[RFC PATCH 1/2] security: Remove security_add_mnt_opt() as it's unused

[David Howells]

Remove the add_mnt_opt LSM hook as it's not actually used.  This makes it
easier to make the context pointers in selinux_mnt_opts non-const.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
cc: Paul Moore <paul@xxxxxxxxxxxxxx>
cc: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
cc: selinux@xxxxxxxxxxxxxxx
cc: linux-security-module@xxxxxxxxxxxxxxx
cc: linux-nfs@xxxxxxxxxxxxxxx
cc: linux-cachefs@xxxxxxxxxx
---

 include/linux/lsm_hook_defs.h |    2 --
 include/linux/lsm_hooks.h     |    2 --
 include/linux/security.h      |    8 --------
 security/security.c           |    8 --------
 security/selinux/hooks.c      |   39 ---------------------------------------
 5 files changed, 59 deletions(-)

diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index df8de62f4710..7f5c35d72082 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -78,8 +78,6 @@ LSM_HOOK(int, 0, sb_set_mnt_opts, struct super_block *sb, void *mnt_opts,
 LSM_HOOK(int, 0, sb_clone_mnt_opts, const struct super_block *oldsb,
 	 struct super_block *newsb, unsigned long kern_flags,
 	 unsigned long *set_kern_flags)
-LSM_HOOK(int, 0, sb_add_mnt_opt, const char *option, const char *val,
-	 int len, void **mnt_opts)
 LSM_HOOK(int, 0, move_mount, const struct path *from_path,
 	 const struct path *to_path)
 LSM_HOOK(int, 0, dentry_init_security, struct dentry *dentry,
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index d45b6f6e27fd..73cb0ab2bc03 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -180,8 +180,6 @@
  *	Copy all security options from a given superblock to another
  *	@oldsb old superblock which contain information to clone
  *	@newsb new superblock which needs filled in
- * @sb_add_mnt_opt:
- * 	Add one mount @option to @mnt_opts.
  * @sb_parse_opts_str:
  *	Parse a string of security data filling in the opts structure
  *	@options string containing all mount options known by the LSM
diff --git a/include/linux/security.h b/include/linux/security.h
index bbf44a466832..a4f0c421dd0c 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -313,8 +313,6 @@ int security_sb_clone_mnt_opts(const struct super_block *oldsb,
 				struct super_block *newsb,
 				unsigned long kern_flags,
 				unsigned long *set_kern_flags);
-int security_add_mnt_opt(const char *option, const char *val,
-				int len, void **mnt_opts);
 int security_move_mount(const struct path *from_path, const struct path *to_path);
 int security_dentry_init_security(struct dentry *dentry, int mode,
 				  const struct qstr *name,
@@ -711,12 +709,6 @@ static inline int security_sb_clone_mnt_opts(const struct super_block *oldsb,
 	return 0;
 }
 
-static inline int security_add_mnt_opt(const char *option, const char *val,
-					int len, void **mnt_opts)
-{
-	return 0;
-}
-
 static inline int security_move_mount(const struct path *from_path,
 				      const struct path *to_path)
 {
diff --git a/security/security.c b/security/security.c
index c88167a414b4..0c49a1f05ac4 100644
--- a/security/security.c
+++ b/security/security.c
@@ -994,14 +994,6 @@ int security_sb_clone_mnt_opts(const struct super_block *oldsb,
 }
 EXPORT_SYMBOL(security_sb_clone_mnt_opts);
 
-int security_add_mnt_opt(const char *option, const char *val, int len,
-			 void **mnt_opts)
-{
-	return call_int_hook(sb_add_mnt_opt, -EINVAL,
-					option, val, len, mnt_opts);
-}
-EXPORT_SYMBOL(security_add_mnt_opt);
-
 int security_move_mount(const struct path *from_path, const struct path *to_path)
 {
 	return call_int_hook(move_mount, 0, from_path, to_path);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 62d30c0a30c2..8ea92f08e6bd 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -1023,44 +1023,6 @@ static int selinux_add_opt(int token, const char *s, void **mnt_opts)
 	return -EINVAL;
 }
 
-static int selinux_add_mnt_opt(const char *option, const char *val, int len,
-			       void **mnt_opts)
-{
-	int token = Opt_error;
-	int rc, i;
-
-	for (i = 0; i < ARRAY_SIZE(tokens); i++) {
-		if (strcmp(option, tokens[i].name) == 0) {
-			token = tokens[i].opt;
-			break;
-		}
-	}
-
-	if (token == Opt_error)
-		return -EINVAL;
-
-	if (token != Opt_seclabel) {
-		val = kmemdup_nul(val, len, GFP_KERNEL);
-		if (!val) {
-			rc = -ENOMEM;
-			goto free_opt;
-		}
-	}
-	rc = selinux_add_opt(token, val, mnt_opts);
-	if (unlikely(rc)) {
-		kfree(val);
-		goto free_opt;
-	}
-	return rc;
-
-free_opt:
-	if (*mnt_opts) {
-		selinux_free_mnt_opts(*mnt_opts);
-		*mnt_opts = NULL;
-	}
-	return rc;
-}
-
 static int show_sid(struct seq_file *m, u32 sid)
 {
 	char *context = NULL;
@@ -7298,7 +7260,6 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(fs_context_dup, selinux_fs_context_dup),
 	LSM_HOOK_INIT(fs_context_parse_param, selinux_fs_context_parse_param),
 	LSM_HOOK_INIT(sb_eat_lsm_opts, selinux_sb_eat_lsm_opts),
-	LSM_HOOK_INIT(sb_add_mnt_opt, selinux_add_mnt_opt),
 #ifdef CONFIG_SECURITY_NETWORK_XFRM
 	LSM_HOOK_INIT(xfrm_policy_clone_security, selinux_xfrm_policy_clone),
 #endif