A not too small part of the recent CVEs were DoS scenarios by letting qemu abort with too large memory allocations. We generally "fixed" these cases by setting some limits on values read from image files that influence the size of allocations.
Because we still need to allow reading large images, this works only to a certain degree and we still can get fairly large allocations, which are not unthinkable to fail on some machines. This series converts potentially large allocations to g_try_malloc() and friends and handles failure gracefully e.g. by returning -ENOMEM. This may cause hot-plug of a new disk or individual requests to fail, but the VM as a whole can keep running. Kevin Wolf (20): block: Introduce qemu_try_blockalign() block: Handle failure for potentially large allocations bochs: Handle failure for potentially large allocations cloop: Handle failure for potentially large allocations curl: Handle failure for potentially large allocations dmg: Handle failure for potentially large allocations iscsi: Handle failure for potentially large allocations nfs: Handle failure for potentially large allocations parallels: Handle failure for potentially large allocations qcow1: Handle failure for potentially large allocations qcow2: Handle failure for potentially large allocations qed: Handle failure for potentially large allocations raw-posix: Handle failure for potentially large allocations raw-win32: Handle failure for potentially large allocations rbd: Handle failure for potentially large allocations vdi: Handle failure for potentially large allocations vhdx: Handle failure for potentially large allocations vmdk: Handle failure for potentially large allocations vpc: Handle failure for potentially large allocations mirror: Handle failure for potentially large allocations block.c | 33 +++++++++++++++++++++++++++------ block/bochs.c | 6 +++++- block/cloop.c | 23 ++++++++++++++++++++--- block/curl.c | 8 +++++++- block/dmg.c | 11 +++++++++-- block/iscsi.c | 16 +++++++++++++--- block/mirror.c | 7 ++++++- block/nfs.c | 6 +++++- block/parallels.c | 6 +++++- block/qcow.c | 29 ++++++++++++++++++++++++----- block/qcow2-cache.c | 12 +++++++++++- block/qcow2-cluster.c | 28 +++++++++++++++++++++++----- block/qcow2-refcount.c | 46 ++++++++++++++++++++++++++++++++++++---------- block/qcow2-snapshot.c | 18 +++++++++++++++--- block/qcow2.c | 37 +++++++++++++++++++++++++++++++------ block/qed-check.c | 7 +++++-- block/qed.c | 6 +++++- block/raw-posix.c | 6 +++++- block/rbd.c | 5 ++++- block/vdi.c | 20 +++++++++++++++++--- block/vhdx-log.c | 6 +++++- block/vhdx.c | 12 ++++++++++-- block/vmdk.c | 12 ++++++++++-- block/vpc.c | 6 +++++- block/win32-aio.c | 6 +++++- include/block/block.h | 1 + include/qemu/osdep.h | 1 + util/oslib-posix.c | 16 ++++++++++------ util/oslib-win32.c | 9 +++++++-- 29 files changed, 327 insertions(+), 72 deletions(-) -- 1.8.3.1