From 0a9007271e3fe87f0fe1dd1b137c534d69908809 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Wed, 29 May 2024 18:47:16 +0200 Subject: [PATCH] ALSA: ump: Don't accept an invalid UMP protocol number commit ac0d71ee534e67c7e53439e8e9cb45ed40731660 upstream. When a UMP Stream Configuration message is received, the driver tries to switch the protocol, but there was no sanity check of the protocol, hence it can pass an invalid value. Add the check and bail out if a wrong value is passed. Fixes: a79807683781 ("ALSA: ump: Add helper to change MIDI protocol") Cc: Link: https://lore.kernel.org/r/20240529164723.18309-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/core/ump.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/sound/core/ump.c b/sound/core/ump.c index fe7911498cc4..3cd07c103d9e 100644 --- a/sound/core/ump.c +++ b/sound/core/ump.c @@ -685,10 +685,17 @@ static void seq_notify_protocol(struct snd_ump_endpoint *ump) */ int snd_ump_switch_protocol(struct snd_ump_endpoint *ump, unsigned int protocol) { + unsigned int type; + protocol &= ump->info.protocol_caps; if (protocol == ump->info.protocol) return 0; + type = protocol & SNDRV_UMP_EP_INFO_PROTO_MIDI_MASK; + if (type != SNDRV_UMP_EP_INFO_PROTO_MIDI1 && + type != SNDRV_UMP_EP_INFO_PROTO_MIDI2) + return 0; + ump->info.protocol = protocol; ump_dbg(ump, "New protocol = %x (caps = %x)\n", protocol, ump->info.protocol_caps);