From 247ff8e610cb63c015de19191db9666754c2ed79 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Fri, 24 Feb 2012 12:47:11 +0000 Subject: 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: Alan Cox Signed-off-by: Greg Kroah-Hartman diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c index a605549..bdf838d 100644 --- a/drivers/tty/vt/keyboard.c +++ b/drivers/tty/vt/keyboard.c @@ -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; +} diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c index 65447c5..80af0f9 100644 --- a/drivers/tty/vt/vt_ioctl.c +++ b/drivers/tty/vt/vt_ioctl.c @@ -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 */ diff --git a/include/linux/vt_kern.h b/include/linux/vt_kern.h index c2164fa..5d8726a 100644 --- a/include/linux/vt_kern.h +++ b/include/linux/vt_kern.h @@ -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 */ -- cgit v0.10.2