2021-03-04 07:25:49

by Dan Carpenter

Subject: [PATCH] ipw2x00: potential buffer overflow in libipw_wx_set_encodeext()

The "ext->key_len" is a u16 that comes from the user. If it's over
SCM_KEY_LEN (32) that could lead to memory corruption.

Fixes: e0d369d1d969 ("[PATCH] ieee82011: Added WE-18 support to default wireless extension handler")
Signed-off-by: Dan Carpenter <[email protected]>
---
drivers/net/wireless/intel/ipw2x00/libipw_wx.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/intel/ipw2x00/libipw_wx.c b/drivers/net/wireless/intel/ipw2x00/libipw_wx.c
index a0cf78c418ac..27f15fa40528 100644
--- a/drivers/net/wireless/intel/ipw2x00/libipw_wx.c
+++ b/drivers/net/wireless/intel/ipw2x00/libipw_wx.c
@@ -633,8 +633,10 @@ int libipw_wx_set_encodeext(struct libipw_device *ieee,
}

if (ext->alg != IW_ENCODE_ALG_NONE) {
- memcpy(sec.keys[idx], ext->key, ext->key_len);
- sec.key_sizes[idx] = ext->key_len;
+ int len = min_t(int, ext->key_len, SCM_KEY_LEN);
+
+ memcpy(sec.keys[idx], ext->key, len);
+ sec.key_sizes[idx] = len;
sec.flags |= (1 << idx);
if (ext->alg == IW_ENCODE_ALG_WEP) {
sec.encode_alg[idx] = SEC_ALG_WEP;
--
2.30.1

2021-04-10 07:00:50

by Stanislav Yakovlev

Subject: Re: [PATCH] ipw2x00: potential buffer overflow in libipw_wx_set_encodeext()

On Tue, 2 Mar 2021 at 15:16, Dan Carpenter <[email protected]> wrote:
>
> The "ext->key_len" is a u16 that comes from the user. If it's over
> SCM_KEY_LEN (32) that could lead to memory corruption.
>
> Fixes: e0d369d1d969 ("[PATCH] ieee82011: Added WE-18 support to default wireless extension handler")
> Signed-off-by: Dan Carpenter <[email protected]>
> ---
> drivers/net/wireless/intel/ipw2x00/libipw_wx.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>

Cc: [email protected]
Acked-by: Stanislav Yakovlev <[email protected]>

Thanks, and sorry for the long review.

Stanislav.


> diff --git a/drivers/net/wireless/intel/ipw2x00/libipw_wx.c b/drivers/net/wireless/intel/ipw2x00/libipw_wx.c
> index a0cf78c418ac..27f15fa40528 100644
> --- a/drivers/net/wireless/intel/ipw2x00/libipw_wx.c
> +++ b/drivers/net/wireless/intel/ipw2x00/libipw_wx.c
> @@ -633,8 +633,10 @@ int libipw_wx_set_encodeext(struct libipw_device *ieee,
> }
>
> if (ext->alg != IW_ENCODE_ALG_NONE) {
> - memcpy(sec.keys[idx], ext->key, ext->key_len);
> - sec.key_sizes[idx] = ext->key_len;
> + int len = min_t(int, ext->key_len, SCM_KEY_LEN);
> +
> + memcpy(sec.keys[idx], ext->key, len);
> + sec.key_sizes[idx] = len;
> sec.flags |= (1 << idx);
> if (ext->alg == IW_ENCODE_ALG_WEP) {
> sec.encode_alg[idx] = SEC_ALG_WEP;
> --
> 2.30.1
>

2021-04-11 09:10:14

by Kalle Valo

Subject: Re: [PATCH] ipw2x00: potential buffer overflow in libipw_wx_set_encodeext()

Stanislav Yakovlev <[email protected]> writes:

> On Tue, 2 Mar 2021 at 15:16, Dan Carpenter <[email protected]> wrote:
>>
>> The "ext->key_len" is a u16 that comes from the user. If it's over
>> SCM_KEY_LEN (32) that could lead to memory corruption.
>>
>> Fixes: e0d369d1d969 ("[PATCH] ieee82011: Added WE-18 support to
>> default wireless extension handler")
>> Signed-off-by: Dan Carpenter <[email protected]>
>> ---
>> drivers/net/wireless/intel/ipw2x00/libipw_wx.c | 6 ++++--
>> 1 file changed, 4 insertions(+), 2 deletions(-)

[...]

>> --- a/drivers/net/wireless/intel/ipw2x00/libipw_wx.c
>> +++ b/drivers/net/wireless/intel/ipw2x00/libipw_wx.c
>> @@ -633,8 +633,10 @@ int libipw_wx_set_encodeext(struct libipw_device *ieee,
>> }
>>
>> if (ext->alg != IW_ENCODE_ALG_NONE) {
>> - memcpy(sec.keys[idx], ext->key, ext->key_len);
>> - sec.key_sizes[idx] = ext->key_len;
>> + int len = min_t(int, ext->key_len, SCM_KEY_LEN);
>> +
>> + memcpy(sec.keys[idx], ext->key, len);
>> + sec.key_sizes[idx] = len;
>> sec.flags |= (1 << idx);
>> if (ext->alg == IW_ENCODE_ALG_WEP) {
>> sec.encode_alg[idx] = SEC_ALG_WEP;

In another thread Linus gave a good tip about clamp_val(), I think it
should be used it here as well to make the check safer and more
readable. And also elsewhere in wireless code with similar limits.

--
https://patchwork.kernel.org/project/linux-wireless/list/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches