From: Greg Kroah-Hartman gregkh@linuxfoundation.org
From: Dmitry Baryshkov dmitry.baryshkov@linaro.org
commit 20c40794eb85ea29852d7bc37c55713802a543d6 upstream.
Verify that user applications are not using the kernel RPC message handle to restrict them from directly attaching to guest OS on the remote subsystem. This is a port of CVE-2019-2308 fix.
Fixes: c68cfb718c8f ("misc: fastrpc: Add support for context Invoke method") Cc: Srinivas Kandagatla srinivas.kandagatla@linaro.org Cc: Jonathan Marek jonathan@marek.ca Cc: stable@vger.kernel.org Signed-off-by: Dmitry Baryshkov dmitry.baryshkov@linaro.org Link: https://lore.kernel.org/r/20210212192658.3476137-1-dmitry.baryshkov@linaro.o... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/misc/fastrpc.c | 5 +++++ 1 file changed, 5 insertions(+)
--- a/drivers/misc/fastrpc.c +++ b/drivers/misc/fastrpc.c @@ -924,6 +924,11 @@ static int fastrpc_internal_invoke(struc if (!fl->cctx->rpdev) return -EPIPE;
+ if (handle == FASTRPC_INIT_HANDLE && !kernel) { + dev_warn_ratelimited(fl->sctx->dev, "user app trying to send a kernel RPC message (%d)\n", handle); + return -EPERM; + } + ctx = fastrpc_context_alloc(fl, kernel, sc, args); if (IS_ERR(ctx)) return PTR_ERR(ctx);