5.5

CVE-2022-48940

bpf: Fix crash due to incorrect copy_map_value

In the Linux kernel, the following vulnerability has been resolved:

bpf: Fix crash due to incorrect copy_map_value

When both bpf_spin_lock and bpf_timer are present in a BPF map value,
copy_map_value needs to skirt both objects when copying a value into and
out of the map. However, the current code does not set both s_off and
t_off in copy_map_value, which leads to a crash when e.g. bpf_spin_lock
is placed in map value with bpf_timer, as bpf_map_update_elem call will
be able to overwrite the other timer object.

When the issue is not fixed, an overwriting can produce the following
splat:

[root@(none) bpf]# ./test_progs -t timer_crash
[   15.930339] bpf_testmod: loading out-of-tree module taints kernel.
[   16.037849] ==================================================================
[   16.038458] BUG: KASAN: user-memory-access in __pv_queued_spin_lock_slowpath+0x32b/0x520
[   16.038944] Write of size 8 at addr 0000000000043ec0 by task test_progs/325
[   16.039399]
[   16.039514] CPU: 0 PID: 325 Comm: test_progs Tainted: G           OE     5.16.0+ #278
[   16.039983] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ArchLinux 1.15.0-1 04/01/2014
[   16.040485] Call Trace:
[   16.040645]  <TASK>
[   16.040805]  dump_stack_lvl+0x59/0x73
[   16.041069]  ? __pv_queued_spin_lock_slowpath+0x32b/0x520
[   16.041427]  kasan_report.cold+0x116/0x11b
[   16.041673]  ? __pv_queued_spin_lock_slowpath+0x32b/0x520
[   16.042040]  __pv_queued_spin_lock_slowpath+0x32b/0x520
[   16.042328]  ? memcpy+0x39/0x60
[   16.042552]  ? pv_hash+0xd0/0xd0
[   16.042785]  ? lockdep_hardirqs_off+0x95/0xd0
[   16.043079]  __bpf_spin_lock_irqsave+0xdf/0xf0
[   16.043366]  ? bpf_get_current_comm+0x50/0x50
[   16.043608]  ? jhash+0x11a/0x270
[   16.043848]  bpf_timer_cancel+0x34/0xe0
[   16.044119]  bpf_prog_c4ea1c0f7449940d_sys_enter+0x7c/0x81
[   16.044500]  bpf_trampoline_6442477838_0+0x36/0x1000
[   16.044836]  __x64_sys_nanosleep+0x5/0x140
[   16.045119]  do_syscall_64+0x59/0x80
[   16.045377]  ? lock_is_held_type+0xe4/0x140
[   16.045670]  ? irqentry_exit_to_user_mode+0xa/0x40
[   16.046001]  ? mark_held_locks+0x24/0x90
[   16.046287]  ? asm_exc_page_fault+0x1e/0x30
[   16.046569]  ? asm_exc_page_fault+0x8/0x30
[   16.046851]  ? lockdep_hardirqs_on+0x7e/0x100
[   16.047137]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[   16.047405] RIP: 0033:0x7f9e4831718d
[   16.047602] Code: b4 0c 00 0f 05 eb a9 66 0f 1f 44 00 00 f3 0f 1e fa 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 b3 6c 0c 00 f7 d8 64 89 01 48
[   16.048764] RSP: 002b:00007fff488086b8 EFLAGS: 00000206 ORIG_RAX: 0000000000000023
[   16.049275] RAX: ffffffffffffffda RBX: 00007f9e48683740 RCX: 00007f9e4831718d
[   16.049747] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007fff488086d0
[   16.050225] RBP: 00007fff488086f0 R08: 00007fff488085d7 R09: 00007f9e4cb594a0
[   16.050648] R10: 0000000000000000 R11: 0000000000000206 R12: 00007f9e484cde30
[   16.051124] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[   16.051608]  </TASK>
[   16.051762] ==================================================================
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version >= 5.15 < 5.15.26
Linux ≫ Linux Kernel Version >= 5.16 < 5.16.12
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.21% 0.107
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
NIST 5.5 1.8 3.6
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.

https://git.kernel.org/stable/c/719d1c2524c89ada78c4c9202641c1d9e942a322
Patch
https://git.kernel.org/stable/c/a8abb0c3dc1e28454851a00f8b7333d9695d566c
Patch
https://git.kernel.org/stable/c/eca9bd215d2233de79d930fa97aefbce03247a98
Patch