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platform/x86: dell-smbios: Fix wrong token data in sysfs

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When reading token data from sysfs on my Inspiron 3505, the token
locations and values are wrong. This happens because match_attribute()
blindly assumes that all entries in da_tokens have an associated
entry in token_attrs.

This however is not true as soon as da_tokens[] contains zeroed
token entries. Those entries are being skipped when initialising
token_attrs, breaking the core assumption of match_attribute().

Fix this by defining an extra struct for each pair of token attributes
and use container_of() to retrieve token information.

Tested on a Dell Inspiron 3050.

Fixes: 33b9ca1e53 ("platform/x86: dell-smbios: Add a sysfs interface for SMBIOS tokens")
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20240528204903.445546-1-W_Armin@gmx.de
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
This commit is contained in:
Armin Wolf 2024-05-28 22:49:02 +02:00 committed by Hans de Goede
parent 078fc56f5c
commit 1981b296f8
1 changed files with 36 additions and 56 deletions
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92
drivers/platform/x86/dell/dell-smbios-base.c
View file

@ -11,6 +11,7 @@
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/container_of.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/capability.h>
@ -25,11 +26,16 @@ static u32 da_supported_commands;
static int da_num_tokens;
static struct platform_device *platform_device;
static struct calling_interface_token *da_tokens;
static struct device_attribute *token_location_attrs;
static struct device_attribute *token_value_attrs;
static struct token_sysfs_data *token_entries;
static struct attribute **token_attrs;
static DEFINE_MUTEX(smbios_mutex);
struct token_sysfs_data {
struct device_attribute location_attr;
struct device_attribute value_attr;
struct calling_interface_token *token;
};
struct smbios_device {
struct list_head list;
struct device *device;
@ -416,47 +422,26 @@ static void __init find_tokens(const struct dmi_header *dm, void *dummy)
}
}
static int match_attribute(struct device *dev,
struct device_attribute *attr)
{
int i;
for (i = 0; i < da_num_tokens * 2; i++) {
if (!token_attrs[i])
continue;
if (strcmp(token_attrs[i]->name, attr->attr.name) == 0)
return i/2;
}
dev_dbg(dev, "couldn't match: %s\n", attr->attr.name);
return -EINVAL;
}
static ssize_t location_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
int i;
struct token_sysfs_data *data = container_of(attr, struct token_sysfs_data, location_attr);
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
i = match_attribute(dev, attr);
if (i > 0)
return sysfs_emit(buf, "%08x", da_tokens[i].location);
return 0;
return sysfs_emit(buf, "%08x", data->token->location);
}
static ssize_t value_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
int i;
struct token_sysfs_data *data = container_of(attr, struct token_sysfs_data, value_attr);
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
i = match_attribute(dev, attr);
if (i > 0)
return sysfs_emit(buf, "%08x", da_tokens[i].value);
return 0;
return sysfs_emit(buf, "%08x", data->token->value);
}
static struct attribute_group smbios_attribute_group = {
@ -473,22 +458,15 @@ static int build_tokens_sysfs(struct platform_device *dev)
{
char *location_name;
char *value_name;
size_t size;
int ret;
int i, j;
/* (number of tokens + 1 for null terminated */
size = sizeof(struct device_attribute) * (da_num_tokens + 1);
token_location_attrs = kzalloc(size, GFP_KERNEL);
if (!token_location_attrs)
token_entries = kcalloc(da_num_tokens, sizeof(*token_entries), GFP_KERNEL);
if (!token_entries)
return -ENOMEM;
token_value_attrs = kzalloc(size, GFP_KERNEL);
if (!token_value_attrs)
goto out_allocate_value;
/* need to store both location and value + terminator*/
size = sizeof(struct attribute *) * ((2 * da_num_tokens) + 1);
token_attrs = kzalloc(size, GFP_KERNEL);
token_attrs = kcalloc((2 * da_num_tokens) + 1, sizeof(*token_attrs), GFP_KERNEL);
if (!token_attrs)
goto out_allocate_attrs;
@ -496,27 +474,32 @@ static int build_tokens_sysfs(struct platform_device *dev)
/* skip empty */
if (da_tokens[i].tokenID == 0)
continue;
token_entries[i].token = &da_tokens[i];
/* add location */
location_name = kasprintf(GFP_KERNEL, "%04x_location",
da_tokens[i].tokenID);
if (location_name == NULL)
goto out_unwind_strings;
sysfs_attr_init(&token_location_attrs[i].attr);
token_location_attrs[i].attr.name = location_name;
token_location_attrs[i].attr.mode = 0444;
token_location_attrs[i].show = location_show;
token_attrs[j++] = &token_location_attrs[i].attr;
sysfs_attr_init(&token_entries[i].location_attr.attr);
token_entries[i].location_attr.attr.name = location_name;
token_entries[i].location_attr.attr.mode = 0444;
token_entries[i].location_attr.show = location_show;
token_attrs[j++] = &token_entries[i].location_attr.attr;
/* add value */
value_name = kasprintf(GFP_KERNEL, "%04x_value",
da_tokens[i].tokenID);
if (value_name == NULL)
goto loop_fail_create_value;
sysfs_attr_init(&token_value_attrs[i].attr);
token_value_attrs[i].attr.name = value_name;
token_value_attrs[i].attr.mode = 0444;
token_value_attrs[i].show = value_show;
token_attrs[j++] = &token_value_attrs[i].attr;
sysfs_attr_init(&token_entries[i].value_attr.attr);
token_entries[i].value_attr.attr.name = value_name;
token_entries[i].value_attr.attr.mode = 0444;
token_entries[i].value_attr.show = value_show;
token_attrs[j++] = &token_entries[i].value_attr.attr;
continue;
loop_fail_create_value:
@ -532,14 +515,12 @@ static int build_tokens_sysfs(struct platform_device *dev)
out_unwind_strings:
while (i--) {
kfree(token_location_attrs[i].attr.name);
kfree(token_value_attrs[i].attr.name);
kfree(token_entries[i].location_attr.attr.name);
kfree(token_entries[i].value_attr.attr.name);
}
kfree(token_attrs);
out_allocate_attrs:
kfree(token_value_attrs);
out_allocate_value:
kfree(token_location_attrs);
kfree(token_entries);
return -ENOMEM;
}
@ -551,12 +532,11 @@ static void free_group(struct platform_device *pdev)
sysfs_remove_group(&pdev->dev.kobj,
&smbios_attribute_group);
for (i = 0; i < da_num_tokens; i++) {
kfree(token_location_attrs[i].attr.name);
kfree(token_value_attrs[i].attr.name);
kfree(token_entries[i].location_attr.attr.name);
kfree(token_entries[i].value_attr.attr.name);
}
kfree(token_attrs);
kfree(token_value_attrs);
kfree(token_location_attrs);
kfree(token_entries);
}
static int __init dell_smbios_init(void)