CVE-2021-47300
bpf: Fix tail_call_reachable rejection for interpreter when jit failed
Severity Score
Exploit Likelihood
Affected Versions
Public Exploits
0Exploited in Wild
-Decision
Descriptions
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix tail_call_reachable rejection for interpreter when jit failed
During testing of f263a81451c1 ("bpf: Track subprog poke descriptors correctly
and fix use-after-free") under various failure conditions, for example, when
jit_subprogs() fails and tries to clean up the program to be run under the
interpreter, we ran into the following freeze:
[...]
#127/8 tailcall_bpf2bpf_3:FAIL
[...]
[ 92.041251] BUG: KASAN: slab-out-of-bounds in ___bpf_prog_run+0x1b9d/0x2e20
[ 92.042408] Read of size 8 at addr ffff88800da67f68 by task test_progs/682
[ 92.043707]
[ 92.044030] CPU: 1 PID: 682 Comm: test_progs Tainted: G O 5.13.0-53301-ge6c08cb33a30-dirty #87
[ 92.045542] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014
[ 92.046785] Call Trace:
[ 92.047171] ? __bpf_prog_run_args64+0xc0/0xc0
[ 92.047773] ? __bpf_prog_run_args32+0x8b/0xb0
[ 92.048389] ? __bpf_prog_run_args64+0xc0/0xc0
[ 92.049019] ? ktime_get+0x117/0x130
[...] // few hundred [similar] lines more
[ 92.659025] ? ktime_get+0x117/0x130
[ 92.659845] ? __bpf_prog_run_args64+0xc0/0xc0
[ 92.660738] ? __bpf_prog_run_args32+0x8b/0xb0
[ 92.661528] ? __bpf_prog_run_args64+0xc0/0xc0
[ 92.662378] ? print_usage_bug+0x50/0x50
[ 92.663221] ? print_usage_bug+0x50/0x50
[ 92.664077] ? bpf_ksym_find+0x9c/0xe0
[ 92.664887] ? ktime_get+0x117/0x130
[ 92.665624] ? kernel_text_address+0xf5/0x100
[ 92.666529] ? __kernel_text_address+0xe/0x30
[ 92.667725] ? unwind_get_return_address+0x2f/0x50
[ 92.668854] ? ___bpf_prog_run+0x15d4/0x2e20
[ 92.670185] ? ktime_get+0x117/0x130
[ 92.671130] ? __bpf_prog_run_args64+0xc0/0xc0
[ 92.672020] ? __bpf_prog_run_args32+0x8b/0xb0
[ 92.672860] ? __bpf_prog_run_args64+0xc0/0xc0
[ 92.675159] ? ktime_get+0x117/0x130
[ 92.677074] ? lock_is_held_type+0xd5/0x130
[ 92.678662] ? ___bpf_prog_run+0x15d4/0x2e20
[ 92.680046] ? ktime_get+0x117/0x130
[ 92.681285] ? __bpf_prog_run32+0x6b/0x90
[ 92.682601] ? __bpf_prog_run64+0x90/0x90
[ 92.683636] ? lock_downgrade+0x370/0x370
[ 92.684647] ? mark_held_locks+0x44/0x90
[ 92.685652] ? ktime_get+0x117/0x130
[ 92.686752] ? lockdep_hardirqs_on+0x79/0x100
[ 92.688004] ? ktime_get+0x117/0x130
[ 92.688573] ? __cant_migrate+0x2b/0x80
[ 92.689192] ? bpf_test_run+0x2f4/0x510
[ 92.689869] ? bpf_test_timer_continue+0x1c0/0x1c0
[ 92.690856] ? rcu_read_lock_bh_held+0x90/0x90
[ 92.691506] ? __kasan_slab_alloc+0x61/0x80
[ 92.692128] ? eth_type_trans+0x128/0x240
[ 92.692737] ? __build_skb+0x46/0x50
[ 92.693252] ? bpf_prog_test_run_skb+0x65e/0xc50
[ 92.693954] ? bpf_prog_test_run_raw_tp+0x2d0/0x2d0
[ 92.694639] ? __fget_light+0xa1/0x100
[ 92.695162] ? bpf_prog_inc+0x23/0x30
[ 92.695685] ? __sys_bpf+0xb40/0x2c80
[ 92.696324] ? bpf_link_get_from_fd+0x90/0x90
[ 92.697150] ? mark_held_locks+0x24/0x90
[ 92.698007] ? lockdep_hardirqs_on_prepare+0x124/0x220
[ 92.699045] ? finish_task_switch+0xe6/0x370
[ 92.700072] ? lockdep_hardirqs_on+0x79/0x100
[ 92.701233] ? finish_task_switch+0x11d/0x370
[ 92.702264] ? __switch_to+0x2c0/0x740
[ 92.703148] ? mark_held_locks+0x24/0x90
[ 92.704155] ? __x64_sys_bpf+0x45/0x50
[ 92.705146] ? do_syscall_64+0x35/0x80
[ 92.706953] ? entry_SYSCALL_64_after_hwframe+0x44/0xae
[...]
Turns out that the program rejection from e411901c0b77 ("bpf: allow for tailcalls
in BPF subprograms for x64 JIT") is buggy since env->prog->aux->tail_call_reachable
is never true. Commit ebf7d1f508a7 ("bpf, x64: rework pro/epilogue and tailcall
handling in JIT") added a tracker into check_max_stack_depth() which propagates
the tail_call_reachable condition throughout the subprograms. This info is then
assigned to the subprogram's
---truncated---
En el kernel de Linux, se resolvió la siguiente vulnerabilidad: bpf: corrige el rechazo de tail_call_reachable para el intérprete cuando falla jit. Durante las pruebas de f263a81451c1 ("bpf: rastrea correctamente los descriptores de inserción del subprog y corrige el use after free") bajo varias condiciones de fallo, por Por ejemplo, cuando jit_subprogs() falla e intenta limpiar el programa que se ejecutará bajo el intérprete, nos encontramos con el siguiente congelamiento: [...] #127/8 tailcall_bpf2bpf_3:FAIL [...] [ 92.041251] ERROR: KASAN: slab fuera de los límites en ___bpf_prog_run+0x1b9d/0x2e20 [92.042408] Lectura de tamaño 8 en la dirección ffff88800da67f68 por tarea test_progs/682 [92.043707] [92.044030] CPU: 1 PID: 682 Comm: _progs Contaminado: GO 5.13. 0-53301-ge6c08cb33a30-dirty #87 [92.045542] Nombre del hardware: PC estándar QEMU (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 01/04/2014 [92.046785] Seguimiento de llamadas: [92.047171] ? __bpf_prog_run_args64+0xc0/0xc0 [92.047773]? __bpf_prog_run_args32+0x8b/0xb0 [92.048389]? __bpf_prog_run_args64+0xc0/0xc0 [92.049019]? ktime_get+0x117/0x130 [...] // ¿unos cientos de líneas [similares] más [92.659025]? ktime_get+0x117/0x130 [92.659845]? __bpf_prog_run_args64+0xc0/0xc0 [92.660738]? __bpf_prog_run_args32+0x8b/0xb0 [92.661528]? __bpf_prog_run_args64+0xc0/0xc0 [92.662378]? print_usage_bug+0x50/0x50 [92.663221]? print_usage_bug+0x50/0x50 [92.664077]? bpf_ksym_find+0x9c/0xe0 [92.664887]? ktime_get+0x117/0x130 [92.665624]? kernel_text_address+0xf5/0x100 [92.666529]? __kernel_text_address+0xe/0x30 [ 92.667725] ? unwind_get_return_address+0x2f/0x50 [92.668854]? ___bpf_prog_run+0x15d4/0x2e20 [ 92.670185] ? ktime_get+0x117/0x130 [92.671130]? __bpf_prog_run_args64+0xc0/0xc0 [92.672020]? __bpf_prog_run_args32+0x8b/0xb0 [92.672860]? __bpf_prog_run_args64+0xc0/0xc0 [92.675159]? ktime_get+0x117/0x130 [92.677074]? lock_is_held_type+0xd5/0x130 [92.678662]? ___bpf_prog_run+0x15d4/0x2e20 [ 92.680046] ? ktime_get+0x117/0x130 [92.681285]? __bpf_prog_run32+0x6b/0x90 [92.682601]? __bpf_prog_run64+0x90/0x90 [92.683636]? lock_downgrade+0x370/0x370 [92.684647]? mark_held_locks+0x44/0x90 [92.685652]? ktime_get+0x117/0x130 [92.686752]? lockdep_hardirqs_on+0x79/0x100 [92.688004]? ktime_get+0x117/0x130 [92.688573]? __cant_migrate+0x2b/0x80 [ 92.689192] ? bpf_test_run+0x2f4/0x510 [92.689869]? bpf_test_timer_continue+0x1c0/0x1c0 [92.690856]? rcu_read_lock_bh_held+0x90/0x90 [92.691506]? __kasan_slab_alloc+0x61/0x80 [92.692128]? eth_type_trans+0x128/0x240 [92.692737]? __build_skb+0x46/0x50 [92.693252]? bpf_prog_test_run_skb+0x65e/0xc50 [92.693954]? bpf_prog_test_run_raw_tp+0x2d0/0x2d0 [92.694639]? __fget_light+0xa1/0x100 [ 92.695162] ? bpf_prog_inc+0x23/0x30 [92.695685]? __sys_bpf+0xb40/0x2c80 [92.696324]? bpf_link_get_from_fd+0x90/0x90 [92.697150]? mark_held_locks+0x24/0x90 [92.698007]? lockdep_hardirqs_on_prepare+0x124/0x220 [92.699045]? finish_task_switch+0xe6/0x370 [92.700072]? lockdep_hardirqs_on+0x79/0x100 [92.701233]? finish_task_switch+0x11d/0x370 [92.702264]? __switch_to+0x2c0/0x740 [ 92.703148] ? mark_held_locks+0x24/0x90 [92.704155]? __x64_sys_bpf+0x45/0x50 [92.705146]? do_syscall_64+0x35/0x80 [92.706953]? Entry_SYSCALL_64_after_hwframe+0x44/0xae [...] Resulta que el rechazo del programa de e411901c0b77 ("bpf: permitir tailcalls en subprogramas BPF para x64 JIT") tiene errores ya que env->prog->aux->tail_call_reachable nunca es cierto. La confirmación ebf7d1f508a7 ("bpf, x64: reelaboración de pro/epílogo y manejo de tailcall en JIT") agregó un rastreador en check_max_stack_ Depth() que propaga la condición tail_call_reachable a través de los subprogramas. Esta información luego se asigna al ---truncado--- del subprograma.
CVSS Scores
SSVC
- Decision:Track
Timeline
- 2024-05-21 CVE Reserved
- 2024-05-21 CVE Published
- 2024-05-22 EPSS Updated
- 2024-12-19 CVE Updated
- ---------- Exploited in Wild
- ---------- KEV Due Date
- ---------- First Exploit
CWE
CAPEC
References (4)
URL | Tag | Source |
---|---|---|
https://git.kernel.org/stable/c/e411901c0b775a3ae7f3e2505f8d2d90ac696178 | Vuln. Introduced |
URL | Date | SRC |
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URL | Date | SRC |
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Affected Vendors, Products, and Versions
Vendor | Product | Version | Other | Status | ||||||
---|---|---|---|---|---|---|---|---|---|---|
Vendor | Product | Version | Other | Status | <-- --> | Vendor | Product | Version | Other | Status |
Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.10 < 5.10.54 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.10 < 5.10.54" | en |
Affected
| ||||||
Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.10 < 5.13.6 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.10 < 5.13.6" | en |
Affected
| ||||||
Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.10 < 5.14 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.10 < 5.14" | en |
Affected
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