ALSA: hwdep: fix a left shifting 1 by 31 UB bug

[ 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>

diff --git a/sound/core/hwdep.c b/sound/core/hwdep.c
index 36d2416f90d994d9408ef75f3e332567a46ea470..96b737adf4d210c88207b07c335060091a672e5e 100644 (file)
--- a/sound/core/hwdep.c
+++ b/sound/core/hwdep.c
@@ -228,14 +228,14 @@ static int snd_hwdep_dsp_load(struct snd_hwdep *hw,
        if (copy_from_user(&info, _info, sizeof(info)))
                return -EFAULT;
        /* check whether the dsp was already loaded */
-       if (hw->dsp_loaded & (1 << info.index))
+       if (hw->dsp_loaded & (1u << info.index))
                return -EBUSY;
        if (!access_ok(VERIFY_READ, info.image, info.length))
                return -EFAULT;
        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;
 }