Hi, On Thu, Jan 9, 2025 at 4:53 PM Marcel Hamer <marcel.hamer@xxxxxxxxxxxxx> wrote: > > On removal of the device or unloading of the kernel module a potential > NULL pointer dereference occurs. > > The following sequence deletes the interface: > > brcmf_detach() > brcmf_remove_interface() > brcmf_del_if() > > Inside the brcmf_del_if() function the drvr->if2bss[ifidx] is updated to > BRCMF_BSSIDX_INVALID (-1) if the bsscfgidx matches. > > After brcmf_remove_interface() call the brcmf_proto_detach() function is > called providing the following sequence: > > brcmf_detach() > brcmf_proto_detach() > brcmf_proto_msgbuf_detach() > brcmf_flowring_detach() > brcmf_msgbuf_delete_flowring() > brcmf_msgbuf_remove_flowring() > brcmf_flowring_delete() > brcmf_get_ifp() > brcmf_txfinalize() > > Since brcmf_get_ip() can and actually will return NULL in this case the > call to brcmf_txfinalize() will result in a NULL pointer dereference > inside brcmf_txfinalize() when trying to update > ifp->ndev->stats.tx_errors. > > This will only happen if a flowring still has an skb. > > Cc: stable@xxxxxxxxxxxxxxx > Signed-off-by: Marcel Hamer <marcel.hamer@xxxxxxxxxxxxx> > Link: https://lore.kernel.org/all/b519e746-ddfd-421f-d897-7620d229e4b2@xxxxxxxxx/ > --- > drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c > index c3a57e30c855..cf731bc7ae24 100644 > --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c > +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c > @@ -549,7 +549,7 @@ void brcmf_txfinalize(struct brcmf_if *ifp, struct sk_buff *txp, bool success) > wake_up(&ifp->pend_8021x_wait); Here is some additional potential ifp access, which happens if the ethtype is ETH_P_PAE. Should this also be guarded? To me it looks it might also break there, just with lower probability. Or is this impossible to reach when detaching? > } > > - if (!success) > + if (!success && ifp) > ifp->ndev->stats.tx_errors++; > > brcmu_pkt_buf_free_skb(txp); Best Regards, Jonas
