pstore/platform: Switch pstore_info::name to const

In order to more cleanly pass around backend names, make the "name" member
const. This means the module param needs to be dynamic (technically, it
was before, so this actually cleans up a minor memory leak if a backend
was specified and then gets unloaded.)

Link: https://lore.kernel.org/lkml/20200510202436.63222-3-keescook@chromium.org/
Signed-off-by: Kees Cook <keescook@chromium.org>

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 8beaeff..715396b 100644 (file)
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -624,7 +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 = psi->name;
+       backend = kstrdup(psi->name, GFP_KERNEL);
 
        pr_info("Registered %s as persistent store backend\n", psi->name);
 
@@ -667,6 +667,7 @@ void pstore_unregister(struct pstore_info *psi)
        free_buf_for_compression();
 
        psinfo = NULL;
+       kfree(backend);
        backend = NULL;
        mutex_unlock(&psinfo_lock);
 }

diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index e779441..f6f22b1 100644 (file)
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -170,7 +170,7 @@ struct pstore_record {
  */
 struct pstore_info {
        struct module   *owner;
-       char            *name;
+       const char      *name;
 
        struct semaphore buf_lock;
        char            *buf;