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authorDaniel THOMPSON <daniel.thompson@st.com>2008-08-15 10:53:38 +0100
committerJaroslav Kysela <perex@perex.cz>2008-08-15 12:38:14 +0200
commit54e8e21ed21ca8788aa75294067494abebf9d550 (patch)
tree354640ce67641af2632212edf6a29fb8e7a6fd9c
parent8daaaa97d6420c7e8b02c12ce591bb29fd959c62 (diff)
downloadop-kernel-dev-54e8e21ed21ca8788aa75294067494abebf9d550.zip
op-kernel-dev-54e8e21ed21ca8788aa75294067494abebf9d550.tar.gz
sound: Fix esoteric double free in the dummy sound driver.
The dummy driver uses runtime->private_free but still frees its pcm structures on error paths. This is esoteric because the error paths in question are unreachable. Thus the bug is only a problem when someone copies this code into other drivers. Signed-off-by: Daniel R Thompson <daniel.thompson@st.com> Signed-off-by: Jaroslav Kysela <perex@perex.cz>
-rw-r--r--sound/drivers/dummy.c10
1 files changed, 4 insertions, 6 deletions
diff --git a/sound/drivers/dummy.c b/sound/drivers/dummy.c
index c873243..4f900d8 100644
--- a/sound/drivers/dummy.c
+++ b/sound/drivers/dummy.c
@@ -354,6 +354,7 @@ static int snd_card_dummy_playback_open(struct snd_pcm_substream *substream)
if ((dpcm = new_pcm_stream(substream)) == NULL)
return -ENOMEM;
runtime->private_data = dpcm;
+ /* makes the infrastructure responsible for freeing dpcm */
runtime->private_free = snd_card_dummy_runtime_free;
runtime->hw = snd_card_dummy_playback;
if (substream->pcm->device & 1) {
@@ -362,10 +363,8 @@ static int snd_card_dummy_playback_open(struct snd_pcm_substream *substream)
}
if (substream->pcm->device & 2)
runtime->hw.info &= ~(SNDRV_PCM_INFO_MMAP|SNDRV_PCM_INFO_MMAP_VALID);
- if ((err = add_playback_constraints(runtime)) < 0) {
- kfree(dpcm);
+ if ((err = add_playback_constraints(runtime)) < 0)
return err;
- }
return 0;
}
@@ -379,6 +378,7 @@ static int snd_card_dummy_capture_open(struct snd_pcm_substream *substream)
if ((dpcm = new_pcm_stream(substream)) == NULL)
return -ENOMEM;
runtime->private_data = dpcm;
+ /* makes the infrastructure responsible for freeing dpcm */
runtime->private_free = snd_card_dummy_runtime_free;
runtime->hw = snd_card_dummy_capture;
if (substream->pcm->device == 1) {
@@ -387,10 +387,8 @@ static int snd_card_dummy_capture_open(struct snd_pcm_substream *substream)
}
if (substream->pcm->device & 2)
runtime->hw.info &= ~(SNDRV_PCM_INFO_MMAP|SNDRV_PCM_INFO_MMAP_VALID);
- if ((err = add_capture_constraints(runtime)) < 0) {
- kfree(dpcm);
+ if ((err = add_capture_constraints(runtime)) < 0)
return err;
- }
return 0;
}
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