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NTB: ntb_tool: uninitialized heap data in tool_fn_write()

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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: 578b881ba9 ("NTB: Add tool test client")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>
This commit is contained in:
Dan Carpenter 2022-07-20 21:28:18 +03:00 committed by Jon Mason
parent a44252d5c3
commit 45e1058b77
1 changed files with 5 additions and 3 deletions
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8
drivers/ntb/test/ntb_tool.c
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@ -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;