** Also affects: zlib (Ubuntu Focal)
Importance: Undecided
Status: New
** Description changed:
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
[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]
- * Only impish and jammy are affected.
+ * Ubuntu jammy, impish and focal are affected.
__________
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);
}
--
You received this bug notification because you are a member of Ubuntu
Touch seeded packages, which is subscribed to zlib in Ubuntu.
https://bugs.launchpad.net/bugs/1961427
Title:
zlib: compressBound() returns an incorrect result on z15
Status in Ubuntu on IBM z Systems:
New
Status in zlib package in Ubuntu:
In Progress
Status in zlib source package in Focal:
New
Status in zlib source package in Impish:
New
Status in zlib source package in Jammy:
In Progress
Bug description:
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
[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.
__________
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);
}
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