[3.11.y.z extended stable] Patch "ALSA: bits vs bytes bug in snd_card_create()" has been added to staging queue

Luis Henriques luis.henriques at canonical.com
Wed Feb 5 13:15:08 UTC 2014


This is a note to let you know that I have just added a patch titled

    ALSA: bits vs bytes bug in snd_card_create()

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 5d90cbd92e91240f4eb06113cb4b9fcf52f865f5 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter at oracle.com>
Date: Thu, 23 Jan 2014 11:21:28 +0300
Subject: ALSA: bits vs bytes bug in snd_card_create()

commit 4c3773eda49c872a3034382f8ec3080002e715bf upstream.

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.

[fix another chunk similarly by tiwai]

Fixes: 7bb2491b35a2 ('ALSA: Add kconfig to specify the max card numbers')
Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com>
Signed-off-by: Takashi Iwai <tiwai at suse.de>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 sound/core/init.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/core/init.c b/sound/core/init.c
index 6b90871..d047851 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -170,7 +170,7 @@ 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 (module_slot_match(module, idx2)) {
@@ -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]) {
--
1.8.3.2





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