When compiling with gcc version 14.0.0 20231206 (experimental)
and CONFIG_FORTIFY_SOURCE=y, I've noticed the following warning:
...
In function 'fortify_memcpy_chk',
inlined from '__ffs_func_bind_do_os_desc' at drivers/usb/gadget/function/f_fs.c:2934:3:
./include/linux/fortify-string.h:588:25: warning: call to '__read_overflow2_field'
declared with attribute warning: detected read beyond size of field (2nd parameter);
maybe use struct_group()? [-Wattribute-warning]
588 | __read_overflow2_field(q_size_field, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This call to 'memcpy()' is interpreted as an attempt to copy both
'CompatibleID' and 'SubCompatibleID' of 'struct usb_ext_compat_desc'
from an address of the first one, which causes an overread warning.
Since we actually want to copy both of them at once, use the
convenient 'struct_group()' and 'sizeof_field()' here.
Signed-off-by: Dmitry Antipov <dmantipov@xxxxxxxxx>
---
v2: fix __struct_group(...) usage in uapi header
---
drivers/usb/gadget/function/f_fs.c | 5 ++---
include/uapi/linux/usb/functionfs.h | 6 ++++--
2 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index efe3e3b85769..dafedc33928d 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -2931,9 +2931,8 @@ static int __ffs_func_bind_do_os_desc(enum ffs_os_desc_type type,
t = &func->function.os_desc_table[desc->bFirstInterfaceNumber];
t->if_id = func->interfaces_nums[desc->bFirstInterfaceNumber];
- memcpy(t->os_desc->ext_compat_id, &desc->CompatibleID,
- ARRAY_SIZE(desc->CompatibleID) +
- ARRAY_SIZE(desc->SubCompatibleID));
+ memcpy(t->os_desc->ext_compat_id, &desc->IDs,
+ sizeof_field(struct usb_ext_compat_desc, IDs));
length = sizeof(*desc);
}
break;
diff --git a/include/uapi/linux/usb/functionfs.h b/include/uapi/linux/usb/functionfs.h
index d77ee6b65328..078098e73fd3 100644
--- a/include/uapi/linux/usb/functionfs.h
+++ b/include/uapi/linux/usb/functionfs.h
@@ -73,8 +73,10 @@ struct usb_os_desc_header {
struct usb_ext_compat_desc {
__u8 bFirstInterfaceNumber;
__u8 Reserved1;
- __u8 CompatibleID[8];
- __u8 SubCompatibleID[8];
+ __struct_group(/* no tag */, IDs, /* no attrs */,
+ __u8 CompatibleID[8];
+ __u8 SubCompatibleID[8];
+ );
__u8 Reserved2[6];
};
--
2.43.0
