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Commit 673637c4 authored by Jason A. Donenfeld's avatar Jason A. Donenfeld Committed by Greg Kroah-Hartman
Browse files

random: cleanup UUID handling 



commit 64276a9939ff414f2f0db38036cf4e1a0a703394 upstream.

Rather than hard coding various lengths, we can use the right constants.
Strings should be `char *` while buffers should be `u8 *`. Rather than
have a nonsensical and unused maxlength, just remove it. Finally, use
snprintf instead of sprintf, just out of good hygiene.

As well, remove the old comment about returning a binary UUID via the
binary sysctl syscall. That syscall was removed from the kernel in 5.5,
and actually, the "uuid_strategy" function and related infrastructure
for even serving it via the binary sysctl syscall was removed with
894d2491 ("sysctl drivers: Remove dead binary sysctl support") back
in 2.6.33.

Reviewed-by: default avatarDominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: default avatarJason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4d5151cc

drivers/char/random.c

+13 −16
Original line number Diff line number Diff line
@@ -1656,22 +1656,25 @@ const struct file_operations urandom_fops = { 
static int sysctl_random_min_urandom_seed = 60;

static int sysctl_random_write_wakeup_bits = POOL_MIN_BITS;

static int sysctl_poolsize = POOL_BITS;

static char sysctl_bootid[16];

static u8 sysctl_bootid[UUID_SIZE];



/*

 * This function is used to return both the bootid UUID, and random

 * UUID. The difference is in whether table->data is NULL; if it is,

 * then a new UUID is generated and returned to the user.

 *

 * If the user accesses this via the proc interface, the UUID will be

 * returned as an ASCII string in the standard UUID format; if via the

 * sysctl system call, as 16 bytes of binary data.

 */

static int proc_do_uuid(struct ctl_table *table, int write,

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

{

	struct ctl_table fake_table;

	unsigned char buf[64], tmp_uuid[16], *uuid;

	u8 tmp_uuid[UUID_SIZE], *uuid;

	char uuid_string[UUID_STRING_LEN + 1];

	struct ctl_table fake_table = {

		.data = uuid_string,

		.maxlen = UUID_STRING_LEN

	};



	if (write)

		return -EPERM;



	uuid = table->data;

	if (!uuid) {
@@ -1686,12 +1689,8 @@ static int proc_do_uuid(struct ctl_table *table, int write, 
		spin_unlock(&bootid_spinlock);

	}



	sprintf(buf, "%pU", uuid);



	fake_table.data = buf;

	fake_table.maxlen = sizeof(buf);



	return proc_dostring(&fake_table, write, buffer, lenp, ppos);

	snprintf(uuid_string, sizeof(uuid_string), "%pU", uuid);

	return proc_dostring(&fake_table, 0, buffer, lenp, ppos);

}



extern struct ctl_table random_table[];
@@ -1727,13 +1726,11 @@ struct ctl_table random_table[] = { 
	{

		.procname	= "boot_id",

		.data		= &sysctl_bootid,

		.maxlen		= 16,

		.mode		= 0444,

		.proc_handler	= proc_do_uuid,

	},

	{

		.procname	= "uuid",

		.maxlen		= 16,

		.mode		= 0444,

		.proc_handler	= proc_do_uuid,

	},