Bug 2298209 (CVE-2022-48865)

Summary: CVE-2022-48865 kernel: tipc: fix kernel panic when enabling bearer
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: dfreiber, drow, jburrell, vkumar
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: kernel 5.10.106, kernel 5.15.29, kernel 5.16.15, kernel 5.17 Doc Type: If docs needed, set a value
Doc Text:
A vulnerability was found in the tipc_mon_prep function in the Linux kernel's TIPC driver. This issue occurs when enabling a bearer on a node, leading to a kernel panic due to a null pointer dereference caused by monitoring data being accessed before it is allocated.
Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2314133    
Bug Blocks:    

Description OSIDB Bzimport 2024-07-16 13:34:53 UTC
In the Linux kernel, the following vulnerability has been resolved:

tipc: fix kernel panic when enabling bearer

When enabling a bearer on a node, a kernel panic is observed:

[    4.498085] RIP: 0010:tipc_mon_prep+0x4e/0x130 [tipc]
...
[    4.520030] Call Trace:
[    4.520689]  <IRQ>
[    4.521236]  tipc_link_build_proto_msg+0x375/0x750 [tipc]
[    4.522654]  tipc_link_build_state_msg+0x48/0xc0 [tipc]
[    4.524034]  __tipc_node_link_up+0xd7/0x290 [tipc]
[    4.525292]  tipc_rcv+0x5da/0x730 [tipc]
[    4.526346]  ? __netif_receive_skb_core+0xb7/0xfc0
[    4.527601]  tipc_l2_rcv_msg+0x5e/0x90 [tipc]
[    4.528737]  __netif_receive_skb_list_core+0x20b/0x260
[    4.530068]  netif_receive_skb_list_internal+0x1bf/0x2e0
[    4.531450]  ? dev_gro_receive+0x4c2/0x680
[    4.532512]  napi_complete_done+0x6f/0x180
[    4.533570]  virtnet_poll+0x29c/0x42e [virtio_net]
...

The node in question is receiving activate messages in another
thread after changing bearer status to allow message sending/
receiving in current thread:

         thread 1           |              thread 2
         --------           |              --------
                            |
tipc_enable_bearer()        |
  test_and_set_bit_lock()   |
    tipc_bearer_xmit_skb()  |
                            | tipc_l2_rcv_msg()
                            |   tipc_rcv()
                            |     __tipc_node_link_up()
                            |       tipc_link_build_state_msg()
                            |         tipc_link_build_proto_msg()
                            |           tipc_mon_prep()
                            |           {
                            |             ...
                            |             // null-pointer dereference
                            |             u16 gen = mon->dom_gen;
                            |             ...
                            |           }
  // Not being executed yet |
  tipc_mon_create()         |
  {                         |
    ...                     |
    // allocate             |
    mon = kzalloc();        |
    ...                     |
  }                         |

Monitoring pointer in thread 2 is dereferenced before monitoring data
is allocated in thread 1. This causes kernel panic.

This commit fixes it by allocating the monitoring data before enabling
the bearer to receive messages.