From 87ad860c622cc8f8916b5232bd8728c08f938fce Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Tue, 20 Nov 2018 19:41:48 +0100 Subject: nvme: fix out-of-bounds access to the CMB MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Because the CMB BAR has a min_access_size of 2, if you read the last byte it will try to memcpy *2* bytes from n->cmbuf, causing an off-by-one error. This is CVE-2018-16847. Another way to fix this might be to register the CMB as a RAM memory region, which would also be more efficient. However, that might be a change for big-endian machines; I didn't think this through and I don't know how real hardware works. Add a basic testcase for the CMB in case somebody does this change later on. Cc: Keith Busch Cc: qemu-block@nongnu.org Reported-by: Li Qiang Reviewed-by: Li Qiang Tested-by: Li Qiang Signed-off-by: Paolo Bonzini Reviewed-by: Philippe Mathieu-Daudé Tested-by: Philippe Mathieu-Daudé Signed-off-by: Kevin Wolf --- hw/block/nvme.c | 2 +- tests/Makefile.include | 2 +- tests/nvme-test.c | 68 ++++++++++++++++++++++++++++++++++++++++++-------- 3 files changed, 60 insertions(+), 12 deletions(-) diff --git a/hw/block/nvme.c b/hw/block/nvme.c index 28d284346d..8c35cab2b4 100644 --- a/hw/block/nvme.c +++ b/hw/block/nvme.c @@ -1201,7 +1201,7 @@ static const MemoryRegionOps nvme_cmb_ops = { .write = nvme_cmb_write, .endianness = DEVICE_LITTLE_ENDIAN, .impl = { - .min_access_size = 2, + .min_access_size = 1, .max_access_size = 8, }, }; diff --git a/tests/Makefile.include b/tests/Makefile.include index 613242bc6e..fb0b449c02 100644 --- a/tests/Makefile.include +++ b/tests/Makefile.include @@ -730,7 +730,7 @@ tests/test-hmp$(EXESUF): tests/test-hmp.o tests/machine-none-test$(EXESUF): tests/machine-none-test.o tests/drive_del-test$(EXESUF): tests/drive_del-test.o $(libqos-virtio-obj-y) tests/qdev-monitor-test$(EXESUF): tests/qdev-monitor-test.o $(libqos-pc-obj-y) -tests/nvme-test$(EXESUF): tests/nvme-test.o +tests/nvme-test$(EXESUF): tests/nvme-test.o $(libqos-pc-obj-y) tests/pvpanic-test$(EXESUF): tests/pvpanic-test.o tests/i82801b11-test$(EXESUF): tests/i82801b11-test.o tests/ac97-test$(EXESUF): tests/ac97-test.o diff --git a/tests/nvme-test.c b/tests/nvme-test.c index 7674a446e4..2700ba838a 100644 --- a/tests/nvme-test.c +++ b/tests/nvme-test.c @@ -8,25 +8,73 @@ */ #include "qemu/osdep.h" +#include "qemu/units.h" #include "libqtest.h" +#include "libqos/libqos-pc.h" + +static QOSState *qnvme_start(const char *extra_opts) +{ + QOSState *qs; + const char *arch = qtest_get_arch(); + const char *cmd = "-drive id=drv0,if=none,file=null-co://,format=raw " + "-device nvme,addr=0x4.0,serial=foo,drive=drv0 %s"; + + if (strcmp(arch, "i386") == 0 || strcmp(arch, "x86_64") == 0) { + qs = qtest_pc_boot(cmd, extra_opts ? : ""); + global_qtest = qs->qts; + return qs; + } + + g_printerr("nvme tests are only available on x86\n"); + exit(EXIT_FAILURE); +} + +static void qnvme_stop(QOSState *qs) +{ + qtest_shutdown(qs); +} -/* Tests only initialization so far. TODO: Replace with functional tests */ static void nop(void) { + QOSState *qs; + + qs = qnvme_start(NULL); + qnvme_stop(qs); } -int main(int argc, char **argv) +static void nvmetest_cmb_test(void) { - int ret; + const int cmb_bar_size = 2 * MiB; + QOSState *qs; + QPCIDevice *pdev; + QPCIBar bar; - g_test_init(&argc, &argv, NULL); - qtest_add_func("/nvme/nop", nop); + qs = qnvme_start("-global nvme.cmb_size_mb=2"); + pdev = qpci_device_find(qs->pcibus, QPCI_DEVFN(4,0)); + g_assert(pdev != NULL); + + qpci_device_enable(pdev); + bar = qpci_iomap(pdev, 2, NULL); + + qpci_io_writel(pdev, bar, 0, 0xccbbaa99); + g_assert_cmpint(qpci_io_readb(pdev, bar, 0), ==, 0x99); + g_assert_cmpint(qpci_io_readw(pdev, bar, 0), ==, 0xaa99); + + /* Test partially out-of-bounds accesses. */ + qpci_io_writel(pdev, bar, cmb_bar_size - 1, 0x44332211); + g_assert_cmpint(qpci_io_readb(pdev, bar, cmb_bar_size - 1), ==, 0x11); + g_assert_cmpint(qpci_io_readw(pdev, bar, cmb_bar_size - 1), !=, 0x2211); + g_assert_cmpint(qpci_io_readl(pdev, bar, cmb_bar_size - 1), !=, 0x44332211); + g_free(pdev); - qtest_start("-drive id=drv0,if=none,file=null-co://,format=raw " - "-device nvme,drive=drv0,serial=foo"); - ret = g_test_run(); + qnvme_stop(qs); +} - qtest_end(); +int main(int argc, char **argv) +{ + g_test_init(&argc, &argv, NULL); + qtest_add_func("/nvme/nop", nop); + qtest_add_func("/nvme/cmb_test", nvmetest_cmb_test); - return ret; + return g_test_run(); } -- cgit v1.2.3