CVE-2024-38601

CVE Details

Release Date:

2024-06-19

Description

In the Linux kernel, the following vulnerability has been resolved:\nring-buffer: Fix a race between readers and resize checks\nThe reader code in rb_get_reader_page() swaps a new reader page into the\nring buffer by doing cmpxchg on old->list.prev->next to point it to the\nnew page. Following that, if the operation is successful,\nold->list.next->prev gets updated too. This means the underlying\ndoubly-linked list is temporarily inconsistent, page->prev->next or\npage->next->prev might not be equal back to page for some page in the\nring buffer.\nThe resize operation in ring_buffer_resize() can be invoked in parallel.\nIt calls rb_check_pages() which can detect the described inconsistency\nand stop further tracing:\n[ 190.271762] ------------[ cut here ]------------\n[ 190.271771] WARNING: CPU: 1 PID: 6186 at kernel/trace/ring_buffer.c:1467 rb_check_pages.isra.0+0x6a/0xa0\n[ 190.271789] Modules linked in: [...]\n[ 190.271991] Unloaded tainted modules: intel_uncore_frequency(E):1 skx_edac(E):1\n[ 190.272002] CPU: 1 PID: 6186 Comm: cmd.sh Kdump: loaded Tainted: G E 6.9.0-rc6-default #5 158d3e1e6d0b091c34c3b96bfd99a1c58306d79f\n[ 190.272011] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.0-0-gd239552c-rebuilt.opensuse.org 04/01/2014\n[ 190.272015] RIP: 0010:rb_check_pages.isra.0+0x6a/0xa0\n[ 190.272023] Code: [...]\n[ 190.272028] RSP: 0018:ffff9c37463abb70 EFLAGS: 00010206\n[ 190.272034] RAX: ffff8eba04b6cb80 RBX: 0000000000000007 RCX: ffff8eba01f13d80\n[ 190.272038] RDX: ffff8eba01f130c0 RSI: ffff8eba04b6cd00 RDI: ffff8eba0004c700\n[ 190.272042] RBP: ffff8eba0004c700 R08: 0000000000010002 R09: 0000000000000000\n[ 190.272045] R10: 00000000ffff7f52 R11: ffff8eba7f600000 R12: ffff8eba0004c720\n[ 190.272049] R13: ffff8eba00223a00 R14: 0000000000000008 R15: ffff8eba067a8000\n[ 190.272053] FS: 00007f1bd64752c0(0000) GS:ffff8eba7f680000(0000) knlGS:0000000000000000\n[ 190.272057] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[ 190.272061] CR2: 00007f1bd6662590 CR3: 000000010291e001 CR4: 0000000000370ef0\n[ 190.272070] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n[ 190.272073] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n[ 190.272077] Call Trace:\n[ 190.272098] \n[ 190.272189] ring_buffer_resize+0x2ab/0x460\n[ 190.272199] __tracing_resize_ring_buffer.part.0+0x23/0xa0\n[ 190.272206] tracing_resize_ring_buffer+0x65/0x90\n[ 190.272216] tracing_entries_write+0x74/0xc0\n[ 190.272225] vfs_write+0xf5/0x420\n[ 190.272248] ksys_write+0x67/0xe0\n[ 190.272256] do_syscall_64+0x82/0x170\n[ 190.272363] entry_SYSCALL_64_after_hwframe+0x76/0x7e\n[ 190.272373] RIP: 0033:0x7f1bd657d263\n[ 190.272381] Code: [...]\n[ 190.272385] RSP: 002b:00007ffe72b643f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001\n[ 190.272391] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f1bd657d263\n[ 190.272395] RDX: 0000000000000002 RSI: 0000555a6eb538e0 RDI: 0000000000000001\n[ 190.272398] RBP: 0000555a6eb538e0 R08: 000000000000000a R09: 0000000000000000\n[ 190.272401] R10: 0000555a6eb55190 R11: 0000000000000246 R12: 00007f1bd6662500\n[ 190.272404] R13: 0000000000000002 R14: 00007f1bd6667c00 R15: 0000000000000002\n[ 190.272412] \n[ 190.272414] ---[ end trace 0000000000000000 ]---\nNote that ring_buffer_resize() calls rb_check_pages() only if the parent\ntrace_buffer has recording disabled. Recent commit d78ab792705c\n('tracing: Stop current tracer when resizing buffer') causes that it is\nnow always the case which makes it more likely to experience this issue.\nThe window to hit this race is nonetheless very small. To help\nreproducing it, one can add a delay loop in rb_get_reader_page():\nret = rb_head_page_replace(reader, cpu_buffer->reader_page);\nif (!ret)\ngoto spin;\nfor (unsigned i = 0; i < 1U << 26; i++) /* inserted delay loop */\n__asm__ __volatile__ ('' : : : 'memory');\nrb_list_head(reader->list.next)->prev = &cpu_buffer->reader_page->list;\n.. \n---truncated---

See more information about CVE-2024-38601 from MITRE CVE dictionary and NIST NVD

CVSS Scoring

NOTE: The following CVSS v3.1 metrics and score provided are preliminary and subject to review.

Base Score:	4.1	CVSS Vector:	CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
Attack Vector:	Local network	Attack Complexity:	High
Privileges Required:	High	User Interaction:	None
Scope:	Unchanged	Confidentiality Impact:	None
Integrity Impact:	None	Availability Impact:	High

Errata information

Platform	Errata	Release Date
Oracle Linux version 7 (kernel-uek)	ELSA-2024-12581	2024-08-12
Oracle Linux version 7 (kernel-uek)	ELSA-2024-12611	2024-09-11
Oracle Linux version 7 (kernel-uek-container)	ELSA-2024-12585	2024-08-12
Oracle Linux version 8 (kernel-uek)	ELSA-2024-12581	2024-08-12
Oracle Linux version 8 (kernel-uek-container)	ELSA-2024-12584	2024-08-12