firmware: dmi_scan: Check DMI structure length
Before accessing DMI data to record it for later, we should ensure
that the DMI structures are large enough to contain the data in
question.
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index fc30249..7830419 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -178,7 +178,7 @@ static void __init dmi_save_ident(const struct dmi_header *dm, int slot,
const char *d = (const char *) dm;
const char *p;
- if (dmi_ident[slot])
+ if (dmi_ident[slot] || dm->length <= string)
return;
p = dmi_string(dm, d[string]);
@@ -191,13 +191,14 @@ static void __init dmi_save_ident(const struct dmi_header *dm, int slot,
static void __init dmi_save_uuid(const struct dmi_header *dm, int slot,
int index)
{
- const u8 *d = (u8 *) dm + index;
+ const u8 *d;
char *s;
int is_ff = 1, is_00 = 1, i;
- if (dmi_ident[slot])
+ if (dmi_ident[slot] || dm->length <= index + 16)
return;
+ d = (u8 *) dm + index;
for (i = 0; i < 16 && (is_ff || is_00); i++) {
if (d[i] != 0x00)
is_00 = 0;
@@ -228,16 +229,17 @@ static void __init dmi_save_uuid(const struct dmi_header *dm, int slot,
static void __init dmi_save_type(const struct dmi_header *dm, int slot,
int index)
{
- const u8 *d = (u8 *) dm + index;
+ const u8 *d;
char *s;
- if (dmi_ident[slot])
+ if (dmi_ident[slot] || dm->length <= index)
return;
s = dmi_alloc(4);
if (!s)
return;
+ d = (u8 *) dm + index;
sprintf(s, "%u", *d & 0x7F);
dmi_ident[slot] = s;
}
@@ -278,9 +280,13 @@ static void __init dmi_save_devices(const struct dmi_header *dm)
static void __init dmi_save_oem_strings_devices(const struct dmi_header *dm)
{
- int i, count = *(u8 *)(dm + 1);
+ int i, count;
struct dmi_device *dev;
+ if (dm->length < 0x05)
+ return;
+
+ count = *(u8 *)(dm + 1);
for (i = 1; i <= count; i++) {
const char *devname = dmi_string(dm, i);
@@ -353,6 +359,9 @@ static void __init dmi_save_extended_devices(const struct dmi_header *dm)
const char *name;
const u8 *d = (u8 *)dm;
+ if (dm->length < 0x0B)
+ return;
+
/* Skip disabled device */
if ((d[0x5] & 0x80) == 0)
return;
@@ -387,7 +396,7 @@ static void __init save_mem_devices(const struct dmi_header *dm, void *v)
const char *d = (const char *)dm;
static int nr;
- if (dm->type != DMI_ENTRY_MEM_DEVICE)
+ if (dm->type != DMI_ENTRY_MEM_DEVICE || dm->length < 0x12)
return;
if (nr >= dmi_memdev_nr) {
pr_warn(FW_BUG "Too many DIMM entries in SMBIOS table\n");