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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.de>,
	Yacine Belkadi <yacine.belkadi.1@gmail.com>,
	alsa-devel@alsa-project.org, kernel-janitors@vger.kernel.org
Subject: [patch] ALSA: bits vs bytes bug in snd_card_create()
Date: Thu, 23 Jan 2014 11:21:28 +0300	[thread overview]
Message-ID: <20140123082128.GA28688@elgon.mountain> (raw)

The test here is intended intended to prevent shift wrapping bugs when
we do "1U << idx2".  We should consider the number of bits in a u32
instead of the number of bytes.

Fixes: 7bb2491b35a2 ('ALSA: Add kconfig to specify the max card numbers')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
WARNING:  Please check this one carefully because I might be wrong.

diff --git a/sound/core/init.c b/sound/core/init.c
index 1351f22f651c..e9e3db321e64 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -183,7 +183,7 @@ int snd_card_create(int idx, const char *xid,
 	if (idx < 0) {
 		for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++) {
 			/* idx == -1 == 0xffff means: take any free slot */
-			if (idx2 < sizeof(int) && !(idx & (1U << idx2)))
+			if (idx2 < 32 && !(idx & (1U << idx2)))
 				continue;
 			if (!test_bit(idx2, snd_cards_lock)) {
 				if (!slots[idx2] || !*slots[idx2]) {

             reply	other threads:[~2014-01-23  8:21 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-23  8:21 Dan Carpenter [this message]
2014-01-23  8:36 ` [patch] ALSA: bits vs bytes bug in snd_card_create() Takashi Iwai
2014-01-23 10:48   ` Takashi Iwai
2014-01-23  8:55 ` walter harms
2014-01-23  9:02   ` Takashi Iwai
2014-01-23  9:27     ` walter harms

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