[Bug 1961427] [NEW] zlib: compressBound() returns an incorrect result on z15
Launchpad Bug Tracker
1961427 at bugs.launchpad.net
Thu Sep 15 15:42:01 UTC 2022
You have been subscribed to a public bug by Matthieu Clemenceau (mclemenceau):
SRU Justification:
==================
[Impact]
* zlib: compressBound() returns an incorrect result on IBM z15 hardware.
* Passing the result of compressBound() to compress() results
in an error code.
* This is because compressBound() is not adjusted for DFLTCC.
[Fix]
* Adjust compressBound() for DFLTCC like it's already done
for deflateBound().
* Since zlib project does not accept patches at the moment,
the fix has been integrated into the DFLTCC pull request:
https://github.com/madler/zlib/pull/410
The commitid is b25781e735363e04f6c56e21431c47e4afc50b17.
* The fix extracted out of the above is:
https://launchpadlibrarian.net/589857296/debdiff_zlib_1.2.11.dfsg-2ubuntu7_to_zlib_1.2.11.dfsg-2ubuntu8_jammy.diff
* On top of this actual zlib fix, there is another patch needed:
'Remove compressBound assertions. (PR #1258)' for htslib.
* But there is a standalone 'htslib' package version, as well as a
htslib version included in (some) 'bedtools' packages.
Both need to be patched (see '[Other]' for more details).
[Test Plan]
* An IBM z15 system (LPAR, z/VM guest or KVM virtual machine)
with Ubuntu Server 21.10 (or 22.04).
* A test can be done based on the following C test program:
#include <assert.h>
#include <stdlib.h>
#include <zlib.h>
int main() {
Bytef in_buf[128], out_buf[1024];
for (size_t i = 0; i < sizeof(in_buf); i++)
in_buf[i] = rand();
uLongf dest_len = compressBound(sizeof(in_buf));
assert(dest_len <= sizeof(out_buf));
int ret = compress(out_buf, &dest_len,
in_buf, sizeof(in_buf));
assert(ret == Z_OK);
}
* The test needs to be done by IBM, due to the requirements
for the special z15 hardware.
* A successful test was just completed, based on the version in jammy-
proposed, which is at the same code level that the impish version this
SRU is targeted for.
[Where problems could occur]
* If the adjustment of compressBound() for DFLTCC is done
erroneously the issue can still be present or in worst case
even affect Z systems other than z15 only.
* The compression can become errorneous with the new changes,
e.g. in compressBound.
* Mistakes in dfltcc_free_window OF and especially DEFLATE_BOUND_COMPLEN,
(incl. the bit definitions), may cause various and unforseen defects.
* Any build time issues that might have been introduced by this patch
can be identified by a test build; this was done and is available here:
https://launchpad.net/~fheimes/+archive/ubuntu/lp1961427
[Other Info]
* Ubuntu jammy, impish and focal are affected by the zlib issue.
* The 'htslib' version '1.13+ds' (as it is part of I, J and K),
already includes the patch,
hence only htslib '1.10.2' in focal needs to be patched.
* The bedtools version '2.30.0+dfsg' (as it is part of I, J and K),
requires the patch,
but version '2.27.1+dfsg' bedtools in focal does not incl. an
embedded htslib, hence does not need to be (actually can't be)
patched.
* Patched version of the affected htslib and bedtools packages
are build and also available at this PPA:
https://launchpad.net/~fheimes/+archive/ubuntu/lp1961427
__________
Description: zlib: compressBound() returns an incorrect result on z15
Symptom: Passing the result of compressBound() to compress()
results in an error code.
Problem: compressBound() is not adjusted for DFLTCC.
Solution: Adjust compressBound() for DFLTCC like it's already done
for deflateBound(). Since zlib project does not accept
patches at the moment, the fix has been integrated into
the DFLTCC pull request:
https://github.com/madler/zlib/pull/410
The commitid is b25781e735363e04f6c56e21431c47e4afc50b17.
Reproduction: z15 only:
#include <assert.h>
#include <stdlib.h>
#include <zlib.h>
int main() {
Bytef in_buf[128], out_buf[1024];
for (size_t i = 0; i < sizeof(in_buf); i++)
in_buf[i] = rand();
uLongf dest_len = compressBound(sizeof(in_buf));
assert(dest_len <= sizeof(out_buf));
int ret = compress(out_buf, &dest_len,
in_buf, sizeof(in_buf));
assert(ret == Z_OK);
}
** Affects: ubuntu-z-systems
Importance: Undecided
Assignee: Skipper Bug Screeners (skipper-screen-team)
Status: Fix Committed
** Affects: bedtools (Ubuntu)
Importance: Undecided
Status: Fix Released
** Affects: htslib (Ubuntu)
Importance: Undecided
Status: Invalid
** Affects: zlib (Ubuntu)
Importance: High
Assignee: Brian Murray (brian-murray)
Status: Fix Released
** Affects: bedtools (Ubuntu Focal)
Importance: Undecided
Status: Invalid
** Affects: htslib (Ubuntu Focal)
Importance: Undecided
Assignee: Brian Murray (brian-murray)
Status: Fix Committed
** Affects: zlib (Ubuntu Focal)
Importance: Undecided
Assignee: Brian Murray (brian-murray)
Status: Fix Committed
** Affects: bedtools (Ubuntu Impish)
Importance: Undecided
Status: Won't Fix
** Affects: htslib (Ubuntu Impish)
Importance: Undecided
Status: Won't Fix
** Affects: zlib (Ubuntu Impish)
Importance: High
Status: Won't Fix
** Affects: bedtools (Ubuntu Jammy)
Importance: Undecided
Assignee: Brian Murray (brian-murray)
Status: Fix Released
** Affects: htslib (Ubuntu Jammy)
Importance: Undecided
Status: Invalid
** Affects: zlib (Ubuntu Jammy)
Importance: High
Assignee: Brian Murray (brian-murray)
Status: Fix Released
** Tags: architecture-s39064 bugnameltc-194923 foundations-todo fr-2079 patch severity-high targetmilestone-inin20045 verification-done verification-done-focal verification-done-jammy
--
zlib: compressBound() returns an incorrect result on z15
https://bugs.launchpad.net/bugs/1961427
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