ghsa-h4jh-5vqp-vw3p
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
x86/mm: Disallow vsyscall page read for copy_from_kernel_nofault()
When trying to use copy_from_kernel_nofault() to read vsyscall page through a bpf program, the following oops was reported:
BUG: unable to handle page fault for address: ffffffffff600000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 3231067 P4D 3231067 PUD 3233067 PMD 3235067 PTE 0
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 1 PID: 20390 Comm: test_progs ...... 6.7.0+ #58
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ......
RIP: 0010:copy_from_kernel_nofault+0x6f/0x110
......
Call Trace:
The oops is triggered when:
1) A bpf program uses bpf_probe_read_kernel() to read from the vsyscall page and invokes copy_from_kernel_nofault() which in turn calls __get_user_asm().
2) Because the vsyscall page address is not readable from kernel space, a page fault exception is triggered accordingly.
3) handle_page_fault() considers the vsyscall page address as a user space address instead of a kernel space address. This results in the fix-up setup by bpf not being applied and a page_fault_oops() is invoked due to SMAP.
Considering handle_page_fault() has already considered the vsyscall page address as a userspace address, fix the problem by disallowing vsyscall page read for copy_from_kernel_nofault().
{
"affected": [],
"aliases": [
"CVE-2024-26906"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-04-17T11:15:11Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/mm: Disallow vsyscall page read for copy_from_kernel_nofault()\n\nWhen trying to use copy_from_kernel_nofault() to read vsyscall page\nthrough a bpf program, the following oops was reported:\n\n BUG: unable to handle page fault for address: ffffffffff600000\n #PF: supervisor read access in kernel mode\n #PF: error_code(0x0000) - not-present page\n PGD 3231067 P4D 3231067 PUD 3233067 PMD 3235067 PTE 0\n Oops: 0000 [#1] PREEMPT SMP PTI\n CPU: 1 PID: 20390 Comm: test_progs ...... 6.7.0+ #58\n Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ......\n RIP: 0010:copy_from_kernel_nofault+0x6f/0x110\n ......\n Call Trace:\n \u003cTASK\u003e\n ? copy_from_kernel_nofault+0x6f/0x110\n bpf_probe_read_kernel+0x1d/0x50\n bpf_prog_2061065e56845f08_do_probe_read+0x51/0x8d\n trace_call_bpf+0xc5/0x1c0\n perf_call_bpf_enter.isra.0+0x69/0xb0\n perf_syscall_enter+0x13e/0x200\n syscall_trace_enter+0x188/0x1c0\n do_syscall_64+0xb5/0xe0\n entry_SYSCALL_64_after_hwframe+0x6e/0x76\n \u003c/TASK\u003e\n ......\n ---[ end trace 0000000000000000 ]---\n\nThe oops is triggered when:\n\n1) A bpf program uses bpf_probe_read_kernel() to read from the vsyscall\npage and invokes copy_from_kernel_nofault() which in turn calls\n__get_user_asm().\n\n2) Because the vsyscall page address is not readable from kernel space,\na page fault exception is triggered accordingly.\n\n3) handle_page_fault() considers the vsyscall page address as a user\nspace address instead of a kernel space address. This results in the\nfix-up setup by bpf not being applied and a page_fault_oops() is invoked\ndue to SMAP.\n\nConsidering handle_page_fault() has already considered the vsyscall page\naddress as a userspace address, fix the problem by disallowing vsyscall\npage read for copy_from_kernel_nofault().",
"id": "GHSA-h4jh-5vqp-vw3p",
"modified": "2024-06-26T00:31:38Z",
"published": "2024-04-17T12:32:05Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-26906"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/29bd6f86904682adafe9affbc7f79b14defcaff8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/32019c659ecfe1d92e3bf9fcdfbb11a7c70acd58"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/57f78c46f08198e1be08ffe99c4c1ccc12855bf5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6e4694e65b6db4c3de125115dd4f55848cc48381"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e8a67fe34b76a49320b33032228a794f40b0316b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f175de546a3eb77614d94d4c02550181c0a8493e"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html"
}
],
"schema_version": "1.4.0",
"severity": []
}