SRU justification provides and added to the bug description. ** 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. + + [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 crc table can be broken, in case the endian detection + or the register initialization is done wrong. + + * 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. + __________ + Description: zlib: compressBound() returns an incorrect result on z15 Symptom: Passing the result of compressBound() to compress() - results in an error code. + 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. + 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); - } + #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 Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1961427 Title: zlib: compressBound() returns an incorrect result on z15 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1961427/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
