2022-06-08 22:29:17

by Kees Cook

Subject: [PATCH] staging: rtl8723bs: Allocate full pwep structure

The pwep allocation was always being allocated smaller than the true
structure size. Avoid this by always allocating the full structure.
Found with GCC 12 and -Warray-bounds:

../drivers/staging/rtl8723bs/os_dep/ioctl_linux.c: In function 'rtw_set_encryption':
../drivers/staging/rtl8723bs/os_dep/ioctl_linux.c:591:29: warning: array subscript 'struct ndis_802_11_wep[0]' is partly outside array bounds of 'void[25]' [-Warray-bounds]
591 | pwep->length = wep_total_len;
| ^~

Cc: Greg Kroah-Hartman <[email protected]>
Cc: Fabio Aiuto <[email protected]>
Cc: Hans de Goede <[email protected]>
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>
---
drivers/staging/rtl8723bs/os_dep/ioctl_linux.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c b/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c
index ece97e37ac91..30374a820496 100644
--- a/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c
+++ b/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c
@@ -90,7 +90,8 @@ static int wpa_set_encryption(struct net_device *dev, struct ieee_param *param,
if (wep_key_len > 0) {
wep_key_len = wep_key_len <= 5 ? 5 : 13;
wep_total_len = wep_key_len + FIELD_OFFSET(struct ndis_802_11_wep, key_material);
- pwep = kzalloc(wep_total_len, GFP_KERNEL);
+ /* Allocate a full structure to avoid potentially running off the end. */
+ pwep = kzalloc(sizeof(*pwep), GFP_KERNEL);
if (!pwep) {
ret = -ENOMEM;
goto exit;
@@ -582,7 +583,8 @@ static int rtw_set_encryption(struct net_device *dev, struct ieee_param *param,
if (wep_key_len > 0) {
wep_key_len = wep_key_len <= 5 ? 5 : 13;
wep_total_len = wep_key_len + FIELD_OFFSET(struct ndis_802_11_wep, key_material);
- pwep = kzalloc(wep_total_len, GFP_KERNEL);
+ /* Allocate a full structure to avoid potentially running off the end. */
+ pwep = kzalloc(sizeof(*pwep), GFP_KERNEL);
if (!pwep)
goto exit;

--
2.32.0

2022-06-18 08:12:45

by Christophe JAILLET

Subject: Re: [PATCH] staging: rtl8723bs: Allocate full pwep structure

Le 08/06/2022 à 23:55, Kees Cook a écrit :
> The pwep allocation was always being allocated smaller than the true
> structure size. Avoid this by always allocating the full structure.
> Found with GCC 12 and -Warray-bounds:
>
> ../drivers/staging/rtl8723bs/os_dep/ioctl_linux.c: In function 'rtw_set_encryption':
> ../drivers/staging/rtl8723bs/os_dep/ioctl_linux.c:591:29: warning: array subscript 'struct ndis_802_11_wep[0]' is partly outside array bounds of 'void[25]' [-Warray-bounds]
> 591 | pwep->length = wep_total_len;
> | ^~
>
> Cc: Greg Kroah-Hartman <[email protected]>
> Cc: Fabio Aiuto <[email protected]>
> Cc: Hans de Goede <[email protected]>
> Cc: [email protected]
> Signed-off-by: Kees Cook <[email protected]>
> ---
> drivers/staging/rtl8723bs/os_dep/ioctl_linux.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c b/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c
> index ece97e37ac91..30374a820496 100644
> --- a/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c
> +++ b/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c
> @@ -90,7 +90,8 @@ static int wpa_set_encryption(struct net_device *dev, struct ieee_param *param,
> if (wep_key_len > 0) {
> wep_key_len = wep_key_len <= 5 ? 5 : 13;
> wep_total_len = wep_key_len + FIELD_OFFSET(struct ndis_802_11_wep, key_material);
> - pwep = kzalloc(wep_total_len, GFP_KERNEL);
> + /* Allocate a full structure to avoid potentially running off the end. */
> + pwep = kzalloc(sizeof(*pwep), GFP_KERNEL);
> if (!pwep) {
> ret = -ENOMEM;
> goto exit;
> @@ -582,7 +583,8 @@ static int rtw_set_encryption(struct net_device *dev, struct ieee_param *param,
> if (wep_key_len > 0) {
> wep_key_len = wep_key_len <= 5 ? 5 : 13;
> wep_total_len = wep_key_len + FIELD_OFFSET(struct ndis_802_11_wep, key_material);
> - pwep = kzalloc(wep_total_len, GFP_KERNEL);
> + /* Allocate a full structure to avoid potentially running off the end. */
> + pwep = kzalloc(sizeof(*pwep), GFP_KERNEL);
> if (!pwep)

Hi,

while at it (and un-related tyo your patch), I think that 'ret' should
also be updated here, otherwise we return 0.

CJ

> goto exit;
>

2022-06-20 10:07:16

by Dan Carpenter

Subject: Re: [PATCH] staging: rtl8723bs: Allocate full pwep structure

On Sat, Jun 18, 2022 at 09:51:36AM +0200, Christophe JAILLET wrote:
> > diff --git a/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c b/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c
> > index ece97e37ac91..30374a820496 100644
> > --- a/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c
> > +++ b/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c
> > @@ -90,7 +90,8 @@ static int wpa_set_encryption(struct net_device *dev, struct ieee_param *param,
> > if (wep_key_len > 0) {
> > wep_key_len = wep_key_len <= 5 ? 5 : 13;
> > wep_total_len = wep_key_len + FIELD_OFFSET(struct ndis_802_11_wep, key_material);
> > - pwep = kzalloc(wep_total_len, GFP_KERNEL);
> > + /* Allocate a full structure to avoid potentially running off the end. */
> > + pwep = kzalloc(sizeof(*pwep), GFP_KERNEL);
> > if (!pwep) {
> > ret = -ENOMEM;
> > goto exit;
> > @@ -582,7 +583,8 @@ static int rtw_set_encryption(struct net_device *dev, struct ieee_param *param,
> > if (wep_key_len > 0) {
> > wep_key_len = wep_key_len <= 5 ? 5 : 13;
> > wep_total_len = wep_key_len + FIELD_OFFSET(struct ndis_802_11_wep, key_material);
> > - pwep = kzalloc(wep_total_len, GFP_KERNEL);
> > + /* Allocate a full structure to avoid potentially running off the end. */
> > + pwep = kzalloc(sizeof(*pwep), GFP_KERNEL);
> > if (!pwep)
>
> Hi,
>
> while at it (and un-related tyo your patch), I think that 'ret' should also
> be updated here, otherwise we return 0.
>

Too late. Smatch does catch that bug btw.

drivers/staging/r8188eu/os_dep/ioctl_linux.c:409 wpa_set_encryption() warn: missing error code here? 'kzalloc()' failed. 'ret' = '0'

regards,
dan carpenter