6:02 a.m.
A QEMU guest can have upto VIR_DOMAIN_BOOT_LAST boot entries
defined. When building the QEMU arg, each entry takes a
single byte. This means the array must be declared to be
VIR_DOMAIN_BOOT_LAST+1 bytes in length to allow for the
trailing null
* src/qemu/qemu_conf.c: Fix off-by-1 boot arg array size
---
src/qemu/qemu_conf.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
index aa34d63..7a37c70 100644
--- a/src/qemu/qemu_conf.c
+++ b/src/qemu/qemu_conf.c
@@ -3662,7 +3662,7 @@ int qemudBuildCommandLine(virConnectPtr conn,
{
int i;
char memory[50];
- char boot[VIR_DOMAIN_BOOT_LAST];
+ char boot[VIR_DOMAIN_BOOT_LAST+1];
struct utsname ut;
int disableKQEMU = 0;
int enableKQEMU = 0;
--
1.7.2.1
6:18 a.m.
On Tue, Aug 24, 2010 at 12:02:38PM +0100, Daniel P. Berrange wrote:
A QEMU guest can have upto VIR_DOMAIN_BOOT_LAST boot entries
defined. When building the QEMU arg, each entry takes a
single byte. This means the array must be declared to be
VIR_DOMAIN_BOOT_LAST+1 bytes in length to allow for the
trailing null
FYI, This bug was introduced by me 2 years ago during the conversion
to common domain APIs. In 6385fe3edebf4593b6dc08eee086f73dcc71b43d.
We already have a test case that covers this precise boundary
condition, but it has never exhibited a problem, even under valgrind.
In Fedora 15 rawhide though, there is more advanced GCC array bounds
checking present and this causes a runtime abort in the test suite.
Nice example of why running 'make check' in the RPM spec is good :-)
Regards,
Daniel
--
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6:30 a.m.
On Tue, Aug 24, 2010 at 12:18:48PM +0100, Daniel P. Berrange wrote:
On Tue, Aug 24, 2010 at 12:02:38PM +0100, Daniel P. Berrange wrote:
> A QEMU guest can have upto VIR_DOMAIN_BOOT_LAST boot entries
> defined. When building the QEMU arg, each entry takes a
> single byte. This means the array must be declared to be
> VIR_DOMAIN_BOOT_LAST+1 bytes in length to allow for the
> trailing null
FYI, This bug was introduced by me 2 years ago during the conversion
to common domain APIs. In 6385fe3edebf4593b6dc08eee086f73dcc71b43d.
We already have a test case that covers this precise boundary
condition, but it has never exhibited a problem, even under valgrind.
In Fedora 15 rawhide though, there is more advanced GCC array bounds
checking present and this causes a runtime abort in the test suite.
Nice example of why running 'make check' in the RPM spec is good :-)
There used to be a 'checker' version of gcc with specific patches for
bound-checking a decade or so ago, good to see this coming to the main
stream :-)
Daniel
--
Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/
daniel(a)veillard.com | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library http://libvirt.org/
9:47 a.m.
On 08/24/2010 05:02 AM, Daniel P. Berrange wrote:
A QEMU guest can have upto VIR_DOMAIN_BOOT_LAST boot entries
defined. When building the QEMU arg, each entry takes a
single byte. This means the array must be declared to be
VIR_DOMAIN_BOOT_LAST+1 bytes in length to allow for the
trailing null
* src/qemu/qemu_conf.c: Fix off-by-1 boot arg array size
ACK.
--
Eric Blake eblake(a)redhat.com +1-801-349-2682
Libvirt virtualization library http://libvirt.org
5238
days inactive
5238
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3 comments
3 participants
participants (3)
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Daniel P. Berrange -
Daniel Veillard -
Eric Blake