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authorKees Cook <keescook@chromium.org>2023-01-13 02:03:16 +0300
committerKees Cook <keescook@chromium.org>2023-01-14 02:22:03 +0300
commit3b293487b8752cc42c1cbf8a0447bc6076c075fa (patch)
tree7503d756954f04b7a1b354fb8bdcdc506e17f4df /drivers
parent88603b6dc419445847923fcb7fe5080067a30f98 (diff)
downloadlinux-3b293487b8752cc42c1cbf8a0447bc6076c075fa.tar.xz
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
Diffstat (limited to 'drivers')
-rw-r--r--drivers/firmware/google/coreboot_table.c9
-rw-r--r--drivers/firmware/google/coreboot_table.h1
2 files changed, 8 insertions, 2 deletions
diff --git a/drivers/firmware/google/coreboot_table.c b/drivers/firmware/google/coreboot_table.c
index 2652c396c423..33ae94745aef 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, ptr_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);
};
};