Commit c4b8b769 authored by Eric W. Biederman's avatar Eric W. Biederman Committed by Linus Torvalds
Browse files

[PATCH] sysctl: implement sysctl_uts_string() 



The problem: When using sys_sysctl we don't read the proper values for the
variables exported from the uts namespace, nor do we do the proper locking.

This patch introduces sysctl_uts_string which properly fetches the values and
does the proper locking.

Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent cf9f151c

kernel/sysctl.c

+32 −5
Original line number Diff line number Diff line
@@ -137,6 +137,10 @@ static int parse_table(int __user *, int, void __user *, size_t __user *, 
static int proc_do_uts_string(ctl_table *table, int write, struct file *filp,

		  void __user *buffer, size_t *lenp, loff_t *ppos);



static int sysctl_uts_string(ctl_table *table, int __user *name, int nlen,

		  void __user *oldval, size_t __user *oldlenp,

		  void __user *newval, size_t newlen, void **context);



#ifdef CONFIG_PROC_SYSCTL

static int proc_do_cad_pid(ctl_table *table, int write, struct file *filp,

		  void __user *buffer, size_t *lenp, loff_t *ppos);
@@ -258,7 +262,7 @@ static ctl_table kern_table[] = { 
		.maxlen		= sizeof(init_uts_ns.name.sysname),

		.mode		= 0444,

		.proc_handler	= &proc_do_uts_string,

		.strategy	= &sysctl_string,

		.strategy	= &sysctl_uts_string,

	},

	{

		.ctl_name	= KERN_OSRELEASE,
@@ -267,7 +271,7 @@ static ctl_table kern_table[] = { 
		.maxlen		= sizeof(init_uts_ns.name.release),

		.mode		= 0444,

		.proc_handler	= &proc_do_uts_string,

		.strategy	= &sysctl_string,

		.strategy	= &sysctl_uts_string,

	},

	{

		.ctl_name	= KERN_VERSION,
@@ -276,7 +280,7 @@ static ctl_table kern_table[] = { 
		.maxlen		= sizeof(init_uts_ns.name.version),

		.mode		= 0444,

		.proc_handler	= &proc_do_uts_string,

		.strategy	= &sysctl_string,

		.strategy	= &sysctl_uts_string,

	},

	{

		.ctl_name	= KERN_NODENAME,
@@ -285,7 +289,7 @@ static ctl_table kern_table[] = { 
		.maxlen		= sizeof(init_uts_ns.name.nodename),

		.mode		= 0644,

		.proc_handler	= &proc_do_uts_string,

		.strategy	= &sysctl_string,

		.strategy	= &sysctl_uts_string,

	},

	{

		.ctl_name	= KERN_DOMAINNAME,
@@ -294,7 +298,7 @@ static ctl_table kern_table[] = { 
		.maxlen		= sizeof(init_uts_ns.name.domainname),

		.mode		= 0644,

		.proc_handler	= &proc_do_uts_string,

		.strategy	= &sysctl_string,

		.strategy	= &sysctl_uts_string,

	},

	{

		.ctl_name	= KERN_PANIC,
@@ -2598,6 +2602,23 @@ int sysctl_ms_jiffies(ctl_table *table, int __user *name, int nlen, 
	return 1;

}





/* The generic string strategy routine: */

static int sysctl_uts_string(ctl_table *table, int __user *name, int nlen,

		  void __user *oldval, size_t __user *oldlenp,

		  void __user *newval, size_t newlen, void **context)

{

	struct ctl_table uts_table;

	int r, write;

	write = newval && newlen;

	memcpy(&uts_table, table, sizeof(uts_table));

	uts_table.data = get_uts(table, write);

	r = sysctl_string(&uts_table, name, nlen,

		oldval, oldlenp, newval, newlen, context);

	put_uts(table, write, uts_table.data);

	return r;

}



#else /* CONFIG_SYSCTL_SYSCALL */
@@ -2662,6 +2683,12 @@ int sysctl_ms_jiffies(ctl_table *table, int __user *name, int nlen, 
	return -ENOSYS;

}



static int sysctl_uts_string(ctl_table *table, int __user *name, int nlen,

		  void __user *oldval, size_t __user *oldlenp,

		  void __user *newval, size_t newlen, void **context)

{

	return -ENOSYS;

}

#endif /* CONFIG_SYSCTL_SYSCALL */



/*