| Message ID | 20210608162650.58426-1-marian.c.rotariu@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | usb: dwc3: ep0: fix NULL pointer exception | expand |
On Tue, Jun 08, 2021 at 07:26:50PM +0300, Marian-Cristian Rotariu wrote: > There is no validation of the index from dwc3_wIndex_to_dep() and we might > be referring a non-existing ep and trigger a NULL pointer exception. In > certain configurations we might use fewer eps and the index might wrongly > indicate a larger ep index than existing. > > By adding this validation from the patch we can actually report a wrong > index back to the caller. > > In our usecase we are using a composite device on an older kernel, but > upstream might use this fix also. Unfortunately, I cannot describe the > hardware for others to reproduce the issue as it is a proprietary > implementation. > > [ 82.958261] Unable to handle kernel NULL pointer dereference at virtual address 00000000000000a4 > [ 82.966891] Mem abort info: > [ 82.969663] ESR = 0x96000006 > [ 82.972703] Exception class = DABT (current EL), IL = 32 bits > [ 82.978603] SET = 0, FnV = 0 > [ 82.981642] EA = 0, S1PTW = 0 > [ 82.984765] Data abort info: > [ 82.987631] ISV = 0, ISS = 0x00000006 > [ 82.991449] CM = 0, WnR = 0 > [ 82.994409] user pgtable: 4k pages, 39-bit VAs, pgdp = 00000000c6210ccc > [ 83.000999] [00000000000000a4] pgd=0000000053aa5003, pud=0000000053aa5003, pmd=0000000000000000 > [ 83.009685] Internal error: Oops: 96000006 [#1] PREEMPT SMP > [ 83.026433] Process irq/62-dwc3 (pid: 303, stack limit = 0x000000003985154c) > [ 83.033470] CPU: 0 PID: 303 Comm: irq/62-dwc3 Not tainted 4.19.124 #1 > [ 83.044836] pstate: 60000085 (nZCv daIf -PAN -UAO) > [ 83.049628] pc : dwc3_ep0_handle_feature+0x414/0x43c > [ 83.054558] lr : dwc3_ep0_interrupt+0x3b4/0xc94 > > ... > > [ 83.141788] Call trace: > [ 83.144227] dwc3_ep0_handle_feature+0x414/0x43c > [ 83.148823] dwc3_ep0_interrupt+0x3b4/0xc94 > [ 83.181546] ---[ end trace aac6b5267d84c32f ]--- > > Signed-off-by: Marian-Cristian Rotariu <marian.c.rotariu@gmail.com> > --- > linux-4.19.124/drivers/usb/dwc3/ep0.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/linux-4.19.124/drivers/usb/dwc3/ep0.c b/linux-4.19.124/drivers/usb/dwc3/ep0.c > index 662a1298b..3a55bbdde 100644 > --- a/linux-4.19.124/drivers/usb/dwc3/ep0.c > +++ b/linux-4.19.124/drivers/usb/dwc3/ep0.c How did you create this? It's one level too "deep" for git. I'll go edit it by hand, but next time be more careful. thanks, greg k-h
> How did you create this? It's one level too "deep" for git. I forgot to rebase it on the adequate kernel repo. Sorry for that. We use an in-house repo where the 4.19 kernel is inside a directory as you could see. > I'll go edit it by hand, but next time be more careful. Thank you! Marian
Marian-Cristian Rotariu <marian.c.rotariu@gmail.com> writes: >> How did you create this? It's one level too "deep" for git. > I forgot to rebase it on the adequate kernel repo. Sorry for that. > We use an in-house repo where the 4.19 kernel is inside a directory > as you could see. Make sure you can reproduce the bug with upstream too. If you can run upstream, at a minimum provide a minimal method for reproducing the NULL pointer deref. -- balbi
diff --git a/linux-4.19.124/drivers/usb/dwc3/ep0.c b/linux-4.19.124/drivers/usb/dwc3/ep0.c index 662a1298b..3a55bbdde 100644 --- a/linux-4.19.124/drivers/usb/dwc3/ep0.c +++ b/linux-4.19.124/drivers/usb/dwc3/ep0.c @@ -292,6 +292,9 @@ static struct dwc3_ep *dwc3_wIndex_to_dep(struct dwc3 *dwc, __le16 wIndex_le) epnum |= 1; dep = dwc->eps[epnum]; + if (dep == NULL) + return NULL; + if (dep->flags & DWC3_EP_ENABLED) return dep;
There is no validation of the index from dwc3_wIndex_to_dep() and we might be referring a non-existing ep and trigger a NULL pointer exception. In certain configurations we might use fewer eps and the index might wrongly indicate a larger ep index than existing. By adding this validation from the patch we can actually report a wrong index back to the caller. In our usecase we are using a composite device on an older kernel, but upstream might use this fix also. Unfortunately, I cannot describe the hardware for others to reproduce the issue as it is a proprietary implementation. [ 82.958261] Unable to handle kernel NULL pointer dereference at virtual address 00000000000000a4 [ 82.966891] Mem abort info: [ 82.969663] ESR = 0x96000006 [ 82.972703] Exception class = DABT (current EL), IL = 32 bits [ 82.978603] SET = 0, FnV = 0 [ 82.981642] EA = 0, S1PTW = 0 [ 82.984765] Data abort info: [ 82.987631] ISV = 0, ISS = 0x00000006 [ 82.991449] CM = 0, WnR = 0 [ 82.994409] user pgtable: 4k pages, 39-bit VAs, pgdp = 00000000c6210ccc [ 83.000999] [00000000000000a4] pgd=0000000053aa5003, pud=0000000053aa5003, pmd=0000000000000000 [ 83.009685] Internal error: Oops: 96000006 [#1] PREEMPT SMP [ 83.026433] Process irq/62-dwc3 (pid: 303, stack limit = 0x000000003985154c) [ 83.033470] CPU: 0 PID: 303 Comm: irq/62-dwc3 Not tainted 4.19.124 #1 [ 83.044836] pstate: 60000085 (nZCv daIf -PAN -UAO) [ 83.049628] pc : dwc3_ep0_handle_feature+0x414/0x43c [ 83.054558] lr : dwc3_ep0_interrupt+0x3b4/0xc94 ... [ 83.141788] Call trace: [ 83.144227] dwc3_ep0_handle_feature+0x414/0x43c [ 83.148823] dwc3_ep0_interrupt+0x3b4/0xc94 [ 83.181546] ---[ end trace aac6b5267d84c32f ]--- Signed-off-by: Marian-Cristian Rotariu <marian.c.rotariu@gmail.com> --- linux-4.19.124/drivers/usb/dwc3/ep0.c | 3 +++ 1 file changed, 3 insertions(+)