From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Sahitya Tummala <stummala@codeaurora.org>,
Christoph Hellwig <hch@lst.de>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 27/45] configfs: Fix use-after-free when accessing sd->s_dentry
Date: Thu, 20 Jun 2019 19:57:29 +0200 [thread overview]
Message-ID: <20190620174338.663341683@linuxfoundation.org> (raw)
In-Reply-To: <20190620174328.608036501@linuxfoundation.org>
[ Upstream commit f6122ed2a4f9c9c1c073ddf6308d1b2ac10e0781 ]
In the vfs_statx() context, during path lookup, the dentry gets
added to sd->s_dentry via configfs_attach_attr(). In the end,
vfs_statx() kills the dentry by calling path_put(), which invokes
configfs_d_iput(). Ideally, this dentry must be removed from
sd->s_dentry but it doesn't if the sd->s_count >= 3. As a result,
sd->s_dentry is holding reference to a stale dentry pointer whose
memory is already freed up. This results in use-after-free issue,
when this stale sd->s_dentry is accessed later in
configfs_readdir() path.
This issue can be easily reproduced, by running the LTP test case -
sh fs_racer_file_list.sh /config
(https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/fs/racer/fs_racer_file_list.sh)
Fixes: 76ae281f6307 ('configfs: fix race between dentry put and lookup')
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/configfs/dir.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index d7955dc56737..a1985a9ad2d6 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -58,15 +58,13 @@ static void configfs_d_iput(struct dentry * dentry,
if (sd) {
/* Coordinate with configfs_readdir */
spin_lock(&configfs_dirent_lock);
- /* Coordinate with configfs_attach_attr where will increase
- * sd->s_count and update sd->s_dentry to new allocated one.
- * Only set sd->dentry to null when this dentry is the only
- * sd owner.
- * If not do so, configfs_d_iput may run just after
- * configfs_attach_attr and set sd->s_dentry to null
- * even it's still in use.
+ /*
+ * Set sd->s_dentry to null only when this dentry is the one
+ * that is going to be killed. Otherwise configfs_d_iput may
+ * run just after configfs_attach_attr and set sd->s_dentry to
+ * NULL even it's still in use.
*/
- if (atomic_read(&sd->s_count) <= 2)
+ if (sd->s_dentry == dentry)
sd->s_dentry = NULL;
spin_unlock(&configfs_dirent_lock);
--
2.20.1
next prev parent reply other threads:[~2019-06-20 18:09 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-20 17:57 [PATCH 4.14 00/45] 4.14.129-stable review Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 01/45] perf machine: Guard against NULL in machine__exit() Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 02/45] ax25: fix inconsistent lock state in ax25_destroy_timer Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 03/45] be2net: Fix number of Rx queues used for flow hashing Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 04/45] ipv6: flowlabel: fl6_sock_lookup() must use atomic_inc_not_zero Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 05/45] lapb: fixed leak of control-blocks Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 06/45] neigh: fix use-after-free read in pneigh_get_next Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 07/45] net: openvswitch: do not free vport if register_netdevice() is failed Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 08/45] sctp: Free cookie before we memdup a new one Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 09/45] sunhv: Fix device naming inconsistency between sunhv_console and sunhv_reg Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 10/45] Staging: vc04_services: Fix a couple error codes Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 11/45] perf/x86/intel/ds: Fix EVENT vs. UEVENT PEBS constraints Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 12/45] netfilter: nf_queue: fix reinject verdict handling Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 13/45] ipvs: Fix use-after-free in ip_vs_in Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 14/45] selftests: netfilter: missing error check when setting up veth interface Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 15/45] clk: ti: clkctrl: Fix clkdm_clk handling Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 16/45] powerpc/powernv: Return for invalid IMC domain Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 17/45] mISDN: make sure device name is NUL terminated Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 18/45] x86/CPU/AMD: Dont force the CPB cap when running under a hypervisor Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 19/45] perf/ring_buffer: Fix exposing a temporarily decreased data_head Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 20/45] perf/ring_buffer: Add ordering to rb->nest increment Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 21/45] perf/ring-buffer: Always use {READ,WRITE}_ONCE() for rb->user_page data Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 22/45] gpio: fix gpio-adp5588 build errors Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 23/45] net: tulip: de4x5: Drop redundant MODULE_DEVICE_TABLE() Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 24/45] net: aquantia: fix LRO with FCS error Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 25/45] i2c: dev: fix potential memory leak in i2cdev_ioctl_rdwr Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 26/45] ALSA: hda - Force polling mode on CNL for fixing codec communication Greg Kroah-Hartman
2019-06-20 17:57 ` Greg Kroah-Hartman [this message]
2019-06-20 17:57 ` [PATCH 4.14 28/45] perf data: Fix strncat may truncate build failure with recent gcc Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 29/45] perf record: Fix s390 missing module symbol and warning for non-root users Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 30/45] ia64: fix build errors by exporting paddr_to_nid() Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 31/45] KVM: PPC: Book3S: Use new mutex to synchronize access to rtas token list Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 32/45] KVM: PPC: Book3S HV: Dont take kvm->lock around kvm_for_each_vcpu Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 33/45] net: sh_eth: fix mdio access in sh_eth_close() for R-Car Gen2 and RZ/A1 SoCs Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 34/45] net: phy: dp83867: Set up RGMII TX delay Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 35/45] scsi: libcxgbi: add a check for NULL pointer in cxgbi_check_route() Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 36/45] scsi: smartpqi: properly set both the DMA mask and the coherent DMA mask Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 37/45] scsi: scsi_dh_alua: Fix possible null-ptr-deref Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 38/45] scsi: libsas: delete sas port if expander discover failed Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 39/45] mlxsw: spectrum: Prevent force of 56G Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 40/45] HID: wacom: Dont set tool type until were in range Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 41/45] HID: wacom: Dont report anything prior to the tool entering range Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 42/45] HID: wacom: Send BTN_TOUCH in response to INTUOSP2_BT eraser contact Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 43/45] coredump: fix race condition between collapse_huge_page() and core dumping Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 44/45] infiniband: fix race condition between infiniband mlx4, mlx5 driver " Greg Kroah-Hartman
2019-06-20 17:57 ` [PATCH 4.14 45/45] Abort file_remove_privs() for non-reg. files Greg Kroah-Hartman
2019-06-20 21:51 ` [PATCH 4.14 00/45] 4.14.129-stable review kernelci.org bot
2019-06-21 3:49 ` Naresh Kamboju
2019-06-22 0:44 ` Guenter Roeck
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