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Commit 2830b683 authored by Eric W. Biederman's avatar Eric W. Biederman
Browse files

sysctl: Refactor the binary sysctl handling to remove duplicate code 



Read in the binary sysctl path once, instead of reread it
from user space each time the code needs to access a path
element.

The deprecated sysctl warning is moved to do_sysctl so
that the compat_sysctl entries syscalls will also warn.

The return of -ENOSYS when !CONFIG_SYSCTL_SYSCALL is moved
to binary_sysctl.  Always leaving a do_sysctl available
that handles !CONFIG_SYSCTL_SYSCALL and printing the
deprecated sysctl warning allows for a single defitition
of the sysctl syscall.

Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
parent afa588b2

kernel/sysctl_binary.c

+58 −65
Original line number Diff line number Diff line
@@ -14,8 +14,6 @@ 
#include <linux/ctype.h>

#include <linux/smp_lock.h>



static int deprecated_sysctl_warning(struct __sysctl_args *args);



#ifdef CONFIG_SYSCTL_SYSCALL



/* Perform the actual read/write of a sysctl table entry. */
@@ -51,7 +49,7 @@ static int do_sysctl_strategy(struct ctl_table_root *root, 
	return 0;

}



static int parse_table(int __user *name, int nlen,

static int parse_table(const int *name, int nlen,

		       void __user *oldval, size_t __user *oldlenp,

		       void __user *newval, size_t newlen,

		       struct ctl_table_root *root,
@@ -61,8 +59,7 @@ static int parse_table(int __user *name, int nlen, 
repeat:

	if (!nlen)

		return -ENOTDIR;

	if (get_user(n, name))

		return -EFAULT;

	n = *name;

	for ( ; table->ctl_name || table->procname; table++) {

		if (!table->ctl_name)

			continue;
@@ -85,19 +82,13 @@ static int parse_table(int __user *name, int nlen, 
	return -ENOTDIR;

}



int do_sysctl(int __user *name, int nlen, void __user *oldval, size_t __user *oldlenp,

static ssize_t binary_sysctl(const int *name, int nlen,

	void __user *oldval, size_t __user *oldlenp,

	void __user *newval, size_t newlen)



{

	struct ctl_table_header *head;

	int error = -ENOTDIR;



	if (nlen <= 0 || nlen >= CTL_MAXNAME)

		return -ENOTDIR;

	if (oldval) {

		int old_len;

		if (!oldlenp || get_user(old_len, oldlenp))

			return -EFAULT;

	}

	ssize_t error = -ENOTDIR;



	for (head = sysctl_head_next(NULL); head;

			head = sysctl_head_next(head)) {
@@ -112,74 +103,76 @@ int do_sysctl(int __user *name, int nlen, void __user *oldval, size_t __user *ol 
	return error;

}



SYSCALL_DEFINE1(sysctl, struct __sysctl_args __user *, args)

{

	struct __sysctl_args tmp;

	int error;



	if (copy_from_user(&tmp, args, sizeof(tmp)))

		return -EFAULT;



	error = deprecated_sysctl_warning(&tmp);

	if (error)

		goto out;



	lock_kernel();

	error = do_sysctl(tmp.name, tmp.nlen, tmp.oldval, tmp.oldlenp,

			  tmp.newval, tmp.newlen);

	unlock_kernel();

out:

	return error;

}



#else /* CONFIG_SYSCTL_SYSCALL */



SYSCALL_DEFINE1(sysctl, struct __sysctl_args __user *, args)

static ssize_t binary_sysctl(const int *ctl_name, int nlen,

	void __user *oldval, size_t __user *oldlenp,

	void __user *newval, size_t newlen)

{

	struct __sysctl_args tmp;

	int error;



	if (copy_from_user(&tmp, args, sizeof(tmp)))

		return -EFAULT;



	error = deprecated_sysctl_warning(&tmp);



	/* If no error reading the parameters then just -ENOSYS ... */

	if (!error)

		error = -ENOSYS;



	return error;

	return -ENOSYS;

}



#endif /* CONFIG_SYSCTL_SYSCALL */



static int deprecated_sysctl_warning(struct __sysctl_args *args)

static void deprecated_sysctl_warning(const int *name, int nlen)

{

	static int msg_count;

	int name[CTL_MAXNAME];

	int i;



	/* Check args->nlen. */

	if (args->nlen < 0 || args->nlen > CTL_MAXNAME)

		return -ENOTDIR;



	/* Read in the sysctl name for better debug message logging */

	for (i = 0; i < args->nlen; i++)

		if (get_user(name[i], args->name + i))

			return -EFAULT;



	/* Ignore accesses to kernel.version */

	if ((args->nlen == 2) && (name[0] == CTL_KERN) && (name[1] == KERN_VERSION))

		return 0;

	if ((nlen == 2) && (name[0] == CTL_KERN) && (name[1] == KERN_VERSION))

		return;



	if (msg_count < 5) {

		msg_count++;

		printk(KERN_INFO

			"warning: process `%s' used the deprecated sysctl "

			"system call with ", current->comm);

		for (i = 0; i < args->nlen; i++)

		for (i = 0; i < nlen; i++)

			printk("%d.", name[i]);

		printk("\n");

	}

	return 0;

	return;

}



int do_sysctl(int __user *args_name, int nlen,

	void __user *oldval, size_t __user *oldlenp,

	void __user *newval, size_t newlen)

{

	int name[CTL_MAXNAME];

	size_t oldlen = 0;

	int i;



	if (nlen <= 0 || nlen >= CTL_MAXNAME)

		return -ENOTDIR;

	if (oldval && !oldlenp)

		return -EFAULT;

	if (oldlenp && get_user(oldlen, oldlenp))

		return -EFAULT;



	/* Read in the sysctl name for simplicity */

	for (i = 0; i < nlen; i++)

		if (get_user(name[i], args_name + i))

			return -EFAULT;



	deprecated_sysctl_warning(name, nlen);



	return binary_sysctl(name, nlen, oldval, oldlenp, newval, newlen);

}





SYSCALL_DEFINE1(sysctl, struct __sysctl_args __user *, args)

{

	struct __sysctl_args tmp;

	int error;



	if (copy_from_user(&tmp, args, sizeof(tmp)))

		return -EFAULT;



	lock_kernel();

	error = do_sysctl(tmp.name, tmp.nlen, tmp.oldval, tmp.oldlenp,

			  tmp.newval, tmp.newlen);

	unlock_kernel();



	return error;

}