device: 0.223
other: 0.203
semantic: 0.132
performance: 0.077
graphic: 0.054
PID: 0.052
vnc: 0.043
network: 0.041
debug: 0.037
permissions: 0.032
files: 0.031
boot: 0.030
socket: 0.028
KVM: 0.017
debug: 0.480
other: 0.092
files: 0.070
semantic: 0.053
performance: 0.053
PID: 0.051
device: 0.049
network: 0.039
boot: 0.031
permissions: 0.022
vnc: 0.019
socket: 0.017
graphic: 0.016
KVM: 0.006

Missing checks for non-existent device in ide_exec_cmd

Several calls in the ide_exec_cmd handler are missing checks for (!s->bs) or similar, resulting in NULL pointer dereferences, divide-by-zero, or possibly other badness if the guest performs operations on a non-existent IDE master.

For example, the WIN_READ_NATIVE_MAX command does a 'ide_set_sector(s, s->nb_sectors - 1);', which does 'cyl = sector_num / (s->heads * s->sectors);', which will fail with a divide-by-zero if heads = sectors = 0.

And WIN_MULTREAD also does not check for s->bs, but does a 'ide_sector_read(s);', which will do 'bdrv_read(s->bs, sector_num, s->io_buffer, n);' on a NULL s->bs, leading to a segfault.

I do not *believe* that a malicious guest can do anything more than cause a crash with these bugs.

The QEMU project is currently considering to move its bug tracking to another system. For this we need to know which bugs are still valid and which could be closed already. Thus we are setting older bugs to "Incomplete" now.
If you still think this bug report here is valid, then please switch the state back to "New" within the next 60 days, otherwise this report will be marked as "Expired". Or mark it as "Fix Released" if the problem has been solved with a newer version of QEMU already. Thank you and sorry for the inconvenience.

[Expired for QEMU because there has been no activity for 60 days.]