Merge: pstore/platform: Add check for kstrdup

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/4322

JIRA: https://issues.redhat.com/browse/RHEL-38128  
CVE: CVE-2023-52869  
  
Build Info: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=61487181  
Tested: Did sanity boot testing Intel (intel-arrowlake-s-02) system.  
  
commit a19d48f  
Author: Jiasheng Jiang <jiasheng@iscas.ac.cn>  
Date:   Fri Jun 23 10:27:06 2023 +0800  
  
    pstore/platform: Add check for kstrdup  
  
    Add check for the return value of kstrdup() and return the error  
    if it fails in order to avoid NULL pointer dereference.  
  
    Fixes: 563ca40 ("pstore/platform: Switch pstore_info::name to const")  
    Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>  
    Link: https://lore.kernel.org/r/20230623022706.32125-1-jiasheng@iscas.ac.cn  
    Signed-off-by: Kees Cook <keescook@chromium.org>  
  
Signed-off-by: Steve Best <sbest@redhat.com>

Approved-by: Lenny Szubowicz <lszubowi@redhat.com>
Approved-by: Tony Camuso <tcamuso@redhat.com>
Approved-by: David Arcari <darcari@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: Lucas Zampieri <lzampier@redhat.com>

Author: zampierilucas

fs/pstore/platform.c

@@ -561,6 +561,8 @@ static int pstore_write_user_compat(struct pstore_record *record,
  */
 int pstore_register(struct pstore_info *psi)
 {
+	char *new_backend;
+
 	if (backend && strcmp(backend, psi->name)) {
 		pr_warn("ignoring unexpected backend '%s'\n", psi->name);
 		return -EPERM;
@@ -580,11 +582,16 @@ int pstore_register(struct pstore_info *psi)
 		return -EINVAL;
 	}
 
+	new_backend = kstrdup(psi->name, GFP_KERNEL);
+	if (!new_backend)
+		return -ENOMEM;
+
 	mutex_lock(&psinfo_lock);
 	if (psinfo) {
 		pr_warn("backend '%s' already loaded: ignoring '%s'\n",
 			psinfo->name, psi->name);
 		mutex_unlock(&psinfo_lock);
+		kfree(new_backend);
 		return -EBUSY;
 	}
 
@@ -617,7 +624,7 @@ int pstore_register(struct pstore_info *psi)
 	 * Update the module parameter backend, so it is visible
 	 * through /sys/module/pstore/parameters/backend
 	 */
-	backend = kstrdup(psi->name, GFP_KERNEL);
+	backend = new_backend;
 
 	pr_info("Registered %s as persistent store backend\n", psi->name);