On 5/18/22 1:00 PM, Eugene Syromiatnikov wrote:
On Wed, May 18, 2022 at 09:34:22AM -0700, Yonghong Song wrote:
On 5/18/22 5:22 AM, Eugene Syromiatnikov wrote:
- size = cnt * sizeof(*syms);
+ if (check_mul_overflow(cnt, (u32)sizeof(*syms), &size))
+ return -EOVERFLOW;
In mm/util.c kvmalloc_node(), we have
/* Don't even allow crazy sizes */
if (unlikely(size > INT_MAX)) {
WARN_ON_ONCE(!(flags & __GFP_NOWARN));
return NULL;
}
Basically the maximum size to be allocated in INT_MAX.
Here, we have 'size' as u32, which means if the size is 0xffff0000,
the check_mul_overflow will return false (no overflow) but
kvzalloc will still have a warning.
I think we should change the type of 'size' to be 'int' which
should catch the above case and be consistent with
what kvmalloc_node() intends to warn.
Huh, it's a bitmore complicated as check_mul_overflow requires types to
match; what do you think about
+ if (check_mul_overflow(cnt, (u32)sizeof(*syms), &size) || size > INT_MAX)
?
This works for me.
