6.12-stable review patch. If anyone has any objections, please let me know.
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From: Junrui Luo moonafterrain@outlook.com
[ Upstream commit 210d77cca3d0494ed30a5c628b20c1d95fa04fb1 ]
The DSP event handling code in hwdep_read() could write more bytes to the user buffer than requested, when a user provides a buffer smaller than the event header size (8 bytes).
Fix by using min_t() to clamp the copy size, This ensures we never copy more than the user requested.
Reported-by: Yuhao Jiang danisjiang@gmail.com Reported-by: Junrui Luo moonafterrain@outlook.com Fixes: 634ec0b2906e ("ALSA: firewire-motu: notify event for parameter change in register DSP model") Signed-off-by: Junrui Luo moonafterrain@outlook.com Link: https://patch.msgid.link/SYBPR01MB78810656377E79E58350D951AFD9A@SYBPR01MB788... Signed-off-by: Takashi Iwai tiwai@suse.de Signed-off-by: Sasha Levin sashal@kernel.org --- sound/firewire/motu/motu-hwdep.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/sound/firewire/motu/motu-hwdep.c b/sound/firewire/motu/motu-hwdep.c index a220ac0c8eb83..28885c8004aea 100644 --- a/sound/firewire/motu/motu-hwdep.c +++ b/sound/firewire/motu/motu-hwdep.c @@ -83,10 +83,11 @@ static long hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count, event.motu_register_dsp_change.type = SNDRV_FIREWIRE_EVENT_MOTU_REGISTER_DSP_CHANGE; event.motu_register_dsp_change.count = (consumed - sizeof(event.motu_register_dsp_change)) / 4; - if (copy_to_user(buf, &event, sizeof(event.motu_register_dsp_change))) + if (copy_to_user(buf, &event, + min_t(long, count, sizeof(event.motu_register_dsp_change)))) return -EFAULT;
- count = consumed; + count = min_t(long, count, consumed); } else { spin_unlock_irq(&motu->lock);