From ecfd41166b72b67d3bdeb88d224ff445f6163869 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Thu, 14 Aug 2025 10:12:43 +0200 Subject: [PATCH] ALSA: usb-audio: Validate UAC3 cluster segment descriptors UAC3 class segment descriptors need to be verified whether their sizes match with the declared lengths and whether they fit with the allocated buffer sizes, too. Otherwise malicious firmware may lead to the unexpected OOB accesses. Fixes: 11785ef53228 ("ALSA: usb-audio: Initial Power Domain support") Reported-and-tested-by: Youngjun Lee Cc: Link: https://patch.msgid.link/20250814081245.8902-2-tiwai@suse.de Signed-off-by: Takashi Iwai --- sound/usb/stream.c | 25 ++++++++++++++++++++++--- 1 file changed, 22 insertions(+), 3 deletions(-) diff --git a/sound/usb/stream.c b/sound/usb/stream.c index ad6ced780634..acf3dc2d79e0 100644 --- a/sound/usb/stream.c +++ b/sound/usb/stream.c @@ -341,20 +341,28 @@ snd_pcm_chmap_elem *convert_chmap_v3(struct uac3_cluster_header_descriptor len = le16_to_cpu(cluster->wLength); c = 0; - p += sizeof(struct uac3_cluster_header_descriptor); + p += sizeof(*cluster); + len -= sizeof(*cluster); - while (((p - (void *)cluster) < len) && (c < channels)) { + while (len > 0 && (c < channels)) { struct uac3_cluster_segment_descriptor *cs_desc = p; u16 cs_len; u8 cs_type; + if (len < sizeof(*p)) + break; cs_len = le16_to_cpu(cs_desc->wLength); + if (len < cs_len) + break; cs_type = cs_desc->bSegmentType; if (cs_type == UAC3_CHANNEL_INFORMATION) { struct uac3_cluster_information_segment_descriptor *is = p; unsigned char map; + if (cs_len < sizeof(*is)) + break; + /* * TODO: this conversion is not complete, update it * after adding UAC3 values to asound.h @@ -456,6 +464,7 @@ snd_pcm_chmap_elem *convert_chmap_v3(struct uac3_cluster_header_descriptor chmap->map[c++] = map; } p += cs_len; + len -= cs_len; } if (channels < c) @@ -881,7 +890,7 @@ snd_usb_get_audioformat_uac3(struct snd_usb_audio *chip, u64 badd_formats = 0; unsigned int num_channels; struct audioformat *fp; - u16 cluster_id, wLength; + u16 cluster_id, wLength, cluster_wLength; int clock = 0; int err; @@ -1011,6 +1020,16 @@ snd_usb_get_audioformat_uac3(struct snd_usb_audio *chip, return ERR_PTR(-EIO); } + cluster_wLength = le16_to_cpu(cluster->wLength); + if (cluster_wLength < sizeof(*cluster) || + cluster_wLength > wLength) { + dev_err(&dev->dev, + "%u:%d : invalid Cluster Descriptor size\n", + iface_no, altno); + kfree(cluster); + return ERR_PTR(-EIO); + } + num_channels = cluster->bNrChannels; chmap = convert_chmap_v3(cluster); kfree(cluster); -- 2.25.1