On Mon, Apr 28, 2025 at 12:30:03PM +0200, Petr Pavlu wrote: > On 4/26/25 08:24, Kees Cook wrote: > > In preparation for making the kmalloc family of allocators type aware, > > we need to make sure that the returned type from the allocation matches > > the type of the variable being assigned. (Before, the allocator would > > always return "void *", which can be implicitly cast to any pointer type.) > > > > The assigned type is "struct page **" but the returned type will be > > "struct page ***". These have the same allocation size (pointer size), but > > the types don't match. Adjust the allocation type to match the assignment. > > > > Signed-off-by: Kees Cook <kees@xxxxxxxxxx> > > --- > > Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx> > > Cc: Petr Pavlu <petr.pavlu@xxxxxxxx> > > Cc: Sami Tolvanen <samitolvanen@xxxxxxxxxx> > > Cc: Daniel Gomez <da.gomez@xxxxxxxxxxx> > > Cc: <linux-modules@xxxxxxxxxxxxxxx> > > --- > > kernel/module/decompress.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/kernel/module/decompress.c b/kernel/module/decompress.c > > index 474e68f0f063..bbb2a55568cd 100644 > > --- a/kernel/module/decompress.c > > +++ b/kernel/module/decompress.c > > @@ -19,7 +19,7 @@ static int module_extend_max_pages(struct load_info *info, unsigned int extent) > > struct page **new_pages; > > > > new_pages = kvmalloc_array(info->max_pages + extent, > > - sizeof(info->pages), GFP_KERNEL); > > + sizeof(*new_pages), GFP_KERNEL); > > if (!new_pages) > > return -ENOMEM; > > > > The function has a similar type mismatch a few lines below: > > memcpy(new_pages, info->pages, info->max_pages * sizeof(info->pages)); > > The sizeof operator is used on 'struct page **', but it should be really > on 'struct page *'. > > Could you please fix this as well? For consistency with your patch, > I suggest changing it to 'sizeof(*new_pages)'. Actually, this whole function is basically just open-coded kvrealloc... I will send a v2. -- Kees Cook
