crypto: ccp - Fix null pointer dereference in __sev_snp_shutdown_locked
CVE: CVE-2024-43874
Component: kernel
CWE: CWE-476
Severity: Moderate
CVSS v3: 5.6/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Release date: 2024-08-21T00:00:00+00:00

In the Linux kernel, the following vulnerability has been resolved:

crypto: ccp - Fix null pointer dereference in __sev_snp_shutdown_locked

Fix a null pointer dereference induced by DEBUG_TEST_DRIVER_REMOVE.
Return from __sev_snp_shutdown_locked() if the psp_device or the
sev_device structs are not initialized. Without the fix, the driver will
produce the following splat:

   ccp 0000:55:00.5: enabling device (0000 -> 0002)
   ccp 0000:55:00.5: sev enabled
   ccp 0000:55:00.5: psp enabled
   BUG: kernel NULL pointer dereference, address: 00000000000000f0
   #PF: supervisor read access in kernel mode
   #PF: error_code(0x0000) - not-present page
   PGD 0 P4D 0
   Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC NOPTI
   CPU: 262 PID: 1 Comm: swapper/0 Not tainted 6.9.0-rc1+ #29
   RIP: 0010:__sev_snp_shutdown_locked+0x2e/0x150
   Code: 00 55 48 89 e5 41 57 41 56 41 54 53 48 83 ec 10 41 89 f7 49 89 fe 65 48 8b 04 25 28 00 00 00 48 89 45 d8 48 8b 05 6a 5a 7f 06 <4c> 8b a0 f0 00 00 00 41 0f b6 9c 24 a2 00 00 00 48 83 fb 02 0f 83
   RSP: 0018:ffffb2ea4014b7b8 EFLAGS: 00010286
   RAX: 0000000000000000 RBX: ffff9e4acd2e0a28 RCX: 0000000000000000
   RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffb2ea4014b808
   RBP: ffffb2ea4014b7e8 R08: 0000000000000106 R09: 000000000003d9c0
   R10: 0000000000000001 R11: ffffffffa39ff070 R12: ffff9e49d40590c8
   R13: 0000000000000000 R14: ffffb2ea4014b808 R15: 0000000000000000
   FS:  0000000000000000(0000) GS:ffff9e58b1e00000(0000) knlGS:0000000000000000
   CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
   CR2: 00000000000000f0 CR3: 0000000418a3e001 CR4: 0000000000770ef0
   PKRU: 55555554
   Call Trace:
    <TASK>
    ? __die_body+0x6f/0xb0
    ? __die+0xcc/0xf0
    ? page_fault_oops+0x330/0x3a0
    ? save_trace+0x2a5/0x360
    ? do_user_addr_fault+0x583/0x630
    ? exc_page_fault+0x81/0x120
    ? asm_exc_page_fault+0x2b/0x30
    ? __sev_snp_shutdown_locked+0x2e/0x150
    __sev_firmware_shutdown+0x349/0x5b0
    ? pm_runtime_barrier+0x66/0xe0
    sev_dev_destroy+0x34/0xb0
    psp_dev_destroy+0x27/0x60
    sp_destroy+0x39/0x90
    sp_pci_remove+0x22/0x60
    pci_device_remove+0x4e/0x110
    really_probe+0x271/0x4e0
    __driver_probe_device+0x8f/0x160
    driver_probe_device+0x24/0x120
    __driver_attach+0xc7/0x280
    ? driver_attach+0x30/0x30
    bus_for_each_dev+0x10d/0x130
    driver_attach+0x22/0x30
    bus_add_driver+0x171/0x2b0
    ? unaccepted_memory_init_kdump+0x20/0x20
    driver_register+0x67/0x100
    __pci_register_driver+0x83/0x90
    sp_pci_init+0x22/0x30
    sp_mod_init+0x13/0x30
    do_one_initcall+0xb8/0x290
    ? sched_clock_noinstr+0xd/0x10
    ? local_clock_noinstr+0x3e/0x100
    ? stack_depot_save_flags+0x21e/0x6a0
    ? local_clock+0x1c/0x60
    ? stack_depot_save_flags+0x21e/0x6a0
    ? sched_clock_noinstr+0xd/0x10
    ? local_clock_noinstr+0x3e/0x100
    ? __lock_acquire+0xd90/0xe30
    ? sched_clock_noinstr+0xd/0x10
    ? local_clock_noinstr+0x3e/0x100
    ? __create_object+0x66/0x100
    ? local_clock+0x1c/0x60
    ? __create_object+0x66/0x100
    ? parameq+0x1b/0x90
    ? parse_one+0x6d/0x1d0
    ? parse_args+0xd7/0x1f0
    ? do_initcall_level+0x180/0x180
    do_initcall_level+0xb0/0x180
    do_initcalls+0x60/0xa0
    ? kernel_init+0x1f/0x1d0
    do_basic_setup+0x41/0x50
    kernel_init_freeable+0x1ac/0x230
    ? rest_init+0x1f0/0x1f0
    kernel_init+0x1f/0x1d0
    ? rest_init+0x1f0/0x1f0
    ret_from_fork+0x3d/0x50
    ? rest_init+0x1f0/0x1f0
    ret_from_fork_asm+0x11/0x20
    </TASK>
   Modules linked in:
   CR2: 00000000000000f0
   ---[ end trace 0000000000000000 ]---
   RIP: 0010:__sev_snp_shutdown_locked+0x2e/0x150
   Code: 00 55 48 89 e5 41 57 41 56 41 54 53 48 83 ec 10 41 89 f7 49 89 fe 65 48 8b 04 25 28 00 00 00 48 89 45 d8 48 8b 05 6a 5a 7f 06 <4c> 8b a0 f0 00 00 00 41 0f b6 9c 24 a2 00 00 00 48 83 fb 02 0f 83
   RSP: 0018:ffffb2ea4014b7b8 EFLAGS: 00010286
   RAX: 0000000000000000 RBX: ffff9e4acd2e0a28 RCX: 0000000000000000
   RDX: 0000000
---truncated---

Statement: Following issue marked as moderate with "not affected or will not fix" for Red Hat Enterprise Linux, as it is not vulnerable to this CVE. This is because the CVE does not impact the versions or configurations of the Linux kernel used in Red Hat's distributions.

Remediation:
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.