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/[email protected] Signed-off-by: Luis Chamberlain <[email protected]> Cc: Al Viro <[email protected]> Cc: Andy Shevchenko <[email protected]> Cc: Antti Palosaari <[email protected]> Cc: Eric Biederman <[email protected]> Cc: Iurii Zaikin <[email protected]> Cc: "J. Bruce Fields" <[email protected]> Cc: Jeff Layton <[email protected]> Cc: Kees Cook <[email protected]> Cc: Lukas Middendorf <[email protected]> Cc: Stephen Kitt <[email protected]> Cc: Xiaoming Ni <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
wafgo · Jan 22, 2022 · 9c011be · 9c011be
1 parent dd81faa
commit 9c011be
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Showing 3 changed files with 54 additions and 41 deletions.
diff --git 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
@@ -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
@@ -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,