[libvirt] [PATCH] blkdeviotune: check for overflow when parsing XML

[Erik Skultety]

According to docs/schemas/domaincommon.rng and _virDomainBlockIoTuneInfo
all the iotune values are interpreted as unsigned long long, however
according to qemu_monitor_json.c, qemu silently truncates numbers
larger than LLONG_MAX. There's really not much of a usage for such
large numbers anyway yet. This patch provides the same overflow
check during domain XML parsing phase as it does during setting
a blkdeviotune element in qemu_driver.c and thus reports an error when
a larger number than LLONG_MAX is detected.
---
 src/conf/domain_conf.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 22a7f7e..4cc900f 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -5711,6 +5711,18 @@ virDomainDiskDefParseXML(virDomainXMLOptionPtr xmlopt,
                     def->blkdeviotune.write_iops_sec = 0;
                 }
 
+                if (def->blkdeviotune.total_bytes_sec > LLONG_MAX ||
+                    def->blkdeviotune.read_bytes_sec > LLONG_MAX ||
+                    def->blkdeviotune.write_bytes_sec > LLONG_MAX ||
+                    def->blkdeviotune.total_iops_sec > LLONG_MAX ||
+                    def->blkdeviotune.read_iops_sec > LLONG_MAX ||
+                    def->blkdeviotune.write_iops_sec > LLONG_MAX) {
+                    virReportError(VIR_ERR_OVERFLOW,
+                                  _("block I/O throttle limit must "
+                                    "be less than %llu"), LLONG_MAX);
+                    goto error;
+                }
+
                 if ((def->blkdeviotune.total_bytes_sec &&
                      def->blkdeviotune.read_bytes_sec) ||
                     (def->blkdeviotune.total_bytes_sec &&
-- 
1.9.3