From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Zheng Liang <zhengliang6@huawei.com>,
Miklos Szeredi <mszeredi@redhat.com>
Subject: [PATCH 4.9 04/25] ovl: fix missing negative dentry check in ovl_rename()
Date: Thu, 14 Oct 2021 16:53:35 +0200 [thread overview]
Message-ID: <20211014145207.721337418@linuxfoundation.org> (raw)
In-Reply-To: <20211014145207.575041491@linuxfoundation.org>
From: Zheng Liang <zhengliang6@huawei.com>
commit a295aef603e109a47af355477326bd41151765b6 upstream.
The following reproducer
mkdir lower upper work merge
touch lower/old
touch lower/new
mount -t overlay overlay -olowerdir=lower,upperdir=upper,workdir=work merge
rm merge/new
mv merge/old merge/new & unlink upper/new
may result in this race:
PROCESS A:
rename("merge/old", "merge/new");
overwrite=true,ovl_lower_positive(old)=true,
ovl_dentry_is_whiteout(new)=true -> flags |= RENAME_EXCHANGE
PROCESS B:
unlink("upper/new");
PROCESS A:
lookup newdentry in new_upperdir
call vfs_rename() with negative newdentry and RENAME_EXCHANGE
Fix by adding the missing check for negative newdentry.
Signed-off-by: Zheng Liang <zhengliang6@huawei.com>
Fixes: e9be9d5e76e3 ("overlay filesystem")
Cc: <stable@vger.kernel.org> # v3.18
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/overlayfs/dir.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -926,9 +926,13 @@ static int ovl_rename2(struct inode *old
goto out_dput;
}
} else {
- if (!d_is_negative(newdentry) &&
- (!new_opaque || !ovl_is_whiteout(newdentry)))
- goto out_dput;
+ if (!d_is_negative(newdentry)) {
+ if (!new_opaque || !ovl_is_whiteout(newdentry))
+ goto out_dput;
+ } else {
+ if (flags & RENAME_EXCHANGE)
+ goto out_dput;
+ }
}
if (olddentry == trap)
next prev parent reply other threads:[~2021-10-14 14:56 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-14 14:53 [PATCH 4.9 00/25] 4.9.287-rc1 review Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 01/25] Partially revert "usb: Kconfig: using select for USB_COMMON dependency" Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 02/25] USB: cdc-acm: fix racy tty buffer accesses Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 03/25] USB: cdc-acm: fix break reporting Greg Kroah-Hartman
2021-10-14 14:53 ` Greg Kroah-Hartman [this message]
2021-10-14 14:53 ` [PATCH 4.9 05/25] nfsd4: Handle the NFSv4 READDIR dircount hint being zero Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 06/25] ARM: dts: omap3430-sdp: Fix NAND device node Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 07/25] xtensa: call irqchip_init only when CONFIG_USE_OF is selected Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 08/25] bpf: Fix integer overflow in prealloc_elems_and_freelist() Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 09/25] phy: mdio: fix memory leak Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 10/25] net_sched: fix NULL deref in fifo_set_limit() Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 11/25] powerpc/fsl/dts: Fix phy-connection-type for fm1mac3 Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 12/25] ptp_pch: Load module automatically if ID matches Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 13/25] ARM: imx6: disable the GIC CPU interface before calling stby-poweroff sequence Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 14/25] net: bridge: use nla_total_size_64bit() in br_get_linkxstats_size() Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 15/25] netlink: annotate data races around nlk->bound Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 16/25] drm/nouveau/debugfs: fix file release memory leak Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 17/25] rtnetlink: fix if_nlmsg_stats_size() under estimation Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 18/25] i40e: fix endless loop under rtnl Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 19/25] gup: document and work around "COW can break either way" issue Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 20/25] HID: apple: Fix logical maximum and usage maximum of Magic Keyboard JIS Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 21/25] netfilter: ip6_tables: zero-initialize fragment offset Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 22/25] mac80211: Drop frames from invalid MAC address in ad-hoc mode Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 23/25] scsi: ses: Fix unsigned comparison with less than zero Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 24/25] scsi: virtio_scsi: Fix spelling mistake "Unsupport" -> "Unsupported" Greg Kroah-Hartman
2021-10-14 14:53 ` [PATCH 4.9 25/25] perf/x86: Reset destroy callback on event init failure Greg Kroah-Hartman
2021-10-14 19:12 ` [PATCH 4.9 00/25] 4.9.287-rc1 review Florian Fainelli
2021-10-14 22:40 ` Shuah Khan
2021-10-15 17:56 ` Daniel Díaz
2021-10-15 22:05 ` Guenter Roeck
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