ALSA: info - Check file position validity in common layer

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>

1 files changed, 20 insertions, 23 deletions

diff --git a/sound/pci/emu10k1/emuproc.c b/sound/pci/emu10k1/emuproc.c
index 347b241..bc38dd4 100644
--- a/sound/pci/emu10k1/emuproc.c
+++ b/sound/pci/emu10k1/emuproc.c
@@ -346,10 +346,12 @@ static ssize_t snd_emu10k1_fx8010_read(struct snd_info_entry *entry,
 				       struct file *file, char __user *buf,
 				       size_t count, loff_t pos)
 {
-	long size;
 	struct snd_emu10k1 *emu = entry->private_data;
 	unsigned int offset;
 	int tram_addr = 0;
+	unsigned int *tmp;
+	long res;
+	unsigned int idx;
 	
 	if (!strcmp(entry->name, "fx8010_tram_addr")) {
 		offset = TANKMEMADDRREGBASE;
@@ -361,30 +363,25 @@ static ssize_t snd_emu10k1_fx8010_read(struct snd_info_entry *entry,
 	} else {
 		offset = emu->audigy ? A_FXGPREGBASE : FXGPREGBASE;
 	}
-	size = count;
-	if (pos + size > entry->size)
-		size = (long)entry->size - pos;
-	if (size > 0) {
-		unsigned int *tmp;
-		long res;
-		unsigned int idx;
-		if ((tmp = kmalloc(size + 8, GFP_KERNEL)) == NULL)
-			return -ENOMEM;
-		for (idx = 0; idx < ((pos & 3) + size + 3) >> 2; idx++)
-			if (tram_addr && emu->audigy) {
-				tmp[idx] = snd_emu10k1_ptr_read(emu, offset + idx + (pos >> 2), 0) >> 11;
-				tmp[idx] |= snd_emu10k1_ptr_read(emu, 0x100 + idx + (pos >> 2), 0) << 20;
-			} else 
-				tmp[idx] = snd_emu10k1_ptr_read(emu, offset + idx + (pos >> 2), 0);
-		if (copy_to_user(buf, ((char *)tmp) + (pos & 3), size))
-			res = -EFAULT;
-		else {
-			res = size;
+
+	tmp = kmalloc(count + 8, GFP_KERNEL);
+	if (!tmp)
+		return -ENOMEM;
+	for (idx = 0; idx < ((pos & 3) + count + 3) >> 2; idx++) {
+		unsigned int val;
+		val = snd_emu10k1_ptr_read(emu, offset + idx + (pos >> 2), 0);
+		if (tram_addr && emu->audigy) {
+			val >>= 11;
+			val |= snd_emu10k1_ptr_read(emu, 0x100 + idx + (pos >> 2), 0) << 20;
 		}
-		kfree(tmp);
-		return res;
+		tmp[idx] = val;
 	}
-	return 0;
+	if (copy_to_user(buf, ((char *)tmp) + (pos & 3), count))
+		res = -EFAULT;
+	else
+		res = count;
+	kfree(tmp);
+	return res;
 }
 
 static void snd_emu10k1_proc_voices_read(struct snd_info_entry *entry,