Re: Patch "tipc: fix kernel warning when sending SYN message" should be probably ported to 5.10 and 5.15 LTS

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Jan 21, 2025 at 11:13:38PM -0800, Xingyu Li wrote:
> Hi,
> 
> We noticed that the patch 11a4d6f67cf5 should be ported to  5.10 and
> 5.15 LTS according to the bug introducing commit. Also, it can be
> applied
> to the latest version of these two LTS branches without conflicts. Its
> bug introducing commit is f25dcc7687d4. The kernel warning and stack
> trace indicate a problem when sending a SYN message in TIPC
> (Transparent Inter-Process Communication). The issue arises because
> `copy_from_iter()` is being called with an uninitialized `iov_iter`
> structure, leading to invalid memory operations. The commit
> (`f25dcc7687d4`) introduces the vulnerability by replacing the old
> data copying mechanisms with the new `copy_from_iter()` function
> without ensuring that the `iov_iter` structure is properly initialized
> in all code paths. The patch adds initialization of `iov_iter` with
> "iov_iter_kvec(&m.msg_iter, ITER_SOURCE, NULL, 0, 0);", which ensures
> that even when there's no data to send, the `iov_iter` is correctly
> set up, preventing the kernel warning/crash when `copy_from_iter()` is
> called.

This change fails to build on those older kernels, which is perhaps why
it was not backported there.  If you wish to see it there, please
provide a working backport.

thanks,

greg k-h