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Vladimir Oltean 7cef293b9a net: dsa: sja1105: fix multicast forwarding working only for last added mdb entry 
The commit cited in Fixes: did 2 things: it refactored the read-back
polling from sja1105_dynamic_config_read() into a new function,
sja1105_dynamic_config_wait_complete(), and it called that from
sja1105_dynamic_config_write() too.

What is problematic is the refactoring.

The refactored code from sja1105_dynamic_config_poll_valid() works like
the previous one, but the problem is that it uses another packed_buf[]
SPI buffer, and there was code at the end of sja1105_dynamic_config_read()
which was relying on the read-back packed_buf[]:

	/* Don't dereference possibly NULL pointer - maybe caller
	 * only wanted to see whether the entry existed or not.
	 */
	if (entry)
		ops->entry_packing(packed_buf, entry, UNPACK);

After the change, the packed_buf[] that this code sees is no longer the
entry read back from hardware, but the original entry that the caller
passed to the sja1105_dynamic_config_read(), packed into this buffer.

This difference is the most notable with the SJA1105_SEARCH uses from
sja1105pqrs_fdb_add() - used for both fdb and mdb. There, we have logic
added by commit 728db843df ("net: dsa: sja1105: ignore the FDB entry
for unknown multicast when adding a new address") to figure out whether
the address we're trying to add matches on any existing hardware entry,
with the exception of the catch-all multicast address.

That logic was broken, because with sja1105_dynamic_config_read() not
working properly, it doesn't return us the entry read back from
hardware, but the entry that we passed to it. And, since for multicast,
a match will always exist, it will tell us that any mdb entry already
exists at index=0 L2 Address Lookup table. It is index=0 because the
caller doesn't know the index - it wants to find it out, and
sja1105_dynamic_config_read() does:

	if (index < 0) { // SJA1105_SEARCH
		/* Avoid copying a signed negative number to an u64 */
		cmd.index = 0; // <- this
		cmd.search = true;
	} else {
		cmd.index = index;
		cmd.search = false;
	}

So, to the caller of sja1105_dynamic_config_read(), the returned info
looks entirely legit, and it will add all mdb entries to FDB index 0.
There, they will always overwrite each other (not to mention,
potentially they can also overwrite a pre-existing bridge fdb entry),
and the user-visible impact will be that only the last mdb entry will be
forwarded as it should. The others won't (will be flooded or dropped,
depending on the egress flood settings).

Fixing is a bit more complicated, and involves either passing the same
packed_buf[] to sja1105_dynamic_config_wait_complete(), or moving all
the extra processing on the packed_buf[] to
sja1105_dynamic_config_wait_complete(). I've opted for the latter,
because it makes sja1105_dynamic_config_wait_complete() a bit more
self-contained.

Fixes: df405910ab ("net: dsa: sja1105: wait for dynamic config command completion on writes too")
Reported-by: Yanan Yang <yanan.yang@nxp.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2023-09-11 08:32:30 +01:00
arch Including fixes from netfilter and bpf. 2023-09-07 18:33:07 -07:00
block for-6.6/block-2023-08-28 2023-08-29 20:21:42 -07:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto This update includes the following changes: 2023-08-29 11:23:29 -07:00
Documentation Including fixes from netfilter and bpf. 2023-09-07 18:33:07 -07:00
drivers net: dsa: sja1105: fix multicast forwarding working only for last added mdb entry 2023-09-11 08:32:30 +01:00
fs ntfs3: drop inode references in ntfs_put_super() 2023-09-07 10:23:37 -07:00
include Including fixes from netfilter and bpf. 2023-09-07 18:33:07 -07:00
init workqueue: Changes for v6.6 2023-09-01 16:06:32 -07:00
io_uring for-6.6/io_uring-2023-08-28 2023-08-29 20:11:33 -07:00
ipc Add x86 shadow stack support 2023-08-31 12:20:12 -07:00
kernel Including fixes from netfilter and bpf. 2023-09-07 18:33:07 -07:00
lib printk changes for 6.6 2023-09-04 13:20:19 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm Seven hotfixes. Four are cc:stable and the remainder pertain to issues 2023-09-05 12:22:39 -07:00
net hsr: Fix uninit-value access in fill_frame_info() 2023-09-11 08:28:36 +01:00
rust Documentation work keeps chugging along; stuff for 6.6 includes: 2023-08-30 20:05:42 -07:00
samples VFIO updates for v6.6-rc1 2023-08-30 20:36:01 -07:00
scripts Including fixes from netfilter and bpf. 2023-09-07 18:33:07 -07:00
security Three cleanup patches, no behavior changes. 2023-09-04 10:38:35 -07:00
sound This pull request contains the following changes for UML: 2023-09-04 11:32:21 -07:00
tools selftests/net: Improve bind_bhash.sh to accommodate predictable network interface names 2023-09-10 18:49:29 +01:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt ARM: 2023-09-07 13:52:20 -07:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: rename binkernel.spec to kernel.spec 2023-07-25 00:59:33 +09:00
.mailmap for-linus-2023083101 2023-09-01 12:31:44 -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 USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
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 RTC for 6.6 2023-09-07 16:07:35 -07:00
Makefile Kbuild updates for v6.6 2023-09-05 11:01:47 -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.