Commit 0c612270 authored Apr 26, 2011 by Gleb Natapov Committed by H. Peter Anvin Apr 27, 2011

x86, setup: Fix EDD3.0 data verification.

Check for nonzero path in edd_has_edd30() has no sense. First, it looks
at the wrong memory. Device path starts at offset 30 of the info->params
structure which is at offset 8 from the beginning of info structure,
but code looks at info + 4 instead. This was correct when code was
introduced, but around v2.6.4 three more fields were added to edd_info
structure (commit 66b61a5c in history.git). Second, even if it will check
correct memory it will always succeed since at offset 30 (params->key)
there will be non-zero values otherwise previous check would fail.

The patch replaces this bogus check with one that verifies checksum.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Link: http://lkml.kernel.org/r/20110426082132.GG2265@redhat.com

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

parent 8e10cd74

drivers/firmware/edd.c

+11 −11

Original line number	Diff line number	Diff line
		@@ -531,8 +531,8 @@ static int
		edd_has_edd30(struct edd_device *edev)
		{
		struct edd_info *info;
		int i, nonzero_path = 0;
		char c;
		int i;
		u8 csum = 0;

		if (!edev)
		return 0;
		@@ -544,16 +544,16 @@ edd_has_edd30(struct edd_device *edev)
		return 0;
		}

		for (i = 30; i <= 73; i++) {
		c = (((uint8_t ) info) + i + 4);
		if (c) {
		nonzero_path++;
		break;
		}
		}
		if (!nonzero_path) {

		/* We support only T13 spec */
		if (info->params.device_path_info_length != 44)
		return 0;

		for (i = 30; i < info->params.device_path_info_length + 30; i++)
		csum += (((u8 )&info->params) + i);

		if (csum)
		return 0;
		}

		return 1;
		}