[libvirt] [PATCH] virEventPollDispatchHandles: Honour array boundaries
When dispatching events from the event loop, the array of registered
handles is searched to see what handles happened an event on. However,
the array is searched in weird way: the check for the array boundaries
is at the end, so we may touch the elements after the end of the
array:
==10434== Invalid read of size 4
==10434== at 0x52D06B6: virEventPollDispatchHandles (vireventpoll.c:486)
==10434== by 0x52D10E4: virEventPollRunOnce (vireventpoll.c:660)
==10434== by 0x52CF207: virEventRunDefaultImpl (virevent.c:308)
==10434== by 0x1639D1: virNetServerRun (virnetserver.c:1139)
==10434== by 0x1220DC: main (libvirtd.c:1507)
==10434== Address 0xc11ff04 is 4 bytes after a block of size 960 alloc'd
==10434== at 0x4C2CA5E: realloc (in
/usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==10434== by 0x52AD378: virReallocN (viralloc.c:245)
==10434== by 0x52AD46E: virExpandN (viralloc.c:294)
==10434== by 0x52AD5B1: virResizeN (viralloc.c:352)
==10434== by 0x52CF2EC: virEventPollAddHandle (vireventpoll.c:116)
==10434== by 0x52CEF5B: virEventAddHandle (virevent.c:78)
==10434== by 0x11F69A90: nodeStateInitialize (node_device_udev.c:1797)
==10434== by 0x53C3C89: virStateInitialize (libvirt.c:743)
==10434== by 0x120563: daemonRunStateInit (libvirtd.c:919)
==10434== by 0x5317719: virThreadHelper (virthread.c:197)
==10434== by 0x8376F39: start_thread (in /lib64/libpthread-2.17.so)
==10434== by 0x8A7F9FC: clone (in /lib64/libc-2.17.so)
Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
---
src/util/vireventpoll.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/src/util/vireventpoll.c b/src/util/vireventpoll.c
index 528b24c..13f40dc 100644
--- a/src/util/vireventpoll.c
+++ b/src/util/vireventpoll.c
@@ -477,46 +477,46 @@ static int virEventPollDispatchTimeouts(void)
static int virEventPollDispatchHandles(int nfds, struct pollfd *fds)
{
size_t i, n;
VIR_DEBUG("Dispatch %d", nfds);
/* NB, use nfds not eventLoop.handlesCount, because new
* fds might be added on end of list, and they're not
* in the fds array we've got */
for (i = 0, n = 0; n < nfds && i < eventLoop.handlesCount; n++) {
- while ((eventLoop.handles[i].fd != fds[n].fd ||
- eventLoop.handles[i].events == 0) &&
- i < eventLoop.handlesCount) {
+ while (i < eventLoop.handlesCount &&
+ (eventLoop.handles[i].fd != fds[n].fd ||
+ eventLoop.handles[i].events == 0)) {
i++;
}
if (i == eventLoop.handlesCount)
break;
VIR_DEBUG("i=%zu w=%d", i, eventLoop.handles[i].watch);
if (eventLoop.handles[i].deleted) {
EVENT_DEBUG("Skip deleted n=%zu w=%d f=%d", i,
eventLoop.handles[i].watch, eventLoop.handles[i].fd);
continue;
}
if (fds[n].revents) {
virEventHandleCallback cb = eventLoop.handles[i].cb;
int watch = eventLoop.handles[i].watch;
void *opaque = eventLoop.handles[i].opaque;
int hEvents = virEventPollFromNativeEvents(fds[n].revents);
PROBE(EVENT_POLL_DISPATCH_HANDLE,
"watch=%d events=%d",
watch, hEvents);
virMutexUnlock(&eventLoop.lock);
(cb)(watch, fds[n].fd, hEvents, opaque);
virMutexLock(&eventLoop.lock);
}
}
return 0;
}
/* Used post dispatch to actually remove any timers that
* were previously marked as deleted. This asynchronous
* cleanup is needed to make dispatch re-entrant safe.
*/
--
1.8.5.5