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: 32927393dc
("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>
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@ -564,6 +564,10 @@ static ssize_t proc_sys_call_handler(struct file *filp, void __user *ubuf,
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if (!table->proc_handler)
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goto out;
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/* don't even try if the size is too large */
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if (count > KMALLOC_MAX_SIZE)
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return -ENOMEM;
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if (write) {
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kbuf = memdup_user_nul(ubuf, count);
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if (IS_ERR(kbuf)) {
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