[PATCH] [4/4] /dev/random: Remove RNDGETPOOL ioctl

[Theodore Ts'o]

Recently, someone has kvetched that RNDGETPOOL is a "security
vulnerability".  Never mind that it is superuser only, and with
superuser privs you could load a nasty kernel module, or read the
entropy pool out of /dev/mem directly, but they are nevertheless still
spreading FUD.

In any case, no one is using it (it was there for debugging purposes
only), so we can remove it as dead code.

patch-random-4-remove-rndgetpool

--- random.c	2004/08/19 22:50:19	1.4
+++ random.c	2004/08/19 22:50:43	1.5
@@ -1741,10 +1741,9 @@
 random_ioctl(struct inode * inode, struct file * file,
 	     unsigned int cmd, unsigned long arg)
 {
-	int *tmp, size, ent_count;
+	int size, ent_count;
 	int __user *p = (int __user *)arg;
 	int retval;
-	unsigned long flags;
 	
 	switch (cmd) {
 	case RNDGETENTCNT:
@@ -1765,40 +1764,6 @@
 		if (random_state->entropy_count >= random_read_wakeup_thresh)
 			wake_up_interruptible(&random_read_wait);
 		return 0;
-	case RNDGETPOOL:
-		if (!capable(CAP_SYS_ADMIN))
-			return -EPERM;
-		if (get_user(size, p) ||
-		    put_user(random_state->poolinfo.poolwords, p++))
-			return -EFAULT;
-		if (size < 0)
-			return -EFAULT;
-		if (size > random_state->poolinfo.poolwords)
-			size = random_state->poolinfo.poolwords;
-
-		/* prepare to atomically snapshot pool */
-
-		tmp = kmalloc(size * sizeof(__u32), GFP_KERNEL);
-
-		if (!tmp)
-			return -ENOMEM;
-
-		spin_lock_irqsave(&random_state->lock, flags);
-		ent_count = random_state->entropy_count;
-		memcpy(tmp, random_state->pool, size * sizeof(__u32));
-		spin_unlock_irqrestore(&random_state->lock, flags);
-
-		if (!copy_to_user(p, tmp, size * sizeof(__u32))) {
-			kfree(tmp);
-			return -EFAULT;
-		}
-
-		kfree(tmp);
-
-		if(put_user(ent_count, p++))
-			return -EFAULT;
-
-		return 0;
 	case RNDADDENTROPY:
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
-
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