Apr 02 2010

ALSA: echoaudio – Eliminate use after free 

Author: Julia Lawall <julia@diku.dk>

Use the call to snd_card_free in the error handling code at the end of the
function, as in the other error cases.

A simplified version of the semantic patch that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// 
@@
expression E,E2;
@@

snd_card_free(E)
...
(
  E = E2
|
* E
)
// 

Signed-off-by: Julia Lawall 
Signed-off-by: Takashi Iwai 

---
 sound/pci/echoaudio/echoaudio.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)
 
diff --git a/sound/pci/echoaudio/echoaudio.c b/sound/pci/echoaudio/echoaudio.c
index 8dab82d..668a5ec 100644
--- a/sound/pci/echoaudio/echoaudio.c
+++ b/sound/pci/echoaudio/echoaudio.c
@@ -2184,10 +2184,9 @@ static int __devinit snd_echo_probe(struct pci_dev *pci,
 			goto ctl_error;
 #endif
 
-	if ((err = snd_card_register(card)) < 0) {
-		snd_card_free(card);
+	err = snd_card_register(card);
+	if (err < 0)
 		goto ctl_error;
-	}
 	snd_printk(KERN_INFO "Card registered: %s\n", card->longname);
 
 	pci_set_drvdata(pci, chip);

qlambert