Messages in this thread Patch in this message | | | Date | Fri, 6 Jan 2023 12:34:52 -0800 | From | Kees Cook <> | Subject | Re: [PATCH] firmware: coreboot: Check size of table entry and split memcpy |
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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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