syzbot found WARNING in qp_broker_alloc[1] in qp_host_alloc_queue() when num_pages is 0x100001, giving queue_size + queue_page_size bigger than KMALLOC_MAX_SIZE for kzalloc(), resulting order >= MAX_ORDER condition.
queue_size + queue_page_size=0x8000d8, where KMALLOC_MAX_SIZE=0x400000. FYI, I've also noticed in vmci_queue_pair.c other SLAB allocations with no length check that might exceed KMALLOC_MAX_SIZE as well, but syzbot doesn't have reproduces for them. in qp_alloc_ppn_set(): produce_ppns = kmalloc_array(num_produce_pages, sizeof(*produce_ppns), GFP_KERNEL); [..] consume_ppns = kmalloc_array(num_consume_pages, sizeof(*consume_ppns), GFP_KERNEL); [..] in qp_alloc_hypercall(): msg_size = sizeof(*alloc_msg) + (size_t) entry->num_ppns * ppn_size; alloc_msg = kmalloc(msg_size, GFP_KERNEL); [..] in qp_broker_create(): entry->local_mem = kcalloc(QPE_NUM_PAGES(entry->qp), PAGE_SIZE, GFP_KERNEL); [1] Call Trace: alloc_pages include/linux/gfp.h:547 [inline] kmalloc_order+0x40/0x130 mm/slab_common.c:837 kmalloc_order_trace+0x15/0x70 mm/slab_common.c:853 kmalloc_large include/linux/slab.h:481 [inline] __kmalloc+0x257/0x330 mm/slub.c:3959 kmalloc include/linux/slab.h:557 [inline] kzalloc include/linux/slab.h:682 [inline] qp_host_alloc_queue drivers/misc/vmw_vmci/vmci_queue_pair.c:540 [inline] qp_broker_create drivers/misc/vmw_vmci/vmci_queue_pair.c:1351 [inline] qp_broker_alloc+0x936/0x2740 drivers/misc/vmw_vmci/vmci_queue_pair.c:1739 Reported-by: syzbot+15ec7391f3d6a1a7c...@syzkaller.appspotmail.com Signed-off-by: Sabyrzhan Tasbolatov <snovit...@gmail.com> --- drivers/misc/vmw_vmci/vmci_queue_pair.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/misc/vmw_vmci/vmci_queue_pair.c b/drivers/misc/vmw_vmci/vmci_queue_pair.c index c49065887e8f..f6af406fda80 100644 --- a/drivers/misc/vmw_vmci/vmci_queue_pair.c +++ b/drivers/misc/vmw_vmci/vmci_queue_pair.c @@ -537,6 +537,11 @@ static struct vmci_queue *qp_host_alloc_queue(u64 size) queue_page_size = num_pages * sizeof(*queue->kernel_if->u.h.page); + if (queue_size + queue_page_size > KMALLOC_MAX_SIZE) { + pr_warn("too big queue to allocate\n"); + return NULL; + } + queue = kzalloc(queue_size + queue_page_size, GFP_KERNEL); if (queue) { queue->q_header = NULL; -- 2.25.1