From: Dmitry Baryshkov Date: Fri, 12 Feb 2021 19:26:58 +0000 (+0300) Subject: misc: fastrpc: restrict user apps from sending kernel RPC messages X-Git-Tag: accepted/tizen/unified/20230118.172025~7644^2~1 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=20c40794eb85ea29852d7bc37c55713802a543d6;p=platform%2Fkernel%2Flinux-rpi.git misc: fastrpc: restrict user apps from sending kernel RPC messages 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 Cc: Jonathan Marek Cc: stable@vger.kernel.org Signed-off-by: Dmitry Baryshkov Link: https://lore.kernel.org/r/20210212192658.3476137-1-dmitry.baryshkov@linaro.org Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c index f12e909..beda610 100644 --- a/drivers/misc/fastrpc.c +++ b/drivers/misc/fastrpc.c @@ -950,6 +950,11 @@ static int fastrpc_internal_invoke(struct fastrpc_user *fl, u32 kernel, 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);