[PATCH 6.1.y 2/4] platform/x86: think-lmi: Replace kstrdup() + strreplace() with kstrdup_and_replace()

[Sasha Levin <sashal@kernel.org>]

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

[ Upstream commit e621198016e99cddc097d32cd3b56b15cee27d91 ]

Replace open coded functionalify of kstrdup_and_replace() with a call.

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230918135116.1248560-1-andriy.shevchenko@linux.intel.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Adapt the current_value_store() conversion to the 6.1 tree, which lacks
bulk-save support. Keep the existing permission and save behavior instead
of introducing references to absent save_mode and reboot_required fields.

Also replace the remaining strip_cr() call in current_password_store()
with strreplace() and remove the now-unused helper. This supplies the
context expected by 54745d563114 ("platform/x86: think-lmi: Fix current
password length check") without adding functions or changing the password
length checks in this dependency.

The earlier kstrdup_and_replace() dependency also assumes the upstream
strreplace() return-value change from d01a77afd6be. In this stable tree,
strreplace() still returns the string's end, so explicitly return dst from
kstrdup_and_replace() after performing the replacement. This preserves the
allocation pointer for the newly converted callers and their frees.

Stable-dep-of: 54745d563114 ("platform/x86: think-lmi: Fix current password length check")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/platform/x86/think-lmi.c | 53 ++++++++++----------------------
 lib/string_helpers.c             |  3 +-
 2 files changed, 18 insertions(+), 38 deletions(-)

diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c
index e7605bc97f2b0..58c070198e59f 100644
--- a/drivers/platform/x86/think-lmi.c
+++ b/drivers/platform/x86/think-lmi.c
@@ -15,7 +15,7 @@
 #include <linux/errno.h>
 #include <linux/fs.h>
 #include <linux/mutex.h>
-#include <linux/string.h>
+#include <linux/string_helpers.h>
 #include <linux/types.h>
 #include <linux/dmi.h>
 #include <linux/wmi.h>
@@ -198,14 +198,6 @@ static struct think_lmi tlmi_priv;
 static struct class *fw_attr_class;
 static DEFINE_MUTEX(tlmi_mutex);
 
-/* ------ Utility functions ------------*/
-/* Strip out CR if one is present */
-static void strip_cr(char *str)
-{
-	char *p = strchrnul(str, '\n');
-	*p = '\0';
-}
-
 /* Convert BIOS WMI error string to suitable error code */
 static int tlmi_errstr_to_err(const char *errstr)
 {
@@ -411,7 +403,7 @@ static ssize_t current_password_store(struct kobject *kobj,
 
 	strscpy(setting->password, buf, setting->maxlen);
 	/* Strip out CR if one is present, setting password won't work if it is present */
-	strip_cr(setting->password);
+	strreplace(setting->password, '\n', '\0');
 	return count;
 }
 
@@ -432,13 +424,11 @@ static ssize_t new_password_store(struct kobject *kobj,
 	if (!tlmi_priv.can_set_bios_password)
 		return -EOPNOTSUPP;
 
-	new_pwd = kstrdup(buf, GFP_KERNEL);
+	/* Strip out CR if one is present, setting password won't work if it is present */
+	new_pwd = kstrdup_and_replace(buf, '\n', '\0', GFP_KERNEL);
 	if (!new_pwd)
 		return -ENOMEM;
 
-	/* Strip out CR if one is present, setting password won't work if it is present */
-	strip_cr(new_pwd);
-
 	/* Use lock in case multiple WMI operations needed */
 	mutex_lock(&tlmi_mutex);
 
@@ -709,13 +699,11 @@ static ssize_t cert_to_password_store(struct kobject *kobj,
 	if (!setting->signature || !setting->signature[0])
 		return -EACCES;
 
-	passwd = kstrdup(buf, GFP_KERNEL);
+	/* Strip out CR if one is present */
+	passwd = kstrdup_and_replace(buf, '\n', '\0', GFP_KERNEL);
 	if (!passwd)
 		return -ENOMEM;
 
-	/* Strip out CR if one is present */
-	strip_cr(passwd);
-
 	/* Format: 'Password,Signature' */
 	auth_str = kasprintf(GFP_KERNEL, "%s,%s", passwd, setting->signature);
 	if (!auth_str) {
@@ -765,11 +753,10 @@ static ssize_t certificate_store(struct kobject *kobj,
 		return ret ?: count;
 	}
 
-	new_cert = kstrdup(buf, GFP_KERNEL);
+	/* Strip out CR if one is present */
+	new_cert = kstrdup_and_replace(buf, '\n', '\0', GFP_KERNEL);
 	if (!new_cert)
 		return -ENOMEM;
-	/* Strip out CR if one is present */
-	strip_cr(new_cert);
 
 	if (setting->cert_installed) {
 		/* Certificate is installed so this is an update */
@@ -817,13 +804,11 @@ static ssize_t signature_store(struct kobject *kobj,
 	if (!tlmi_priv.certificate_support)
 		return -EOPNOTSUPP;
 
-	new_signature = kstrdup(buf, GFP_KERNEL);
+	/* Strip out CR if one is present */
+	new_signature = kstrdup_and_replace(buf, '\n', '\0', GFP_KERNEL);
 	if (!new_signature)
 		return -ENOMEM;
 
-	/* Strip out CR if one is present */
-	strip_cr(new_signature);
-
 	/* Free any previous signature */
 	kfree(setting->signature);
 	setting->signature = new_signature;
@@ -846,13 +831,11 @@ static ssize_t save_signature_store(struct kobject *kobj,
 	if (!tlmi_priv.certificate_support)
 		return -EOPNOTSUPP;
 
-	new_signature = kstrdup(buf, GFP_KERNEL);
+	/* Strip out CR if one is present */
+	new_signature = kstrdup_and_replace(buf, '\n', '\0', GFP_KERNEL);
 	if (!new_signature)
 		return -ENOMEM;
 
-	/* Strip out CR if one is present */
-	strip_cr(new_signature);
-
 	/* Free any previous signature */
 	kfree(setting->save_signature);
 	setting->save_signature = new_signature;
@@ -981,13 +964,11 @@ static ssize_t current_value_store(struct kobject *kobj,
 	if (!tlmi_priv.can_set_bios_settings)
 		return -EOPNOTSUPP;
 
-	new_setting = kstrdup(buf, GFP_KERNEL);
+	/* Strip out CR if one is present */
+	new_setting = kstrdup_and_replace(buf, '\n', '\0', GFP_KERNEL);
 	if (!new_setting)
 		return -ENOMEM;
 
-	/* Strip out CR if one is present */
-	strip_cr(new_setting);
-
 	/* Use lock in case multiple WMI operations needed */
 	mutex_lock(&tlmi_mutex);
 
@@ -1160,13 +1141,11 @@ static ssize_t debug_cmd_store(struct kobject *kobj, struct kobj_attribute *attr
 	if (!tlmi_priv.can_debug_cmd)
 		return -EOPNOTSUPP;
 
-	new_setting = kstrdup(buf, GFP_KERNEL);
+	/* Strip out CR if one is present */
+	new_setting = kstrdup_and_replace(buf, '\n', '\0', GFP_KERNEL);
 	if (!new_setting)
 		return -ENOMEM;
 
-	/* Strip out CR if one is present */
-	strip_cr(new_setting);
-
 	if (tlmi_priv.pwd_admin->valid && tlmi_priv.pwd_admin->password[0]) {
 		auth_str = kasprintf(GFP_KERNEL, "%s,%s,%s;",
 				tlmi_priv.pwd_admin->password,
diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index 2f975395b49e5..9be6a3cfaed4a 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -730,7 +730,8 @@ char *kstrdup_and_replace(const char *src, char old, char new, gfp_t gfp)
 	if (!dst)
 		return NULL;
 
-	return strreplace(dst, old, new);
+	strreplace(dst, old, new);
+	return dst;
 }
 EXPORT_SYMBOL_GPL(kstrdup_and_replace);
 
-- 
2.53.0