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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	Michael Labriola <michael.d.labriola@gmail.com>,
	Amir Goldstein <amir73il@gmail.com>,
	Miklos Szeredi <mszeredi@redhat.com>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 08/50] ovl: skip getxattr of security labels
Date: Mon, 22 Feb 2021 13:12:59 +0100
Message-ID: <20210222121021.769360483@linuxfoundation.org> (raw)
In-Reply-To: <20210222121019.925481519@linuxfoundation.org>

From: Amir Goldstein <amir73il@gmail.com>

[ Upstream commit 03fedf93593c82538b18476d8c4f0e8f8435ea70 ]

When inode has no listxattr op of its own (e.g. squashfs) vfs_listxattr
calls the LSM inode_listsecurity hooks to list the xattrs that LSMs will
intercept in inode_getxattr hooks.

When selinux LSM is installed but not initialized, it will list the
security.selinux xattr in inode_listsecurity, but will not intercept it
in inode_getxattr.  This results in -ENODATA for a getxattr call for an
xattr returned by listxattr.

This situation was manifested as overlayfs failure to copy up lower
files from squashfs when selinux is built-in but not initialized,
because ovl_copy_xattr() iterates the lower inode xattrs by
vfs_listxattr() and vfs_getxattr().

ovl_copy_xattr() skips copy up of security labels that are indentified by
inode_copy_up_xattr LSM hooks, but it does that after vfs_getxattr().
Since we are not going to copy them, skip vfs_getxattr() of the security
labels.

Reported-by: Michael Labriola <michael.d.labriola@gmail.com>
Tested-by: Michael Labriola <michael.d.labriola@gmail.com>
Link: https://lore.kernel.org/linux-unionfs/2nv9d47zt7.fsf@aldarion.sourceruckus.org/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/overlayfs/copy_up.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 6eb0b882ad231..e164f489d01d9 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -79,6 +79,14 @@ int ovl_copy_xattr(struct dentry *old, struct dentry *new)
 
 		if (ovl_is_private_xattr(name))
 			continue;
+
+		error = security_inode_copy_up_xattr(name);
+		if (error < 0 && error != -EOPNOTSUPP)
+			break;
+		if (error == 1) {
+			error = 0;
+			continue; /* Discard */
+		}
 retry:
 		size = vfs_getxattr(old, name, value, value_size);
 		if (size == -ERANGE)
@@ -102,13 +110,6 @@ retry:
 			goto retry;
 		}
 
-		error = security_inode_copy_up_xattr(name);
-		if (error < 0 && error != -EOPNOTSUPP)
-			break;
-		if (error == 1) {
-			error = 0;
-			continue; /* Discard */
-		}
 		error = vfs_setxattr(new, name, value, size, 0);
 		if (error)
 			break;
-- 
2.27.0




  parent reply index

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-22 12:12 [PATCH 4.19 00/50] 4.19.177-rc1 review Greg Kroah-Hartman
2021-02-22 12:12 ` [PATCH 4.19 01/50] tracing: Do not count ftrace events in top level enable output Greg Kroah-Hartman
2021-02-22 12:12 ` [PATCH 4.19 02/50] tracing: Check length before giving out the filter buffer Greg Kroah-Hartman
2021-02-22 12:12 ` [PATCH 4.19 03/50] arm/xen: Dont probe xenbus as part of an early initcall Greg Kroah-Hartman
2021-02-22 12:12 ` [PATCH 4.19 04/50] arm64: dts: rockchip: Fix PCIe DT properties on rk3399 Greg Kroah-Hartman
2021-02-22 12:12 ` [PATCH 4.19 05/50] platform/x86: hp-wmi: Disable tablet-mode reporting by default Greg Kroah-Hartman
2021-02-22 12:12 ` [PATCH 4.19 06/50] ovl: perform vfs_getxattr() with mounter creds Greg Kroah-Hartman
2021-02-22 12:12 ` [PATCH 4.19 07/50] cap: fix conversions on getxattr Greg Kroah-Hartman
2021-02-22 12:12 ` Greg Kroah-Hartman [this message]
2021-02-22 12:13 ` [PATCH 4.19 09/50] drm/amd/display: Fix dc_sink kref count in emulated_link_detect Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 10/50] drm/amd/display: Free atomic state after drm_atomic_commit Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 11/50] riscv: virt_addr_valid must check the address belongs to linear mapping Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 12/50] bfq-iosched: Revert "bfq: Fix computation of shallow depth" Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 13/50] ARM: dts: lpc32xx: Revert set default clock rate of HCLK PLL Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 14/50] ARM: ensure the signal page contains defined contents Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 15/50] ARM: kexec: fix oops after TLB are invalidated Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 16/50] mt76: dma: fix a possible memory leak in mt76_add_fragment() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 17/50] bpf: Check for integer overflow when using roundup_pow_of_two() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 18/50] netfilter: xt_recent: Fix attempt to update deleted entry Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 19/50] netfilter: flowtable: fix tcp and udp header checksum update Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 20/50] xen/netback: avoid race in xenvif_rx_ring_slots_available() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 21/50] net: stmmac: set TxQ mode back to DCB after disabling CBS Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 22/50] netfilter: conntrack: skip identical origin tuple in same zone only Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 23/50] net: hns3: add a check for queue_id in hclge_reset_vf_queue() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 24/50] firmware_loader: align .builtin_fw to 8 Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 25/50] i2c: stm32f7: fix configuration of the digital filter Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 26/50] h8300: fix PREEMPTION build, TI_PRE_COUNT undefined Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 27/50] usb: dwc3: ulpi: fix checkpatch warning Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 28/50] usb: dwc3: ulpi: Replace CPU-based busyloop with Protocol-based one Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 29/50] net: fix iteration for sctp transport seq_files Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 30/50] net/vmw_vsock: improve locking in vsock_connect_timeout() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 31/50] net: watchdog: hold device global xmit lock during tx disable Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 32/50] vsock/virtio: update credit only if socket is not closed Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 33/50] vsock: fix locking in vsock_shutdown() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 34/50] net/rds: restrict iovecs length for RDS_CMSG_RDMA_ARGS Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 35/50] net/qrtr: restrict user-controlled length in qrtr_tun_write_iter() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 36/50] ovl: expand warning in ovl_d_real() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 37/50] x86/build: Disable CET instrumentation in the kernel for 32-bit too Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 38/50] KVM: SEV: fix double locking due to incorrect backport Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 39/50] net: qrtr: Fix port ID for control messages Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 40/50] Xen/x86: dont bail early from clear_foreign_p2m_mapping() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 41/50] Xen/x86: also check kernel mapping in set_foreign_p2m_mapping() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 42/50] Xen/gntdev: correct dev_bus_addr handling in gntdev_map_grant_pages() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 43/50] Xen/gntdev: correct error checking " Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 44/50] xen/arm: dont ignore return errors from set_phys_to_machine Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 45/50] xen-blkback: dont "handle" error by BUG() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 46/50] xen-netback: " Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 47/50] xen-scsiback: " Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 48/50] xen-blkback: fix error handling in xen_blkbk_map() Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 49/50] scsi: qla2xxx: Fix crash during driver load on big endian machines Greg Kroah-Hartman
2021-02-22 12:13 ` [PATCH 4.19 50/50] kvm: check tlbs_dirty directly Greg Kroah-Hartman
2021-02-22 18:40 ` [PATCH 4.19 00/50] 4.19.177-rc1 review Pavel Machek
2021-02-22 21:28 ` Guenter Roeck
2021-02-22 21:49 ` Igor
2021-02-23 10:10 ` Naresh Kamboju
2021-02-23 21:17 ` Shuah Khan

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