[Expired for QEMU because there has been no activity for 60 days.]
** Changed in: qemu
Status: Incomplete => Expired
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https://bugs.launchpad.net/bugs/786208
Title:
Missing checks for non-existent device in ide_exec_cmd
Status in QEMU:
Expired
Bug description:
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.
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