[PATCH v3 1/8] staging: r8188eu: fix struct rt_firmware_hdr

From: Michael Straube
Date: Fri Apr 15 2022 - 08:10:43 EST


The size of struct rt_firmware_hdr is 36 bytes.

$ pahole -C rt_firmware_hdr drivers/staging/r8188eu/r8188eu.o
struct rt_firmware_hdr {
__le16 Signature; /* 0 2 */
u8 Category; /* 2 1 */
u8 Function; /* 3 1 */
__le16 Version; /* 4 2 */
u8 Subversion; /* 6 1 */

/* XXX 1 byte hole, try to pack */

u16 Rsvd1; /* 8 2 */
u8 Month; /* 10 1 */
u8 Date; /* 11 1 */
u8 Hour; /* 12 1 */
u8 Minute; /* 13 1 */
__le16 RamCodeSize; /* 14 2 */
u8 Foundry; /* 16 1 */
u8 Rsvd2; /* 17 1 */

/* XXX 2 bytes hole, try to pack */

__le32 SvnIdx; /* 20 4 */
u32 Rsvd3; /* 24 4 */
u32 Rsvd4; /* 28 4 */
u32 Rsvd5; /* 32 4 */

/* size: 36, cachelines: 1, members: 17 */
/* sum members: 33, holes: 2, sum holes: 3 */
/* last cacheline: 36 bytes */
};

But the header in the firmware file is only 32 bytes long.

The hexdump of rtl8188eufw.bin shows that the field Rsvd1 should be u8
instead of __le16.

OFFSET rtl8188eufw.bin
-----------------------------------------------------------
0x00000000 E1 88 10 00 0B 00 01 00 01 21 11 27 30 36 00 00
0x00000010 2D 07 00 00 00 00 00 00 00 00 00 00 00 00 00 00

0x00000000 E1 88 10 00 0B 00 01 00 01 21 11 27 30 36 00 00
^ ^ ^ ^ ^ ^
Subversion Rsvd1 Month Date Hour Minute

With the change of field Rsvd1 from __le16 to u8 the structure has the
correct size 32.

$ pahole -C rt_firmware_hdr drivers/staging/r8188eu/r8188eu.o
struct rt_firmware_hdr {
__le16 Signature; /* 0 2 */
u8 Category; /* 2 1 */
u8 Function; /* 3 1 */
__le16 Version; /* 4 2 */
u8 Subversion; /* 6 1 */
u8 Rsvd1; /* 7 1 */
u8 Month; /* 8 1 */
u8 Date; /* 9 1 */
u8 Hour; /* 10 1 */
u8 Minute; /* 11 1 */
__le16 RamCodeSize; /* 12 2 */
u8 Foundry; /* 14 1 */
u8 Rsvd2; /* 15 1 */
__le32 SvnIdx; /* 16 4 */
u32 Rsvd3; /* 20 4 */
u32 Rsvd4; /* 24 4 */
u32 Rsvd5; /* 28 4 */

/* size: 32, cachelines: 1, members: 17 */
/* last cacheline: 32 bytes */

The wrong size had no effect because the header size is hardcoded to
32 where it is used in the code and the fields after Subversion are
not used.

Fixes: 7884fc0a1473 ("staging: r8188eu: introduce new include dir for RTL8188eu driver")
Signed-off-by: Michael Straube <straube.linux@xxxxxxxxx>
---
v3:
- updated the commit message
- moved the u32 to __le32 conversions to a separate patch

v2:
- no changes

drivers/staging/r8188eu/core/rtw_fw.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/r8188eu/core/rtw_fw.c b/drivers/staging/r8188eu/core/rtw_fw.c
index 8620f3c92b52..eb4ab11f6b28 100644
--- a/drivers/staging/r8188eu/core/rtw_fw.c
+++ b/drivers/staging/r8188eu/core/rtw_fw.c
@@ -29,7 +29,7 @@ struct rt_firmware_hdr {
* FW for different conditions */
__le16 Version; /* FW Version */
u8 Subversion; /* FW Subversion, default 0x00 */
- u16 Rsvd1;
+ u8 Rsvd1;

/* LONG WORD 1 ---- */
u8 Month; /* Release time Month field */
--
2.35.1