Re: [libvirt] [PATCH 1/2] conf: Check if number of vCPUs fits in the storage variable
On 01/22/2013 09:31 AM, Peter Krempa wrote:
The count of vCPUs for a domain is extracted as a usingned long
variable
but is stored in a unsigned short. If the actual number was too large,
a faulty number was stored.
---
src/conf/domain_conf.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 0b9ba13..3e95ec9 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -9085,7 +9085,7 @@ static virDomainDefPtr virDomainDefParseXML(virCapsPtr caps,
def->maxvcpus = 1;
} else {
def->maxvcpus = count;
- if (count == 0) {
+ if (count == 0 || (unsigned short) count != count) {
maxvcpus is a 'unsigned short' and count is an 'unsigned long', thus if
def->maxvcpus != count after this point, then we have the overflow,
right? Or would the compiler "adjust" that comparison behind our back
on an if check?
virReportError(VIR_ERR_XML_ERROR,
_("invalid maxvcpus %lu"), count);
goto error;
@@ -9101,7 +9101,7 @@ static virDomainDefPtr virDomainDefParseXML(virCapsPtr caps,
def->vcpus = def->maxvcpus;
} else {
def->vcpus = count;
- if (count == 0) {
+ if (count == 0 || (unsigned short) count != count) {
Same comment as 'maxvcpus'
virReportError(VIR_ERR_XML_ERROR,
_("invalid current vcpus %lu"), count);
goto error;
ACK - I think what you've done is right, although perhaps someone with a
bit more knowledge of what the compiler does could pipe in (I'm curious
too).
John