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x86, setup: Fix EDD3.0 data verification.

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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>
This commit is contained in:
Gleb Natapov 2011-04-26 11:21:32 +03:00 committed by H. Peter Anvin
parent 8e10cd7434
commit 0c61227094
1 changed files with 11 additions and 11 deletions
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22
drivers/firmware/edd.c
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@ -531,8 +531,8 @@ static int
edd_has_edd30(struct edd_device *edev) edd_has_edd30(struct edd_device *edev)
{ {
struct edd_info *info; struct edd_info *info;
int i, nonzero_path = 0; int i;
char c; u8 csum = 0;
if (!edev) if (!edev)
return 0; return 0;
@ -544,16 +544,16 @@ edd_has_edd30(struct edd_device *edev)
return 0; return 0;
} }
for (i = 30; i <= 73; i++) {
c = *(((uint8_t *) info) + i + 4); /* We support only T13 spec */
if (c) { if (info->params.device_path_info_length != 44)
nonzero_path++; return 0;
break;
} for (i = 30; i < info->params.device_path_info_length + 30; i++)
} csum += *(((u8 *)&info->params) + i);
if (!nonzero_path) {
if (csum)
return 0; return 0;
}
return 1; return 1;
} }