On Thu, Feb 09, 2017 at 05:43:20PM +0000, David Laight wrote: > From: Scott Bauer > > Sent: 09 February 2017 17:20 > > It may be too late to change anyhting in the uapi header. When we > > switched over to using IOC_SIZE I found a bug where I had switched > > up a structure in one of the series from v4 to v5 but never changed > > the structure in the IOW. The structure that was in there was to small > > so when we kzalloc on it we don't request enough space. It worked before > > because we were using the cmd strictly as a command #, not using the IOC > > and friends. > > > > If it's too late to modify that IOW, I can work around it by reallocing > > on the correct size for that command only. I verified the rest of the > > commands and the structures are the same. > > > > Let me know what you think, please. > > Maybe define IOC_OPAL_ACTIVATE_LSP_OLD to the incorrect value and > IOC_OPAL_ACTIVATE_LSP to the correct one. > But that relies on any users specifying the correct structure. > I wouldn't guarantee that. I think I'm the only userspace user right now, this went in on monday, so I can can change my tooling easily. I just wasnt sure if there was a set time where the user ABI cannot be changed. > > At the top of the driver's ioctl path add: > if (cmd == IOC_OPAL_ACTIVATE_LSP_OLD) cmd = IOC_OPAL_ACTIVATE_LSP; > I think it would have to be the other way around the correct sized one would be IOC_OPAL_ACTIAVE_LSP_NEW so the check would be: if (cmd == IOC_OPAL_ACTIVATE_LSP) cmd = IOC_OPAL_ACTIVATE_LSP_NEW. If we're allowed to change it (the bad sized one) from LSP to LSP_OLD then we should just change the structure. If we have to leave it we need to introduce a _NEW with the correct size. > For some code I added a userspace wrapper on ioctl() to check the > size of the supplied arg matched that required by the 'cmd'. > I've also done the same in the kernel. > (all as compile time checks). > > David > >
