This is a note to let you know that I've just added the patch titled
usb: chipidea: core: fix possible constant 0 if use
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
From f96c0384047257365371a8ac217107c0371586f1 Mon Sep 17 00:00:00 2001
From: Xu Yang <xu.yang_2(a)nxp.com>
Date: Thu, 15 Dec 2022 13:54:09 +0800
Subject: usb: chipidea: core: fix possible constant 0 if use
IS_ERR(ci->role_switch)
After successfully probed, ci->role_switch would only be NULL or a valid
pointer. IS_ERR(ci->role_switch) will always return 0. So no need to wrap
it with IS_ERR, otherwise the logic is wrong.
Fixes: e1b5d2bed67c ("usb: chipidea: core: handle usb role switch in a common way")
cc: <stable(a)vger.kernel.org>
Signed-off-by: Xu Yang <xu.yang_2(a)nxp.com>
Link: https://lore.kernel.org/r/20221215055409.3760523-1-xu.yang_2@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
drivers/usb/chipidea/core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
index 484b1cd23431..27c601296130 100644
--- a/drivers/usb/chipidea/core.c
+++ b/drivers/usb/chipidea/core.c
@@ -1294,12 +1294,12 @@ static void ci_extcon_wakeup_int(struct ci_hdrc *ci)
cable_id = &ci->platdata->id_extcon;
cable_vbus = &ci->platdata->vbus_extcon;
- if ((!IS_ERR(cable_id->edev) || !IS_ERR(ci->role_switch))
+ if ((!IS_ERR(cable_id->edev) || ci->role_switch)
&& ci->is_otg &&
(otgsc & OTGSC_IDIE) && (otgsc & OTGSC_IDIS))
ci_irq(ci);
- if ((!IS_ERR(cable_vbus->edev) || !IS_ERR(ci->role_switch))
+ if ((!IS_ERR(cable_vbus->edev) || ci->role_switch)
&& ci->is_otg &&
(otgsc & OTGSC_BSVIE) && (otgsc & OTGSC_BSVIS))
ci_irq(ci);
--
2.39.0
This is a note to let you know that I've just added the patch titled
USB: gadgetfs: Fix race between mounting and unmounting
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
From d18dcfe9860e842f394e37ba01ca9440ab2178f4 Mon Sep 17 00:00:00 2001
From: Alan Stern <stern(a)rowland.harvard.edu>
Date: Fri, 23 Dec 2022 09:59:09 -0500
Subject: USB: gadgetfs: Fix race between mounting and unmounting
The syzbot fuzzer and Gerald Lee have identified a use-after-free bug
in the gadgetfs driver, involving processes concurrently mounting and
unmounting the gadgetfs filesystem. In particular, gadgetfs_fill_super()
can race with gadgetfs_kill_sb(), causing the latter to deallocate
the_device while the former is using it. The output from KASAN says,
in part:
BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:102 [inline]
BUG: KASAN: use-after-free in atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:176 [inline]
BUG: KASAN: use-after-free in __refcount_sub_and_test include/linux/refcount.h:272 [inline]
BUG: KASAN: use-after-free in __refcount_dec_and_test include/linux/refcount.h:315 [inline]
BUG: KASAN: use-after-free in refcount_dec_and_test include/linux/refcount.h:333 [inline]
BUG: KASAN: use-after-free in put_dev drivers/usb/gadget/legacy/inode.c:159 [inline]
BUG: KASAN: use-after-free in gadgetfs_kill_sb+0x33/0x100 drivers/usb/gadget/legacy/inode.c:2086
Write of size 4 at addr ffff8880276d7840 by task syz-executor126/18689
CPU: 0 PID: 18689 Comm: syz-executor126 Not tainted 6.1.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
<TASK>
...
atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:176 [inline]
__refcount_sub_and_test include/linux/refcount.h:272 [inline]
__refcount_dec_and_test include/linux/refcount.h:315 [inline]
refcount_dec_and_test include/linux/refcount.h:333 [inline]
put_dev drivers/usb/gadget/legacy/inode.c:159 [inline]
gadgetfs_kill_sb+0x33/0x100 drivers/usb/gadget/legacy/inode.c:2086
deactivate_locked_super+0xa7/0xf0 fs/super.c:332
vfs_get_super fs/super.c:1190 [inline]
get_tree_single+0xd0/0x160 fs/super.c:1207
vfs_get_tree+0x88/0x270 fs/super.c:1531
vfs_fsconfig_locked fs/fsopen.c:232 [inline]
The simplest solution is to ensure that gadgetfs_fill_super() and
gadgetfs_kill_sb() are serialized by making them both acquire a new
mutex.
Signed-off-by: Alan Stern <stern(a)rowland.harvard.edu>
Reported-and-tested-by: syzbot+33d7ad66d65044b93f16(a)syzkaller.appspotmail.com
Reported-and-tested-by: Gerald Lee <sundaywind2004(a)gmail.com>
Link: https://lore.kernel.org/linux-usb/CAO3qeMVzXDP-JU6v1u5Ags6Q-bb35kg3=C6d04Dj…
Fixes: e5d82a7360d1 ("vfs: Convert gadgetfs to use the new mount API")
CC: <stable(a)vger.kernel.org>
Link: https://lore.kernel.org/r/Y6XCPXBpn3tmjdCC@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
drivers/usb/gadget/legacy/inode.c | 28 +++++++++++++++++++++-------
1 file changed, 21 insertions(+), 7 deletions(-)
diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c
index 01c3ead7d1b4..d605bc2e7e8f 100644
--- a/drivers/usb/gadget/legacy/inode.c
+++ b/drivers/usb/gadget/legacy/inode.c
@@ -229,6 +229,7 @@ static void put_ep (struct ep_data *data)
*/
static const char *CHIP;
+static DEFINE_MUTEX(sb_mutex); /* Serialize superblock operations */
/*----------------------------------------------------------------------*/
@@ -2010,13 +2011,20 @@ gadgetfs_fill_super (struct super_block *sb, struct fs_context *fc)
{
struct inode *inode;
struct dev_data *dev;
+ int rc;
- if (the_device)
- return -ESRCH;
+ mutex_lock(&sb_mutex);
+
+ if (the_device) {
+ rc = -ESRCH;
+ goto Done;
+ }
CHIP = usb_get_gadget_udc_name();
- if (!CHIP)
- return -ENODEV;
+ if (!CHIP) {
+ rc = -ENODEV;
+ goto Done;
+ }
/* superblock */
sb->s_blocksize = PAGE_SIZE;
@@ -2053,13 +2061,17 @@ gadgetfs_fill_super (struct super_block *sb, struct fs_context *fc)
* from binding to a controller.
*/
the_device = dev;
- return 0;
+ rc = 0;
+ goto Done;
-Enomem:
+ Enomem:
kfree(CHIP);
CHIP = NULL;
+ rc = -ENOMEM;
- return -ENOMEM;
+ Done:
+ mutex_unlock(&sb_mutex);
+ return rc;
}
/* "mount -t gadgetfs path /dev/gadget" ends up here */
@@ -2081,6 +2093,7 @@ static int gadgetfs_init_fs_context(struct fs_context *fc)
static void
gadgetfs_kill_sb (struct super_block *sb)
{
+ mutex_lock(&sb_mutex);
kill_litter_super (sb);
if (the_device) {
put_dev (the_device);
@@ -2088,6 +2101,7 @@ gadgetfs_kill_sb (struct super_block *sb)
}
kfree(CHIP);
CHIP = NULL;
+ mutex_unlock(&sb_mutex);
}
/*----------------------------------------------------------------------*/
--
2.39.0