From: Manos Pitsidianakis Date: Fri, 20 Feb 2026 09:40:14 +0000 (+0200) Subject: virtio-snd: handle 5.14.6.2 for PCM_INFO properly X-Git-Tag: v11.0.0-rc0~58^2~3 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=61679d7dcfa2dffc8fb115aa19b09e0e7cf5ea5c;p=thirdparty%2Fqemu.git virtio-snd: handle 5.14.6.2 for PCM_INFO properly The section 5.14.6.2 of the VIRTIO spec says: 5.14.6.2 Driver Requirements: Item Information Request - The driver MUST NOT set start_id and count such that start_id + count is greater than the total number of particular items that is indicated in the device configuration space. - The driver MUST provide a buffer of sizeof(struct virtio_snd_hdr) + count * size bytes for the response. While we performed some check for the second requirement, it failed to check for integer overflow. Add also a check for the first requirement, which should limit exposure to any overflow, since realistically the number of streams will be low enough in value such that overflow is improbable. Cc: qemu-stable@nongnu.org Reported-by: 罗铭源 Signed-off-by: Manos Pitsidianakis Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Message-Id: <20260220-virtio-snd-series-v1-3-207c4f7200a2@linaro.org> --- diff --git a/hw/audio/virtio-snd.c b/hw/audio/virtio-snd.c index 232179a04ad..ae8bfbca431 100644 --- a/hw/audio/virtio-snd.c +++ b/hw/audio/virtio-snd.c @@ -156,7 +156,7 @@ static virtio_snd_pcm_set_params *virtio_snd_pcm_get_params(VirtIOSound *s, static void virtio_snd_handle_pcm_info(VirtIOSound *s, virtio_snd_ctrl_command *cmd) { - uint32_t stream_id, start_id, count, size; + uint32_t stream_id, start_id, count, size, tmp; virtio_snd_pcm_info val; virtio_snd_query_info req; VirtIOSoundPCMStream *stream = NULL; @@ -179,11 +179,34 @@ static void virtio_snd_handle_pcm_info(VirtIOSound *s, count = le32_to_cpu(req.count); size = le32_to_cpu(req.size); - if (iov_size(cmd->elem->in_sg, cmd->elem->in_num) < - sizeof(virtio_snd_hdr) + size * count) { + /* + * 5.14.6.2 Driver Requirements: Item Information Request + * "The driver MUST NOT set start_id and count such that start_id + count + * is greater than the total number of particular items that is indicated + * in the device configuration space." + */ + if (start_id > s->snd_conf.streams + || !g_uint_checked_add(&tmp, start_id, count) + || start_id + count > s->snd_conf.streams) { + error_report("pcm info: start_id + count is greater than the total " + "number of streams, got: start_id = %u, count = %u", + start_id, count); + cmd->resp.code = cpu_to_le32(VIRTIO_SND_S_BAD_MSG); + return; + } + + /* + * 5.14.6.2 Driver Requirements: Item Information Request + * "The driver MUST provide a buffer of sizeof(struct virtio_snd_hdr) + + * count * size bytes for the response." + */ + if (!g_uint_checked_mul(&tmp, size, count) + || !g_uint_checked_add(&tmp, tmp, sizeof(virtio_snd_hdr)) + || iov_size(cmd->elem->in_sg, cmd->elem->in_num) < + sizeof(virtio_snd_hdr) + size * count) { error_report("pcm info: buffer too small, got: %zu, needed: %zu", iov_size(cmd->elem->in_sg, cmd->elem->in_num), - sizeof(virtio_snd_pcm_info)); + sizeof(virtio_snd_pcm_info) * count); cmd->resp.code = cpu_to_le32(VIRTIO_SND_S_BAD_MSG); return; }