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ALSA: info - Check file position validity in common layer

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Check the validity of the file position in the common info layer before
calling read or write callbacks in assumption that entry->size is set up
properly to indicate the max file size.

Removed the redundant checks from the callbacks as well.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai
2010-04-13 11:33:54 +02:00
parent 24e4a1211f
commit d97e1b7823
7 changed files with 60 additions and 105 deletions
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14
sound/core/info.c
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@@ -232,10 +232,15 @@ static ssize_t snd_info_entry_read(struct file *file, char __user *buffer,
return -EFAULT;
break;
case SNDRV_INFO_CONTENT_DATA:
if (entry->c.ops->read)
if (pos >= entry->size)
return 0;
if (entry->c.ops->read) {
size = entry->size - pos;
size = min(count, size);
size = entry->c.ops->read(entry,
data->file_private_data,
file, buffer, count, pos);
file, buffer, size, pos);
}
break;
}
if ((ssize_t) size > 0)
@@ -282,10 +287,13 @@ static ssize_t snd_info_entry_write(struct file *file, const char __user *buffer
size = count;
break;
case SNDRV_INFO_CONTENT_DATA:
if (entry->c.ops->write)
if (entry->c.ops->write && count > 0) {
size_t maxsize = entry->size - pos;
count = min(count, maxsize);
size = entry->c.ops->write(entry,
data->file_private_data,
file, buffer, count, pos);
}
break;
}
if ((ssize_t) size > 0)