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Commit 30800d99 authored by Kees Cook's avatar Kees Cook
Browse files

pstore: simplify write_user_compat() 



Nothing actually uses write_user_compat() currently, but there is no
reason to reuse the dmesg buffer. Instead, just allocate a new record
buffer, copy in from userspace, and pass it to write() as normal.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent 4c9ec219

fs/pstore/platform.c

+20 −26
Original line number Diff line number Diff line
@@ -635,33 +635,27 @@ static void pstore_unregister_console(void) {} 
static int pstore_write_user_compat(struct pstore_record *record,

				    const char __user *buf)

{

	unsigned long flags = 0;

	size_t i, bufsize, total_size = record->size;

	long ret = 0;



	if (unlikely(!access_ok(VERIFY_READ, buf, total_size)))

		return -EFAULT;

	bufsize = total_size;

	if (bufsize > psinfo->bufsize)

		bufsize = psinfo->bufsize;

	record->buf = psinfo->buf;

	spin_lock_irqsave(&psinfo->buf_lock, flags);

	for (i = 0; i < total_size; ) {

		size_t c = min(total_size - i, bufsize);

	int ret = 0;



	if (record->buf)

		return -EINVAL;



		ret = __copy_from_user(record->buf, buf + i, c);

		if (unlikely(ret != 0)) {

	record->buf = kmalloc(record->size, GFP_KERNEL);

	if (!record->buf)

		return -ENOMEM;



	if (unlikely(copy_from_user(record->buf, buf, record->size))) {

		ret = -EFAULT;

			break;

		goto out;

	}

		record->size = c;



	ret = record->psi->write(record);

		if (unlikely(ret < 0))

			break;

		i += c;

	}

	spin_unlock_irqrestore(&psinfo->buf_lock, flags);

	return unlikely(ret < 0) ? ret : total_size;



out:

	kfree(record->buf);

	record->buf = NULL;



	return unlikely(ret < 0) ? ret : record->size;

}



/*