diff options
| author | Erick Archer <erick.archer@outlook.com> | 2024-06-02 18:13:10 +0200 |
|---|---|---|
| committer | Kalle Valo <kvalo@kernel.org> | 2024-06-12 15:00:33 +0300 |
| commit | bbef1d006cb1c2774c4b44eb70441d784d3aef44 (patch) | |
| tree | 3b348f425b140b9fc1a7adafd4fda00b7d2f4290 | |
| parent | aea9165ccfd1577be801fd75515fc9d4a9595b90 (diff) | |
wifi: at76c50x: prefer struct_size over open coded arithmetic
This is an effort to get rid of all multiplications from allocation
functions in order to prevent integer overflows [1][2].
As the "cmd_buf" variable is a pointer to "struct at76_command" and
this structure ends in a flexible array:
struct at76_command {
[...]
u8 data[];
} __packed;
the preferred way in the kernel is to use the struct_size() helper to
do the arithmetic instead of the calculation "size + count" in the
kmalloc() function.
Also, declare a new variable (total_size) since the return value of the
struct_size() helper is used several times.
At the same time, prepare for the coming implementation by GCC and Clang
of the __counted_by attribute. Flexible array members annotated with
__counted_by can have their accesses bounds-checked at run-time via
CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for
strcpy/memcpy-family functions). In this case, it is important to note
that the attribute used is "__counted_by_le" since the counter type is
"__le16".
This way, the code is more readable and safer.
Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1]
Link: https://github.com/KSPP/linux/issues/160 [2]
Signed-off-by: Erick Archer <erick.archer@outlook.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/AS8PR02MB7237578654CEDDFE5F8C17BA8BFE2@AS8PR02MB7237.eurprd02.prod.outlook.com
| -rw-r--r-- | drivers/net/wireless/atmel/at76c50x-usb.c | 12 | ||||
| -rw-r--r-- | drivers/net/wireless/atmel/at76c50x-usb.h | 2 |
2 files changed, 7 insertions, 7 deletions
diff --git a/drivers/net/wireless/atmel/at76c50x-usb.c b/drivers/net/wireless/atmel/at76c50x-usb.c index 0ca2f629683d..baa53cfefe48 100644 --- a/drivers/net/wireless/atmel/at76c50x-usb.c +++ b/drivers/net/wireless/atmel/at76c50x-usb.c @@ -721,9 +721,11 @@ static int at76_set_card_command(struct usb_device *udev, u8 cmd, void *buf, int buf_size) { int ret; - struct at76_command *cmd_buf = kmalloc(sizeof(struct at76_command) + - buf_size, GFP_KERNEL); + size_t total_size; + struct at76_command *cmd_buf; + total_size = struct_size(cmd_buf, data, buf_size); + cmd_buf = kmalloc(total_size, GFP_KERNEL); if (!cmd_buf) return -ENOMEM; @@ -732,15 +734,13 @@ static int at76_set_card_command(struct usb_device *udev, u8 cmd, void *buf, cmd_buf->size = cpu_to_le16(buf_size); memcpy(cmd_buf->data, buf, buf_size); - at76_dbg_dump(DBG_CMD, cmd_buf, sizeof(struct at76_command) + buf_size, + at76_dbg_dump(DBG_CMD, cmd_buf, total_size, "issuing command %s (0x%02x)", at76_get_cmd_string(cmd), cmd); ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0x0e, USB_TYPE_VENDOR | USB_DIR_OUT | USB_RECIP_DEVICE, - 0, 0, cmd_buf, - sizeof(struct at76_command) + buf_size, - USB_CTRL_GET_TIMEOUT); + 0, 0, cmd_buf, total_size, USB_CTRL_GET_TIMEOUT); kfree(cmd_buf); return ret; } diff --git a/drivers/net/wireless/atmel/at76c50x-usb.h b/drivers/net/wireless/atmel/at76c50x-usb.h index 746e64dfd8aa..843146a0de64 100644 --- a/drivers/net/wireless/atmel/at76c50x-usb.h +++ b/drivers/net/wireless/atmel/at76c50x-usb.h @@ -151,7 +151,7 @@ struct at76_command { u8 cmd; u8 reserved; __le16 size; - u8 data[]; + u8 data[] __counted_by_le(size); } __packed; /* Length of Atmel-specific Rx header before 802.11 frame */ |