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

[Arend Van Spriel <arend.vanspriel@broadcom.com>]

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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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