CVE-2024-40947

Advisory lineage Upstream: 0 Downstream: 19
Modified
Published: 12 Jul 2024, 12:31
Last modified:23 May 2026, 15:51

Vulnerability Summary

Overall Risk (default)
low
22/100
CVSS Score
5.5 MEDIUM
v3.1 (nvd)
EPSS Score
0.01% LOW
0% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

12 Jul 2024, 12:31
Published
Vulnerability first disclosed
23 May 2026, 15:51
Last Modified
Vulnerability information updated

Description

In the Linux kernel, the following vulnerability has been resolved: ima: Avoid blocking in RCU read-side critical section A panic happens in ima_match_policy: BUG: unable to handle kernel NULL pointer dereference at 0000000000000010 PGD 42f873067 P4D 0 Oops: 0000 [#1] SMP NOPTI CPU: 5 PID: 1286325 Comm: kubeletmonit.sh Kdump: loaded Tainted: P Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 RIP: 0010:ima_match_policy+0x84/0x450 Code: 49 89 fc 41 89 cf 31 ed 89 44 24 14 eb 1c 44 39 7b 18 74 26 41 83 ff 05 74 20 48 8b 1b 48 3b 1d f2 b9 f4 00 0f 84 9c 01 00 00 <44> 85 73 10 74 ea 44 8b 6b 14 41 f6 c5 01 75 d4 41 f6 c5 02 74 0f RSP: 0018:ff71570009e07a80 EFLAGS: 00010207 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000200 RDX: ffffffffad8dc7c0 RSI: 0000000024924925 RDI: ff3e27850dea2000 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffffabfce739 R10: ff3e27810cc42400 R11: 0000000000000000 R12: ff3e2781825ef970 R13: 00000000ff3e2785 R14: 000000000000000c R15: 0000000000000001 FS: 00007f5195b51740(0000) GS:ff3e278b12d40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000010 CR3: 0000000626d24002 CR4: 0000000000361ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ima_get_action+0x22/0x30 process_measurement+0xb0/0x830 ? page_add_file_rmap+0x15/0x170 ? alloc_set_pte+0x269/0x4c0 ? prep_new_page+0x81/0x140 ? simple_xattr_get+0x75/0xa0 ? selinux_file_open+0x9d/0xf0 ima_file_check+0x64/0x90 path_openat+0x571/0x1720 do_filp_open+0x9b/0x110 ? page_counter_try_charge+0x57/0xc0 ? files_cgroup_alloc_fd+0x38/0x60 ? __alloc_fd+0xd4/0x250 ? do_sys_open+0x1bd/0x250 do_sys_open+0x1bd/0x250 do_syscall_64+0x5d/0x1d0 entry_SYSCALL_64_after_hwframe+0x65/0xca Commit c7423dbdbc9e ("ima: Handle -ESTALE returned by ima_filter_rule_match()") introduced call to ima_lsm_copy_rule within a RCU read-side critical section which contains kmalloc with GFP_KERNEL. This implies a possible sleep and violates limitations of RCU read-side critical sections on non-PREEMPT systems. Sleeping within RCU read-side critical section might cause synchronize_rcu() returning early and break RCU protection, allowing a UAF to happen. The root cause of this issue could be described as follows: | Thread A | Thread B | | |ima_match_policy | | | rcu_read_lock | |ima_lsm_update_rule | | | synchronize_rcu | | | | kmalloc(GFP_KERNEL)| | | sleep | ==> synchronize_rcu returns early | kfree(entry) | | | | entry = entry->next| ==> UAF happens and entry now becomes NULL (or could be anything). | | entry->action | ==> Accessing entry might cause panic. To fix this issue, we are converting all kmalloc that is called within RCU read-side critical section to use GFP_ATOMIC. [PM: fixed missing comment, long lines, !CONFIG_IMA_LSM_RULES case]

CVSS Metrics

  • v3.1•MEDIUM•Score: 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Trends

Current EPSS score: 0.01%• Percentile: 1%

Techniques & Countermeasures

  • CWE-476•NULL Pointer Dereference

    The product dereferences a pointer that it expects to be valid but is NULL.

Affected Systems

  • linux•linux

    ≥ c4b035b1f036ddd53fbfced49046e586c5ad8a3e, < a6176a802c4bfb83bf7524591aa75f44a639a853 | ≥ 2d4bc60693c4206c64723e94ae5f7a04c0b8f18f, < a38e02265c681b51997a264aaf743095e2ee400a | ≥ 8008f1691c15f353f5a53dc5d450b8262cb57421, < 9c3906c3738562b1fedc6f1cfc81756a7cfefff0 | ≥ c7423dbdbc9ecef7fff5239d144cad4b9887f4de, < 28d0ecc52f6c927d0e9ba70a4f2c1ea15453ee88 | ≥ c7423dbdbc9ecef7fff5239d144cad4b9887f4de, < 58275455893066149e9f4df2223ab2fdbdc59f9c | ≥ c7423dbdbc9ecef7fff5239d144cad4b9887f4de, < 9a95c5bfbf02a0a7f5983280fe284a0ff0836c34 | 38d48fd224036717fcb3437e7af1314f6ebcd2d0 | 69c60b2a2dbb4887739d3a13297cc0dae3793f35 | ≥ 5.10.163, < 5.10.222 | ≥ 5.15.86, < 5.15.163 | ≥ 6.1.2, < 6.1.98 | ≥ 5.4.229, < 5.5 | ≥ 6.0.16, < 6.1 | 6.2

  • linux•linux_kernel

    ≥ 5.4.229, < 5.5 | ≥ 5.10.163, < 5.10.222 | ≥ 5.15.86, < 5.15.163 | ≥ 6.0.16, < 6.1 | ≥ 6.1.2, < 6.1.98 | ≥ 6.2, < 6.6.39 | ≥ 6.7, < 6.9.7 | 6.10:rc1 | 6.10:rc2 | 6.10:rc3 | 6.10:rc4

References (7)