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SubjectRe: [PATCH] staging: rtl8712: uninitialized memory in read_bbreg_hdl()
On Thu, Mar 21, 2019 at 09:26:38AM +0300, Dan Carpenter wrote:
> Colin King reported a bug in read_bbreg_hdl():
>
> memcpy(pcmd->rsp, (u8 *)&val, pcmd->rspsz);
>
> The problem is that "val" is uninitialized.
>
> This code is obviously not useful, but so far as I can tell
> "pcmd->cmdcode" is never GEN_CMD_CODE(_Read_BBREG) so it's not harmful
> either. For now the easiest fix is to just call r8712_free_cmd_obj()
> and return.
>
> Fixes: 2865d42c78a9 ("staging: r8712u: Add the new driver to the mainline kernel")
> Reported-by: Colin Ian King <colin.king@canonical.com>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> drivers/staging/rtl8712/rtl8712_cmd.c | 10 +---------
> drivers/staging/rtl8712/rtl8712_cmd.h | 2 +-
> 2 files changed, 2 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/staging/rtl8712/rtl8712_cmd.h b/drivers/staging/rtl8712/rtl8712_cmd.h
> index 92fb77666d44..1ef86b8c592f 100644
> --- a/drivers/staging/rtl8712/rtl8712_cmd.h
> +++ b/drivers/staging/rtl8712/rtl8712_cmd.h
> @@ -140,7 +140,7 @@ enum rtl8712_h2c_cmd {
> static struct _cmd_callback cmd_callback[] = {
> {GEN_CMD_CODE(_Read_MACREG), NULL}, /*0*/
> {GEN_CMD_CODE(_Write_MACREG), NULL},
> - {GEN_CMD_CODE(_Read_BBREG), &r8712_getbbrfreg_cmdrsp_callback},
> + {GEN_CMD_CODE(_Read_BBREG), NULL},
> {GEN_CMD_CODE(_Write_BBREG), NULL},
> {GEN_CMD_CODE(_Read_RFREG), &r8712_getbbrfreg_cmdrsp_callback},
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> {GEN_CMD_CODE(_Write_RFREG), NULL}, /*5*/

The other place that calls r8712_getbbrfreg_cmdrsp_callback() is
read_rfreg_hdl(). For GEN_CMD_CODE(_Read_RFREG) we don't allocate
the ->rsp pointer so we can't kfree() it. The read_rfreg_hdl()
functions calls r8712_free_cmd_obj() which kfrees it. But fortunately
that is dead code.

This code is obviously staging code...

It would be fairly straight forward to get rid of the cmd_callback[]
array.

regards,
dan carpenter

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