Re: [PATCH 0/2] use unsigned type for MegasasState fields

[Alexander Bulekov]

On 200513 1919, P J P wrote:
>   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

Also, this assertion seems to happen while parsing one of the "write"
commands. Maybe the formatting was corrupted in the email. I uploaded
the commands here, just in case:

wget https://paste.debian.net/plain/1146573

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 < 1146573
-Alex
> 
> Thank you.
> --
> Prasad J Pandit / Red Hat Product Security Team
> 8685 545E B54C 486B C6EB 271E E285 8B5A F050 DE8D
>