Re: [PATCH 3.2 068/221] firmware: dmi_scan: Fix dmi_len type

From: ivan.khoronzhuk
Date: Wed May 06 2015 - 04:43:56 EST


Hi Ben,

There is no need in this patch for 3.2, only beginning from 3.19.
SMBIOSv3 is absent in k3.2, and for previous SMBIOS versions 16-bit dmi len
is enough. It should had been mentioned in the commit/code, sorry.

On 05.05.15 04:16, Ben Hutchings wrote:
3.2.69-rc1 review patch. If anyone has any objections, please let me know.

------------------

From: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx>

commit 6d9ff473317245e3e5cd9922b4520411c2296388 upstream.

According to SMBIOSv3 specification the length of DMI table can be
up to 32bits wide. So use appropriate type to avoid overflow.

It's obvious that dmi_num theoretically can be more than u16 also,
so it's can be changed to u32 or at least it's better to use int
instead of u16, but on that moment I cannot imagine dmi structure
count more than 65535 and it can require changing type of vars that
work with it. So I didn't correct it.

Acked-by: Ard Biesheuvel <ard@xxxxxxxxxx>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx>
Signed-off-by: Matt Fleming <matt.fleming@xxxxxxxxx>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
drivers/firmware/dmi_scan.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -69,7 +69,7 @@ static char * __init dmi_string(const st
* We have to be cautious here. We have seen BIOSes with DMI pointers
* pointing to completely the wrong place for example
*/
-static void dmi_table(u8 *buf, int len, int num,
+static void dmi_table(u8 *buf, u32 len, int num,
void (*decode)(const struct dmi_header *, void *),
void *private_data)
{
@@ -99,7 +99,7 @@ static void dmi_table(u8 *buf, int len,
}
static u32 dmi_base;
-static u16 dmi_len;
+static u32 dmi_len;
static u16 dmi_num;
static int __init dmi_walk_early(void (*decode)(const struct dmi_header *,

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Regards,
Ivan Khoronzhuk

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