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| author | Nicolas Boichat <drinkcat@chromium.org> | 2016-01-18 21:35:00 +0800 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2016-01-27 09:56:28 +0100 |
| commit | 73c6819503642b1318343be17bf37bf4682669fe (patch) | |
| tree | ffd32ece7bce4e4b27efd887dd87819ae5dcd6e8 /sound/core | |
| parent | c22f48895eca5b5fca1147f2605f81e8fd5f4538 (diff) | |
| download | lwn-73c6819503642b1318343be17bf37bf4682669fe.tar.gz lwn-73c6819503642b1318343be17bf37bf4682669fe.zip | |
ALSA: pcm: Fix snd_pcm_hw_params struct copy in compat mode
commit 43c54b8c7cfe22f868a751ba8a59abf1724160b1 upstream.
This reverts one hunk of
commit ef44a1ec6eee ("ALSA: sound/core: use memdup_user()"), which
replaced a number of kmalloc followed by memcpy with memdup calls.
In this case, we are copying from a struct snd_pcm_hw_params32 to
a struct snd_pcm_hw_params, but the latter is 4 bytes longer than
the 32-bit version, so we need to separate kmalloc and copy calls.
This actually leads to an out-of-bounds memory access later on
in sound/soc/soc-pcm.c:soc_pcm_hw_params() (detected using KASan).
Fixes: ef44a1ec6eee ('ALSA: sound/core: use memdup_user()')
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Diffstat (limited to 'sound/core')
| -rw-r--r-- | sound/core/pcm_compat.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/sound/core/pcm_compat.c b/sound/core/pcm_compat.c index c4ac3c1e19af..1bb1a43c7d03 100644 --- a/sound/core/pcm_compat.c +++ b/sound/core/pcm_compat.c @@ -236,10 +236,15 @@ static int snd_pcm_ioctl_hw_params_compat(struct snd_pcm_substream *substream, if (! (runtime = substream->runtime)) return -ENOTTY; - /* only fifo_size is different, so just copy all */ - data = memdup_user(data32, sizeof(*data32)); - if (IS_ERR(data)) - return PTR_ERR(data); + data = kmalloc(sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + /* only fifo_size (RO from userspace) is different, so just copy all */ + if (copy_from_user(data, data32, sizeof(*data32))) { + err = -EFAULT; + goto error; + } if (refine) err = snd_pcm_hw_refine(substream, data); |