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Tsirkin" Subject: Re: [PATCH v2 5/6] virtio-snd: cap maximum buffer_bytes to half a GiB Message-ID: References: <20261110-virtio-snd-fixes-v2-0-d5b654217676@linaro.org> <20261110-virtio-snd-fixes-v2-5-d5b654217676@linaro.org> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261110-virtio-snd-fixes-v2-5-d5b654217676@linaro.org> Received-SPF: pass client-ip=2a00:1450:4864:20::432; envelope-from=jim.macarthur@linaro.org; helo=mail-wr1-x432.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org X-Spam-Status: No, score=-20.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Tue, Nov 10, 2026 at 02:39:34PM +0200, Manos Pitsidianakis wrote: > A faulty/malicious guest can try to exhaust host memory. Cap the buffer > size to 500 MiB. > > Resolves: https://gitlab.com/qemu-project/qemu/-/work_items/3587 > Signed-off-by: Manos Pitsidianakis > --- > hw/audio/virtio-snd.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/hw/audio/virtio-snd.c b/hw/audio/virtio-snd.c > index a7d749f24f..a6036d5b75 100644 > --- a/hw/audio/virtio-snd.c > +++ b/hw/audio/virtio-snd.c > @@ -17,6 +17,7 @@ > > #include "qemu/osdep.h" > #include "qemu/iov.h" > +#include "qemu/units.h" > #include "qemu/log.h" > #include "qemu/error-report.h" > #include "system/runstate.h" > @@ -24,6 +25,8 @@ > #include "qapi/error.h" > #include "hw/audio/virtio-snd.h" > > +#define MAX_BUFFER_MIB 500 > + > #define VIRTIO_SOUND_JACK_DEFAULT 0 > #define VIRTIO_SOUND_STREAM_DEFAULT 2 > #define VIRTIO_SOUND_CHMAP_DEFAULT 0 > @@ -368,6 +371,14 @@ uint32_t virtio_snd_set_pcm_params(VirtIOSound *s, > & ~(stream->info.features)); > return cpu_to_le32(VIRTIO_SND_S_BAD_MSG); > } > + if (le32_to_cpu(params->buffer_bytes) > MAX_BUFFER_MIB * MiB) { > + error_report("%s: given buffer_bytes value %"PRIu32" " > + "is too big: over %d MiB", > + VIRTIO_DEVICE(s)->name, > + le32_to_cpu(params->buffer_bytes), > + MAX_BUFFER_MIB); > + return cpu_to_le32(VIRTIO_SND_S_BAD_MSG); > + } > > st_params = virtio_snd_pcm_get_params(s, stream_id); > > @@ -1037,6 +1048,8 @@ static void virtio_snd_handle_tx_xfer(VirtIODevice *vdev, VirtQueue *vq) > } > > stream = &vsnd->streams[stream_id]; > + size = MIN(stream->params.buffer_bytes, size); > + > if (stream->info.direction != VIRTIO_SND_D_OUTPUT) { > goto tx_err; > } > > -- > 2.56.0 > > Reviewed-by: Jim MacArthur