On 9/19/21 04:45, Len Baker wrote: > As noted in the "Deprecated Interfaces, Language Features, Attributes, > and Conventions" documentation [1], size calculations (especially > multiplication) should not be performed in memory allocator (or similar) > function arguments due to the risk of them overflowing. This could lead > to values wrapping around and a smaller allocation being made than the > caller was expecting. Using those allocations could lead to linear > overflows of heap memory and other misbehaviors. > > So, use the struct_size() helper to do the arithmetic instead of the > argument "size + size * count" in the kzalloc() function. > > [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments > > Signed-off-by: Len Baker <len.baker@xxxxxxx> Reviewed-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> Thanks -- Gustavo > --- > fs/aio.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/fs/aio.c b/fs/aio.c > index 51b08ab01dff..c2978c0b872c 100644 > --- a/fs/aio.c > +++ b/fs/aio.c > @@ -659,8 +659,7 @@ static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm) > new_nr = (table ? table->nr : 1) * 4; > spin_unlock(&mm->ioctx_lock); > > - table = kzalloc(sizeof(*table) + sizeof(struct kioctx *) * > - new_nr, GFP_KERNEL); > + table = kzalloc(struct_size(table, table, new_nr), GFP_KERNEL); > if (!table) > return -ENOMEM; > > -- > 2.25.1 >
