From 472a07a6e2bd410f5679cd8a16384a6d3f474679 Mon Sep 17 00:00:00 2001 From: Alexander Bulekov Date: Wed, 19 Feb 2020 23:11:17 -0500 Subject: [PATCH] fuzz: add virtio-scsi fuzz target The virtio-scsi fuzz target sets up and fuzzes the available virtio-scsi queues. After an element is placed on a queue, the fuzzer can select whether to perform a kick, or continue adding elements. Signed-off-by: Alexander Bulekov Reviewed-by: Darren Kenny Message-id: 20200220041118.23264-22-alxndr@bu.edu Signed-off-by: Stefan Hajnoczi --- tests/qtest/fuzz/Makefile.include | 1 + tests/qtest/fuzz/virtio_scsi_fuzz.c | 213 ++++++++++++++++++++++++++++ 2 files changed, 214 insertions(+) create mode 100644 tests/qtest/fuzz/virtio_scsi_fuzz.c diff --git a/tests/qtest/fuzz/Makefile.include b/tests/qtest/fuzz/Makefile.include index 77385777ef..cde3e9636c 100644 --- a/tests/qtest/fuzz/Makefile.include +++ b/tests/qtest/fuzz/Makefile.include @@ -9,6 +9,7 @@ fuzz-obj-y += tests/qtest/fuzz/qos_fuzz.o # Targets fuzz-obj-y += tests/qtest/fuzz/i440fx_fuzz.o fuzz-obj-y += tests/qtest/fuzz/virtio_net_fuzz.o +fuzz-obj-y += tests/qtest/fuzz/virtio_scsi_fuzz.o FUZZ_CFLAGS += -I$(SRC_PATH)/tests -I$(SRC_PATH)/tests/qtest diff --git a/tests/qtest/fuzz/virtio_scsi_fuzz.c b/tests/qtest/fuzz/virtio_scsi_fuzz.c new file mode 100644 index 0000000000..3b95247f12 --- /dev/null +++ b/tests/qtest/fuzz/virtio_scsi_fuzz.c @@ -0,0 +1,213 @@ +/* + * virtio-serial Fuzzing Target + * + * Copyright Red Hat Inc., 2019 + * + * Authors: + * Alexander Bulekov + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#include "qemu/osdep.h" + +#include "tests/qtest/libqtest.h" +#include "libqos/virtio-scsi.h" +#include "libqos/virtio.h" +#include "libqos/virtio-pci.h" +#include "standard-headers/linux/virtio_ids.h" +#include "standard-headers/linux/virtio_pci.h" +#include "standard-headers/linux/virtio_scsi.h" +#include "fuzz.h" +#include "fork_fuzz.h" +#include "qos_fuzz.h" + +#define PCI_SLOT 0x02 +#define PCI_FN 0x00 +#define QVIRTIO_SCSI_TIMEOUT_US (1 * 1000 * 1000) + +#define MAX_NUM_QUEUES 64 + +/* Based on tests/virtio-scsi-test.c */ +typedef struct { + int num_queues; + QVirtQueue *vq[MAX_NUM_QUEUES + 2]; +} QVirtioSCSIQueues; + +static QVirtioSCSIQueues *qvirtio_scsi_init(QVirtioDevice *dev, uint64_t mask) +{ + QVirtioSCSIQueues *vs; + uint64_t feat; + int i; + + vs = g_new0(QVirtioSCSIQueues, 1); + + feat = qvirtio_get_features(dev); + if (mask) { + feat &= ~QVIRTIO_F_BAD_FEATURE | mask; + } else { + feat &= ~(QVIRTIO_F_BAD_FEATURE | (1ull << VIRTIO_RING_F_EVENT_IDX)); + } + qvirtio_set_features(dev, feat); + + vs->num_queues = qvirtio_config_readl(dev, 0); + + for (i = 0; i < vs->num_queues + 2; i++) { + vs->vq[i] = qvirtqueue_setup(dev, fuzz_qos_alloc, i); + } + + qvirtio_set_driver_ok(dev); + + return vs; +} + +static void virtio_scsi_fuzz(QTestState *s, QVirtioSCSIQueues* queues, + const unsigned char *Data, size_t Size) +{ + /* + * Data is a sequence of random bytes. We split them up into "actions", + * followed by data: + * [vqa][dddddddd][vqa][dddd][vqa][dddddddddddd] ... + * The length of the data is specified by the preceding vqa.length + */ + typedef struct vq_action { + uint8_t queue; + uint8_t length; + uint8_t write; + uint8_t next; + uint8_t kick; + } vq_action; + + /* Keep track of the free head for each queue we interact with */ + bool vq_touched[MAX_NUM_QUEUES + 2] = {0}; + uint32_t free_head[MAX_NUM_QUEUES + 2]; + + QGuestAllocator *t_alloc = fuzz_qos_alloc; + + QVirtioSCSI *scsi = fuzz_qos_obj; + QVirtioDevice *dev = scsi->vdev; + QVirtQueue *q; + vq_action vqa; + while (Size >= sizeof(vqa)) { + /* Copy the action, so we can normalize length, queue and flags */ + memcpy(&vqa, Data, sizeof(vqa)); + + Data += sizeof(vqa); + Size -= sizeof(vqa); + + vqa.queue = vqa.queue % queues->num_queues; + /* Cap length at the number of remaining bytes in data */ + vqa.length = vqa.length >= Size ? Size : vqa.length; + vqa.write = vqa.write & 1; + vqa.next = vqa.next & 1; + vqa.kick = vqa.kick & 1; + + + q = queues->vq[vqa.queue]; + + /* Copy the data into ram, and place it on the virtqueue */ + uint64_t req_addr = guest_alloc(t_alloc, vqa.length); + qtest_memwrite(s, req_addr, Data, vqa.length); + if (vq_touched[vqa.queue] == 0) { + vq_touched[vqa.queue] = 1; + free_head[vqa.queue] = qvirtqueue_add(s, q, req_addr, vqa.length, + vqa.write, vqa.next); + } else { + qvirtqueue_add(s, q, req_addr, vqa.length, vqa.write , vqa.next); + } + + if (vqa.kick) { + qvirtqueue_kick(s, dev, q, free_head[vqa.queue]); + free_head[vqa.queue] = 0; + } + Data += vqa.length; + Size -= vqa.length; + } + /* In the end, kick each queue we interacted with */ + for (int i = 0; i < MAX_NUM_QUEUES + 2; i++) { + if (vq_touched[i]) { + qvirtqueue_kick(s, dev, queues->vq[i], free_head[i]); + } + } +} + +static void virtio_scsi_fork_fuzz(QTestState *s, + const unsigned char *Data, size_t Size) +{ + QVirtioSCSI *scsi = fuzz_qos_obj; + static QVirtioSCSIQueues *queues; + if (!queues) { + queues = qvirtio_scsi_init(scsi->vdev, 0); + } + if (fork() == 0) { + virtio_scsi_fuzz(s, queues, Data, Size); + flush_events(s); + _Exit(0); + } else { + wait(NULL); + } +} + +static void virtio_scsi_with_flag_fuzz(QTestState *s, + const unsigned char *Data, size_t Size) +{ + QVirtioSCSI *scsi = fuzz_qos_obj; + static QVirtioSCSIQueues *queues; + + if (fork() == 0) { + if (Size >= sizeof(uint64_t)) { + queues = qvirtio_scsi_init(scsi->vdev, *(uint64_t *)Data); + virtio_scsi_fuzz(s, queues, + Data + sizeof(uint64_t), Size - sizeof(uint64_t)); + flush_events(s); + } + _Exit(0); + } else { + wait(NULL); + } +} + +static void virtio_scsi_pre_fuzz(QTestState *s) +{ + qos_init_path(s); + counter_shm_init(); +} + +static void *virtio_scsi_test_setup(GString *cmd_line, void *arg) +{ + g_string_append(cmd_line, + " -drive file=blkdebug::null-co://," + "file.image.read-zeroes=on," + "if=none,id=dr1,format=raw,file.align=4k " + "-device scsi-hd,drive=dr1,lun=0,scsi-id=1"); + return arg; +} + + +static void register_virtio_scsi_fuzz_targets(void) +{ + fuzz_add_qos_target(&(FuzzTarget){ + .name = "virtio-scsi-fuzz", + .description = "Fuzz the virtio-scsi virtual queues, forking" + "for each fuzz run", + .pre_vm_init = &counter_shm_init, + .pre_fuzz = &virtio_scsi_pre_fuzz, + .fuzz = virtio_scsi_fork_fuzz,}, + "virtio-scsi", + &(QOSGraphTestOptions){.before = virtio_scsi_test_setup} + ); + + fuzz_add_qos_target(&(FuzzTarget){ + .name = "virtio-scsi-flags-fuzz", + .description = "Fuzz the virtio-scsi virtual queues, forking" + "for each fuzz run (also fuzzes the virtio flags)", + .pre_vm_init = &counter_shm_init, + .pre_fuzz = &virtio_scsi_pre_fuzz, + .fuzz = virtio_scsi_with_flag_fuzz,}, + "virtio-scsi", + &(QOSGraphTestOptions){.before = virtio_scsi_test_setup} + ); +} + +fuzz_target_init(register_virtio_scsi_fuzz_targets);