CVE-2024-26688
fs,hugetlb: fix NULL pointer dereference in hugetlbs_fill_super
Severity Score
Exploit Likelihood
Affected Versions
Public Exploits
0Exploited in Wild
-Decision
Descriptions
In the Linux kernel, the following vulnerability has been resolved:
fs,hugetlb: fix NULL pointer dereference in hugetlbs_fill_super
When configuring a hugetlb filesystem via the fsconfig() syscall, there is
a possible NULL dereference in hugetlbfs_fill_super() caused by assigning
NULL to ctx->hstate in hugetlbfs_parse_param() when the requested pagesize
is non valid.
E.g: Taking the following steps:
fd = fsopen("hugetlbfs", FSOPEN_CLOEXEC);
fsconfig(fd, FSCONFIG_SET_STRING, "pagesize", "1024", 0);
fsconfig(fd, FSCONFIG_CMD_CREATE, NULL, NULL, 0);
Given that the requested "pagesize" is invalid, ctxt->hstate will be replaced
with NULL, losing its previous value, and we will print an error:
...
...
case Opt_pagesize:
ps = memparse(param->string, &rest);
ctx->hstate = h;
if (!ctx->hstate) {
pr_err("Unsupported page size %lu MB
", ps / SZ_1M);
return -EINVAL;
}
return 0;
...
...
This is a problem because later on, we will dereference ctxt->hstate in
hugetlbfs_fill_super()
...
...
sb->s_blocksize = huge_page_size(ctx->hstate);
...
...
Causing below Oops.
Fix this by replacing cxt->hstate value only when then pagesize is known
to be valid.
kernel: hugetlbfs: Unsupported page size 0 MB
kernel: BUG: kernel NULL pointer dereference, address: 0000000000000028
kernel: #PF: supervisor read access in kernel mode
kernel: #PF: error_code(0x0000) - not-present page
kernel: PGD 800000010f66c067 P4D 800000010f66c067 PUD 1b22f8067 PMD 0
kernel: Oops: 0000 [#1] PREEMPT SMP PTI
kernel: CPU: 4 PID: 5659 Comm: syscall Tainted: G E 6.8.0-rc2-default+ #22 5a47c3fef76212addcc6eb71344aabc35190ae8f
kernel: Hardware name: Intel Corp. GROVEPORT/GROVEPORT, BIOS GVPRCRB1.86B.0016.D04.1705030402 05/03/2017
kernel: RIP: 0010:hugetlbfs_fill_super+0xb4/0x1a0
kernel: Code: 48 8b 3b e8 3e c6 ed ff 48 85 c0 48 89 45 20 0f 84 d6 00 00 00 48 b8 ff ff ff ff ff ff ff 7f 4c 89 e7 49 89 44 24 20 48 8b 03 <8b> 48 28 b8 00 10 00 00 48 d3 e0 49 89 44 24 18 48 8b 03 8b 40 28
kernel: RSP: 0018:ffffbe9960fcbd48 EFLAGS: 00010246
kernel: RAX: 0000000000000000 RBX: ffff9af5272ae780 RCX: 0000000000372004
kernel: RDX: ffffffffffffffff RSI: ffffffffffffffff RDI: ffff9af555e9b000
kernel: RBP: ffff9af52ee66b00 R08: 0000000000000040 R09: 0000000000370004
kernel: R10: ffffbe9960fcbd48 R11: 0000000000000040 R12: ffff9af555e9b000
kernel: R13: ffffffffa66b86c0 R14: ffff9af507d2f400 R15: ffff9af507d2f400
kernel: FS: 00007ffbc0ba4740(0000) GS:ffff9b0bd7000000(0000) knlGS:0000000000000000
kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
kernel: CR2: 0000000000000028 CR3: 00000001b1ee0000 CR4: 00000000001506f0
kernel: Call Trace:
kernel: <TASK>
kernel: ? __die_body+0x1a/0x60
kernel: ? page_fault_oops+0x16f/0x4a0
kernel: ? search_bpf_extables+0x65/0x70
kernel: ? fixup_exception+0x22/0x310
kernel: ? exc_page_fault+0x69/0x150
kernel: ? asm_exc_page_fault+0x22/0x30
kernel: ? __pfx_hugetlbfs_fill_super+0x10/0x10
kernel: ? hugetlbfs_fill_super+0xb4/0x1a0
kernel: ? hugetlbfs_fill_super+0x28/0x1a0
kernel: ? __pfx_hugetlbfs_fill_super+0x10/0x10
kernel: vfs_get_super+0x40/0xa0
kernel: ? __pfx_bpf_lsm_capable+0x10/0x10
kernel: vfs_get_tree+0x25/0xd0
kernel: vfs_cmd_create+0x64/0xe0
kernel: __x64_sys_fsconfig+0x395/0x410
kernel: do_syscall_64+0x80/0x160
kernel: ? syscall_exit_to_user_mode+0x82/0x240
kernel: ? do_syscall_64+0x8d/0x160
kernel: ? syscall_exit_to_user_mode+0x82/0x240
kernel: ? do_syscall_64+0x8d/0x160
kernel: ? exc_page_fault+0x69/0x150
kernel: entry_SYSCALL_64_after_hwframe+0x6e/0x76
kernel: RIP: 0033:0x7ffbc0cb87c9
kernel: Code: 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 97 96 0d 00 f7 d8 64 89 01 48
kernel: RSP: 002b:00007ffc29d2f388 EFLAGS: 00000206 ORIG_RAX: 00000000000001af
kernel: RAX: fffffffffff
---truncated---
En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: fs,hugetlb: corrige la desreferencia del puntero NULL en hugetlbs_fill_super Al configurar un SYSTEM de archivos de Hugetlb a través de la llamada al SYSTEM fsconfig(), existe una posible desreferencia de NULL en hugetlbfs_fill_super() causada por la asignación de NULL a ctx. ->hstate en hugetlbfs_parse_param() cuando el tamaño de página solicitado no es válido. Por ejemplo: siguiendo los siguientes pasos: fd = fsopen("hugetlbfs", FSOPEN_CLOEXEC); fsconfig(fd, FSCONFIG_SET_STRING, "tamaño de página", "1024", 0); fsconfig(fd, FSCONFIG_CMD_CREATE, NULL, NULL, 0); Dado que el "tamaño de página" solicitado no es válido, ctxt->hstate será reemplazado por NULL, perdiendo su valor anterior, e imprimiremos un error: ... ... case Opt_pagesize: ps = memparse(param->string, &descansar); ctx->hestado = h; if (!ctx->hstate) { pr_err("Tamaño de página no admitido %lu MB
", ps / SZ_1M); devolver -EINVAL; } devolver 0; ... ... Esto es un problema porque más adelante eliminaremos la referencia a ctxt->hstate en hugetlbfs_fill_super() ... ... sb->s_blocksize = huge_page_size(ctx->hstate); ... ... Causando debajo Ups. Solucione este problema reemplazando el valor cxt->hstate solo cuando se sepa que el tamaño de página es válido. kernel: hugetlbfs: Tamaño de página no admitido 0 MB kernel: ERROR: desreferencia del puntero NULL del kernel, dirección: 0000000000000028 kernel: #PF: acceso de lectura del supervisor en modo kernel kernel: #PF: código_error(0x0000) - página no presente kernel: PGD 800000010f66c067 P4D 800000010f66c067 PUD 1b22f8067 PMD 0 kernel: Ups: 0000 [#1] PREEMPT SMP PTI kernel: CPU: 4 PID: 5659 Comm: syscall Contaminado: GE 6.8.0-rc2-default+ #22 5a47c3fef76212addcc6eb71344 Kernel aabc35190ae8f: Nombre del hardware: Intel Corp. GROVEPORT/GROVEPORT, BIOS GVPRCRB1.86B.0016.D04.1705030402 03/05/2017 kernel: RIP: 0010:hugetlbfs_fill_super+0xb4/0x1a0 kernel: Código: 48 8b 3b e8 3e c6 ed ff 48 85 c0 48 89 45 20 0f 84 d6 00 00 00 48 b8 ff ff ff ff ff ff ff 7f 4c 89 e7 49 89 44 24 20 48 8b 03 <8b> 48 28 b8 00 10 00 00 48 d3 e0 49 89 44 24 18 48 8b 03 8b 40 28 kernel: RSP: 0018:ffffbe9960fcbd48 EFLAGS: 00010246 kernel: RAX: 0000000000000000 RBX: ffff9af5272ae780 RCX: 0000000000372004 kernel: RDX: ffffffffffffffff RSI: ffffffffffffffff R DI: ffff9af555e9b000 kernel: RBP: ffff9af52ee66b00 R08: 0000000000000040 R09: 0000000000370004 kernel: R10: ffffbe9960fcbd48 R11: 0000000000000040 R12: ffff9af555e9b000 kernel: R13: fffffffa66b86c0 R14: ffff9af507d2f400 R15: ffff9af507d2f400 kernel: FS: 00007ffbc0ba4740(0000) GS:ffff9b0bd7 000000(0000) knlGS:0000000000000000 kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 kernel: CR2: 0000000000000028 CR3: 00000001b1ee0000 CR4: 00000000001506f0 kernel: Seguimiento de llamadas: kernel: kernel: ? __die_body+0x1a/0x60 núcleo: ? page_fault_oops+0x16f/0x4a0 núcleo:? search_bpf_extables+0x65/0x70 núcleo:? fixup_exception+0x22/0x310 kernel:? exc_page_fault+0x69/0x150 núcleo:? asm_exc_page_fault+0x22/0x30 núcleo:? __pfx_hugetlbfs_fill_super+0x10/0x10 núcleo:? núcleo enormetlbfs_fill_super+0xb4/0x1a0:? enormetlbfs_fill_super+0x28/0x1a0 kernel:? __pfx_hugetlbfs_fill_super+0x10/0x10 kernel: vfs_get_super+0x40/0xa0 kernel:? __pfx_bpf_lsm_capable+0x10/0x10 kernel: vfs_get_tree+0x25/0xd0 kernel: vfs_cmd_create+0x64/0xe0 kernel: __x64_sys_fsconfig+0x395/0x410 kernel: do_syscall_64+0x80/0x160 kernel: ? syscall_exit_to_user_mode+0x82/0x240 kernel:? do_syscall_64+0x8d/0x160 núcleo:? syscall_exit_to_user_mode+0x82/0x240 kernel:? do_syscall_64+0x8d/0x160 núcleo:? exc_page_fault+0x69/0x150 kernel: Entry_SYSCALL_64_after_hwframe+0x6e/0x76 kernel: RIP: 0033:0x7ffbc0cb87c9 kernel: Código: 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 97 96 0d 00 f7 d8 64 89 01 48 ---truncado---
CVSS Scores
SSVC
- Decision:Track
Timeline
- 2024-02-19 CVE Reserved
- 2024-04-03 CVE Published
- 2024-04-04 EPSS Updated
- 2024-12-19 CVE Updated
- ---------- Exploited in Wild
- ---------- KEV Due Date
- ---------- First Exploit
CWE
CAPEC
References (9)
| URL | Tag | Source |
|---|---|---|
| https://git.kernel.org/stable/c/32021982a324dce93b4ae00c06213bf45fb319c8 | Vuln. Introduced | |
| https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html |
|
| 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" | >= 5.1 < 5.4.271 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.1 < 5.4.271" | en |
Affected
| ||||||
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.1 < 5.10.212 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.1 < 5.10.212" | en |
Affected
| ||||||
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.1 < 5.15.151 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.1 < 5.15.151" | en |
Affected
| ||||||
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.1 < 6.1.79 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.1 < 6.1.79" | en |
Affected
| ||||||
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.1 < 6.6.18 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.1 < 6.6.18" | en |
Affected
| ||||||
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.1 < 6.7.6 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.1 < 6.7.6" | en |
Affected
| ||||||
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.1 < 6.8 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.1 < 6.8" | en |
Affected
| ||||||