USB: Fix CDC EEM host driver 'sentinel' CRC validation (9ca33a0f) · Commits · 戴 / test

This is an alternate solution to the EEM 'sentinel' CRC valiation issue. CDC EEM allows using a 'sentinel' ethernet frame CRC of 0xdeadbeef in place of a real CRC. The 'sentinel' value is transmitted in big-endian order whereas the normal CRC is little-endian. This patch handles both cases appropriately. Signed-off-by:

Brian Niebuhr <bniebuhr@efjohnson.com> Signed-off-by:

Greg Kroah-Hartman <gregkh@suse.de>

drivers/net/usb/cdc_eem.c

+10 −7

Original line number	Diff line number	Diff line
		@@ -300,20 +300,23 @@ static int eem_rx_fixup(struct usbnet dev, struct sk_buff skb)
		return 0;
		}

		crc = get_unaligned_le32(skb2->data
		+ len - ETH_FCS_LEN);
		skb_trim(skb2, len - ETH_FCS_LEN);

		/*
		* The bmCRC helps to denote when the CRC field in
		* the Ethernet frame contains a calculated CRC:
		* bmCRC = 1 : CRC is calculated
		* bmCRC = 0 : CRC = 0xDEADBEEF
		*/
		if (header & BIT(14))
		crc2 = ~crc32_le(~0, skb2->data, skb2->len);
		else
		if (header & BIT(14)) {
		crc = get_unaligned_le32(skb2->data
		+ len - ETH_FCS_LEN);
		crc2 = ~crc32_le(~0, skb2->data, skb2->len
		- ETH_FCS_LEN);
		} else {
		crc = get_unaligned_be32(skb2->data
		+ len - ETH_FCS_LEN);
		crc2 = 0xdeadbeef;
		}
		skb_trim(skb2, len - ETH_FCS_LEN);

		if (is_last)
		return crc == crc2;

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