fedora's policy to close all
bug reports from releases that are no longer maintained.  At that time
this bug will be closed as WONTFIX if it remains open with a Fedora 
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Comment 6 Bug Zapper 2009-07-14 14:34:17 UTC
Fedora 9 changed to end-of-life (EOL) status on 2009-07-10. Fedora 9 is 
no longer maintained, which means that it will not receive any further 
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of 
Fedora please feel free to reopen this bug against that version.

Thank you for reporting this bug and we are sorry it could not be fixed.