security: declare member holding string literal const

The struct security_hook_list member lsm is assigned in
security_add_hooks() with string literals passed from the individual
security modules.  Declare the function parameter and the struct member
const to signal their immutability.

Reported by Clang [-Wwrite-strings]:

    security/selinux/hooks.c:7388:63: error: passing 'const char [8]'
      to parameter of type 'char *' discards qualifiers
      [-Werror,-Wincompatible-pointer-types-discards-qualifiers]
            security_add_hooks(selinux_hooks,
                               ARRAY_SIZE(selinux_hooks), selinux);
                                                          ^~~~~~~~~
    ./include/linux/lsm_hooks.h:1629:11: note: passing argument to
      parameter 'lsm' here
                                    char *lsm);
                                          ^

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Reviewed-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 419b5fe..47cdf3f 100644 (file)
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1595,7 +1595,7 @@ struct security_hook_list {
        struct hlist_node               list;
        struct hlist_head               *head;
        union security_list_options     hook;
-       char                            *lsm;
+       const char                      *lsm;
 } __randomize_layout;
 
 /*
@@ -1630,7 +1630,7 @@ extern struct security_hook_heads security_hook_heads;
 extern char *lsm_names;
 
 extern void security_add_hooks(struct security_hook_list *hooks, int count,
-                               char *lsm);
+                               const char *lsm);
 
 #define LSM_FLAG_LEGACY_MAJOR  BIT(0)
 #define LSM_FLAG_EXCLUSIVE     BIT(1)

diff --git a/security/security.c b/security/security.c
index b7cf5cb..985afd1 100644 (file)
--- a/security/security.c
+++ b/security/security.c
@@ -478,7 +478,7 @@ static int lsm_append(const char *new, char **result)
  * Each LSM has to register its hooks with the infrastructure.
  */
 void __init security_add_hooks(struct security_hook_list *hooks, int count,
-                               char *lsm)
+                               const char *lsm)
 {
        int i;