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usb: udc: lpc32xx: fix bad bit shift operation

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It seems that the right variable to use in this case is *i*, instead of
*n*, otherwise there is an undefined behavior when right shifiting by more
than 31 bits when multiplying n by 8; notice that *n* can take values
equal or greater than 4 (4, 8, 16, ...).

Also, notice that under the current conditions (bl = 3), we are skiping
the handling of bytes 3, 7, 31... So, fix this by updating this logic
and limit *bl* up to 4 instead of up to 3.

This fix is based on function udc_stuff_fifo().

Addresses-Coverity-ID: 1454834 ("Bad bit shift operation")
Fixes: 24a28e4283 ("USB: gadget driver for LPC32xx")
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Link: https://lore.kernel.org/r/20191014191830.GA10721@embeddedor
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Gustavo A. R. Silva 2019-10-14 14:18:30 -05:00 committed by Greg Kroah-Hartman
parent f616c3bda4
commit b987b66ac3
1 changed files with 3 additions and 3 deletions
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6
drivers/usb/gadget/udc/lpc32xx_udc.c
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@ -1177,11 +1177,11 @@ static void udc_pop_fifo(struct lpc32xx_udc *udc, u8 *data, u32 bytes)
tmp = readl(USBD_RXDATA(udc->udp_baseaddr));
bl = bytes - n;
if (bl > 3)
bl = 3;
if (bl > 4)
bl = 4;
for (i = 0; i < bl; i++)
data[n + i] = (u8) ((tmp >> (n * 8)) & 0xFF);
data[n + i] = (u8) ((tmp >> (i * 8)) & 0xFF);
}
break;