On Sat, Feb 20, 2021 at 07:58:46PM -0800, Ben Widawsky wrote:
> When submitting a command for userspace, input and output payload bounce
> buffers are allocated. For a given command, both input and output
> buffers may exist and so when allocation of the input buffer fails, the
> output buffer must be freed too.
>
> As far as I can tell, userspace can't easily exploit the leak to OOM a
> machine unless the machine was already near OOM state.
>
> Fixes: 583fa5e71cae ("cxl/mem: Add basic IOCTL interface")
> Reported-by: Konrad Rzeszutek Wilk <[email protected]>
And lets add the other R-tag:
Reviewed-by: Konrad Rzeszutek Wilk <[email protected]>
Thank you for quick turn-around!
> Signed-off-by: Ben Widawsky <[email protected]>
> ---
> drivers/cxl/mem.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
> index df895bcca63a..244cb7d89678 100644
> --- a/drivers/cxl/mem.c
> +++ b/drivers/cxl/mem.c
> @@ -514,8 +514,10 @@ static int handle_mailbox_cmd_from_user(struct cxl_mem
> *cxlm,
> if (cmd->info.size_in) {
> mbox_cmd.payload_in = vmemdup_user(u64_to_user_ptr(in_payload),
> cmd->info.size_in);
> - if (IS_ERR(mbox_cmd.payload_in))
> + if (IS_ERR(mbox_cmd.payload_in)) {
> + kvfree(mbox_cmd.payload_out);
> return PTR_ERR(mbox_cmd.payload_in);
> + }
> }
>
> rc = cxl_mem_mbox_get(cxlm);
> --
> 2.30.1
>
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