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| author | Nicolas Boichat <drinkcat@chromium.org> | 2016-01-18 21:35:00 +0800 |
|---|---|---|
| committer | Willy Tarreau <w@1wt.eu> | 2016-03-12 14:25:44 +0100 |
| commit | 8c1f2d6307bca9f9e43583497d691ce72cfb7c6c (patch) | |
| tree | c0b83cf76762b7c143917105b18929949dfd7ccb /sound | |
| parent | 206f71299754e0e8de4cef2936cbfd3bd4e6f002 (diff) | |
| download | lwn-8c1f2d6307bca9f9e43583497d691ce72cfb7c6c.tar.gz lwn-8c1f2d6307bca9f9e43583497d691ce72cfb7c6c.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: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Diffstat (limited to 'sound')
| -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 038232d220cf..0423434c41c8 100644 --- a/sound/core/pcm_compat.c +++ b/sound/core/pcm_compat.c @@ -232,10 +232,15 @@ 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); |