[PATCH AUTOSEL 5.6 318/606] ALSA: hwdep: fix a left shifting 1 by 31 UB bug

Sasha Levin
2020-06-08T23:23:48Z

From: Changming Liu <liu.changm@northeastern.edu>

[ Upstream commit fb8cd6481ffd126f35e9e146a0dcf0c4e8899f2e ]

The "info.index" variable can be 31 in "1 << info.index".
This might trigger an undefined behavior since 1 is signed.

Fix this by casting 1 to 1u just to be sure "1u << 31" is defined.

Signed-off-by: Changming Liu <liu.changm@northeastern.edu>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/BL0PR06MB4548170B842CB055C9AF695DE5B00@BL0PR06MB4548.namprd06.prod.outlook.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
sound/core/hwdep.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/core/hwdep.c b/sound/core/hwdep.c
index b412d3b3d5ff..21edb8ac95eb 100644
--- a/sound/core/hwdep.c
+++ b/sound/core/hwdep.c
@@ -216,12 +216,12 @@ static int snd_hwdep_dsp_load(struct snd_hwdep *hw,
if (info.index >= 32)
return -EINVAL;
/* check whether the dsp was already loaded */
- if (hw->dsp_loaded & (1 << info.index))
+ if (hw->dsp_loaded & (1u << info.index))
return -EBUSY;
err = hw->ops.dsp_load(hw, &info);
if (err < 0)
return err;
- hw->dsp_loaded |= (1 << info.index);
+ hw->dsp_loaded |= (1u << info.index);
return 0;
}

--
2.25.1