On Tue, 2024-02-27 at 12:21 +0100, Arend van Spriel wrote:
> On 2/27/2024 9:06 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.
>
> NAK (see below)
>
> Also this issue was reported earlier by Joe Perches. Not sure if he
> wants to be mentioned as such.
I think it's unimportant to be mentioned.
I think it's more important that the code be researched
that the simple return of -ENOMEM the appropriate fix
and is handled by all possible callers of the function.
>
> > Fixes: a96202acaea4 ("wifi: brcmfmac: cfg80211: Add support for PMKID_V3 operations")
> > Signed-off-by: Duoming Zhou <[email protected]>
> > ---
> > drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c | 5 +++++
> > 1 file changed, 5 insertions(+)
> >
> > diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.cq b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> > index 28d6a30cc01..3b420b33188 100644
> > --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> > +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> > @@ -4322,6 +4322,10 @@ 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;
> > + goto out;
> > + }
>
> There is really no need to introduce a new label for this. Although you
> can kfree() a NULL pointer there is no need to do so when you know
> already it is NULL. Just return -ENOMEM and be done with it.
>
> Regards,
> Arend
>
> > pmk_op->version = cpu_to_le16(BRCMF_PMKSA_VER_3);
> >
> > if (!pmksa) {
> > @@ -4340,6 +4344,7 @@ brcmf_pmksa_v3_op(struct brcmf_if *ifp, struct cfg80211_pmksa *pmksa,
> > pmk_op->length = cpu_to_le16(length);
> >
> > ret = brcmf_fil_iovar_data_set(ifp, "pmkid_info", pmk_op, sizeof(*pmk_op));
> > +out:
> > kfree(pmk_op);
> > return ret;
> > }
On Tue, 27 Feb 2024 03:42:13 -0800 Joe Perches 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.
> >
> > NAK (see below)
> >
> > Also this issue was reported earlier by Joe Perches. Not sure if he
> > wants to be mentioned as such.
>
> I think it's unimportant to be mentioned.
>
> I think it's more important that the code be researched
> that the simple return of -ENOMEM the appropriate fix
> and is handled by all possible callers of the function.
There are three functions that call the brcmf_pmksa_v3_op(),
including brcmf_cfg80211_set_pmksa(), brcmf_cfg80211_del_pmksa()
and brcmf_cfg80211_flush_pmksa(). The return type of the above
three functions is s32. If brcmf_pmksa_v3_op() returns -ENOMEM,
the above three functions will also return -ENOMEM. It could be
handled appropriately by the callers of the function. So I think
the simple return of -ENOMEM is appropriate.
> > > Fixes: a96202acaea4 ("wifi: brcmfmac: cfg80211: Add support for PMKID_V3 operations")
> > > Signed-off-by: Duoming Zhou <[email protected]>
> > > ---
> > > drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c | 5 +++++
> > > 1 file changed, 5 insertions(+)
> > >
> > > diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.cq b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> > > index 28d6a30cc01..3b420b33188 100644
> > > --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> > > +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
> > > @@ -4322,6 +4322,10 @@ 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;
> > > + goto out;
> > > + }
> >
> > There is really no need to introduce a new label for this. Although you
> > can kfree() a NULL pointer there is no need to do so when you know
> > already it is NULL. Just return -ENOMEM and be done with it.
> >
> > Regards,
> > Arend
> >
> > > pmk_op->version = cpu_to_le16(BRCMF_PMKSA_VER_3);
> > >
> > > if (!pmksa) {
> > > @@ -4340,6 +4344,7 @@ brcmf_pmksa_v3_op(struct brcmf_if *ifp, struct cfg80211_pmksa *pmksa,
> > > pmk_op->length = cpu_to_le16(length);
> > >
> > > ret = brcmf_fil_iovar_data_set(ifp, "pmkid_info", pmk_op, sizeof(*pmk_op));
> > > +out:
> > > kfree(pmk_op);
> > > return ret;
> > > }
Best regards,
Duoming Zhou