| Message ID | 20230203041644.581649-1-zyytlz.wz@163.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Kalle Valo |
| Headers | show |
| Series | wifi: plfxlc: fix potential NULL pointer dereference in plfxlc_usb_wreq_async() | expand |
Le 03/02/2023 à 05:16, Zheng Wang a écrit : > Although the usb_alloc_urb uses GFP_ATOMIC, tring to make sure the memory > allocated not to be NULL. But in some low-memory situation, it's still > possible to return NULL. It'll pass urb as argument in > usb_fill_bulk_urb, which will finally lead to a NULL pointer dereference. > > Fix it by adding additional check. > > Note that, as a bug found by static analysis, it can be a false > positive or hard to trigger. > > Fixes: 68d57a07bfe5 ("wireless: add plfxlc driver for pureLiFi X, XL, XC devices") > > Signed-off-by: Zheng Wang <zyytlz.wz@163.com> > --- > drivers/net/wireless/purelifi/plfxlc/usb.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/net/wireless/purelifi/plfxlc/usb.c b/drivers/net/wireless/purelifi/plfxlc/usb.c > index 76d0a778636a..ac149aa64908 100644 > --- a/drivers/net/wireless/purelifi/plfxlc/usb.c > +++ b/drivers/net/wireless/purelifi/plfxlc/usb.c > @@ -496,10 +496,17 @@ int plfxlc_usb_wreq_async(struct plfxlc_usb *usb, const u8 *buffer, > struct urb *urb = usb_alloc_urb(0, GFP_ATOMIC); > int r; > > + if (!urb) { > + r = -ENOMEM; > + kfree(urb); Hi, why kfree() in such a case? CJ > + goto out; > + } > usb_fill_bulk_urb(urb, udev, usb_sndbulkpipe(udev, EP_DATA_OUT), > (void *)buffer, buffer_len, complete_fn, context); > > r = usb_submit_urb(urb, GFP_ATOMIC); > + > +out: > if (r) > dev_err(&udev->dev, "Async write submit failed (%d)\n", r); >
At 2023-02-03 13:25:45, "Christophe JAILLET" <christophe.jaillet@wanadoo.fr> wrote: >Le 03/02/2023 à 05:16, Zheng Wang a écrit : >> Although the usb_alloc_urb uses GFP_ATOMIC, tring to make sure the memory >> allocated not to be NULL. But in some low-memory situation, it's still >> possible to return NULL. It'll pass urb as argument in >> usb_fill_bulk_urb, which will finally lead to a NULL pointer dereference. >> >> Fix it by adding additional check. >> >> Note that, as a bug found by static analysis, it can be a false >> positive or hard to trigger. >> >> Fixes: 68d57a07bfe5 ("wireless: add plfxlc driver for pureLiFi X, XL, XC devices") >> >> Signed-off-by: Zheng Wang <zyytlz.wz@163.com> >> --- >> drivers/net/wireless/purelifi/plfxlc/usb.c | 7 +++++++ >> 1 file changed, 7 insertions(+) >> >> diff --git a/drivers/net/wireless/purelifi/plfxlc/usb.c b/drivers/net/wireless/purelifi/plfxlc/usb.c >> index 76d0a778636a..ac149aa64908 100644 >> --- a/drivers/net/wireless/purelifi/plfxlc/usb.c >> +++ b/drivers/net/wireless/purelifi/plfxlc/usb.c >> @@ -496,10 +496,17 @@ int plfxlc_usb_wreq_async(struct plfxlc_usb *usb, const u8 *buffer, >> struct urb *urb = usb_alloc_urb(0, GFP_ATOMIC); >> int r; >> >> + if (!urb) { >> + r = -ENOMEM; >> + kfree(urb); > >Hi, >why kfree() in such a case? Hello CJ, Thanks for pointing that out. Kfree is unnecessary in such case, we can just return. Regards, Zheng Wang > >> + goto out; >> + } >> usb_fill_bulk_urb(urb, udev, usb_sndbulkpipe(udev, EP_DATA_OUT), >> (void *)buffer, buffer_len, complete_fn, context); >> >> r = usb_submit_urb(urb, GFP_ATOMIC); >> + >> +out: >> if (r) >> dev_err(&udev->dev, "Async write submit failed (%d)\n", r); >>
diff --git a/drivers/net/wireless/purelifi/plfxlc/usb.c b/drivers/net/wireless/purelifi/plfxlc/usb.c index 76d0a778636a..ac149aa64908 100644 --- a/drivers/net/wireless/purelifi/plfxlc/usb.c +++ b/drivers/net/wireless/purelifi/plfxlc/usb.c @@ -496,10 +496,17 @@ int plfxlc_usb_wreq_async(struct plfxlc_usb *usb, const u8 *buffer, struct urb *urb = usb_alloc_urb(0, GFP_ATOMIC); int r; + if (!urb) { + r = -ENOMEM; + kfree(urb); + goto out; + } usb_fill_bulk_urb(urb, udev, usb_sndbulkpipe(udev, EP_DATA_OUT), (void *)buffer, buffer_len, complete_fn, context); r = usb_submit_urb(urb, GFP_ATOMIC); + +out: if (r) dev_err(&udev->dev, "Async write submit failed (%d)\n", r);
Although the usb_alloc_urb uses GFP_ATOMIC, tring to make sure the memory allocated not to be NULL. But in some low-memory situation, it's still possible to return NULL. It'll pass urb as argument in usb_fill_bulk_urb, which will finally lead to a NULL pointer dereference. Fix it by adding additional check. Note that, as a bug found by static analysis, it can be a false positive or hard to trigger. Fixes: 68d57a07bfe5 ("wireless: add plfxlc driver for pureLiFi X, XL, XC devices") Signed-off-by: Zheng Wang <zyytlz.wz@163.com> --- drivers/net/wireless/purelifi/plfxlc/usb.c | 7 +++++++ 1 file changed, 7 insertions(+)