diff options
| -rw-r--r-- | hw/scsi/lsi53c895a.c | 23 | ||||
| -rw-r--r-- | tests/qtest/fuzz-lsi53c895a-test.c | 33 |
2 files changed, 50 insertions, 6 deletions
diff --git a/hw/scsi/lsi53c895a.c b/hw/scsi/lsi53c895a.c index af93557a9a..bbf32d3f73 100644 --- a/hw/scsi/lsi53c895a.c +++ b/hw/scsi/lsi53c895a.c @@ -1134,15 +1134,24 @@ static void lsi_execute_script(LSIState *s) uint32_t addr, addr_high; int opcode; int insn_processed = 0; + static int reentrancy_level; + + reentrancy_level++; s->istat1 |= LSI_ISTAT1_SRUN; again: - if (++insn_processed > LSI_MAX_INSN) { - /* Some windows drivers make the device spin waiting for a memory - location to change. If we have been executed a lot of code then - assume this is the case and force an unexpected device disconnect. - This is apparently sufficient to beat the drivers into submission. - */ + /* + * Some windows drivers make the device spin waiting for a memory location + * to change. If we have executed more than LSI_MAX_INSN instructions then + * assume this is the case and force an unexpected device disconnect. This + * is apparently sufficient to beat the drivers into submission. + * + * Another issue (CVE-2023-0330) can occur if the script is programmed to + * trigger itself again and again. Avoid this problem by stopping after + * being called multiple times in a reentrant way (8 is an arbitrary value + * which should be enough for all valid use cases). + */ + if (++insn_processed > LSI_MAX_INSN || reentrancy_level > 8) { if (!(s->sien0 & LSI_SIST0_UDC)) { qemu_log_mask(LOG_GUEST_ERROR, "lsi_scsi: inf. loop with UDC masked"); @@ -1596,6 +1605,8 @@ again: } } trace_lsi_execute_script_stop(); + + reentrancy_level--; } static uint8_t lsi_reg_readb(LSIState *s, int offset) diff --git a/tests/qtest/fuzz-lsi53c895a-test.c b/tests/qtest/fuzz-lsi53c895a-test.c index 2012bd54b7..1b55928b9f 100644 --- a/tests/qtest/fuzz-lsi53c895a-test.c +++ b/tests/qtest/fuzz-lsi53c895a-test.c @@ -9,6 +9,36 @@ #include "libqtest.h" /* + * This used to trigger a DMA reentrancy issue + * leading to memory corruption bugs like stack + * overflow or use-after-free + * https://gitlab.com/qemu-project/qemu/-/issues/1563 + */ +static void test_lsi_dma_reentrancy(void) +{ + QTestState *s; + + s = qtest_init("-M q35 -m 512M -nodefaults " + "-blockdev driver=null-co,node-name=null0 " + "-device lsi53c810 -device scsi-cd,drive=null0"); + + qtest_outl(s, 0xcf8, 0x80000804); /* PCI Command Register */ + qtest_outw(s, 0xcfc, 0x7); /* Enables accesses */ + qtest_outl(s, 0xcf8, 0x80000814); /* Memory Bar 1 */ + qtest_outl(s, 0xcfc, 0xff100000); /* Set MMIO Address*/ + qtest_outl(s, 0xcf8, 0x80000818); /* Memory Bar 2 */ + qtest_outl(s, 0xcfc, 0xff000000); /* Set RAM Address*/ + qtest_writel(s, 0xff000000, 0xc0000024); + qtest_writel(s, 0xff000114, 0x00000080); + qtest_writel(s, 0xff00012c, 0xff000000); + qtest_writel(s, 0xff000004, 0xff000114); + qtest_writel(s, 0xff000008, 0xff100014); + qtest_writel(s, 0xff10002f, 0x000000ff); + + qtest_quit(s); +} + +/* * This used to trigger a UAF in lsi_do_msgout() * https://gitlab.com/qemu-project/qemu/-/issues/972 */ @@ -124,5 +154,8 @@ int main(int argc, char **argv) qtest_add_func("fuzz/lsi53c895a/lsi_do_msgout_cancel_req", test_lsi_do_msgout_cancel_req); + qtest_add_func("fuzz/lsi53c895a/lsi_dma_reentrancy", + test_lsi_dma_reentrancy); + return g_test_run(); } |