pstore/platform: Add check for kstrdup

[ Upstream commit a19d48f7c5d57c0f0405a7d4334d1d38fe9d3c1c ]

Add check for the return value of kstrdup() and return the error
if it fails in order to avoid NULL pointer dereference.

Fixes: 563ca40ddf40 ("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: Sasha Levin <sashal@kernel.org>

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 0c034ea..7787fb5 100644 (file)
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -561,6 +561,8 @@ out:
  */
 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);