* static analysis bug report: staging r8712u memcpy of uninitialized variable
@ 2019-03-18 11:20 Colin Ian King
2019-03-20 8:58 ` Dan Carpenter
0 siblings, 1 reply; 4+ messages in thread
From: Colin Ian King @ 2019-03-18 11:20 UTC (permalink / raw)
To: Larry Finger; +Cc: linux-kernel, devel
Hi,
Static analysis with cppcheck found a couple of interesting issues with
memcpy'ing of an uninitialized variable. Two occurrences of the same
issue are found in drivers/staging/rtl8712/rtl8712_cmd.c in functions
read_bbreg_hdl and read_rfreg_hdl.
For example:
static u8 read_bbreg_hdl(struct _adapter *padapter, u8 *pbuf)
{
u32 val;
void (*pcmd_callback)(struct _adapter *dev, struct cmd_obj
*pcmd);
struct cmd_obj *pcmd = (struct cmd_obj *)pbuf;
if (pcmd->rsp && pcmd->rspsz > 0)
memcpy(pcmd->rsp, (u8 *)&val, pcmd->rspsz);
....
}
I don't understand why the contents of val is being memcpy'd to
pcmd->rsp, especially when val is uninitialized and hence contains
garbage. Any ideas?
Colin
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: static analysis bug report: staging r8712u memcpy of uninitialized variable
2019-03-18 11:20 static analysis bug report: staging r8712u memcpy of uninitialized variable Colin Ian King
@ 2019-03-20 8:58 ` Dan Carpenter
2019-03-21 6:26 ` [PATCH] staging: rtl8712: uninitialized memory in read_bbreg_hdl() Dan Carpenter
0 siblings, 1 reply; 4+ messages in thread
From: Dan Carpenter @ 2019-03-20 8:58 UTC (permalink / raw)
To: Colin Ian King; +Cc: Larry Finger, devel, linux-kernel
On Mon, Mar 18, 2019 at 11:20:51AM +0000, Colin Ian King wrote:
> Hi,
>
> Static analysis with cppcheck found a couple of interesting issues with
> memcpy'ing of an uninitialized variable. Two occurrences of the same
> issue are found in drivers/staging/rtl8712/rtl8712_cmd.c in functions
> read_bbreg_hdl and read_rfreg_hdl.
>
> For example:
>
> static u8 read_bbreg_hdl(struct _adapter *padapter, u8 *pbuf)
> {
> u32 val;
> void (*pcmd_callback)(struct _adapter *dev, struct cmd_obj
> *pcmd);
> struct cmd_obj *pcmd = (struct cmd_obj *)pbuf;
>
> if (pcmd->rsp && pcmd->rspsz > 0)
> memcpy(pcmd->rsp, (u8 *)&val, pcmd->rspsz);
>
> ....
>
> }
>
> I don't understand why the contents of val is being memcpy'd to
> pcmd->rsp, especially when val is uninitialized and hence contains
> garbage. Any ideas?
>
The concern would be that it's reading a user specified amount of
stack memory to pcmd->rsp and that sounds like an information leak.
The pcmd_callback function pointer is always r8712_getbbrfreg_cmdrsp_callback()
which frees pcmd->parmbuf and pcmd but leaks pcmd->rsp. I don't see
a way for anyone to access the ->rsp memory so probably there aren't any
security implications.
Anyway, let me send a patch.
regards,
dan carpenter
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] staging: rtl8712: uninitialized memory in read_bbreg_hdl()
2019-03-20 8:58 ` Dan Carpenter
@ 2019-03-21 6:26 ` Dan Carpenter
2019-03-21 6:45 ` Dan Carpenter
0 siblings, 1 reply; 4+ messages in thread
From: Dan Carpenter @ 2019-03-21 6:26 UTC (permalink / raw)
To: Larry Finger, Colin Ian King
Cc: Florian Schilhabel, Greg Kroah-Hartman, Michael Straube, devel,
linux-kernel
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*/
diff --git a/drivers/staging/rtl8712/rtl8712_cmd.c b/drivers/staging/rtl8712/rtl8712_cmd.c
index 1920d02f7c9f..8c36acedf507 100644
--- a/drivers/staging/rtl8712/rtl8712_cmd.c
+++ b/drivers/staging/rtl8712/rtl8712_cmd.c
@@ -147,17 +147,9 @@ static u8 write_macreg_hdl(struct _adapter *padapter, u8 *pbuf)
static u8 read_bbreg_hdl(struct _adapter *padapter, u8 *pbuf)
{
- u32 val;
- void (*pcmd_callback)(struct _adapter *dev, struct cmd_obj *pcmd);
struct cmd_obj *pcmd = (struct cmd_obj *)pbuf;
- if (pcmd->rsp && pcmd->rspsz > 0)
- memcpy(pcmd->rsp, (u8 *)&val, pcmd->rspsz);
- pcmd_callback = cmd_callback[pcmd->cmdcode].callback;
- if (!pcmd_callback)
- r8712_free_cmd_obj(pcmd);
- else
- pcmd_callback(padapter, pcmd);
+ r8712_free_cmd_obj(pcmd);
return H2C_SUCCESS;
}
--
2.17.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] staging: rtl8712: uninitialized memory in read_bbreg_hdl()
2019-03-21 6:26 ` [PATCH] staging: rtl8712: uninitialized memory in read_bbreg_hdl() Dan Carpenter
@ 2019-03-21 6:45 ` Dan Carpenter
0 siblings, 0 replies; 4+ messages in thread
From: Dan Carpenter @ 2019-03-21 6:45 UTC (permalink / raw)
To: Larry Finger, Colin Ian King
Cc: Florian Schilhabel, Greg Kroah-Hartman, Michael Straube, devel,
linux-kernel
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
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-03-21 6:45 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-03-18 11:20 static analysis bug report: staging r8712u memcpy of uninitialized variable Colin Ian King
2019-03-20 8:58 ` Dan Carpenter
2019-03-21 6:26 ` [PATCH] staging: rtl8712: uninitialized memory in read_bbreg_hdl() Dan Carpenter
2019-03-21 6:45 ` Dan Carpenter
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).