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Diffstat (limited to 'results/scraper/launchpad-without-comments/1912780')
| -rw-r--r-- | results/scraper/launchpad-without-comments/1912780 | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/results/scraper/launchpad-without-comments/1912780 b/results/scraper/launchpad-without-comments/1912780 new file mode 100644 index 000000000..54827c8c3 --- /dev/null +++ b/results/scraper/launchpad-without-comments/1912780 @@ -0,0 +1,78 @@ +QEMU: Null Pointer Failure in fdctrl_read() in hw/block/fdc.c + +[via qemu-security list] + +This is Gaoning Pan from Zhejiang University & Ant Security Light-Year Lab. +I found a Null Pointer issue locates in fdctrl_read() in hw/block/fdc.c. +This flaw allows a malicious guest user or process in a denial of service condition. + +This issus was discovered in the latest Qemu-5.2.0. When using floppy device, there are several +choices to get specific drive in get_drv(), depending on fdctrl->cur_drv. But not all drives are +initialized properly, leaving fdctrl->drives[0]->blk as NULL. So when the drive was used in +blk_pread(cur_drv->blk, fd_offset(cur_drv), fdctrl->fifo, BDRV_SECTOR_SIZE) at line 1918, +null pointer access triggers, thus denial of service.My reproduced environment is as follows: + + Host: ubuntu 18.04 + Guest: ubuntu 18.04 + +My boot command is as follows: + + qemu-system-x86_64 -enable-kvm -boot c -m 2G -drive format=qcow2,file=./ubuntu.img \ + -nic user,hostfwd=tcp:0.0.0.0:5555-:22 -device floppy,unit=1,drive=mydrive \ + -drive id=mydrive,file=null-co://,size=2M,format=raw,if=none -display none + +ASAN output is as follows: +================================================================= +==14688==ERROR: AddressSanitizer: SEGV on unknown address 0x00000000034c (pc 0x5636eee9bbaf bp 0x7ff2a53fdea0 sp 0x7ff2a53fde90 T3) +==14688==The signal is caused by a WRITE memory access. +==14688==Hint: address points to the zero page. + #0 0x5636eee9bbae in blk_inc_in_flight ../block/block-backend.c:1356 + #1 0x5636eee9b766 in blk_prw ../block/block-backend.c:1328 + #2 0x5636eee9cd76 in blk_pread ../block/block-backend.c:1491 + #3 0x5636ee1adf24 in fdctrl_read_data ../hw/block/fdc.c:1918 + #4 0x5636ee1a6654 in fdctrl_read ../hw/block/fdc.c:935 + #5 0x5636eebb84c8 in portio_read ../softmmu/ioport.c:179 + #6 0x5636ee9848c5 in memory_region_read_accessor ../softmmu/memory.c:442 + #7 0x5636ee9855c2 in access_with_adjusted_size ../softmmu/memory.c:552 + #8 0x5636ee98f0b7 in memory_region_dispatch_read1 ../softmmu/memory.c:1420 + #9 0x5636ee98f311 in memory_region_dispatch_read ../softmmu/memory.c:1449 + #10 0x5636ee8ff64a in flatview_read_continue ../softmmu/physmem.c:2822 + #11 0x5636ee8ff9e5 in flatview_read ../softmmu/physmem.c:2862 + #12 0x5636ee8ffb83 in address_space_read_full ../softmmu/physmem.c:2875 + #13 0x5636ee8ffdeb in address_space_rw ../softmmu/physmem.c:2903 + #14 0x5636eea6a924 in kvm_handle_io ../accel/kvm/kvm-all.c:2285 + #15 0x5636eea6c5e3 in kvm_cpu_exec ../accel/kvm/kvm-all.c:2531 + #16 0x5636eeca492b in kvm_vcpu_thread_fn ../accel/kvm/kvm-cpus.c:49 + #17 0x5636ef1bc296 in qemu_thread_start ../util/qemu-thread-posix.c:521 + #18 0x7ff337c736da in start_thread (/lib/x86_64-linux-gnu/libpthread.so.0+0x76da) + #19 0x7ff33799ca3e in __clone (/lib/x86_64-linux-gnu/libc.so.6+0x121a3e) + +AddressSanitizer can not provide additional info. +SUMMARY: AddressSanitizer: SEGV ../block/block-backend.c:1356 in blk_inc_in_flight +Thread T3 created by T0 here: + #0 0x7ff33c580d2f in __interceptor_pthread_create (/usr/lib/x86_64-linux-gnu/libasan.so.4+0x37d2f) + #1 0x5636ef1bc673 in qemu_thread_create ../util/qemu-thread-posix.c:558 + #2 0x5636eeca4ce7 in kvm_start_vcpu_thread ../accel/kvm/kvm-cpus.c:73 + #3 0x5636ee9aa965 in qemu_init_vcpu ../softmmu/cpus.c:622 + #4 0x5636ee82a9b4 in x86_cpu_realizefn ../target/i386/cpu.c:6731 + #5 0x5636eed002f4 in device_set_realized ../hw/core/qdev.c:886 + #6 0x5636eecc59bc in property_set_bool ../qom/object.c:2251 + #7 0x5636eecc0c28 in object_property_set ../qom/object.c:1398 + #8 0x5636eecb6fb9 in object_property_set_qobject ../qom/qom-qobject.c:28 + #9 0x5636eecc1175 in object_property_set_bool ../qom/object.c:1465 + #10 0x5636eecfc286 in qdev_realize ../hw/core/qdev.c:399 + #11 0x5636ee739b34 in x86_cpu_new ../hw/i386/x86.c:111 + #12 0x5636ee739d6d in x86_cpus_init ../hw/i386/x86.c:138 + #13 0x5636ee6f843e in pc_init1 ../hw/i386/pc_piix.c:159 + #14 0x5636ee6fab1e in pc_init_v5_2 ../hw/i386/pc_piix.c:438 + #15 0x5636ee1cb4a7 in machine_run_board_init ../hw/core/machine.c:1134 + #16 0x5636ee9c323d in qemu_init ../softmmu/vl.c:4369 + #17 0x5636edd92c71 in main ../softmmu/main.c:49 + #18 0x7ff33789cb96 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b96) + +==14688==ABORTING + +Reproducer is attached. + +Best regards. +Gaoning Pan of Zhejiang University & Ant Security Light-Year Lab \ No newline at end of file |