Messages in this thread | | | From | Andy Lutomirski <> | Date | Mon, 12 Dec 2016 15:57:52 -0800 | Subject | Re: [PATCH] wusbcore: Fix one more crypto-on-the-stack bug |
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On Mon, Dec 12, 2016 at 1:44 PM, Greg KH <gregkh@linuxfoundation.org> wrote: > On Mon, Dec 12, 2016 at 12:52:45PM -0800, Andy Lutomirski wrote: >> The driver put a constant buffer of all zeros on the stack and >> pointed a scatterlist entry at it. This doesn't work with virtual >> stacks. Make the buffer static to fix it. >> >> Cc: stable@vger.kernel.org # 4.9 only >> Reported-by: Eric Biggers <ebiggers3@gmail.com> >> Signed-off-by: Andy Lutomirski <luto@kernel.org> >> --- >> drivers/usb/wusbcore/crypto.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/usb/wusbcore/crypto.c b/drivers/usb/wusbcore/crypto.c >> index 79451f7ef1b7..a7e007a0cd49 100644 >> --- a/drivers/usb/wusbcore/crypto.c >> +++ b/drivers/usb/wusbcore/crypto.c >> @@ -216,7 +216,7 @@ static int wusb_ccm_mac(struct crypto_skcipher *tfm_cbc, >> struct scatterlist sg[4], sg_dst; >> void *dst_buf; >> size_t dst_size; >> - const u8 bzero[16] = { 0 }; >> + static const u8 bzero[16] = { 0 }; > > Hm, can static memory handle DMA? That's a requirement of the USB > stack, does this data later end up being sent down to a USB host > controller?
I think it doesn't, but I'll switch it to use empty_zero_page instead.
--Andy
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