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authorTakashi Iwai <tiwai@suse.de>2023-09-05 10:12:10 +0200
committerTakashi Iwai <tiwai@suse.de>2023-09-05 10:13:46 +0200
commit86496fd4a2fabb7c978fdaca2d4b718207a96d36 (patch)
treee460ea9fbcdcdbc864fdce8a84cada363352191d /sound/core/seq
parentb1757fa30ef14f254f4719bf6f7d54a4c8207216 (diff)
ALSA: seq: Fix snd_seq_expand_var_event() call to user-space
The recent fix to clear the padding bytes at snd_seq_expand_var_event() broke the read to user-space with in_kernel=0 parameter. For user-space address, it has to use clear_user() instead of memset(). Fixes: f80e6d60d677 ("ALSA: seq: Clear padded bytes at expanding events") Reported-and-tested-by: Ash Holland <ash@sorrel.sh> Closes: https://lore.kernel.org/r/8a555319-9f31-4ea2-878f-adc338bc40d4@sorrel.sh Link: https://lore.kernel.org/r/20230905052631.18240-1-tiwai@suse.de Link: https://lore.kernel.org/r/20230905081210.6731-1-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/core/seq')
-rw-r--r--sound/core/seq/seq_memory.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/sound/core/seq/seq_memory.c b/sound/core/seq/seq_memory.c
index 174585bf59d2..b603bb93f896 100644
--- a/sound/core/seq/seq_memory.c
+++ b/sound/core/seq/seq_memory.c
@@ -187,8 +187,13 @@ int snd_seq_expand_var_event(const struct snd_seq_event *event, int count, char
err = expand_var_event(event, 0, len, buf, in_kernel);
if (err < 0)
return err;
- if (len != newlen)
- memset(buf + len, 0, newlen - len);
+ if (len != newlen) {
+ if (in_kernel)
+ memset(buf + len, 0, newlen - len);
+ else if (clear_user((__force void __user *)buf + len,
+ newlen - len))
+ return -EFAULT;
+ }
return newlen;
}
EXPORT_SYMBOL(snd_seq_expand_var_event);