On 17/12/2021 09:10, Dan Carpenter wrote: > On Fri, Dec 17, 2021 at 08:55:50AM +0000, Steven Price wrote: >> However this one is harder to fix without setting an arbitrary cap on >> the number of BOs during a sumbit. I'm not sure how other drivers handle >> this - the ones I've looked at so far all have the same issue. There's >> obviously the list that Dan already sent, but e.g. msm has the same bug >> in msm_gem_submit.c:submit_create() with an amusing bug where the check >> for (sz > SIZE_MAX) will never hit, although the call is to kzalloc() so >> large allocations are going to fail anyway. > > sz is u64 and SIZE_MAX is ULONG_MAX so the (sz > SIZE_MAX) condition > does work to prevent an integer overflow on 32bit systems. But it's not > beautiful. sz is the result of struct_size() which returns a size_t, and SIZE_MAX in case of an overflow. However the check is *greater than* SIZE_MAX which will never occur even on 32 bit systems. However the chances of kzalloc() allocating SIZE_MAX are 0 so I don't see it's an exploitable bug. Steve
