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\n", 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---
Analysis and contextual insights are available on OpenCVE Cloud.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
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| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-3842-1 | linux-5.10 security update |
Debian DSA |
DSA-5658-1 | linux security update |
Debian DSA |
DSA-5681-1 | linux security update |
Ubuntu USN |
USN-6820-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6820-2 | Linux kernel (NVIDIA) vulnerabilities |
Ubuntu USN |
USN-6821-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6821-2 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6821-3 | Linux kernel (AWS) vulnerabilities |
Ubuntu USN |
USN-6821-4 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-6828-1 | Linux kernel (Intel IoTG) vulnerabilities |
Ubuntu USN |
USN-6831-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6871-1 | Linux kernel (HWE) vulnerabilities |
Ubuntu USN |
USN-6892-1 | Linux kernel (IBM) vulnerabilities |
Ubuntu USN |
USN-6895-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6895-2 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6895-3 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6895-4 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6900-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6919-1 | Linux kernel vulnerabilities |
Tue, 07 Jan 2025 21:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Debian
Debian debian Linux Linux Linux linux Kernel |
|
| CPEs | cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.8:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.8:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.8:rc3:*:*:*:*:*:* |
|
| Vendors & Products |
Debian
Debian debian Linux Linux Linux linux Kernel |
|
| Metrics |
cvssV3_1
|
cvssV3_1
|
Fri, 22 Nov 2024 12:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
Tue, 05 Nov 2024 10:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
Tue, 05 Nov 2024 10:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Wed, 11 Sep 2024 18:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Wed, 11 Sep 2024 13:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-11T20:02:16.640Z
Reserved: 2024-02-19T14:20:24.154Z
Link: CVE-2024-26688
Updated: 2024-08-02T00:14:12.699Z
Status : Analyzed
Published: 2024-04-03T15:15:52.370
Modified: 2025-01-07T21:12:29.727
Link: CVE-2024-26688
OpenCVE Enrichment
No data.
Debian DLA
Debian DSA
Ubuntu USN