From 035dec25a84e8a69c0546c81c58f14746e6fd329 Mon Sep 17 00:00:00 2001 From: Prasad J Pandit Date: Wed, 14 Oct 2020 15:00:20 +0800 Subject: [PATCH 1/2] pci: check bus pointer before dereference fix CVE-2020-25742 While mapping IRQ level in pci_change_irq_level() routine, it does not check if pci_get_bus() returned a valid pointer. It may lead to a NULL pointer dereference issue. Add check to avoid it. -> https://ruhr-uni-bochum.sciebo.de/s/NNWP2GfwzYKeKwE?path=%2Flsi_nullptr1 ==1183858==Hint: address points to the zero page. #0 pci_change_irq_level hw/pci/pci.c:259 #1 pci_irq_handler hw/pci/pci.c:1445 #2 pci_set_irq hw/pci/pci.c:1463 #3 lsi_set_irq hw/scsi/lsi53c895a.c:488 #4 lsi_update_irq hw/scsi/lsi53c895a.c:523 #5 lsi_script_scsi_interrupt hw/scsi/lsi53c895a.c:554 #6 lsi_execute_script hw/scsi/lsi53c895a.c:1149 #7 lsi_reg_writeb hw/scsi/lsi53c895a.c:1984 #8 lsi_io_write hw/scsi/lsi53c895a.c:2146 ... Reported-by: Ruhr-University Signed-off-by: Prasad J Pandit --- hw/pci/pci.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/hw/pci/pci.c b/hw/pci/pci.c index de0fae10ab9..df5a2c32949 100644 --- a/hw/pci/pci.c +++ b/hw/pci/pci.c @@ -253,6 +253,9 @@ static void pci_change_irq_level(PCIDevice *pci_dev, int irq_num, int change) PCIBus *bus; for (;;) { bus = pci_get_bus(pci_dev); + if (!bus) { + return; + } irq_num = bus->map_irq(pci_dev, irq_num); if (bus->set_irq) break; -- Gitee From 4093369588982ac9b43e69af0f82eeb9ea5e2273 Mon Sep 17 00:00:00 2001 From: Prasad J Pandit Date: Wed, 14 Oct 2020 15:57:18 +0800 Subject: [PATCH 2/2] hw/ide: check null block before _cancel_dma_sync fix CVE-2020-25743 When canceling an i/o operation via ide_cancel_dam_sync(), a block pointer may be null. Add check to avoid null pointer dereference. -> https://ruhr-uni-bochum.sciebo.de/s/NNWP2GfwzYKeKwE?path=%2Fide_nullptr1 ==1803100==Hint: address points to the zero page. #0 blk_bs ../block/block-backend.c:714 #1 blk_drain ../block/block-backend.c:1715 #2 ide_cancel_dma_sync ../hw/ide/core.c:723 #3 bmdma_cmd_writeb ../hw/ide/core.c:723 #4 bmdma_write ../hw/ide/pci.c:298 #5 memory_region_write_accessor ../softmmu/memory.c:483 #6 access_with_adjusted_size ../softmmu/memory.c:544 #7 memory_region_dispatch_write ../softmmu/memory.c:1465 #8 flatview_write_continue ../exe.c:3176 ... Reported-by: Ruhr-University Signed-off-by: Prasad J Pandit --- hw/ide/core.c | 1 + hw/ide/pci.c | 5 ++++- 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/hw/ide/core.c b/hw/ide/core.c index f76f7e5234b..8105187f497 100644 --- a/hw/ide/core.c +++ b/hw/ide/core.c @@ -718,6 +718,7 @@ void ide_cancel_dma_sync(IDEState *s) * whole DMA operation will be submitted to disk with a single * aio operation with preadv/pwritev. */ + assert(s->blk); if (s->bus->dma->aiocb) { trace_ide_cancel_dma_sync_remaining(); blk_drain(s->blk); diff --git a/hw/ide/pci.c b/hw/ide/pci.c index b50091b615c..b47e675456f 100644 --- a/hw/ide/pci.c +++ b/hw/ide/pci.c @@ -295,7 +295,10 @@ void bmdma_cmd_writeb(BMDMAState *bm, uint32_t val) /* Ignore writes to SSBM if it keeps the old value */ if ((val & BM_CMD_START) != (bm->cmd & BM_CMD_START)) { if (!(val & BM_CMD_START)) { - ide_cancel_dma_sync(idebus_active_if(bm->bus)); + IDEState *s = idebus_active_if(bm->bus); + if (s->blk) { + ide_cancel_dma_sync(s); + } bm->status &= ~BM_STATUS_DMAING; } else { bm->cur_addr = bm->addr; -- Gitee