Public bug reported: Hello,
== QTest Reproducer == /* * cat << EOF | ./qemu-system-i386 -display none -machine accel=qtest, -m \ * 512M -machine q35 -nodefaults -device megasas -device \ * scsi-cd,drive=null0 -blockdev \ * driver=null-co,read-zeroes=on,node-name=null0 -qtest stdio * outl 0xcf8 0x80000801 * outl 0xcfc 0x05000000 * outl 0xcf8 0x80000816 * outl 0xcfc 0x19000000 * write 0x1e1ed300 0x1 0x01 * write 0x1e1ed307 0x1 0x01 * write 0x1e1ed316 0x1 0x01 * write 0x1e1ed328 0x1 0x01 * write 0x1e1ed32f 0x1 0x01 * outl 0x1940 0x1e1ed300 * outl 0x19c0 0x00 * EOF */ static void null_deref_megasas_finish_dcmd(void) { QTestState *s = qtest_init( "-display none , -m 512M -machine q35 -nodefaults -device megasas -device " "scsi-cd,drive=null0 -blockdev driver=null-co,read-zeroes=on,node-name=null0 "); qtest_outl(s, 0xcf8, 0x80000801); qtest_outl(s, 0xcfc, 0x05000000); qtest_outl(s, 0xcf8, 0x80000816); qtest_outl(s, 0xcfc, 0x19000000); qtest_bufwrite(s, 0x1e1ed300, "\x01", 0x1); qtest_bufwrite(s, 0x1e1ed307, "\x01", 0x1); qtest_bufwrite(s, 0x1e1ed316, "\x01", 0x1); qtest_bufwrite(s, 0x1e1ed328, "\x01", 0x1); qtest_bufwrite(s, 0x1e1ed32f, "\x01", 0x1); qtest_outl(s, 0x1940, 0x1e1ed300); qtest_outl(s, 0x19c0, 0x00); qtest_quit(s); } int main(int argc, char **argv) { const char *arch = qtest_get_arch(); g_test_init(&argc, &argv, NULL); if (strcmp(arch, "i386") == 0) { qtest_add_func("fuzz/null_deref_megasas_finish_dcmd", null_deref_megasas_finish_dcmd); } return g_test_run(); } == Stack Trace == ../hw/scsi/megasas.c:1884:21: runtime error: member access within null pointer of type 'union mfi_frame' SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior ../hw/scsi/megasas.c:1884:21 in ../hw/scsi/megasas.c:1884:21: runtime error: member access within null pointer of type 'struct mfi_frame_header' SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior ../hw/scsi/megasas.c:1884:21 in AddressSanitizer:DEADLYSIGNAL ================================================================= ==314546==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000003 (pc 0x55b1b4f4de73 bp 0x7ffcfc5a8bb0 sp 0x7ffcfc5a8900 T0) ==314546==The signal is caused by a WRITE memory access. ==314546==Hint: address points to the zero page. #0 0x55b1b4f4de73 in megasas_command_complete build/../hw/scsi/megasas.c:1884:40 #1 0x55b1b5613914 in scsi_req_complete build/../hw/scsi/scsi-bus.c:1515:5 #2 0x55b1b5448aeb in scsi_dma_complete_noio build/../hw/scsi/scsi-disk.c:345:9 #3 0x55b1b5446fc7 in scsi_dma_complete build/../hw/scsi/scsi-disk.c:366:5 #4 0x55b1b4fffc56 in dma_complete build/../softmmu/dma-helpers.c:121:9 #5 0x55b1b4fffc56 in dma_blk_cb build/../softmmu/dma-helpers.c:139:9 #6 0x55b1b6856016 in blk_aio_complete build/../block/block-backend.c:1412:9 #7 0x55b1b6f48b06 in aio_bh_poll build/../util/async.c:164:13 #8 0x55b1b6f08cec in aio_dispatch build/../util/aio-posix.c:381:5 #9 0x55b1b6f4d59c in aio_ctx_dispatch build/../util/async.c:306:5 #10 0x7fd88c098baa in g_main_context_dispatch (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x51baa) #11 0x55b1b6f59a3c in glib_pollfds_poll build/../util/main-loop.c:232:9 #12 0x55b1b6f59a3c in os_host_main_loop_wait build/../util/main-loop.c:255:5 #13 0x55b1b6f59a3c in main_loop_wait build/../util/main-loop.c:531:11 #14 0x55b1b61a78a9 in qemu_main_loop build/../softmmu/runstate.c:725:9 #15 0x55b1b4c751e5 in main build/../softmmu/main.c:50:5 #16 0x7fd88aec6d09 in __libc_start_main csu/../csu/libc-start.c:308:16 #17 0x55b1b4bc8bb9 in _start (system-i386+0x2b5fbb9) ** Affects: qemu Importance: Undecided Status: New ** Tags: fuzzer -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1918321 Title: [OSS-Fuzz] Issue 31875 megasas: Null-ptr dereference in megasas_finish_dcmd Status in QEMU: New Bug description: Hello, == QTest Reproducer == /* * cat << EOF | ./qemu-system-i386 -display none -machine accel=qtest, -m \ * 512M -machine q35 -nodefaults -device megasas -device \ * scsi-cd,drive=null0 -blockdev \ * driver=null-co,read-zeroes=on,node-name=null0 -qtest stdio * outl 0xcf8 0x80000801 * outl 0xcfc 0x05000000 * outl 0xcf8 0x80000816 * outl 0xcfc 0x19000000 * write 0x1e1ed300 0x1 0x01 * write 0x1e1ed307 0x1 0x01 * write 0x1e1ed316 0x1 0x01 * write 0x1e1ed328 0x1 0x01 * write 0x1e1ed32f 0x1 0x01 * outl 0x1940 0x1e1ed300 * outl 0x19c0 0x00 * EOF */ static void null_deref_megasas_finish_dcmd(void) { QTestState *s = qtest_init( "-display none , -m 512M -machine q35 -nodefaults -device megasas -device " "scsi-cd,drive=null0 -blockdev driver=null-co,read-zeroes=on,node-name=null0 "); qtest_outl(s, 0xcf8, 0x80000801); qtest_outl(s, 0xcfc, 0x05000000); qtest_outl(s, 0xcf8, 0x80000816); qtest_outl(s, 0xcfc, 0x19000000); qtest_bufwrite(s, 0x1e1ed300, "\x01", 0x1); qtest_bufwrite(s, 0x1e1ed307, "\x01", 0x1); qtest_bufwrite(s, 0x1e1ed316, "\x01", 0x1); qtest_bufwrite(s, 0x1e1ed328, "\x01", 0x1); qtest_bufwrite(s, 0x1e1ed32f, "\x01", 0x1); qtest_outl(s, 0x1940, 0x1e1ed300); qtest_outl(s, 0x19c0, 0x00); qtest_quit(s); } int main(int argc, char **argv) { const char *arch = qtest_get_arch(); g_test_init(&argc, &argv, NULL); if (strcmp(arch, "i386") == 0) { qtest_add_func("fuzz/null_deref_megasas_finish_dcmd", null_deref_megasas_finish_dcmd); } return g_test_run(); } == Stack Trace == ../hw/scsi/megasas.c:1884:21: runtime error: member access within null pointer of type 'union mfi_frame' SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior ../hw/scsi/megasas.c:1884:21 in ../hw/scsi/megasas.c:1884:21: runtime error: member access within null pointer of type 'struct mfi_frame_header' SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior ../hw/scsi/megasas.c:1884:21 in AddressSanitizer:DEADLYSIGNAL ================================================================= ==314546==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000003 (pc 0x55b1b4f4de73 bp 0x7ffcfc5a8bb0 sp 0x7ffcfc5a8900 T0) ==314546==The signal is caused by a WRITE memory access. ==314546==Hint: address points to the zero page. #0 0x55b1b4f4de73 in megasas_command_complete build/../hw/scsi/megasas.c:1884:40 #1 0x55b1b5613914 in scsi_req_complete build/../hw/scsi/scsi-bus.c:1515:5 #2 0x55b1b5448aeb in scsi_dma_complete_noio build/../hw/scsi/scsi-disk.c:345:9 #3 0x55b1b5446fc7 in scsi_dma_complete build/../hw/scsi/scsi-disk.c:366:5 #4 0x55b1b4fffc56 in dma_complete build/../softmmu/dma-helpers.c:121:9 #5 0x55b1b4fffc56 in dma_blk_cb build/../softmmu/dma-helpers.c:139:9 #6 0x55b1b6856016 in blk_aio_complete build/../block/block-backend.c:1412:9 #7 0x55b1b6f48b06 in aio_bh_poll build/../util/async.c:164:13 #8 0x55b1b6f08cec in aio_dispatch build/../util/aio-posix.c:381:5 #9 0x55b1b6f4d59c in aio_ctx_dispatch build/../util/async.c:306:5 #10 0x7fd88c098baa in g_main_context_dispatch (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x51baa) #11 0x55b1b6f59a3c in glib_pollfds_poll build/../util/main-loop.c:232:9 #12 0x55b1b6f59a3c in os_host_main_loop_wait build/../util/main-loop.c:255:5 #13 0x55b1b6f59a3c in main_loop_wait build/../util/main-loop.c:531:11 #14 0x55b1b61a78a9 in qemu_main_loop build/../softmmu/runstate.c:725:9 #15 0x55b1b4c751e5 in main build/../softmmu/main.c:50:5 #16 0x7fd88aec6d09 in __libc_start_main csu/../csu/libc-start.c:308:16 #17 0x55b1b4bc8bb9 in _start (system-i386+0x2b5fbb9) To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1918321/+subscriptions