From: Marian-Cristian Rotariu marian.c.rotariu@gmail.com

stable inclusion from stable-v4.19.195 commit bd551e7c85939de2182010273450bfa78c3742fc category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9R4C8 CVE: CVE-2021-47269

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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commit d00889080ab60051627dab1d85831cd9db750e2a upstream.

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 Cc: stable stable@vger.kernel.org Link: https://lore.kernel.org/r/20210608162650.58426-1-marian.c.rotariu@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zheng Yejian zhengyejian1@huawei.com --- drivers/usb/dwc3/ep0.c | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c index 2fb02f877401..095704dcee77 100644 --- a/drivers/usb/dwc3/ep0.c +++ b/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;