Commit a1d13886 authored Jul 20, 2022 by Dan Carpenter Committed by Greg Kroah-Hartman Aug 25, 2022

NTB: ntb_tool: uninitialized heap data in tool_fn_write()



commit 45e1058b77feade4e36402828bfe3e0d3363177b upstream.

The call to:

	ret = simple_write_to_buffer(buf, size, offp, ubuf, size);

will return success if it is able to write even one byte to "buf".
The value of "*offp" controls which byte.  This could result in
reading uninitialized data when we do the sscanf() on the next line.

This code is not really desigined to handle partial writes where
*offp is non-zero and the "buf" is preserved and re-used between writes.
Just ban partial writes and replace the simple_write_to_buffer() with
copy_from_user().

Fixes: 578b881b ("NTB: Add tool test client")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 215cbd3c

drivers/ntb/test/ntb_tool.c

+5 −3

Original line number	Diff line number	Diff line
		@@ -367,14 +367,16 @@ static ssize_t tool_fn_write(struct tool_ctx *tc,
		u64 bits;
		int n;

		if (*offp)
		return 0;

		buf = kmalloc(size + 1, GFP_KERNEL);
		if (!buf)
		return -ENOMEM;

		ret = simple_write_to_buffer(buf, size, offp, ubuf, size);
		if (ret < 0) {
		if (copy_from_user(buf, ubuf, size)) {
		kfree(buf);
		return ret;
		return -EFAULT;
		}

		buf[size] = 0;