CVE-2021-47077: scsi: qedf: Add pointer checks in qedf_update_link_speed()

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-03-01 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: scsi: qedf: Add pointer checks in qedf_update_link_speed() The following trace was observed: [ 14.042059] Call Trace: [ 14.042061] <IRQ> [ 14.042068] qedf_link_update+0x144/0x1f0 [qedf] [ 14.042117] qed_link_update+0x5c/0x80 [qed] [ 14.042135] qed_mcp_handle_link_change+0x2d2/0x410 [qed] [ 14.042155] ? qed_set_ptt+0x70/0x80 [qed] [ 14.042170] ? qed_set_ptt+0x70/0x80 [qed] [ 14.042186] ? qed_rd+0x13/0x40 [qed] [ 14.042205] qed_mcp_handle_events+0x437/0x690 [qed] [ 14.042221] ? qed_set_ptt+0x70/0x80 [qed] [ 14.042239] qed_int_sp_dpc+0x3a6/0x3e0 [qed] [ 14.042245] tasklet_action_common.isra.14+0x5a/0x100 [ 14.042250] __do_softirq+0xe4/0x2f8 [ 14.042253] irq_exit+0xf7/0x100 [ 14.042255] do_IRQ+0x7f/0xd0 [ 14.042257] common_interrupt+0xf/0xf [ 14.042259] </IRQ> API qedf_link_update() is getting called from QED but by that time shost_data is not initialised. This results in a NULL pointer dereference when we try to dereference shost_data while updating supported_speeds. Add a NULL pointer check before dereferencing shost_data.

Affected products

Linux kernel: from 4.11 before 5.10.40; from 5.11 before 5.12.7; 5.13-rc1, 5.13-rc2 — fixed in 5.10.40, 5.12.7

How to fix

Upgrade to a fixed version: Linux kernel 5.10.40, 5.12.7. Check the vendor advisory for mitigations.

References

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