Bug 485148

Summary:	"Cannot open disk image" when using qcow1
Product:	[Fedora] Fedora	Reporter:	Eduardo Habkost <ehabkost>
Component:	qemu	Assignee:	Glauber Costa <gcosta>
Status:	CLOSED RAWHIDE	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	medium	Docs Contact:
Priority:	low
Version:	rawhide	CC:	berrange, clalance, dwmw2, ehabkost, gcosta, markmc, quintela, virt-maint
Target Milestone:	---
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2009-03-16 08:52:46 EDT	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---
Bug Depends On:
Bug Blocks:	484343

Description Eduardo Habkost 2009-02-11 16:09:41 EST

Steps to reproduce:
$ qemu-img create -f qcow /tmp/qcow.img 1G
$ qemu-kvm -hda /tmp/qcow.img
qemu: could not open disk image /tmp/qcow.img


It is triggered by the CVE-2008-0928 fix. The qcow code tries to read beyond the end of file at this line of block-qcow.c (qcow_open()):

if (bdrv_pread(s->hd, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) != s->l1_size * sizeof(uint64_t))

Comment 1 Eduardo Habkost 2009-02-11 17:30:02 EST

Found the issue: qcow is _not_ trying to read beyond the end of file. The issue is that the range check code uses sector counts instead of bytes, and the qcow file size isn't a multiple of sector size. On my test case, the file size is 4144, and qcow tries to read 4096 bytes starting on byte 48.

Comment 2 Eduardo Habkost 2009-02-20 11:08:22 EST

Fix submitted upstream: http://marc.info/?l=qemu-devel&m=123507873324650

Comment 3 Eduardo Habkost 2009-02-27 13:30:03 EST

Anthony has posted an alternative (and better) fix: http://marc.info/?l=qemu-devel&m=123575165010024

Comment 4 Daniel Berrange 2009-03-11 08:40:33 EDT

Reassigning: The kvm package no longer exists in rawhide/F11, since it is now part of 'qemu'.

Comment 5 Daniel Berrange 2009-03-16 08:52:46 EDT

Fix now in rawhide qemu-0.10-0.9.kvm20090310git.fc11.x86_64