From: Dan Carpenter dan.carpenter@oracle.com
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: 578b881ba9c4 ("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 --- drivers/ntb/test/ntb_tool.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
--- a/drivers/ntb/test/ntb_tool.c +++ b/drivers/ntb/test/ntb_tool.c @@ -367,14 +367,16 @@ static ssize_t tool_fn_write(struct tool 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;