From: Sasha Levin <sashal@kernel.org>
To: stable@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Pan Bian <bianpan2016@163.com>, Al Viro <viro@zeniv.linux.org.uk>,
Sasha Levin <sashal@kernel.org>
Subject: [PATCH AUTOSEL 4.4 12/33] exportfs: do not read dentry after free
Date: Wed, 5 Dec 2018 04:51:10 -0500 [thread overview]
Message-ID: <20181205095131.7685-12-sashal@kernel.org> (raw)
In-Reply-To: <20181205095131.7685-1-sashal@kernel.org>
From: Pan Bian <bianpan2016@163.com>
[ Upstream commit 2084ac6c505a58f7efdec13eba633c6aaa085ca5 ]
The function dentry_connected calls dput(dentry) to drop the previously
acquired reference to dentry. In this case, dentry can be released.
After that, IS_ROOT(dentry) checks the condition
(dentry == dentry->d_parent), which may result in a use-after-free bug.
This patch directly compares dentry with its parent obtained before
dropping the reference.
Fixes: a056cc8934c("exportfs: stop retrying once we race with
rename/remove")
Signed-off-by: Pan Bian <bianpan2016@163.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/exportfs/expfs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index 714cd37a6ba3..6599c6124552 100644
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -76,7 +76,7 @@ static bool dentry_connected(struct dentry *dentry)
struct dentry *parent = dget_parent(dentry);
dput(dentry);
- if (IS_ROOT(dentry)) {
+ if (dentry == parent) {
dput(parent);
return false;
}
--
2.17.1
next prev parent reply other threads:[~2018-12-05 9:51 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-05 9:50 [PATCH AUTOSEL 4.4 01/33] ARM: OMAP2+: prm44xx: Fix section annotation on omap44xx_prm_enable_io_wakeup Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 02/33] ARM: OMAP1: ams-delta: Fix possible use of uninitialized field Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 03/33] sysv: return 'err' instead of 0 in __sysv_write_inode Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 04/33] s390/cpum_cf: Reject request for sampling in event initialization Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 05/33] hwmon: (ina2xx) Fix current value calculation Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 06/33] ASoC: dapm: Recalculate audio map forcely when card instantiated Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 07/33] hwmon: (w83795) temp4_type has writable permission Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 08/33] Btrfs: send, fix infinite loop due to directory rename dependencies Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 09/33] uprobes: Fix handle_swbp() vs. unregister() + register() race once more Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 10/33] ASoC: omap-mcpdm: Add pm_qos handling to avoid under/overruns with CPU_IDLE Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 11/33] ASoC: omap-dmic: Add pm_qos handling to avoid overruns " Sasha Levin
2018-12-05 9:51 ` Sasha Levin [this message]
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 13/33] bpf: fix check of allowed specifiers in bpf_trace_printk Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 14/33] USB: omap_udc: use devm_request_irq() Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 15/33] USB: omap_udc: fix crashes on probe error and module removal Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 16/33] USB: omap_udc: fix omap_udc_start() on 15xx machines Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 17/33] USB: omap_udc: fix USB gadget functionality on Palm Tungsten E Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 18/33] KVM: x86: fix empty-body warnings Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 19/33] net: thunderx: fix NULL pointer dereference in nic_remove Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 20/33] ixgbe: recognize 1000BaseLX SFP modules as 1Gbps Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 21/33] rapidio/rionet: do not free skb before reading its length Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 22/33] net: hisilicon: remove unexpected free_netdev Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 23/33] s390/qeth: fix length check in SNMP processing Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 24/33] drm/ast: fixed reading monitor EDID not stable issue Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 25/33] xen: xlate_mmu: add missing header to fix 'W=1' warning Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 26/33] fscache: fix race between enablement and dropping of object Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 27/33] fscache, cachefiles: remove redundant variable 'cache' Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 28/33] unifdef: use memcpy instead of strncpy Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 29/33] ocfs2: fix deadlock caused by ocfs2_defrag_extent() Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 30/33] hfs: do not free node before using Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 31/33] hfsplus: " Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 32/33] debugobjects: avoid recursive calls with kmemleak Sasha Levin
2018-12-05 9:51 ` [PATCH AUTOSEL 4.4 33/33] ocfs2: fix potential use after free Sasha Levin
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