linux/drivers/firmware/google/coreboot_table.h
Kees Cook 3b293487b8 firmware: coreboot: Check size of table entry and use flex-array
The memcpy() of the data following a coreboot_table_entry couldn't
be evaluated by the compiler under CONFIG_FORTIFY_SOURCE. To make it
easier to reason about, add an explicit flexible array member to struct
coreboot_device so the entire entry can be copied at once. Additionally,
validate the sizes before copying. Avoids this run-time false positive
warning:

  memcpy: detected field-spanning write (size 168) of single field "&device->entry" at drivers/firmware/google/coreboot_table.c:103 (size 8)

Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Link: https://lore.kernel.org/all/03ae2704-8c30-f9f0-215b-7cdf4ad35a9a@molgen.mpg.de/
Cc: Jack Rosenthal <jrosenth@chromium.org>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Julius Werner <jwerner@chromium.org>
Cc: Brian Norris <briannorris@chromium.org>
Cc: Stephen Boyd <swboyd@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Link: https://lore.kernel.org/r/20230107031406.gonna.761-kees@kernel.org
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>
Link: https://lore.kernel.org/r/20230112230312.give.446-kees@kernel.org
2023-01-13 15:22:03 -08:00

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2.6 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* coreboot_table.h
*
* Internal header for coreboot table access.
*
* Copyright 2014 Gerd Hoffmann <kraxel@redhat.com>
* Copyright 2017 Google Inc.
* Copyright 2017 Samuel Holland <samuel@sholland.org>
*/
#ifndef __COREBOOT_TABLE_H
#define __COREBOOT_TABLE_H
#include <linux/device.h>
/* Coreboot table header structure */
struct coreboot_table_header {
char signature[4];
u32 header_bytes;
u32 header_checksum;
u32 table_bytes;
u32 table_checksum;
u32 table_entries;
};
/* List of coreboot entry structures that is used */
/* Generic */
struct coreboot_table_entry {
u32 tag;
u32 size;
};
/* Points to a CBMEM entry */
struct lb_cbmem_ref {
u32 tag;
u32 size;
u64 cbmem_addr;
};
#define LB_TAG_CBMEM_ENTRY 0x31
/* Corresponds to LB_TAG_CBMEM_ENTRY */
struct lb_cbmem_entry {
u32 tag;
u32 size;
u64 address;
u32 entry_size;
u32 id;
};
/* Describes framebuffer setup by coreboot */
struct lb_framebuffer {
u32 tag;
u32 size;
u64 physical_address;
u32 x_resolution;
u32 y_resolution;
u32 bytes_per_line;
u8 bits_per_pixel;
u8 red_mask_pos;
u8 red_mask_size;
u8 green_mask_pos;
u8 green_mask_size;
u8 blue_mask_pos;
u8 blue_mask_size;
u8 reserved_mask_pos;
u8 reserved_mask_size;
};
/* A device, additionally with information from coreboot. */
struct coreboot_device {
struct device dev;
union {
struct coreboot_table_entry entry;
struct lb_cbmem_ref cbmem_ref;
struct lb_cbmem_entry cbmem_entry;
struct lb_framebuffer framebuffer;
DECLARE_FLEX_ARRAY(u8, raw);
};
};
static inline struct coreboot_device *dev_to_coreboot_device(struct device *dev)
{
return container_of(dev, struct coreboot_device, dev);
}
/* A driver for handling devices described in coreboot tables. */
struct coreboot_driver {
int (*probe)(struct coreboot_device *);
void (*remove)(struct coreboot_device *);
struct device_driver drv;
u32 tag;
};
/* Register a driver that uses the data from a coreboot table. */
int coreboot_driver_register(struct coreboot_driver *driver);
/* Unregister a driver that uses the data from a coreboot table. */
void coreboot_driver_unregister(struct coreboot_driver *driver);
/* module_coreboot_driver() - Helper macro for drivers that don't do
* anything special in module init/exit. This eliminates a lot of
* boilerplate. Each module may only use this macro once, and
* calling it replaces module_init() and module_exit()
*/
#define module_coreboot_driver(__coreboot_driver) \
module_driver(__coreboot_driver, coreboot_driver_register, \
coreboot_driver_unregister)
#endif /* __COREBOOT_TABLE_H */