[PATCH v2] wifi: brcm80211: handle pmk_op allocation failure

[PATCH v2] wifi: brcm80211: handle pmk_op allocation failure

[Duoming Zhou]

The kzalloc() in brcmf_pmksa_v3_op() will return null if the
physical memory has run out. As a result, if we dereference
the null value, the null pointer dereference bug will happen.

Return -ENOMEM from brcmf_pmksa_v3_op() if kzalloc() fails
for pmk_op.

Fixes: a96202acaea4 ("wifi: brcmfmac: cfg80211: Add support for PMKID_V3 operations")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
---
Changes in v2:
  - Drop the new label and just return -ENOMEM.

 drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
index 28d6a30cc01..7af6d6448b9 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
@@ -4322,6 +4322,9 @@ brcmf_pmksa_v3_op(struct brcmf_if *ifp, struct cfg80211_pmksa *pmksa,
 	int ret;
 
 	pmk_op = kzalloc(sizeof(*pmk_op), GFP_KERNEL);
+	if (!pmk_op)
+		ret = -ENOMEM;
+
 	pmk_op->version = cpu_to_le16(BRCMF_PMKSA_VER_3);
 
 	if (!pmksa) {
-- 
2.17.1

Re: [PATCH v2] wifi: brcm80211: handle pmk_op allocation failure

[Arend van Spriel]

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On 2/28/2024 7:34 AM, Duoming Zhou wrote:
> The kzalloc() in brcmf_pmksa_v3_op() will return null if the
> physical memory has run out. As a result, if we dereference
> the null value, the null pointer dereference bug will happen.
> 
> Return -ENOMEM from brcmf_pmksa_v3_op() if kzalloc() fails
> for pmk_op.
> 
> Fixes: a96202acaea4 ("wifi: brcmfmac: cfg80211: Add support for PMKID_V3 operations")

Thanks!

Acked-by: Arend van Spriel <arend.vanspriel@broadcom.com>
> Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
> ---
> Changes in v2:
>    - Drop the new label and just return -ENOMEM.
> 
>   drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c | 3 +++
>   1 file changed, 3 insertions(+)

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Re: [PATCH v2] wifi: brcm80211: handle pmk_op allocation failure

[Kees Cook]

On February 27, 2024 10:34:08 PM PST, Duoming Zhou <duoming@zju.edu.cn> wrote:
>The kzalloc() in brcmf_pmksa_v3_op() will return null if the
>physical memory has run out. As a result, if we dereference
>the null value, the null pointer dereference bug will happen.
>
>Return -ENOMEM from brcmf_pmksa_v3_op() if kzalloc() fails
>for pmk_op.
>
>Fixes: a96202acaea4 ("wifi: brcmfmac: cfg80211: Add support for PMKID_V3 operations")
>Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
>---
>Changes in v2:
>  - Drop the new label and just return -ENOMEM.
>
> drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c | 3 +++
> 1 file changed, 3 insertions(+)
>
>diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
>index 28d6a30cc01..7af6d6448b9 100644
>--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
>+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
>@@ -4322,6 +4322,9 @@ brcmf_pmksa_v3_op(struct brcmf_if *ifp, struct cfg80211_pmksa *pmksa,
> 	int ret;
> 
> 	pmk_op = kzalloc(sizeof(*pmk_op), GFP_KERNEL);
>+	if (!pmk_op)
>+		ret = -ENOMEM;

This doesn't fix anything. It doesn't stop the execution path; it'll continue and immediately dereference the NULL pmk_op in the next line...

>+
> 	pmk_op->version = cpu_to_le16(BRCMF_PMKSA_VER_3);
> 
> 	if (!pmksa) {

-- 
Kees Cook

Re: [PATCH v2] wifi: brcm80211: handle pmk_op allocation failure

[Arend Van Spriel]

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On February 28, 2024 3:48:18 PM Kees Cook <kees@kernel.org> wrote:

> On February 27, 2024 10:34:08 PM PST, Duoming Zhou <duoming@zju.edu.cn> wrote:
>> The kzalloc() in brcmf_pmksa_v3_op() will return null if the
>> physical memory has run out. As a result, if we dereference
>> the null value, the null pointer dereference bug will happen.
>>
>> Return -ENOMEM from brcmf_pmksa_v3_op() if kzalloc() fails
>> for pmk_op.
>>
>> Fixes: a96202acaea4 ("wifi: brcmfmac: cfg80211: Add support for PMKID_V3 
>> operations")
>> Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
>> ---
>> Changes in v2:
>> - Drop the new label and just return -ENOMEM.
>>
>> drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c 
>> b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
>> index 28d6a30cc01..7af6d6448b9 100644
>> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
>> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
>> @@ -4322,6 +4322,9 @@ brcmf_pmksa_v3_op(struct brcmf_if *ifp, struct 
>> cfg80211_pmksa *pmksa,
>> int ret;
>>
>> pmk_op = kzalloc(sizeof(*pmk_op), GFP_KERNEL);
>> + if (!pmk_op)
>> + ret = -ENOMEM;
>
> This doesn't fix anything. It doesn't stop the execution path; it'll 
> continue and immediately dereference the NULL pmk_op in the next line...

Crap. Do I look bad :-( Thanks for catching my blunder. I was seeing what I 
wanted to see I guess.

Regards,
Arend

>
>> +
>> pmk_op->version = cpu_to_le16(BRCMF_PMKSA_VER_3);
>>
>> if (!pmksa) {
>
> --
> Kees Cook




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