| From | gregkh@linuxfou ... | Subject | [PATCH 5.11 220/306] misc: fastrpc: restrict user apps from sending kernel RPC messages | Date | Mon, 15 Mar 2021 14:54:43 +0100 |
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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.org 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 @@ -950,6 +950,11 @@ 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);
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