Bug 760657
| Summary: | uncompress fails to uncompress a file it compressed | |||
|---|---|---|---|---|
| Product: | Red Hat Enterprise Linux 6 | Reporter: | daryl herzmann <akrherz> | |
| Component: | ncompress | Assignee: | Pavel Raiskup <praiskup> | |
| Status: | CLOSED CURRENTRELEASE | QA Contact: | qe-baseos-daemons | |
| Severity: | high | Docs Contact: | ||
| Priority: | urgent | |||
| Version: | 6.2 | CC: | azelinka, kdudka, masahiko.ando.yv, mdarade, mfuruta, msvoboda, psklenar, rdassen, yoshihide.sonoda.ua | |
| Target Milestone: | rc | Keywords: | Regression, ZStream | |
| Target Release: | --- | |||
| Hardware: | x86_64 | |||
| OS: | Linux | |||
| Whiteboard: | ||||
| Fixed In Version: | Doc Type: | Bug Fix | ||
| Doc Text: |
The ncompress utility previously relied on the glibc implementation of the memcpy() function. A recent glibc update optimized memcpy(), which resulted in data corruption in ncompress file compression and decompression. This update replaces memcpy() with the memmove() function and ncompress now works as expected.
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Story Points: | --- | |
| Clone Of: | ||||
| : | 821708 (view as bug list) | Environment: | ||
| Last Closed: | 2012-10-09 12:41:20 UTC | Type: | --- | |
| Regression: | --- | Mount Type: | --- | |
| Documentation: | --- | CRM: | ||
| Verified Versions: | Category: | --- | ||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | ||
| Cloudforms Team: | --- | Target Upstream Version: | ||
| Embargoed: | ||||
| Bug Depends On: | ||||
| Bug Blocks: | 781973, 821708 | |||
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Description
daryl herzmann
2011-12-06 17:51:38 UTC
sorry, my example dropped the Z $ uncompress n0q_0.tif.Z insize:1036 posbits:169 inbuf:E4 20 B0 0E 3C (1) uncompress: corrupt input Thanks for report, there was no update of ncompress package in RHEL-6.2, therefore probably related to something else. You mentioned that ncompress started to fail after 6.2 update - you updated from 6.1, right? It works for me on 32-bit system (ok, not really 100% 6.2, but very close to it)... is it always reproducible for you (and/or is it reproducible with other files) ? I am reproducing it 100% on 64bit RHEL6.2, I don't have 32bit around to try it. Are you able to try it on 64bit? Thanks for the help. Yes, no problem, I'll try it on 64bit, but it still will be useful to get answer for the questions from comment #3 prior that. Sorry, yes, each day I cron "yum -y update", so it was an updated 6.1 prior to the 6.2 rollout yesterday, when things broke. It is not reproducible for all file types though. Why is this now a private bug? please revert. (In reply to comment #7) > I see memory overlap during compress but when I do uncompress it is working > fine. Thanks for debugging it. This is a clear bug in ncompress. We have to use memmove() instead of memcpy() when shifting within outbuf. I believe this will fix it: --- a/compress42.c +++ b/compress42.c @@ -1441,7 +1441,7 @@ compress(fdin, fdout) boff = -(((OBUFSIZ<<3)-boff)%(n_bits<<3)); bytes_out += OBUFSIZ; - memcpy(outbuf, outbuf+OBUFSIZ, (outbits>>3)+1); + memmove(outbuf, outbuf+OBUFSIZ, (outbits>>3)+1); memset(outbuf+(outbits>>3)+1, '\0', OBUFSIZ); } So the bug is private again, why?
Technical note added. If any revisions are required, please edit the "Technical Notes" field
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New Contents:
The ncompress utility previously relied on the glibc implementation of the memcpy() function. A recent glibc update optimized memcpy(), which resulted in data corruption in ncompress file compression and decompression. This update replaces memcpy() with the memmove() function and ncompress now works as expected.
Since this is a parent bug of an issue that has already been released via Z-Stream (e.g. rhel-6.3.z), this bug is going to be CLOSED as CURRENTRELEASE. |