Messages in this thread | | | From | Julius Werner <> | Date | Fri, 6 Jan 2023 23:27:04 +0100 | Subject | Re: [PATCH] firmware: coreboot: Check size of table entry and split memcpy |
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Yeah, exactly. Isn't that a bit simpler? (I wasn't aware of the flexible array member in union issue, but it sounds like we have a neat solution for that already.)
On Fri, Jan 6, 2023 at 9:35 PM Kees Cook <keescook@chromium.org> wrote: > > On Fri, Jan 06, 2023 at 04:03:35PM +0100, Julius Werner wrote: > > Have you considered adding the flexible array member directly to the > > union in struct coreboot_device instead? I think that would make this > > a bit simpler by not having to copy header and data portion > > separately. > > Are you thinking something like this? > > > diff --git a/drivers/firmware/google/coreboot_table.c b/drivers/firmware/google/coreboot_table.c > index 2652c396c423..564a3c908838 100644 > --- a/drivers/firmware/google/coreboot_table.c > +++ b/drivers/firmware/google/coreboot_table.c > @@ -93,14 +93,19 @@ static int coreboot_table_populate(struct device *dev, void *ptr) > for (i = 0; i < header->table_entries; i++) { > entry = ptr_entry; > > - device = kzalloc(sizeof(struct device) + entry->size, GFP_KERNEL); > + if (entry->size < sizeof(*entry)) { > + dev_warn(dev, "coreboot table entry too small!\n"); > + return -EINVAL; > + } > + > + device = kzalloc(sizeof(device->dev) + entry->size, GFP_KERNEL); > if (!device) > return -ENOMEM; > > device->dev.parent = dev; > device->dev.bus = &coreboot_bus_type; > device->dev.release = coreboot_device_release; > - memcpy(&device->entry, ptr_entry, entry->size); > + memcpy(device->raw, entry, entry->size); > > switch (device->entry.tag) { > case LB_TAG_CBMEM_ENTRY: > diff --git a/drivers/firmware/google/coreboot_table.h b/drivers/firmware/google/coreboot_table.h > index 37f4d335a606..d814dca33a08 100644 > --- a/drivers/firmware/google/coreboot_table.h > +++ b/drivers/firmware/google/coreboot_table.h > @@ -79,6 +79,7 @@ struct coreboot_device { > struct lb_cbmem_ref cbmem_ref; > struct lb_cbmem_entry cbmem_entry; > struct lb_framebuffer framebuffer; > + DECLARE_FLEX_ARRAY(u8, raw); > }; > }; > > > -- > Kees Cook
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