Public bug reported:
Hello,
While fuzzing, I found an input that triggers a null-pointer dereference in
megasas_command_complete:
==14959==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000003 (pc
0x55b1d11b4df1 bp 0x7ffeb55ca450 sp 0x7ffeb55ca1e0 T0)
==14959==The signal is caused by a WRITE memory access.
==14959==Hint: address points to the zero page.
#0 0x55b1d11b4df1 in megasas_command_complete
/home/alxndr/Development/qemu/hw/scsi/megasas.c:1877:40
#1 0x55b1d11759ec in scsi_req_complete
/home/alxndr/Development/qemu/hw/scsi/scsi-bus.c:1430:5
#2 0x55b1d115c98f in scsi_aio_complete
/home/alxndr/Development/qemu/hw/scsi/scsi-disk.c:216:5
#3 0x55b1d151c638 in blk_aio_complete
/home/alxndr/Development/qemu/block/block-backend.c:1375:9
#4 0x55b1d151c638 in blk_aio_complete_bh
/home/alxndr/Development/qemu/block/block-backend.c:1385:5
#5 0x55b1d16f3a5b in aio_bh_call
/home/alxndr/Development/qemu/util/async.c:136:5
#6 0x55b1d16f3a5b in aio_bh_poll
/home/alxndr/Development/qemu/util/async.c:164:13
#7 0x55b1d16fe43e in aio_dispatch
/home/alxndr/Development/qemu/util/aio-posix.c:380:5
#8 0x55b1d16f54fa in aio_ctx_dispatch
/home/alxndr/Development/qemu/util/async.c:306:5
#9 0x7f47937c89ed in g_main_context_dispatch
(/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x4e9ed)
#10 0x55b1d16fbef4 in glib_pollfds_poll
/home/alxndr/Development/qemu/util/main-loop.c:219:9
#11 0x55b1d16fbef4 in os_host_main_loop_wait
/home/alxndr/Development/qemu/util/main-loop.c:242:5
#12 0x55b1d16fbef4 in main_loop_wait
/home/alxndr/Development/qemu/util/main-loop.c:518:11
#13 0x55b1d0cd16a6 in qemu_main_loop
/home/alxndr/Development/qemu/softmmu/vl.c:1664:9
#14 0x55b1d1608dca in main /home/alxndr/Development/qemu/softmmu/main.c:49:5
#15 0x7f4792378e0a in __libc_start_main
/build/glibc-GwnBeO/glibc-2.30/csu/../csu/libc-start.c:308:16
#16 0x55b1d091d7b9 in _start
(/home/alxndr/Development/qemu/build/i386-softmmu/qemu-system-i386+0x8f47b9)
I can reproduce it in qemu 5.0 built with using:
cat << EOF | ~/Development/qemu/build/i386-softmmu/qemu-system-i386 -M
pc-q35-5.0 -no-shutdown -M q35 -device megasas -device scsi-cd,drive=null0
-blockdev driver=null-co,read-zeroes=on,node-name=null0 -nographic -qtest stdio
-monitor none -serial none
outl 0xcf8 0x80001814
outl 0xcfc 0xc021
outl 0xcf8 0x80001818
outl 0xcf8 0x80001804
outw 0xcfc 0x7
outl 0xcf8 0x80001810
outl 0xcfc 0xe10c0000
outl 0xcf8 0x8000f810
write 0x44b20 0x1 0x35
write 0x44b00 0x1 0x03
write 0xc021e10c0040 0x81
0x014b04000131000000014b04000138000000014b0400013f000000014b04000146000000014b0400014d000000014b04000154000000014b0400015b000000014b04000162000000014b04000169000000014b04000170000000014b04000177000000014b0400017e000000014b04000185000000014b0400018c000000014b04
EOF
I also attached the trace to this launchpad report, in case the
formatting is broken:
qemu-system-i386 -qtest stdio -monitor none -serial none -M pc-q35-5.0
-no-shutdown -M q35 -device megasas -device scsi-cd,drive=null0
-blockdev driver=null-co,read-zeroes=on,node-name=null0 -nographic <
attachment
Please let me know if I can provide any further info.
-Alex
** Affects: qemu
Importance: Undecided
Status: New
** Attachment added: "attachment"
https://bugs.launchpad.net/bugs/1878057/+attachment/5369968/+files/attachment
--
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1878057
Title:
null-ptr dereference in megasas_command_complete
Status in QEMU:
New
Bug description:
Hello,
While fuzzing, I found an input that triggers a null-pointer dereference in
megasas_command_complete:
==14959==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000003 (pc
0x55b1d11b4df1 bp 0x7ffeb55ca450 sp 0x7ffeb55ca1e0 T0)
==14959==The signal is caused by a WRITE memory access.
==14959==Hint: address points to the zero page.
#0 0x55b1d11b4df1 in megasas_command_complete
/home/alxndr/Development/qemu/hw/scsi/megasas.c:1877:40
#1 0x55b1d11759ec in scsi_req_complete
/home/alxndr/Development/qemu/hw/scsi/scsi-bus.c:1430:5
#2 0x55b1d115c98f in scsi_aio_complete
/home/alxndr/Development/qemu/hw/scsi/scsi-disk.c:216:5
#3 0x55b1d151c638 in blk_aio_complete
/home/alxndr/Development/qemu/block/block-backend.c:1375:9
#4 0x55b1d151c638 in blk_aio_complete_bh
/home/alxndr/Development/qemu/block/block-backend.c:1385:5
#5 0x55b1d16f3a5b in aio_bh_call
/home/alxndr/Development/qemu/util/async.c:136:5
#6 0x55b1d16f3a5b in aio_bh_poll
/home/alxndr/Development/qemu/util/async.c:164:13
#7 0x55b1d16fe43e in aio_dispatch
/home/alxndr/Development/qemu/util/aio-posix.c:380:5
#8 0x55b1d16f54fa in aio_ctx_dispatch
/home/alxndr/Development/qemu/util/async.c:306:5
#9 0x7f47937c89ed in g_main_context_dispatch
(/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x4e9ed)
#10 0x55b1d16fbef4 in glib_pollfds_poll
/home/alxndr/Development/qemu/util/main-loop.c:219:9
#11 0x55b1d16fbef4 in os_host_main_loop_wait
/home/alxndr/Development/qemu/util/main-loop.c:242:5
#12 0x55b1d16fbef4 in main_loop_wait
/home/alxndr/Development/qemu/util/main-loop.c:518:11
#13 0x55b1d0cd16a6 in qemu_main_loop
/home/alxndr/Development/qemu/softmmu/vl.c:1664:9
#14 0x55b1d1608dca in main
/home/alxndr/Development/qemu/softmmu/main.c:49:5
#15 0x7f4792378e0a in __libc_start_main
/build/glibc-GwnBeO/glibc-2.30/csu/../csu/libc-start.c:308:16
#16 0x55b1d091d7b9 in _start
(/home/alxndr/Development/qemu/build/i386-softmmu/qemu-system-i386+0x8f47b9)
I can reproduce it in qemu 5.0 built with using:
cat << EOF | ~/Development/qemu/build/i386-softmmu/qemu-system-i386 -M
pc-q35-5.0 -no-shutdown -M q35 -device megasas -device scsi-cd,drive=null0
-blockdev driver=null-co,read-zeroes=on,node-name=null0 -nographic -qtest stdio
-monitor none -serial none
outl 0xcf8 0x80001814
outl 0xcfc 0xc021
outl 0xcf8 0x80001818
outl 0xcf8 0x80001804
outw 0xcfc 0x7
outl 0xcf8 0x80001810
outl 0xcfc 0xe10c0000
outl 0xcf8 0x8000f810
write 0x44b20 0x1 0x35
write 0x44b00 0x1 0x03
write 0xc021e10c0040 0x81
0x014b04000131000000014b04000138000000014b0400013f000000014b04000146000000014b0400014d000000014b04000154000000014b0400015b000000014b04000162000000014b04000169000000014b04000170000000014b04000177000000014b0400017e000000014b04000185000000014b0400018c000000014b04
EOF
I also attached the trace to this launchpad report, in case the
formatting is broken:
qemu-system-i386 -qtest stdio -monitor none -serial none -M pc-q35-5.0
-no-shutdown -M q35 -device megasas -device scsi-cd,drive=null0
-blockdev driver=null-co,read-zeroes=on,node-name=null0 -nographic <
attachment
Please let me know if I can provide any further info.
-Alex
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1878057/+subscriptions
