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authorNicolas Boichat <drinkcat@chromium.org>2016-01-18 21:35:00 +0800
committerTakashi Iwai <tiwai@suse.de>2016-01-18 14:39:00 +0100
commit43c54b8c7cfe22f868a751ba8a59abf1724160b1 (patch)
tree717ac1144e8724117ea8d66896c0d36709584c46 /sound/core/pcm_compat.c
parent2ba1fe7a06d3624f9a7586d672b55f08f7c670f3 (diff)
downloadlinux-43c54b8c7cfe22f868a751ba8a59abf1724160b1.tar.bz2
ALSA: pcm: Fix snd_pcm_hw_params struct copy in compat mode
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> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/core/pcm_compat.c')
-rw-r--r--sound/core/pcm_compat.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/sound/core/pcm_compat.c b/sound/core/pcm_compat.c
index b48b434444ed..9630e9f72b7b 100644
--- a/sound/core/pcm_compat.c
+++ b/sound/core/pcm_compat.c
@@ -255,10 +255,15 @@ 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);