From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Miklos Szeredi <mszeredi@redhat.com>,
lijiazi <lijiazi@xiaomi.com>, Sasha Levin <sashal@kernel.org>,
linux-fsdevel@vger.kernel.org
Subject: [PATCH AUTOSEL 5.4 04/14] fuse: fix use after free in fuse_read_interrupt()
Date: Sat, 11 Sep 2021 09:13:35 -0400 [thread overview]
Message-ID: <20210911131345.285564-4-sashal@kernel.org> (raw)
In-Reply-To: <20210911131345.285564-1-sashal@kernel.org>
From: Miklos Szeredi <mszeredi@redhat.com>
[ Upstream commit e1e71c168813564be0f6ea3d6740a059ca42d177 ]
There is a potential race between fuse_read_interrupt() and
fuse_request_end().
TASK1
in fuse_read_interrupt(): delete req->intr_entry (while holding
fiq->lock)
TASK2
in fuse_request_end(): req->intr_entry is empty -> skip fiq->lock
wake up TASK3
TASK3
request is freed
TASK1
in fuse_read_interrupt(): dereference req->in.h.unique ***BAM***
Fix by always grabbing fiq->lock if the request was ever interrupted
(FR_INTERRUPTED set) thereby serializing with concurrent
fuse_read_interrupt() calls.
FR_INTERRUPTED is set before the request is queued on fiq->interrupts.
Dequeing the request is done with list_del_init() but FR_INTERRUPTED is not
cleared in this case.
Reported-by: lijiazi <lijiazi@xiaomi.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/fuse/dev.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 16aa55b73ccf..7205a89fbb5f 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -282,10 +282,10 @@ void fuse_request_end(struct fuse_conn *fc, struct fuse_req *req)
/*
* test_and_set_bit() implies smp_mb() between bit
- * changing and below intr_entry check. Pairs with
+ * changing and below FR_INTERRUPTED check. Pairs with
* smp_mb() from queue_interrupt().
*/
- if (!list_empty(&req->intr_entry)) {
+ if (test_bit(FR_INTERRUPTED, &req->flags)) {
spin_lock(&fiq->lock);
list_del_init(&req->intr_entry);
spin_unlock(&fiq->lock);
--
2.30.2
next prev parent reply other threads:[~2021-09-11 13:22 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-11 13:13 [PATCH AUTOSEL 5.4 01/14] dt-bindings: mtd: gpmc: Fix the ECC bytes vs. OOB bytes equation Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.4 02/14] mfd: db8500-prcmu: Adjust map to reality Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.4 03/14] PCI: Add ACS quirks for NXP LX2xx0 and LX2xx2 platforms Sasha Levin
2021-09-11 13:13 ` Sasha Levin [this message]
2021-09-11 13:13 ` [PATCH AUTOSEL 5.4 05/14] mfd: Don't use irq_create_mapping() to resolve a mapping Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.4 06/14] tracing/probes: Reject events which have the same name of existing one Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.4 07/14] PCI: Add ACS quirks for Cavium multi-function devices Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.4 08/14] Set fc_nlinfo in nh_create_ipv4, nh_create_ipv6 Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.4 09/14] net: usb: cdc_mbim: avoid altsetting toggling for Telit LN920 Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.4 10/14] block, bfq: honor already-setup queue merges Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.4 11/14] PCI: ibmphp: Fix double unmap of io_mem Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.4 12/14] ethtool: Fix an error code in cxgb2.c Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.4 13/14] NTB: Fix an error code in ntb_msit_probe() Sasha Levin
2021-09-11 13:13 ` [PATCH AUTOSEL 5.4 14/14] NTB: perf: Fix an error code in perf_setup_inbuf() Sasha Levin
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