CVE-2021-47592
June 19, 2024, 3:15 p.m.
None
No Score
Description
In the Linux kernel, the following vulnerability has been resolved:
net: stmmac: fix tc flower deletion for VLAN priority Rx steering
To replicate the issue:-
1) Add 1 flower filter for VLAN Priority based frame steering:-
$ IFDEVNAME=eth0
$ tc qdisc add dev $IFDEVNAME ingress
$ tc qdisc add dev $IFDEVNAME root mqprio num_tc 8 \
map 0 1 2 3 4 5 6 7 0 0 0 0 0 0 0 0 \
queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 hw 0
$ tc filter add dev $IFDEVNAME parent ffff: protocol 802.1Q \
flower vlan_prio 0 hw_tc 0
2) Get the 'pref' id
$ tc filter show dev $IFDEVNAME ingress
3) Delete a specific tc flower record (say pref 49151)
$ tc filter del dev $IFDEVNAME parent ffff: pref 49151
From dmesg, we will observe kernel NULL pointer ooops
[ 197.170464] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 197.171367] #PF: supervisor read access in kernel mode
[ 197.171367] #PF: error_code(0x0000) - not-present page
[ 197.171367] PGD 0 P4D 0
[ 197.171367] Oops: 0000 [#1] PREEMPT SMP NOPTI
<snip>
[ 197.171367] RIP: 0010:tc_setup_cls+0x20b/0x4a0 [stmmac]
<snip>
[ 197.171367] Call Trace:
[ 197.171367] <TASK>
[ 197.171367] ? __stmmac_disable_all_queues+0xa8/0xe0 [stmmac]
[ 197.171367] stmmac_setup_tc_block_cb+0x70/0x110 [stmmac]
[ 197.171367] tc_setup_cb_destroy+0xb3/0x180
[ 197.171367] fl_hw_destroy_filter+0x94/0xc0 [cls_flower]
The above issue is due to previous incorrect implementation of
tc_del_vlan_flow(), shown below, that uses flow_cls_offload_flow_rule()
to get struct flow_rule *rule which is no longer valid for tc filter
delete operation.
struct flow_rule *rule = flow_cls_offload_flow_rule(cls);
struct flow_dissector *dissector = rule->match.dissector;
So, to ensure tc_del_vlan_flow() deletes the right VLAN cls record for
earlier configured RX queue (configured by hw_tc) in tc_add_vlan_flow(),
this patch introduces stmmac_rfs_entry as driver-side flow_cls_offload
record for 'RX frame steering' tc flower, currently used for VLAN
priority. The implementation has taken consideration for future extension
to include other type RX frame steering such as EtherType based.
v2:
- Clean up overly extensive backtrace and rewrite git message to better
explain the kernel NULL pointer issue.
Product(s) Impacted
Product | Versions |
---|---|
Linux kernel |
|
Weaknesses
Common security weaknesses mapped to this vulnerability.
Tags
Timeline
Published: June 19, 2024, 3:15 p.m.
Last Modified: June 19, 2024, 3:15 p.m.
Last Modified: June 19, 2024, 3:15 p.m.
Status : Received
CVE has been recently published to the CVE List and has been received by the NVD.
More infoSource
416baaa9-dc9f-4396-8d5f-8c081fb06d67
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