CVE-2024-40947
ima: Avoid blocking in RCU read-side critical section
Severity Score
Exploit Likelihood
Affected Versions
Public Exploits
0Exploited in Wild
-Decision
Descriptions
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]
En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ima: Evite el bloqueo en la sección crítica del lado de lectura de RCU Ocurre un pánico en ima_match_policy: ERROR: no se puede manejar la desreferencia del puntero NULL del kernel en 00000000000000010 PGD 42f873067 P4D 0 Ups: 0000 [#1 ] SMP NOPTI CPU: 5 PID: 1286325 Comm: kubeletmonit.sh Kdump: cargado Contaminado: P Nombre del hardware: QEMU PC estándar (i440FX + PIIX, 1996), BIOS 0.0.0 06/02/2015 RIP: 0010:ima_match_policy+0x84 /0x450 Código: 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 <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: 0000000000 RCX: 0000000000000200 RDX: ffffffffad8dc7c0 RSI: 0000000024924925 RDI: ff3e27850dea2000 RBP: 0000000000000000 R08 : 0000000000000000 R09: ffffffffabfce739 R10: ff3e27810cc42400 R11: 0000000000000000 R12: ff3e2781825ef970 R13: 00000000ff3e2785 R14: 000000000c R15: 0000000000000001 FS: 00007f5195b51740(0000) GS:ff3e278b12d40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: : 0000000080050033 CR2: 0000000000000010 CR3: 0000000626d24002 CR4: 0000000000361ee0 DR0: 0000000000000000 DR1: 00000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Seguimiento de llamadas: 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 devuelto por ima_filter_rule_match()") introdujo la llamada a ima_lsm _copy_rule dentro de una sección crítica del lado de lectura de RCU que contiene kmalloc con GFP_KERNEL. Esto implica una posible suspensión y viola las limitaciones de las secciones críticas del lado de lectura de RCU en sistemas que no son PREEMPT. Dormir dentro de la sección crítica del lado de lectura de la RCU puede provocar que sincronizar_rcu() regrese antes de tiempo y rompa la protección de la RCU, lo que permite que se produzca una UAF. La causa raíz de este problema podría describirse de la siguiente manera: | Hilo A | Hilo B | | |ima_match_policy | | | rcu_read_lock | |ima_lsm_update_rule | | | sincronizar_rcu | | | | kmalloc(GFP_KERNEL)| | | dormir | ==> sincronizar_rcu regresa temprano | kfree(entrada) | | | | entrada = entrada->siguiente| ==> Sucede UAF y la entrada ahora se vuelve NULL (o podría ser cualquier cosa). | | entrada->acción | ==> Acceder a la entrada puede causar pánico. Para solucionar este problema, estamos convirtiendo todos los kmalloc que se llaman dentro de la sección crítica del lado de lectura de RCU para usar GFP_ATOMIC. [PM: comentario faltante corregido, líneas largas, caso !CONFIG_IMA_LSM_RULES]
CVSS Scores
SSVC
- Decision:Track
Timeline
- 2024-07-12 CVE Reserved
- 2024-07-12 CVE Published
- 2024-07-19 EPSS Updated
- 2024-09-11 CVE Updated
- ---------- Exploited in Wild
- ---------- KEV Due Date
- ---------- First Exploit
CWE
CAPEC
References (12)
| URL | Tag | Source |
|---|---|---|
| https://git.kernel.org/stable/c/c4b035b1f036ddd53fbfced49046e586c5ad8a3e | Vuln. Introduced | |
| https://git.kernel.org/stable/c/2d4bc60693c4206c64723e94ae5f7a04c0b8f18f | Vuln. Introduced | |
| https://git.kernel.org/stable/c/8008f1691c15f353f5a53dc5d450b8262cb57421 | Vuln. Introduced | |
| https://git.kernel.org/stable/c/c7423dbdbc9ecef7fff5239d144cad4b9887f4de | Vuln. Introduced | |
| https://git.kernel.org/stable/c/38d48fd224036717fcb3437e7af1314f6ebcd2d0 | Vuln. Introduced | |
| https://git.kernel.org/stable/c/69c60b2a2dbb4887739d3a13297cc0dae3793f35 | Vuln. Introduced |
| URL | Date | SRC |
|---|
| URL | Date | SRC |
|---|
Affected Vendors, Products, and Versions
| Vendor | Product | Version | Other | Status | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Vendor | Product | Version | Other | Status | <-- --> | Vendor | Product | Version | Other | Status |
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.10.163 < 5.10.222 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.10.163 < 5.10.222" | en |
Affected
| ||||||
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.15.86 < 5.15.163 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.15.86 < 5.15.163" | en |
Affected
| ||||||
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 6.1.2 < 6.1.98 Search vendor "Linux" for product "Linux Kernel" and version " >= 6.1.2 < 6.1.98" | en |
Affected
| ||||||
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 6.2 < 6.6.39 Search vendor "Linux" for product "Linux Kernel" and version " >= 6.2 < 6.6.39" | en |
Affected
| ||||||
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 6.2 < 6.9.7 Search vendor "Linux" for product "Linux Kernel" and version " >= 6.2 < 6.9.7" | en |
Affected
| ||||||
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 6.2 < 6.10 Search vendor "Linux" for product "Linux Kernel" and version " >= 6.2 < 6.10" | en |
Affected
| ||||||
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | 5.4.229 Search vendor "Linux" for product "Linux Kernel" and version "5.4.229" | en |
Affected
| ||||||
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | 6.0.16 Search vendor "Linux" for product "Linux Kernel" and version "6.0.16" | en |
Affected
| ||||||