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Vladimir Oltean eb1ab7650d net: dsa: fix db type confusion in host fdb/mdb add/del 
We have the following code paths:

Host FDB (unicast RX filtering):

dsa_port_standalone_host_fdb_add()   dsa_port_bridge_host_fdb_add()
               |                                     |
               +--------------+         +------------+
                              |         |
                              v         v
                         dsa_port_host_fdb_add()

dsa_port_standalone_host_fdb_del()   dsa_port_bridge_host_fdb_del()
               |                                     |
               +--------------+         +------------+
                              |         |
                              v         v
                         dsa_port_host_fdb_del()

Host MDB (multicast RX filtering):

dsa_port_standalone_host_mdb_add()   dsa_port_bridge_host_mdb_add()
               |                                     |
               +--------------+         +------------+
                              |         |
                              v         v
                         dsa_port_host_mdb_add()

dsa_port_standalone_host_mdb_del()   dsa_port_bridge_host_mdb_del()
               |                                     |
               +--------------+         +------------+
                              |         |
                              v         v
                         dsa_port_host_mdb_del()

The logic added by commit 5e8a1e03aa ("net: dsa: install secondary
unicast and multicast addresses as host FDB/MDB") zeroes out
db.bridge.num if the switch doesn't support ds->fdb_isolation
(the majority doesn't). This is done for a reason explained in commit
c26933639b ("net: dsa: request drivers to perform FDB isolation").

Taking a single code path as example - dsa_port_host_fdb_add() - the
others are similar - the problem is that this function handles:
- DSA_DB_PORT databases, when called from
  dsa_port_standalone_host_fdb_add()
- DSA_DB_BRIDGE databases, when called from
  dsa_port_bridge_host_fdb_add()

So, if dsa_port_host_fdb_add() were to make any change on the
"bridge.num" attribute of the database, this would only be correct for a
DSA_DB_BRIDGE, and a type confusion for a DSA_DB_PORT bridge.

However, this bug is without consequences, for 2 reasons:

- dsa_port_standalone_host_fdb_add() is only called from code which is
  (in)directly guarded by dsa_switch_supports_uc_filtering(ds), and that
  function only returns true if ds->fdb_isolation is set. So, the code
  only executed for DSA_DB_BRIDGE databases.

- Even if the code was not dead for DSA_DB_PORT, we have the following
  memory layout:

struct dsa_bridge {
	struct net_device *dev;
	unsigned int num;
	bool tx_fwd_offload;
	refcount_t refcount;
};

struct dsa_db {
	enum dsa_db_type type;

	union {
		const struct dsa_port *dp; // DSA_DB_PORT
		struct dsa_lag lag;
		struct dsa_bridge bridge; // DSA_DB_BRIDGE
	};
};

So, the zeroization of dsa_db :: bridge :: num on a dsa_db structure of
type DSA_DB_PORT would access memory which is unused, because we only
use dsa_db :: dp for DSA_DB_PORT, and this is mapped at the same address
with dsa_db :: dev for DSA_DB_BRIDGE, thanks to the union definition.

It is correct to fix up dsa_db :: bridge :: num only from code paths
that come from the bridge / switchdev, so move these there.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20230329133819.697642-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-03-30 23:19:55 -07:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-03-30 14:43:03 -07:00
block block: remove obsolete config BLOCK_COMPAT 2023-03-16 09:35:44 -06:00
certs Kbuild updates for v6.3 2023-02-26 11:53:25 -08:00
crypto asymmetric_keys: log on fatal failures in PE/pkcs7 2023-03-21 16:23:56 +00:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-03-30 14:43:03 -07:00
drivers net: ksz884x: remove unused change variable 2023-03-30 23:18:48 -07:00
fs Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-03-30 14:43:03 -07:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-03-30 14:43:03 -07:00
init bootconfig: Change message if no bootconfig with CONFIG_BOOT_CONFIG_FORCE=y 2023-03-22 22:21:43 +09:00
io_uring Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-03-30 14:43:03 -07:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-03-30 14:43:03 -07:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-03-30 14:43:03 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm 21 hotfixes, 8 of which are cc:stable. 11 are for MM, the remainder are 2023-03-24 18:06:11 -07:00
net net: dsa: fix db type confusion in host fdb/mdb add/del 2023-03-30 23:19:55 -07:00
rust Rust fixes for 6.3-rc1 2023-03-03 14:51:15 -08:00
samples LoongArch changes for v6.3 2023-03-01 09:27:00 -08:00
scripts Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-03-30 14:43:03 -07:00
security Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-03-24 10:10:20 -07:00
sound ALSA: hda/realtek: Add quirk for Lenovo ZhaoYang CF4620Z 2023-03-29 14:45:07 +02:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-03-30 14:43:03 -07:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM/riscv changes for 6.3 2023-02-15 12:33:28 -05:00
.clang-format cpumask: re-introduce constant-sized cpumask optimizations 2023-03-05 14:30:34 -08:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for *.dtso files 2023-02-26 15:28:23 +09:00
.gitignore kbuild: rpm-pkg: move source components to rpmbuild/SOURCES 2023-03-16 22:45:56 +09:00
.mailmap mailmap: add entries for Richard Leitner 2023-03-23 17:18:35 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS There is no particular theme here - mainly quick hits all over the tree. 2023-02-23 17:55:40 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-03-30 14:43:03 -07:00
Makefile Linux 6.3-rc4 2023-03-26 14:40:20 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.