Bug 2426026 (CVE-2023-54274)

Summary: CVE-2023-54274 kernel: RDMA/srpt: Add a check for valid 'mad_agent' pointer
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was addressed in the Linux kernel’s RDMA SRPT (SCSI RDMA Protocol Target) subsystem. When unregistering a MAD (Management Datagram) agent, the SRPT module previously performed a non-NULL check on the mad_agent pointer before invoking ib_unregister_mad_agent(). Under rare timing conditions—specifically, concurrent execution of srpt_add_one() and srpt_remove_one()—mad_agent may hold an error value that passes the non-NULL test. This can lead to a NULL pointer dereference and kernel crash when the RoCE driver unregisters an ib_device
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Description OSIDB Bzimport 2025-12-30 13:03:13 UTC 
In the Linux kernel, the following vulnerability has been resolved:

RDMA/srpt: Add a check for valid 'mad_agent' pointer

When unregistering MAD agent, srpt module has a non-null check
for 'mad_agent' pointer before invoking ib_unregister_mad_agent().
This check can pass if 'mad_agent' variable holds an error value.
The 'mad_agent' can have an error value for a short window when
srpt_add_one() and srpt_remove_one() is executed simultaneously.

In srpt module, added a valid pointer check for 'sport->mad_agent'
before unregistering MAD agent.

This issue can hit when RoCE driver unregisters ib_device

Stack Trace:
------------
BUG: kernel NULL pointer dereference, address: 000000000000004d
PGD 145003067 P4D 145003067 PUD 2324fe067 PMD 0
Oops: 0002 [#1] PREEMPT SMP NOPTI
CPU: 10 PID: 4459 Comm: kworker/u80:0 Kdump: loaded Tainted: P
Hardware name: Dell Inc. PowerEdge R640/06NR82, BIOS 2.5.4 01/13/2020
Workqueue: bnxt_re bnxt_re_task [bnxt_re]
RIP: 0010:_raw_spin_lock_irqsave+0x19/0x40
Call Trace:
  ib_unregister_mad_agent+0x46/0x2f0 [ib_core]
  IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready
  ? __schedule+0x20b/0x560
  srpt_unregister_mad_agent+0x93/0xd0 [ib_srpt]
  srpt_remove_one+0x20/0x150 [ib_srpt]
  remove_client_context+0x88/0xd0 [ib_core]
  bond0: (slave p2p1): link status definitely up, 100000 Mbps full duplex
  disable_device+0x8a/0x160 [ib_core]
  bond0: active interface up!
  ? kernfs_name_hash+0x12/0x80
 (NULL device *): Bonding Info Received: rdev: 000000006c0b8247
  __ib_unregister_device+0x42/0xb0 [ib_core]
 (NULL device *):         Master: mode: 4 num_slaves:2
  ib_unregister_device+0x22/0x30 [ib_core]
 (NULL device *):         Slave: id: 105069936 name:p2p1 link:0 state:0
  bnxt_re_stopqps_and_ib_uninit+0x83/0x90 [bnxt_re]
  bnxt_re_alloc_lag+0x12e/0x4e0 [bnxt_re]
Comment 1 Alexander B 2025-12-31 14:43:42 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025123002-CVE-2023-54274-79a7@gregkh/T