On Mon, 09 Jul 2018, Manfred Spraul wrote:
ipc_addid() initializes kern_ipc_perm.id after having called
ipc_idr_alloc().
Thus a parallel semop() or msgrcv() that uses ipc_obtain_object_idr()
may see an uninitialized value.
The patch moves all accesses to kern_ipc_perm.id under the spin_lock().
Yeah this is a lot better than my kzalloc() idea. I was considering
completions to avoid these races with ->getnew(), but careful init beats
that idea for obvious reasons.
The only thing I would say is that the title should be more descriptive.
Unlike the next patch, this one isn't really reorganizing anything.
How about:
ipc: compute kern_ipc_perm.id under the ipc lock for stat cmds
The issues is related to the finding of
[email protected]:
syzbot found an issue with kern_ipc_perm.seq
Signed-off-by: Manfred Spraul <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Reviewed-by: Davidlohr Bueso <[email protected]>
