When doing a full block pull job (base == NULL) and the config XML contains a compatible disk, the completer function would leave a dangling pointer in 'cfgdisk->src->backingStore' as cfgdisk->src would be set to the value of 'cfgbase' which was always set to 'cfgdisk->src->backingStore'. This is wrong though since for the live definition XML we set the respective counterpart to 'job->data.pull.base' which is NULL in the above scenario. This leads to a invalid pointer read when saving the config XML and may end up in a crash. Resolve it by setting 'cfgbase' only when 'job->data.pull.base' is non-NULL. Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1946918 Signed-off-by: Peter Krempa <pkrempa@xxxxxxxxxx> --- src/qemu/qemu_blockjob.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/src/qemu/qemu_blockjob.c b/src/qemu/qemu_blockjob.c index 66268a365a..d708fd18fd 100644 --- a/src/qemu/qemu_blockjob.c +++ b/src/qemu/qemu_blockjob.c @@ -1005,10 +1005,7 @@ qemuBlockJobProcessEventCompletedPull(virQEMUDriverPtr driver, if (!job->disk) return; - if ((cfgdisk = qemuBlockJobGetConfigDisk(vm, job->disk, job->data.pull.base))) - cfgbase = cfgdisk->src->backingStore; - - if (!cfgdisk) + if (!(cfgdisk = qemuBlockJobGetConfigDisk(vm, job->disk, job->data.pull.base))) qemuBlockJobClearConfigChain(vm, job->disk); qemuBlockJobProcessEventCompletedPullBitmaps(vm, job, asyncJob); @@ -1018,6 +1015,8 @@ qemuBlockJobProcessEventCompletedPull(virQEMUDriverPtr driver, return; if (job->data.pull.base) { + if (cfgdisk) + cfgbase = cfgdisk->src->backingStore; for (n = job->disk->src->backingStore; n && n != job->data.pull.base; n = n->backingStore) { /* find the image on top of 'base' */ -- 2.30.2
