Hello Alex, +-- On Tue, 12 May 2020, Alexander Bulekov wrote --+ | I noticed this since I found a similar issue recently, using a fuzzer. I | applied your patches, but I can still reproduce the heap-overflow, unless | I'm missing something:
Strange, because with uint16_t type, 'reply_queue_head' should not turn negative. | cat << EOF | qemu-system-i386 -qtest stdio -nographic -monitor none \ | -serial none -M q35 -device megasas -device scsi-cd,drive=null0 \ | -blockdev driver=null-co,read-zeroes=on,node-name=null0 -nographic | 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 0x0 0x18 0x060017e1ff00f8ffffffff60efffffffffffffffffffffff | write 0xff00 0x1 0x06 | write 0xc021e10c0040 0x81 0x755e08ff0000845e08ff0000935e08ff0000a25e08ff0000b15e08ff0000c05e08ff0000cf5e08ff0000de5e08ff0000ed5e08ff0000fc5e08ff00000b5e08ff00001a5e08ff0000295e08ff0000385e08ff0000475e08ff0000565e08ff0000655e08ff0000745e08ff0000835e08ff0000925e08ff0000a15e08ff0000b05e08 | -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 | EOF Are qemu options just above EOF right? This leads to an assert failure below qemu/qtest.c:546:qtest_process_command: assertion failed: (words[1] && words[2] && words[3]) ... Aborted (core dumped) /tmp/im/bin/qemu-system-x86_64 -qtest stdio -nographic -monitor none -serial none -M q35 -device megasas -device scsi-cd,drive=null0 -blockdev driver=null-co,read-zeroes=on,node-name=null0 -nographic < ins Thank you. -- Prasad J Pandit / Red Hat Product Security Team 8685 545E B54C 486B C6EB 271E E285 8B5A F050 DE8D
