Commit ef9d965b authored Jun 09, 2020 by Christoph Hellwig Committed by Al Viro Jun 10, 2020

sysctl: reject gigantic reads/write to sysctl files



Instead of triggering a WARN_ON deep down in the page allocator just
give up early on allocations that are way larger than the usual sysctl
values.

Fixes: 32927393 ("sysctl: pass kernel pointers to ->proc_handler")
Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

parent 8c46fa96

fs/proc/proc_sysctl.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -564,6 +564,10 @@ static ssize_t proc_sys_call_handler(struct file filp, void __user ubuf,
		if (!table->proc_handler)
		goto out;

		/* don't even try if the size is too large */
		if (count > KMALLOC_MAX_SIZE)
		return -ENOMEM;

		if (write) {
		kbuf = memdup_user_nul(ubuf, count);
		if (IS_ERR(kbuf)) {

Admin message