Messages in this thread Patch in this message | | | From | Hui Peng <> | Subject | [PATCH] Fix an OOB bug in uac_mixer_unit_bmControls | Date | Sat, 17 Aug 2019 00:32:07 -0400 |
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`uac_mixer_unit_get_channels` calls `uac_mixer_unit_bmControls` to get pointer to bmControls field. The current implementation of `uac_mixer_unit_get_channels` does properly check the size of uac_mixer_unit_descriptor descriptor and may allow OOB access in `uac_mixer_unit_bmControls`.
Reported-by: Hui Peng <benquike@gmail.com> Reported-by: Mathias Payer <mathias.payer@nebelwelt.net> Signed-off-by: Hui Peng <benquike@gmail.com> --- sound/usb/mixer.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-)
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c index b5927c3d5bc0..00e6274a63c3 100644 --- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -738,28 +738,39 @@ static int get_cluster_channels_v3(struct mixer_build *state, unsigned int clust static int uac_mixer_unit_get_channels(struct mixer_build *state, struct uac_mixer_unit_descriptor *desc) { - int mu_channels; + int mu_channels = 0; void *c; - if (desc->bLength < sizeof(*desc)) - return -EINVAL; if (!desc->bNrInPins) return -EINVAL; - if (desc->bLength < sizeof(*desc) + desc->bNrInPins) - return -EINVAL; switch (state->mixer->protocol) { case UAC_VERSION_1: + // limit derived from uac_mixer_unit_bmControls + if (desc->bLength < sizeof(*desc) + desc->bNrInPins + 4) + return 0; + + mu_channels = uac_mixer_unit_bNrChannels(desc); + break; + case UAC_VERSION_2: - default: - if (desc->bLength < sizeof(*desc) + desc->bNrInPins + 1) + // limit derived from uac_mixer_unit_bmControls + if (desc->bLength < sizeof(*desc) + desc->bNrInPins + 6) return 0; /* no bmControls -> skip */ + mu_channels = uac_mixer_unit_bNrChannels(desc); break; case UAC_VERSION_3: + // limit derived from uac_mixer_unit_bmControls + if (desc->bLength < sizeof(*desc) + desc->bNrInPins + 2) + return 0; /* no bmControls -> skip */ + mu_channels = get_cluster_channels_v3(state, uac3_mixer_unit_wClusterDescrID(desc)); break; + + default: + break; } if (!mu_channels) -- 2.22.1
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