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Commit 247ff8e6 authored by Alan Cox's avatar Alan Cox Committed by Greg Kroah-Hartman
Browse files

vt: lock the accent table 



First step to debletcherising the vt console layer - pick a victim and fix
the locking

This is a nice simple object with its own rules so lets pick it out for
treatment. The user of the table already has a lock so we will also use the
same lock for updates.

Signed-off-by: default avatarAlan Cox <alan@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ce1000dd

drivers/tty/vt/keyboard.c

+162 −0
Original line number Diff line number Diff line
@@ -1452,3 +1452,165 @@ int __init kbd_init(void) 


	return 0;

}



/* Ioctl support code */



/**

 *	vt_do_diacrit		-	diacritical table updates

 *	@cmd: ioctl request

 *	@up: pointer to user data for ioctl

 *	@perm: permissions check computed by caller

 *

 *	Update the diacritical tables atomically and safely. Lock them

 *	against simultaneous keypresses

 */

int vt_do_diacrit(unsigned int cmd, void __user *up, int perm)

{

	struct kbdiacrs __user *a = up;

	unsigned long flags;

	int asize;

	int ret = 0;



	switch (cmd) {

	case KDGKBDIACR:

	{

		struct kbdiacr *diacr;

		int i;



		diacr = kmalloc(MAX_DIACR * sizeof(struct kbdiacr),

								GFP_KERNEL);

		if (diacr == NULL)

			return -ENOMEM;



		/* Lock the diacriticals table, make a copy and then

		   copy it after we unlock */

		spin_lock_irqsave(&kbd_event_lock, flags);



		asize = accent_table_size;

		for (i = 0; i < asize; i++) {

			diacr[i].diacr = conv_uni_to_8bit(

						accent_table[i].diacr);

			diacr[i].base = conv_uni_to_8bit(

						accent_table[i].base);

			diacr[i].result = conv_uni_to_8bit(

						accent_table[i].result);

		}

		spin_unlock_irqrestore(&kbd_event_lock, flags);



		if (put_user(asize, &a->kb_cnt))

			ret = -EFAULT;

		else  if (copy_to_user(a->kbdiacr, diacr,

				asize * sizeof(struct kbdiacr)))

			ret = -EFAULT;

		kfree(diacr);

		return ret;

	}

	case KDGKBDIACRUC:

	{

		struct kbdiacrsuc __user *a = up;

		void *buf;



		buf = kmalloc(MAX_DIACR * sizeof(struct kbdiacruc),

								GFP_KERNEL);

		if (buf == NULL)

			return -ENOMEM;



		/* Lock the diacriticals table, make a copy and then

		   copy it after we unlock */

		spin_lock_irqsave(&kbd_event_lock, flags);



		asize = accent_table_size;

		memcpy(buf, accent_table, asize * sizeof(struct kbdiacruc));



		spin_unlock_irqrestore(&kbd_event_lock, flags);



		if (put_user(asize, &a->kb_cnt))

			ret = -EFAULT;

		else if (copy_to_user(a->kbdiacruc, buf,

				asize*sizeof(struct kbdiacruc)))

			ret = -EFAULT;

		kfree(buf);

		return ret;

	}



	case KDSKBDIACR:

	{

		struct kbdiacrs __user *a = up;

		struct kbdiacr *diacr = NULL;

		unsigned int ct;

		int i;



		if (!perm)

			return -EPERM;

		if (get_user(ct, &a->kb_cnt))

			return -EFAULT;

		if (ct >= MAX_DIACR)

			return -EINVAL;



		if (ct) {

			diacr = kmalloc(sizeof(struct kbdiacr) * ct,

								GFP_KERNEL);

			if (diacr == NULL)

				return -ENOMEM;



			if (copy_from_user(diacr, a->kbdiacr,

					sizeof(struct kbdiacr) * ct)) {

				kfree(diacr);

				return -EFAULT;

			}

		}



		spin_lock_irqsave(&kbd_event_lock, flags);

		accent_table_size = ct;

		for (i = 0; i < ct; i++) {

			accent_table[i].diacr =

					conv_8bit_to_uni(diacr[i].diacr);

			accent_table[i].base =

					conv_8bit_to_uni(diacr[i].base);

			accent_table[i].result =

					conv_8bit_to_uni(diacr[i].result);

		}

		spin_unlock_irqrestore(&kbd_event_lock, flags);

		kfree(diacr);

		return 0;

	}



	case KDSKBDIACRUC:

	{

		struct kbdiacrsuc __user *a = up;

		unsigned int ct;

		void *buf = NULL;



		if (!perm)

			return -EPERM;



		if (get_user(ct, &a->kb_cnt))

			return -EFAULT;



		if (ct >= MAX_DIACR)

			return -EINVAL;



		if (ct) {

			buf = kmalloc(ct * sizeof(struct kbdiacruc),

								GFP_KERNEL);

			if (buf == NULL)

				return -ENOMEM;



			if (copy_from_user(buf, a->kbdiacruc,

					ct * sizeof(struct kbdiacruc))) {

				kfree(buf);

				return -EFAULT;

			}

		} 

		spin_lock_irqsave(&kbd_event_lock, flags);

		if (ct)

			memcpy(accent_table, buf,

					ct * sizeof(struct kbdiacruc));

		accent_table_size = ct;

		spin_unlock_irqrestore(&kbd_event_lock, flags);

		kfree(buf);

		return 0;

	}

	}

	return ret;

}

drivers/tty/vt/vt_ioctl.c

+3 −78
Original line number Diff line number Diff line
@@ -753,89 +753,14 @@ int vt_ioctl(struct tty_struct *tty, 
		ret = do_kdgkb_ioctl(cmd, up, perm);

		break;



	/* Diacritical processing. Handled in keyboard.c as it has

	   to operate on the keyboard locks and structures */

	case KDGKBDIACR:

	{

		struct kbdiacrs __user *a = up;

		struct kbdiacr diacr;

		int i;



		if (put_user(accent_table_size, &a->kb_cnt)) {

			ret = -EFAULT;

			break;

		}

		for (i = 0; i < accent_table_size; i++) {

			diacr.diacr = conv_uni_to_8bit(accent_table[i].diacr);

			diacr.base = conv_uni_to_8bit(accent_table[i].base);

			diacr.result = conv_uni_to_8bit(accent_table[i].result);

			if (copy_to_user(a->kbdiacr + i, &diacr, sizeof(struct kbdiacr))) {

				ret = -EFAULT;

				break;

			}

		}

		break;

	}

	case KDGKBDIACRUC:

	{

		struct kbdiacrsuc __user *a = up;



		if (put_user(accent_table_size, &a->kb_cnt))

			ret = -EFAULT;

		else if (copy_to_user(a->kbdiacruc, accent_table,

				accent_table_size*sizeof(struct kbdiacruc)))

			ret = -EFAULT;

		break;

	}



	case KDSKBDIACR:

	{

		struct kbdiacrs __user *a = up;

		struct kbdiacr diacr;

		unsigned int ct;

		int i;



		if (!perm)

			goto eperm;

		if (get_user(ct,&a->kb_cnt)) {

			ret = -EFAULT;

			break;

		}

		if (ct >= MAX_DIACR) {

			ret = -EINVAL;

			break;

		}

		accent_table_size = ct;

		for (i = 0; i < ct; i++) {

			if (copy_from_user(&diacr, a->kbdiacr + i, sizeof(struct kbdiacr))) {

				ret = -EFAULT;

				break;

			}

			accent_table[i].diacr = conv_8bit_to_uni(diacr.diacr);

			accent_table[i].base = conv_8bit_to_uni(diacr.base);

			accent_table[i].result = conv_8bit_to_uni(diacr.result);

		}

		break;

	}



	case KDSKBDIACRUC:

	{

		struct kbdiacrsuc __user *a = up;

		unsigned int ct;



		if (!perm)

			goto eperm;

		if (get_user(ct,&a->kb_cnt)) {

			ret = -EFAULT;

			break;

		}

		if (ct >= MAX_DIACR) {

			ret = -EINVAL;

			break;

		}

		accent_table_size = ct;

		if (copy_from_user(accent_table, a->kbdiacruc, ct*sizeof(struct kbdiacruc)))

			ret = -EFAULT;

		ret = vt_do_diacrit(cmd, up, perm);

		break;

	}



	/* the ioctls below read/set the flags usually shown in the leds */

	/* don't use them - they will go away without warning */

include/linux/vt_kern.h

+3 −0
Original line number Diff line number Diff line
@@ -167,4 +167,7 @@ extern int unregister_vt_notifier(struct notifier_block *nb); 


extern void hide_boot_cursor(bool hide);



/* keyboard  provided interfaces */

extern int vt_do_diacrit(unsigned int cmd, void __user *up, int eperm);



#endif /* _VT_KERN_H */