[PATCH 3.14 50/88] ACPI / PCI: Fix sysfs acpi_index and label errors

Greg Kroah-Hartman
2014-09-03T23:28:17Z

From: Simone Gotti <simone.gotti@gmail.com>

commit dcfa9be83866e28fcb8b7e22b4eeb4ba63bd3174 upstream.

Fix errors in handling "device label" _DSM return values.

If _DSM returns a Unicode string, the ACPI type is ACPI_TYPE_BUFFER, not
ACPI_TYPE_STRING. Fix dsm_label_utf16s_to_utf8s() to convert UTF-16 from
acpi_object->buffer instead of acpi_object->string.

Prior to v3.14, we accepted Unicode labels (ACPI_TYPE_BUFFER return
values). But after 1d0fcef73283, we accepted only ASCII (ACPI_TYPE_STRING)
(and we incorrectly tried to convert those ASCII labels from UTF-16 to
UTF-8).

Rejecting Unicode labels made us return -EPERM when reading sysfs
"acpi_index" or "label" files, which in turn caused on-board network
interfaces on a Dell PowerEdge E420 to be renamed (by udev net_id internal)
from eno1/eno2 to enp2s0f0/enp2s0f1.

Fix this by accepting either ACPI_TYPE_STRING (and treating it as ASCII) or
ACPI_TYPE_BUFFER (and converting from UTF-16 to UTF-8).

[bhelgaas: changelog]
Fixes: 1d0fcef73283 ("ACPI / PCI: replace open-coded _DSM code with helper functions")
Signed-off-by: Simone Gotti <simone.gotti@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/pci/pci-label.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)

--- a/drivers/pci/pci-label.c
+++ b/drivers/pci/pci-label.c
@@ -168,8 +168,8 @@ enum acpi_attr_enum {
static void dsm_label_utf16s_to_utf8s(union acpi_object *obj, char *buf)
{
int len;
- len = utf16s_to_utf8s((const wchar_t *)obj->string.pointer,
- obj->string.length,
+ len = utf16s_to_utf8s((const wchar_t *)obj->buffer.pointer,
+ obj->buffer.length,
UTF16_LITTLE_ENDIAN,
buf, PAGE_SIZE);
buf[len] = '\n';
@@ -194,16 +194,22 @@ dsm_get_label(struct device *dev, char *
tmp = obj->package.elements;
if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 2 &&
tmp[0].type == ACPI_TYPE_INTEGER &&
- tmp[1].type == ACPI_TYPE_STRING) {
+ (tmp[1].type == ACPI_TYPE_STRING ||
+ tmp[1].type == ACPI_TYPE_BUFFER)) {
/*
* The second string element is optional even when
* this _DSM is implemented; when not implemented,
* this entry must return a null string.
*/
- if (attr == ACPI_ATTR_INDEX_SHOW)
+ if (attr == ACPI_ATTR_INDEX_SHOW) {
scnprintf(buf, PAGE_SIZE, "%llu\n", tmp->integer.value);
- else if (attr == ACPI_ATTR_LABEL_SHOW)
- dsm_label_utf16s_to_utf8s(tmp + 1, buf);
+ } else if (attr == ACPI_ATTR_LABEL_SHOW) {
+ if (tmp[1].type == ACPI_TYPE_STRING)
+ scnprintf(buf, PAGE_SIZE, "%s\n",
+ tmp[1].string.pointer);
+ else if (tmp[1].type == ACPI_TYPE_BUFFER)
+ dsm_label_utf16s_to_utf8s(tmp + 1, buf);
+ }
len = strlen(buf) > 0 ? strlen(buf) : -1;
}