[PATCH] ieee802154: hwsim: fix possible null-pointer dereference in mac802154_hwsim.c

[PATCH] ieee802154: hwsim: fix possible null-pointer dereference in mac802154_hwsim.c

[Tuo Li]

In hwsim_new_edge_nl() and hwsim_set_edge_lqi(), if only one of the two
info->attrs is NULL, the functions will not return.
  if (!info->attrs[MAC802154_HWSIM_ATTR_RADIO_ID] &&
      !info->attrs[MAC802154_HWSIM_ATTR_RADIO_EDGE])
	  return -EINVAL;

However, both of them may be dereferenced in the function
nla_parse_nested_deprecated(), causing a null-pointer dereference.
To fix this possible null-pointer dereference, the function returns
-EINVAL if any info_attr is NULL.

Similarly, in hwsim_set_edge_lqi(), if only one of the two edge_attrs is
NULL, both nla_get_u32() and nla_get_u8() will be called, causing a
null-pointer dereference.
Also, to fix this possible null-pointer dereference, the function returns
-EINVAL if any edge_attr is NULL.

Fixes: f25da51fdc38 ("ieee802154: hwsim: add replacement for fakelb")
Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Signed-off-by: Tuo Li <islituo@gmail.com>
---
 drivers/net/ieee802154/mac802154_hwsim.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ieee802154/mac802154_hwsim.c b/drivers/net/ieee802154/mac802154_hwsim.c
index ebc976b7fcc2..8caa61ec718f 100644
--- a/drivers/net/ieee802154/mac802154_hwsim.c
+++ b/drivers/net/ieee802154/mac802154_hwsim.c
@@ -418,7 +418,7 @@ static int hwsim_new_edge_nl(struct sk_buff *msg, struct genl_info *info)
 	struct hwsim_edge *e;
 	u32 v0, v1;
 
-	if (!info->attrs[MAC802154_HWSIM_ATTR_RADIO_ID] &&
+	if (!info->attrs[MAC802154_HWSIM_ATTR_RADIO_ID] ||
 	    !info->attrs[MAC802154_HWSIM_ATTR_RADIO_EDGE])
 		return -EINVAL;
 
@@ -528,14 +528,14 @@ static int hwsim_set_edge_lqi(struct sk_buff *msg, struct genl_info *info)
 	u32 v0, v1;
 	u8 lqi;
 
-	if (!info->attrs[MAC802154_HWSIM_ATTR_RADIO_ID] &&
+	if (!info->attrs[MAC802154_HWSIM_ATTR_RADIO_ID] ||
 	    !info->attrs[MAC802154_HWSIM_ATTR_RADIO_EDGE])
 		return -EINVAL;
 
 	if (nla_parse_nested_deprecated(edge_attrs, MAC802154_HWSIM_EDGE_ATTR_MAX, info->attrs[MAC802154_HWSIM_ATTR_RADIO_EDGE], hwsim_edge_policy, NULL))
 		return -EINVAL;
 
-	if (!edge_attrs[MAC802154_HWSIM_EDGE_ATTR_ENDPOINT_ID] &&
+	if (!edge_attrs[MAC802154_HWSIM_EDGE_ATTR_ENDPOINT_ID] ||
 	    !edge_attrs[MAC802154_HWSIM_EDGE_ATTR_LQI])
 		return -EINVAL;
 
-- 
2.25.1

Re: [PATCH] ieee802154: hwsim: fix possible null-pointer dereference in mac802154_hwsim.c

[Stefan Schmidt]

Hello.

On 11.08.21 04:36, Tuo Li wrote:
> In hwsim_new_edge_nl() and hwsim_set_edge_lqi(), if only one of the two
> info->attrs is NULL, the functions will not return.
>    if (!info->attrs[MAC802154_HWSIM_ATTR_RADIO_ID] &&
>        !info->attrs[MAC802154_HWSIM_ATTR_RADIO_EDGE])
> 	  return -EINVAL;
> 
> However, both of them may be dereferenced in the function
> nla_parse_nested_deprecated(), causing a null-pointer dereference.
> To fix this possible null-pointer dereference, the function returns
> -EINVAL if any info_attr is NULL.
> 
> Similarly, in hwsim_set_edge_lqi(), if only one of the two edge_attrs is
> NULL, both nla_get_u32() and nla_get_u8() will be called, causing a
> null-pointer dereference.
> Also, to fix this possible null-pointer dereference, the function returns
> -EINVAL if any edge_attr is NULL.
> 
> Fixes: f25da51fdc38 ("ieee802154: hwsim: add replacement for fakelb")
> Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
> Signed-off-by: Tuo Li <islituo@gmail.com>

Thanks for your patch. This has already been fixed with patches in the 
wpan tree.
https://git.kernel.org/pub/scm/linux/kernel/git/sschmidt/wpan.git/

I just sent a pull request including them to get pulled into net.

regards
Stefan Schmidt