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

[Arend Van Spriel <arend.vanspriel@xxxxxxxxxxxx>]

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

> On February 27, 2024 10:34:08 PM PST, Duoming Zhou <duoming@xxxxxxxxxx> 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@xxxxxxxxxx>
> > ---
> > 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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