Re: [PATCH] libertas: Avoid reading past end of buffer

[Kalle Valo]

Joe Perches  writes:

> unrelated trivia:
>
> lbs_deb_enter is used incorrectly here at
> function exit as both enter and leave calls.
>
> That type of copy/paste defect may be common.
>
> $ git grep -w lbs_deb_enter | wc -l
> 148
> $ git grep -w lbs_deb_leave | wc -l
> 71
>
> One would expect these numbers to be the same.
>
> Another option would be to delete all these
> calls as ftrace function tracing works well.

Yeah, deleting all the enter/exit calls would be better.

-- 
Kalle Valo

Re: [PATCH] libertas: Avoid reading past end of buffer

[Kalle Valo]

Joe Perches  writes:

> unrelated trivia:
>
> lbs_deb_enter is used incorrectly here at
> function exit as both enter and leave calls.
>
> That type of copy/paste defect may be common.
>
> $ git grep -w lbs_deb_enter | wc -l
> 148
> $ git grep -w lbs_deb_leave | wc -l
> 71
>
> One would expect these numbers to be the same.
>
> Another option would be to delete all these
> calls as ftrace function tracing works well.

Yeah, deleting all the enter/exit calls would be better.

-- 
Kalle Valo

Re: [PATCH] libertas: Avoid reading past end of buffer

[Joe Perches]

On Wed, 2017-05-10 at 12:24 -0700, Kees Cook wrote:
> Using memcpy() from a string that is shorter than the length copied means
> the destination buffer is being filled with arbitrary data from the kernel
> rodata segment. 

another bit of trivia:

> diff --git a/drivers/net/wireless/marvell/libertas/mesh.c 
> b/drivers/net/wireless/marvell/libertas/mesh.c
[]
> @@ -1170,17 +1170,11 @@ int lbs_mesh_ethtool_get_sset_count(struct net_device 
> *dev, int sset)
[]
> + memcpy(s, *mesh_stat_strings, sizeof(mesh_stat_strings));

That * isn't necessary.

Re: [PATCH] libertas: Avoid reading past end of buffer

[Joe Perches]

On Wed, 2017-05-10 at 12:24 -0700, Kees Cook wrote:
> Using memcpy() from a string that is shorter than the length copied means
> the destination buffer is being filled with arbitrary data from the kernel
> rodata segment. 

another bit of trivia:

> diff --git a/drivers/net/wireless/marvell/libertas/mesh.c 
> b/drivers/net/wireless/marvell/libertas/mesh.c
[]
> @@ -1170,17 +1170,11 @@ int lbs_mesh_ethtool_get_sset_count(struct net_device 
> *dev, int sset)
[]
> + memcpy(s, *mesh_stat_strings, sizeof(mesh_stat_strings));

That * isn't necessary.

Re: [PATCH] libertas: Avoid reading past end of buffer

[Joe Perches]

On Wed, 2017-05-10 at 12:24 -0700, Kees Cook wrote:
> Using memcpy() from a string that is shorter than the length copied means
[]
> diff --git a/drivers/net/wireless/marvell/libertas/mesh.c 
> b/drivers/net/wireless/marvell/libertas/mesh.c
[]
> @@ -1170,17 +1170,11 @@ int lbs_mesh_ethtool_get_sset_count(struct net_device 
> *dev, int sset)
>  void lbs_mesh_ethtool_get_strings(struct net_device *dev,
>   uint32_t stringset, uint8_t *s)
>  {
> - int i;
> -
>   lbs_deb_enter(LBS_DEB_ETHTOOL);
>  
>   switch (stringset) {
>   case ETH_SS_STATS:
> - for (i = 0; i < MESH_STATS_NUM; i++) {
> - memcpy(s + i * ETH_GSTRING_LEN,
> - mesh_stat_strings[i],
> - ETH_GSTRING_LEN);
> - }
> + memcpy(s, *mesh_stat_strings, sizeof(mesh_stat_strings));
>   break;
>   }
>   lbs_deb_enter(LBS_DEB_ETHTOOL);

unrelated trivia:

lbs_deb_enter is used incorrectly here at
function exit as both enter and leave calls.

That type of copy/paste defect may be common.

$ git grep -w lbs_deb_enter | wc -l
148
$ git grep -w lbs_deb_leave | wc -l
71

One would expect these numbers to be the same.

Another option would be to delete all these
calls as ftrace function tracing works well.

Re: [PATCH] libertas: Avoid reading past end of buffer

[Joe Perches]

On Wed, 2017-05-10 at 12:24 -0700, Kees Cook wrote:
> Using memcpy() from a string that is shorter than the length copied means
[]
> diff --git a/drivers/net/wireless/marvell/libertas/mesh.c 
> b/drivers/net/wireless/marvell/libertas/mesh.c
[]
> @@ -1170,17 +1170,11 @@ int lbs_mesh_ethtool_get_sset_count(struct net_device 
> *dev, int sset)
>  void lbs_mesh_ethtool_get_strings(struct net_device *dev,
>   uint32_t stringset, uint8_t *s)
>  {
> - int i;
> -
>   lbs_deb_enter(LBS_DEB_ETHTOOL);
>  
>   switch (stringset) {
>   case ETH_SS_STATS:
> - for (i = 0; i < MESH_STATS_NUM; i++) {
> - memcpy(s + i * ETH_GSTRING_LEN,
> - mesh_stat_strings[i],
> - ETH_GSTRING_LEN);
> - }
> + memcpy(s, *mesh_stat_strings, sizeof(mesh_stat_strings));
>   break;
>   }
>   lbs_deb_enter(LBS_DEB_ETHTOOL);

unrelated trivia:

lbs_deb_enter is used incorrectly here at
function exit as both enter and leave calls.

That type of copy/paste defect may be common.

$ git grep -w lbs_deb_enter | wc -l
148
$ git grep -w lbs_deb_leave | wc -l
71

One would expect these numbers to be the same.

Another option would be to delete all these
calls as ftrace function tracing works well.

Re: [PATCH] libertas: Avoid reading past end of buffer

[Kees Cook]

On Tue, May 9, 2017 at 9:33 PM, Joe Perches  wrote:
> On Tue, 2017-05-09 at 16:23 -0700, Kees Cook wrote:
>> Using memcpy() from a string that is shorter than the length copied means
>> the destination buffer is being filled with arbitrary data from the kernel
>> rodata segment. Instead, use strncpy() which will fill the trailing bytes
>> with zeros. Additionally adjust indentation to keep checkpatch.pl happy.
>>
>> This was found with the future CONFIG_FORTIFY_SOURCE feature.
> []
>> diff --git a/drivers/net/wireless/marvell/libertas/mesh.c 
>> b/drivers/net/wireless/marvell/libertas/mesh.c
> []
>> @@ -1177,9 +1177,9 @@ void lbs_mesh_ethtool_get_strings(struct net_device 
>> *dev,
>>   switch (stringset) {
>>   case ETH_SS_STATS:
>>   for (i = 0; i < MESH_STATS_NUM; i++) {
>> - memcpy(s + i * ETH_GSTRING_LEN,
>> - mesh_stat_strings[i],
>> - ETH_GSTRING_LEN);
>> + strncpy(s + i * ETH_GSTRING_LEN,
>> + mesh_stat_strings[i],
>> + ETH_GSTRING_LEN);
>>   }
>
> The better solution is to declare
> mesh_stat_strings in in the normal way
>
> ---
>  drivers/net/wireless/marvell/libertas/mesh.c | 18 +-
>  1 file changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/net/wireless/marvell/libertas/mesh.c 
> b/drivers/net/wireless/marvell/libertas/mesh.c
> index d0c881dd5846..a535e7f48d2d 100644
> --- a/drivers/net/wireless/marvell/libertas/mesh.c
> +++ b/drivers/net/wireless/marvell/libertas/mesh.c
> @@ -1108,15 +1108,15 @@ void lbs_mesh_set_txpd(struct lbs_private *priv,
>   * Ethtool related
>   */
>
> -static const char * const mesh_stat_strings[] = {
> -   "drop_duplicate_bcast",
> -   "drop_ttl_zero",
> -   "drop_no_fwd_route",
> -   "drop_no_buffers",
> -   "fwded_unicast_cnt",
> -   "fwded_bcast_cnt",
> -   "drop_blind_table",
> -   "tx_failed_cnt"
> +static const char mesh_stat_strings[][ETH_GSTRING_LEN] = {
> +   "drop_duplicate_bcast",
> +   "drop_ttl_zero",
> +   "drop_no_fwd_route",
> +   "drop_no_buffers",
> +   "fwded_unicast_cnt",
> +   "fwded_bcast_cnt",
> +   "drop_blind_table",
> +   "tx_failed_cnt",
>  };
>
>  void lbs_mesh_ethtool_get_stats(struct net_device *dev,

Ah yeah! And that simplifies the memcpy too, since it can just do it
in one go. New patch on the way...

-Kees

-- 
Kees Cook
Pixel Security

Re: [PATCH] libertas: Avoid reading past end of buffer

[Kees Cook]

On Tue, May 9, 2017 at 9:33 PM, Joe Perches  wrote:
> On Tue, 2017-05-09 at 16:23 -0700, Kees Cook wrote:
>> Using memcpy() from a string that is shorter than the length copied means
>> the destination buffer is being filled with arbitrary data from the kernel
>> rodata segment. Instead, use strncpy() which will fill the trailing bytes
>> with zeros. Additionally adjust indentation to keep checkpatch.pl happy.
>>
>> This was found with the future CONFIG_FORTIFY_SOURCE feature.
> []
>> diff --git a/drivers/net/wireless/marvell/libertas/mesh.c 
>> b/drivers/net/wireless/marvell/libertas/mesh.c
> []
>> @@ -1177,9 +1177,9 @@ void lbs_mesh_ethtool_get_strings(struct net_device 
>> *dev,
>>   switch (stringset) {
>>   case ETH_SS_STATS:
>>   for (i = 0; i < MESH_STATS_NUM; i++) {
>> - memcpy(s + i * ETH_GSTRING_LEN,
>> - mesh_stat_strings[i],
>> - ETH_GSTRING_LEN);
>> + strncpy(s + i * ETH_GSTRING_LEN,
>> + mesh_stat_strings[i],
>> + ETH_GSTRING_LEN);
>>   }
>
> The better solution is to declare
> mesh_stat_strings in in the normal way
>
> ---
>  drivers/net/wireless/marvell/libertas/mesh.c | 18 +-
>  1 file changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/net/wireless/marvell/libertas/mesh.c 
> b/drivers/net/wireless/marvell/libertas/mesh.c
> index d0c881dd5846..a535e7f48d2d 100644
> --- a/drivers/net/wireless/marvell/libertas/mesh.c
> +++ b/drivers/net/wireless/marvell/libertas/mesh.c
> @@ -1108,15 +1108,15 @@ void lbs_mesh_set_txpd(struct lbs_private *priv,
>   * Ethtool related
>   */
>
> -static const char * const mesh_stat_strings[] = {
> -   "drop_duplicate_bcast",
> -   "drop_ttl_zero",
> -   "drop_no_fwd_route",
> -   "drop_no_buffers",
> -   "fwded_unicast_cnt",
> -   "fwded_bcast_cnt",
> -   "drop_blind_table",
> -   "tx_failed_cnt"
> +static const char mesh_stat_strings[][ETH_GSTRING_LEN] = {
> +   "drop_duplicate_bcast",
> +   "drop_ttl_zero",
> +   "drop_no_fwd_route",
> +   "drop_no_buffers",
> +   "fwded_unicast_cnt",
> +   "fwded_bcast_cnt",
> +   "drop_blind_table",
> +   "tx_failed_cnt",
>  };
>
>  void lbs_mesh_ethtool_get_stats(struct net_device *dev,

Ah yeah! And that simplifies the memcpy too, since it can just do it
in one go. New patch on the way...

-Kees

-- 
Kees Cook
Pixel Security

Re: [PATCH] libertas: Avoid reading past end of buffer

[Joe Perches]

On Tue, 2017-05-09 at 16:23 -0700, Kees Cook wrote:
> Using memcpy() from a string that is shorter than the length copied means
> the destination buffer is being filled with arbitrary data from the kernel
> rodata segment. Instead, use strncpy() which will fill the trailing bytes
> with zeros. Additionally adjust indentation to keep checkpatch.pl happy.
> 
> This was found with the future CONFIG_FORTIFY_SOURCE feature.
[]
> diff --git a/drivers/net/wireless/marvell/libertas/mesh.c 
> b/drivers/net/wireless/marvell/libertas/mesh.c
[]
> @@ -1177,9 +1177,9 @@ void lbs_mesh_ethtool_get_strings(struct net_device 
> *dev,
>   switch (stringset) {
>   case ETH_SS_STATS:
>   for (i = 0; i < MESH_STATS_NUM; i++) {
> - memcpy(s + i * ETH_GSTRING_LEN,
> - mesh_stat_strings[i],
> - ETH_GSTRING_LEN);
> + strncpy(s + i * ETH_GSTRING_LEN,
> + mesh_stat_strings[i],
> + ETH_GSTRING_LEN);
>   }

The better solution is to declare
mesh_stat_strings in in the normal way

---
 drivers/net/wireless/marvell/libertas/mesh.c | 18 +-
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/net/wireless/marvell/libertas/mesh.c 
b/drivers/net/wireless/marvell/libertas/mesh.c
index d0c881dd5846..a535e7f48d2d 100644
--- a/drivers/net/wireless/marvell/libertas/mesh.c
+++ b/drivers/net/wireless/marvell/libertas/mesh.c
@@ -1108,15 +1108,15 @@ void lbs_mesh_set_txpd(struct lbs_private *priv,
  * Ethtool related
  */
 
-static const char * const mesh_stat_strings[] = {
-   "drop_duplicate_bcast",
-   "drop_ttl_zero",
-   "drop_no_fwd_route",
-   "drop_no_buffers",
-   "fwded_unicast_cnt",
-   "fwded_bcast_cnt",
-   "drop_blind_table",
-   "tx_failed_cnt"
+static const char mesh_stat_strings[][ETH_GSTRING_LEN] = {
+   "drop_duplicate_bcast",
+   "drop_ttl_zero",
+   "drop_no_fwd_route",
+   "drop_no_buffers",
+   "fwded_unicast_cnt",
+   "fwded_bcast_cnt",
+   "drop_blind_table",
+   "tx_failed_cnt",
 };
 
 void lbs_mesh_ethtool_get_stats(struct net_device *dev,

Re: [PATCH] libertas: Avoid reading past end of buffer

[Joe Perches]

On Tue, 2017-05-09 at 16:23 -0700, Kees Cook wrote:
> Using memcpy() from a string that is shorter than the length copied means
> the destination buffer is being filled with arbitrary data from the kernel
> rodata segment. Instead, use strncpy() which will fill the trailing bytes
> with zeros. Additionally adjust indentation to keep checkpatch.pl happy.
> 
> This was found with the future CONFIG_FORTIFY_SOURCE feature.
[]
> diff --git a/drivers/net/wireless/marvell/libertas/mesh.c 
> b/drivers/net/wireless/marvell/libertas/mesh.c
[]
> @@ -1177,9 +1177,9 @@ void lbs_mesh_ethtool_get_strings(struct net_device 
> *dev,
>   switch (stringset) {
>   case ETH_SS_STATS:
>   for (i = 0; i < MESH_STATS_NUM; i++) {
> - memcpy(s + i * ETH_GSTRING_LEN,
> - mesh_stat_strings[i],
> - ETH_GSTRING_LEN);
> + strncpy(s + i * ETH_GSTRING_LEN,
> + mesh_stat_strings[i],
> + ETH_GSTRING_LEN);
>   }

The better solution is to declare
mesh_stat_strings in in the normal way

---
 drivers/net/wireless/marvell/libertas/mesh.c | 18 +-
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/net/wireless/marvell/libertas/mesh.c 
b/drivers/net/wireless/marvell/libertas/mesh.c
index d0c881dd5846..a535e7f48d2d 100644
--- a/drivers/net/wireless/marvell/libertas/mesh.c
+++ b/drivers/net/wireless/marvell/libertas/mesh.c
@@ -1108,15 +1108,15 @@ void lbs_mesh_set_txpd(struct lbs_private *priv,
  * Ethtool related
  */
 
-static const char * const mesh_stat_strings[] = {
-   "drop_duplicate_bcast",
-   "drop_ttl_zero",
-   "drop_no_fwd_route",
-   "drop_no_buffers",
-   "fwded_unicast_cnt",
-   "fwded_bcast_cnt",
-   "drop_blind_table",
-   "tx_failed_cnt"
+static const char mesh_stat_strings[][ETH_GSTRING_LEN] = {
+   "drop_duplicate_bcast",
+   "drop_ttl_zero",
+   "drop_no_fwd_route",
+   "drop_no_buffers",
+   "fwded_unicast_cnt",
+   "fwded_bcast_cnt",
+   "drop_blind_table",
+   "tx_failed_cnt",
 };
 
 void lbs_mesh_ethtool_get_stats(struct net_device *dev,