[PATCH] ALSA: hda - fix out of bounds read on spec->smux_paths
From: Colin King
Date: Tue Jan 14 2020 - 10:44:19 EST
From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
It is possible for the call to snd_hda_get_num_conns to fail and return
a negative error code that gets assigned to num_conns. In that specific
case, the check of very large values of val against num_conns will not
fail the -EINVAL check and later on an out of bounds array read on
spec->smux_paths will occur. Fix this by sanity checking for an error
return from the call to snd_hda_get_num_conns.
Addresses-Coverity: ("Out-of-bounds read")
Fixes: 272f3ea31776 ("ALSA: hda - Add SPDIF mux control to AD codec auto-parser")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
sound/pci/hda/patch_analog.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/sound/pci/hda/patch_analog.c b/sound/pci/hda/patch_analog.c
index 88c46b051d14..399561369495 100644
--- a/sound/pci/hda/patch_analog.c
+++ b/sound/pci/hda/patch_analog.c
@@ -756,9 +756,11 @@ static int ad1988_auto_smux_enum_put(struct snd_kcontrol *kcontrol,
struct ad198x_spec *spec = codec->spec;
unsigned int val = ucontrol->value.enumerated.item[0];
struct nid_path *path;
- int num_conns = snd_hda_get_num_conns(codec, 0x0b) + 1;
+ int num_conns = snd_hda_get_num_conns(codec, 0x0b);
- if (val >= num_conns)
+ if (num_conns < 0)
+ return num_conns;
+ if (val >= num_conns + 1)
return -EINVAL;
if (spec->cur_smux == val)
return 0;
--
2.24.0