fs: move namei sysctls to its own file

kernel/sysctl.c is a kitchen sink where everyone leaves their dirty
dishes, this makes it very difficult to maintain.

To help with this maintenance let's start by moving sysctls to places
where they actually belong.  The proc sysctl maintainers do not want to
know what sysctl knobs you wish to add for your own piece of code, we
just care about the core logic.

So move namei's own sysctl knobs to its own file.

Other than the move we also avoid initializing two static variables to 0
as this is not needed:

  * sysctl_protected_symlinks
  * sysctl_protected_hardlinks

Link: https://lkml.kernel.org/r/20211129205548.605569-8-mcgrof@kernel.org
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Antti Palosaari <crope@iki.fi>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Lukas Middendorf <kernel@tuxforce.de>
Cc: Stephen Kitt <steve@sk2.org>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/namei.c b/fs/namei.c
index d81f04f8d81880b84d34598948126a63e33319f2..b867a92c078ec3402b5c2a7274e5e183bd4210bc 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1020,10 +1020,60 @@ static inline void put_link(struct nameidata *nd)
                path_put(&last->link);
 }
 
-int sysctl_protected_symlinks __read_mostly = 0;
-int sysctl_protected_hardlinks __read_mostly = 0;
-int sysctl_protected_fifos __read_mostly;
-int sysctl_protected_regular __read_mostly;
+static int sysctl_protected_symlinks __read_mostly;
+static int sysctl_protected_hardlinks __read_mostly;
+static int sysctl_protected_fifos __read_mostly;
+static int sysctl_protected_regular __read_mostly;
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table namei_sysctls[] = {
+       {
+               .procname       = "protected_symlinks",
+               .data           = &sysctl_protected_symlinks,
+               .maxlen         = sizeof(int),
+               .mode           = 0600,
+               .proc_handler   = proc_dointvec_minmax,
+               .extra1         = SYSCTL_ZERO,
+               .extra2         = SYSCTL_ONE,
+       },
+       {
+               .procname       = "protected_hardlinks",
+               .data           = &sysctl_protected_hardlinks,
+               .maxlen         = sizeof(int),
+               .mode           = 0600,
+               .proc_handler   = proc_dointvec_minmax,
+               .extra1         = SYSCTL_ZERO,
+               .extra2         = SYSCTL_ONE,
+       },
+       {
+               .procname       = "protected_fifos",
+               .data           = &sysctl_protected_fifos,
+               .maxlen         = sizeof(int),
+               .mode           = 0600,
+               .proc_handler   = proc_dointvec_minmax,
+               .extra1         = SYSCTL_ZERO,
+               .extra2         = SYSCTL_TWO,
+       },
+       {
+               .procname       = "protected_regular",
+               .data           = &sysctl_protected_regular,
+               .maxlen         = sizeof(int),
+               .mode           = 0600,
+               .proc_handler   = proc_dointvec_minmax,
+               .extra1         = SYSCTL_ZERO,
+               .extra2         = SYSCTL_TWO,
+       },
+       { }
+};
+
+static int __init init_fs_namei_sysctls(void)
+{
+       register_sysctl_init("fs", namei_sysctls);
+       return 0;
+}
+fs_initcall(init_fs_namei_sysctls);
+
+#endif /* CONFIG_SYSCTL */
 
 /**
  * may_follow_link - Check symlink following for unsafe situations

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 0e08c3dd8f756216183508ff82b39569734ace87..9617dea249782601f878d79b4c7f10a8a50dbcb5 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -81,7 +81,6 @@ extern void __init files_maxfiles_init(void);
 
 extern unsigned long get_max_files(void);
 extern unsigned int sysctl_nr_open;
-extern int leases_enable, lease_break_time;
 
 typedef __kernel_rwf_t rwf_t;
 

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 073948e9d1651afb48e605708ece8d2eedf0b955..53fb4692facc95905f44334d00853e1a8f67a597 100644 (file)
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2897,42 +2897,6 @@ static struct ctl_table vm_table[] = {
 };
 
 static struct ctl_table fs_table[] = {
-       {
-               .procname       = "protected_symlinks",
-               .data           = &sysctl_protected_symlinks,
-               .maxlen         = sizeof(int),
-               .mode           = 0600,
-               .proc_handler   = proc_dointvec_minmax,
-               .extra1         = SYSCTL_ZERO,
-               .extra2         = SYSCTL_ONE,
-       },
-       {
-               .procname       = "protected_hardlinks",
-               .data           = &sysctl_protected_hardlinks,
-               .maxlen         = sizeof(int),
-               .mode           = 0600,
-               .proc_handler   = proc_dointvec_minmax,
-               .extra1         = SYSCTL_ZERO,
-               .extra2         = SYSCTL_ONE,
-       },
-       {
-               .procname       = "protected_fifos",
-               .data           = &sysctl_protected_fifos,
-               .maxlen         = sizeof(int),
-               .mode           = 0600,
-               .proc_handler   = proc_dointvec_minmax,
-               .extra1         = SYSCTL_ZERO,
-               .extra2         = SYSCTL_TWO,
-       },
-       {
-               .procname       = "protected_regular",
-               .data           = &sysctl_protected_regular,
-               .maxlen         = sizeof(int),
-               .mode           = 0600,
-               .proc_handler   = proc_dointvec_minmax,
-               .extra1         = SYSCTL_ZERO,
-               .extra2         = SYSCTL_TWO,
-       },
        {
                .procname       = "suid_dumpable",
                .data           = &suid_dumpable,