In the Linux kernel, the following vulnerability has been resolved:
net: dsa: don't leak tagger-owned storage on switch driver unbind
In the initial commit dc452a471dba ("net: dsa: introduce tagger-owned
storage for private and shared data"), we had a call to
tag_ops->disconnect(dst) issued from dsa_tree_free(), which is called at
tree teardown time.
There were problems with connecting to a switch tree as a whole, so this
got reworked to connecting to individual switches within the tree. In
this process, tag_ops->disconnect(ds) was made to be called only from
switch.c (cross-chip notifiers emitted as a result of dynamic tag proto
changes), but the normal driver teardown code path wasn't replaced with
anything.
Solve this problem by adding a function that does the opposite of
dsa_switch_setup_tag_protocol(), which is called from the equivalent
spot in dsa_switch_teardown(). The positioning here also ensures that we
won't have any use-after-free in tagging protocol (*rcv) ops, since the
teardown sequence is as follows:
dsa_tree_teardown
-> dsa_tree_teardown_master
-> dsa_master_teardown
-> unsets master->dsa_ptr, making no further packets match the
ETH_P_XDSA packet type handler
-> dsa_tree_teardown_ports
-> dsa_port_teardown
-> dsa_slave_destroy
-> unregisters DSA net devices, there is even a synchronize_net()
in unregister_netdevice_many()
-> dsa_tree_teardown_switches
-> dsa_switch_teardown
-> dsa_switch_teardown_tag_protocol
-> finally frees the tagger-owned storage
Metrics
Affected Vendors & Products
References
History
Fri, 02 May 2025 14:00:00 +0000
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cvssV3_1
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Thu, 01 May 2025 14:30:00 +0000
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Description | In the Linux kernel, the following vulnerability has been resolved: net: dsa: don't leak tagger-owned storage on switch driver unbind In the initial commit dc452a471dba ("net: dsa: introduce tagger-owned storage for private and shared data"), we had a call to tag_ops->disconnect(dst) issued from dsa_tree_free(), which is called at tree teardown time. There were problems with connecting to a switch tree as a whole, so this got reworked to connecting to individual switches within the tree. In this process, tag_ops->disconnect(ds) was made to be called only from switch.c (cross-chip notifiers emitted as a result of dynamic tag proto changes), but the normal driver teardown code path wasn't replaced with anything. Solve this problem by adding a function that does the opposite of dsa_switch_setup_tag_protocol(), which is called from the equivalent spot in dsa_switch_teardown(). The positioning here also ensures that we won't have any use-after-free in tagging protocol (*rcv) ops, since the teardown sequence is as follows: dsa_tree_teardown -> dsa_tree_teardown_master -> dsa_master_teardown -> unsets master->dsa_ptr, making no further packets match the ETH_P_XDSA packet type handler -> dsa_tree_teardown_ports -> dsa_port_teardown -> dsa_slave_destroy -> unregisters DSA net devices, there is even a synchronize_net() in unregister_netdevice_many() -> dsa_tree_teardown_switches -> dsa_switch_teardown -> dsa_switch_teardown_tag_protocol -> finally frees the tagger-owned storage | |
Title | net: dsa: don't leak tagger-owned storage on switch driver unbind | |
References |
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Status: PUBLISHED
Assigner: Linux
Published: 2025-05-01T14:09:34.130Z
Updated: 2025-05-04T08:45:47.599Z
Reserved: 2025-05-01T14:05:17.226Z
Link: CVE-2022-49808

No data.

Status : Awaiting Analysis
Published: 2025-05-01T15:16:04.130
Modified: 2025-05-02T13:53:20.943
Link: CVE-2022-49808
