From: Gleb Natapov Date: Tue, 26 Apr 2011 08:21:32 +0000 (+0300) Subject: x86, setup: Fix EDD3.0 data verification. X-Git-Tag: firefly_0821_release~7613^2~1384^3 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=0c61227094b3ddaca2f847ee287c4a2e3762b5a2;p=firefly-linux-kernel-4.4.55.git 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 Link: http://lkml.kernel.org/r/20110426082132.GG2265@redhat.com Signed-off-by: H. Peter Anvin --- diff --git a/drivers/firmware/edd.c b/drivers/firmware/edd.c index 96c25d93eed1..f1b7f659d3c9 100644 --- a/drivers/firmware/edd.c +++ b/drivers/firmware/edd.c @@ -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; }