This is a note to let you know that I've just added the patch titled ALSA: hda: prevent undefined shift in snd_hdac_ext_bus_get_link() to the 5.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: alsa-hda-prevent-undefined-shift-in-snd_hdac_ext_bus.patch and it can be found in the queue-5.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 0149302a30bc1010922510e171470f9e07683d36 Author: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Date: Tue Nov 3 13:18:07 2020 +0300 ALSA: hda: prevent undefined shift in snd_hdac_ext_bus_get_link() [ Upstream commit 158e1886b6262c1d1c96a18c85fac5219b8bf804 ] This is harmless, but the "addr" comes from the user and it could lead to a negative shift or to shift wrapping if it's too high. Fixes: 0b00a5615dc4 ("ALSA: hdac_ext: add hdac extended controller") Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Link: https://lore.kernel.org/r/20201103101807.GC1127762@mwanda Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/sound/hda/ext/hdac_ext_controller.c b/sound/hda/ext/hdac_ext_controller.c index 4d060d5b1db6d..b0c0ef824d7d9 100644 --- a/sound/hda/ext/hdac_ext_controller.c +++ b/sound/hda/ext/hdac_ext_controller.c @@ -148,6 +148,8 @@ struct hdac_ext_link *snd_hdac_ext_bus_get_link(struct hdac_bus *bus, return NULL; if (bus->idx != bus_idx) return NULL; + if (addr < 0 || addr > 31) + return NULL; list_for_each_entry(hlink, &bus->hlink_list, list) { for (i = 0; i < HDA_MAX_CODECS; i++) {