Vulnerabilities > CVE-2022-48937 - Improper Locking vulnerability in Linux Kernel
Summary
In the Linux kernel, the following vulnerability has been resolved: io_uring: add a schedule point in io_add_buffers() Looping ~65535 times doing kmalloc() calls can trigger soft lockups, especially with DEBUG features (like KASAN). [ 253.536212] watchdog: BUG: soft lockup - CPU#64 stuck for 26s! [b219417889:12575] [ 253.544433] Modules linked in: vfat fat i2c_mux_pca954x i2c_mux spidev cdc_acm xhci_pci xhci_hcd sha3_generic gq(O) [ 253.544451] CPU: 64 PID: 12575 Comm: b219417889 Tainted: G S O 5.17.0-smp-DEV #801 [ 253.544457] RIP: 0010:kernel_text_address (./include/asm-generic/sections.h:192 ./include/linux/kallsyms.h:29 kernel/extable.c:67 kernel/extable.c:98) [ 253.544464] Code: 0f 93 c0 48 c7 c1 e0 63 d7 a4 48 39 cb 0f 92 c1 20 c1 0f b6 c1 5b 5d c3 90 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 53 48 89 fb <48> c7 c0 00 00 80 a0 41 be 01 00 00 00 48 39 c7 72 0c 48 c7 c0 40 [ 253.544468] RSP: 0018:ffff8882d8baf4c0 EFLAGS: 00000246 [ 253.544471] RAX: 1ffff1105b175e00 RBX: ffffffffa13ef09a RCX: 00000000a13ef001 [ 253.544474] RDX: ffffffffa13ef09a RSI: ffff8882d8baf558 RDI: ffffffffa13ef09a [ 253.544476] RBP: ffff8882d8baf4d8 R08: ffff8882d8baf5e0 R09: 0000000000000004 [ 253.544479] R10: ffff8882d8baf5e8 R11: ffffffffa0d59a50 R12: ffff8882eab20380 [ 253.544481] R13: ffffffffa0d59a50 R14: dffffc0000000000 R15: 1ffff1105b175eb0 [ 253.544483] FS: 00000000016d3380(0000) GS:ffff88af48c00000(0000) knlGS:0000000000000000 [ 253.544486] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 253.544488] CR2: 00000000004af0f0 CR3: 00000002eabfa004 CR4: 00000000003706e0 [ 253.544491] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 253.544492] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 253.544494] Call Trace: [ 253.544496] <TASK> [ 253.544498] ? io_queue_sqe (fs/io_uring.c:7143) [ 253.544505] __kernel_text_address (kernel/extable.c:78) [ 253.544508] unwind_get_return_address (arch/x86/kernel/unwind_frame.c:19) [ 253.544514] arch_stack_walk (arch/x86/kernel/stacktrace.c:27) [ 253.544517] ? io_queue_sqe (fs/io_uring.c:7143) [ 253.544521] stack_trace_save (kernel/stacktrace.c:123) [ 253.544527] ____kasan_kmalloc (mm/kasan/common.c:39 mm/kasan/common.c:45 mm/kasan/common.c:436 mm/kasan/common.c:515) [ 253.544531] ? ____kasan_kmalloc (mm/kasan/common.c:39 mm/kasan/common.c:45 mm/kasan/common.c:436 mm/kasan/common.c:515) [ 253.544533] ? __kasan_kmalloc (mm/kasan/common.c:524) [ 253.544535] ? kmem_cache_alloc_trace (./include/linux/kasan.h:270 mm/slab.c:3567) [ 253.544541] ? io_issue_sqe (fs/io_uring.c:4556 fs/io_uring.c:4589 fs/io_uring.c:6828) [ 253.544544] ? __io_queue_sqe (fs/io_uring.c:?) [ 253.544551] __kasan_kmalloc (mm/kasan/common.c:524) [ 253.544553] kmem_cache_alloc_trace (./include/linux/kasan.h:270 mm/slab.c:3567) [ 253.544556] ? io_issue_sqe (fs/io_uring.c:4556 fs/io_uring.c:4589 fs/io_uring.c:6828) [ 253.544560] io_issue_sqe (fs/io_uring.c:4556 fs/io_uring.c:4589 fs/io_uring.c:6828) [ 253.544564] ? __kasan_slab_alloc (mm/kasan/common.c:45 mm/kasan/common.c:436 mm/kasan/common.c:469) [ 253.544567] ? __kasan_slab_alloc (mm/kasan/common.c:39 mm/kasan/common.c:45 mm/kasan/common.c:436 mm/kasan/common.c:469) [ 253.544569] ? kmem_cache_alloc_bulk (mm/slab.h:732 mm/slab.c:3546) [ 253.544573] ? __io_alloc_req_refill (fs/io_uring.c:2078) [ 253.544578] ? io_submit_sqes (fs/io_uring.c:7441) [ 253.544581] ? __se_sys_io_uring_enter (fs/io_uring.c:10154 fs/io_uring.c:10096) [ 253.544584] ? __x64_sys_io_uring_enter (fs/io_uring.c:10096) [ 253.544587] ? do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80) [ 253.544590] ? entry_SYSCALL_64_after_hwframe (??:?) [ 253.544596] __io_queue_sqe (fs/io_uring.c:?) [ 253.544600] io_queue_sqe (fs/io_uring.c:7143) [ 253.544603] io_submit_sqe (fs/io_uring.c:?) [ 253.544608] io_submit_sqes (fs/io_uring.c:?) [ 253.544612] __se_sys_io_uring_enter (fs/io_uring.c:10154 fs/io_uri ---truncated---
Vulnerable Configurations
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Leveraging Race Conditions This attack targets a race condition occurring when multiple processes access and manipulate the same resource concurrently and the outcome of the execution depends on the particular order in which the access takes place. The attacker can leverage a race condition by "running the race", modifying the resource and modifying the normal execution flow. For instance a race condition can occur while accessing a file, the attacker can trick the system by replacing the original file with his version and cause the system to read the malicious file.
- Leveraging Race Conditions via Symbolic Links This attack leverages the use of symbolic links (Symlinks) in order to write to sensitive files. An attacker can create a Symlink link to a target file not otherwise accessible to her. When the privileged program tries to create a temporary file with the same name as the Symlink link, it will actually write to the target file pointed to by the attackers' Symlink link. If the attacker can insert malicious content in the temporary file she will be writing to the sensitive file by using the Symlink. The race occurs because the system checks if the temporary file exists, then creates the file. The attacker would typically create the Symlink during the interval between the check and the creation of the temporary file.