[ 28/82] dmi_scan: fix missing check for _DMI_ signature in smbios_present()

Ben Hutchings
2013-03-18T04:37:10Z

From: Ben Hutchings <ben@decadent.org.uk>

commit a40e7cf8f06b4e322ba902e4e9f6a6b0c2daa907 upstream.

Commit 9f9c9cbb6057 ("drivers/firmware/dmi_scan.c: fetch dmi version
from SMBIOS if it exists") hoisted the check for "_DMI_" into
dmi_scan_machine(), which means that we don't bother to check for
"_DMI_" at offset 16 in an SMBIOS entry. smbios_present() may also call
dmi_present() for an address where we found "_SM_", if it failed further
validation.

Check for "_DMI_" in smbios_present() before calling dmi_present().

[akpm@linux-foundation.org: fix build]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Reported-by: Tim McGrath <tmhikaru@gmail.com>
Tested-by: Tim Mcgrath <tmhikaru@gmail.com>
Cc: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
drivers/firmware/dmi_scan.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -442,7 +442,6 @@ static int __init dmi_present(const char
static int __init smbios_present(const char __iomem *p)
{
u8 buf[32];
- int offset = 0;

memcpy_fromio(buf, p, 32);
if ((buf[5] < 32) && dmi_checksum(buf, buf[5])) {
@@ -461,9 +460,9 @@ static int __init smbios_present(const c
dmi_ver = 0x0206;
break;
}
- offset = 16;
+ return memcmp(p + 16, "_DMI_", 5) || dmi_present(p + 16);
}
- return dmi_present(buf + offset);
+ return 1;
}

void __init dmi_scan_machine(void)