From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Daniel Borkmann <daniel@iogearbox.net>
Subject: [PATCH 5.15 04/41] bpf: Fix out of bounds access from invalid *_or_null type verification
Date: Fri, 14 Jan 2022 09:16:04 +0100 [thread overview]
Message-ID: <20220114081545.310308233@linuxfoundation.org> (raw)
In-Reply-To: <20220114081545.158363487@linuxfoundation.org>
From: Daniel Borkmann <daniel@iogearbox.net>
[ no upstream commit given implicitly fixed through the larger refactoring
in c25b2ae136039ffa820c26138ed4a5e5f3ab3841 ]
While auditing some other code, I noticed missing checks inside the pointer
arithmetic simulation, more specifically, adjust_ptr_min_max_vals(). Several
*_OR_NULL types are not rejected whereas they are _required_ to be rejected
given the expectation is that they get promoted into a 'real' pointer type
for the success case, that is, after an explicit != NULL check.
One case which stands out and is accessible from unprivileged (iff enabled
given disabled by default) is BPF ring buffer. From crafting a PoC, the NULL
check can be bypassed through an offset, and its id marking will then lead
to promotion of mem_or_null to a mem type.
bpf_ringbuf_reserve() helper can trigger this case through passing of reserved
flags, for example.
func#0 @0
0: R1=ctx(id=0,off=0,imm=0) R10=fp0
0: (7a) *(u64 *)(r10 -8) = 0
1: R1=ctx(id=0,off=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm
1: (18) r1 = 0x0
3: R1_w=map_ptr(id=0,off=0,ks=0,vs=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm
3: (b7) r2 = 8
4: R1_w=map_ptr(id=0,off=0,ks=0,vs=0,imm=0) R2_w=invP8 R10=fp0 fp-8_w=mmmmmmmm
4: (b7) r3 = 0
5: R1_w=map_ptr(id=0,off=0,ks=0,vs=0,imm=0) R2_w=invP8 R3_w=invP0 R10=fp0 fp-8_w=mmmmmmmm
5: (85) call bpf_ringbuf_reserve#131
6: R0_w=mem_or_null(id=2,ref_obj_id=2,off=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm refs=2
6: (bf) r6 = r0
7: R0_w=mem_or_null(id=2,ref_obj_id=2,off=0,imm=0) R6_w=mem_or_null(id=2,ref_obj_id=2,off=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm refs=2
7: (07) r0 += 1
8: R0_w=mem_or_null(id=2,ref_obj_id=2,off=1,imm=0) R6_w=mem_or_null(id=2,ref_obj_id=2,off=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm refs=2
8: (15) if r0 == 0x0 goto pc+4
R0_w=mem(id=0,ref_obj_id=0,off=0,imm=0) R6_w=mem(id=0,ref_obj_id=2,off=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm refs=2
9: R0_w=mem(id=0,ref_obj_id=0,off=0,imm=0) R6_w=mem(id=0,ref_obj_id=2,off=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm refs=2
9: (62) *(u32 *)(r6 +0) = 0
R0_w=mem(id=0,ref_obj_id=0,off=0,imm=0) R6_w=mem(id=0,ref_obj_id=2,off=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm refs=2
10: R0_w=mem(id=0,ref_obj_id=0,off=0,imm=0) R6_w=mem(id=0,ref_obj_id=2,off=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm refs=2
10: (bf) r1 = r6
11: R0_w=mem(id=0,ref_obj_id=0,off=0,imm=0) R1_w=mem(id=0,ref_obj_id=2,off=0,imm=0) R6_w=mem(id=0,ref_obj_id=2,off=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm refs=2
11: (b7) r2 = 0
12: R0_w=mem(id=0,ref_obj_id=0,off=0,imm=0) R1_w=mem(id=0,ref_obj_id=2,off=0,imm=0) R2_w=invP0 R6_w=mem(id=0,ref_obj_id=2,off=0,imm=0) R10=fp0 fp-8_w=mmmmmmmm refs=2
12: (85) call bpf_ringbuf_submit#132
13: R6=invP(id=0) R10=fp0 fp-8=mmmmmmmm
13: (b7) r0 = 0
14: R0_w=invP0 R6=invP(id=0) R10=fp0 fp-8=mmmmmmmm
14: (95) exit
from 8 to 13: safe
processed 15 insns (limit 1000000) max_states_per_insn 0 total_states 1 peak_states 1 mark_read 0
OK
All three commits, that is b121b341e598 ("bpf: Add PTR_TO_BTF_ID_OR_NULL support"),
457f44363a88 ("bpf: Implement BPF ring buffer and verifier support for it"), and the
afbf21dce668 ("bpf: Support readonly/readwrite buffers in verifier") suffer the same
cause and their *_OR_NULL type pendants must be rejected in adjust_ptr_min_max_vals().
Make the test more robust by reusing reg_type_may_be_null() helper such that we catch
all *_OR_NULL types we have today and in future.
Note that pointer arithmetic on PTR_TO_BTF_ID, PTR_TO_RDONLY_BUF, and PTR_TO_RDWR_BUF
is generally allowed.
Fixes: b121b341e598 ("bpf: Add PTR_TO_BTF_ID_OR_NULL support")
Fixes: 457f44363a88 ("bpf: Implement BPF ring buffer and verifier support for it")
Fixes: afbf21dce668 ("bpf: Support readonly/readwrite buffers in verifier")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/bpf/verifier.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -7039,16 +7039,16 @@ static int adjust_ptr_min_max_vals(struc
fallthrough;
case PTR_TO_PACKET_END:
case PTR_TO_SOCKET:
- case PTR_TO_SOCKET_OR_NULL:
case PTR_TO_SOCK_COMMON:
- case PTR_TO_SOCK_COMMON_OR_NULL:
case PTR_TO_TCP_SOCK:
- case PTR_TO_TCP_SOCK_OR_NULL:
case PTR_TO_XDP_SOCK:
+reject:
verbose(env, "R%d pointer arithmetic on %s prohibited\n",
dst, reg_type_str[ptr_reg->type]);
return -EACCES;
default:
+ if (reg_type_may_be_null(ptr_reg->type))
+ goto reject;
break;
}
next prev parent reply other threads:[~2022-01-14 8:21 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-14 8:16 [PATCH 5.15 00/41] 5.15.15-rc1 review Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 01/41] s390/kexec: handle R_390_PLT32DBL rela in arch_kexec_apply_relocations_add() Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 02/41] workqueue: Fix unbind_workers() VS wq_worker_running() race Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 03/41] staging: r8188eu: switch the led off during deinit Greg Kroah-Hartman
2022-01-14 8:16 ` Greg Kroah-Hartman [this message]
2022-01-14 8:16 ` [PATCH 5.15 05/41] Bluetooth: btusb: Add protocol for MediaTek bluetooth devices(MT7922) Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 06/41] Bluetooth: btusb: Add the new support ID for Realtek RTL8852A Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 07/41] Bluetooth: btusb: Add support for IMC Networks Mediatek Chip(MT7921) Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 08/41] Bbluetooth: btusb: Add another Bluetooth part for Realtek 8852AE Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 09/41] Bluetooth: btusb: fix memory leak in btusb_mtk_submit_wmt_recv_urb() Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 10/41] Bluetooth: btusb: enable Mediatek to support AOSP extension Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 11/41] Bluetooth: btusb: Add one more Bluetooth part for the Realtek RTL8852AE Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 12/41] Bluetooth: btusb: Add the new support IDs for WCN6855 Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 13/41] fget: clarify and improve __fget_files() implementation Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 14/41] Bluetooth: btusb: Add one more Bluetooth part for WCN6855 Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 15/41] Bluetooth: btusb: Add two more Bluetooth parts " Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 16/41] Bluetooth: btusb: Add support for Foxconn MT7922A Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 17/41] Bluetooth: btintel: Fix broken LED quirk for legacy ROM devices Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 18/41] Bluetooth: btusb: Add support for Foxconn QCA 0xe0d0 Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 19/41] Bluetooth: bfusb: fix division by zero in send path Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 20/41] ARM: dts: exynos: Fix BCM4330 Bluetooth reset polarity in I9100 Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 21/41] USB: core: Fix bug in resuming hubs handling of wakeup requests Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 22/41] USB: Fix "slab-out-of-bounds Write" bug in usb_hcd_poll_rh_status Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 23/41] ath11k: Fix buffer overflow when scanning with extraie Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 24/41] mmc: sdhci-pci: Add PCI ID for Intel ADL Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 25/41] Bluetooth: add quirk disabling LE Read Transmit Power Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 26/41] Bluetooth: btbcm: disable read tx power for some Macs with the T2 Security chip Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 27/41] Bluetooth: btbcm: disable read tx power for MacBook Air 8,1 and 8,2 Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 28/41] veth: Do not record rx queue hint in veth_xmit Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 29/41] mfd: intel-lpss: Fix too early PM enablement in the ACPI ->probe() Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 30/41] x86/mce: Remove noinstr annotation from mce_setup() Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 31/41] can: gs_usb: fix use of uninitialized variable, detach device on reception of invalid USB data Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 32/41] can: isotp: convert struct tpcon::{idx,len} to unsigned int Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 33/41] can: gs_usb: gs_can_start_xmit(): zero-initialize hf->{flags,reserved} Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 34/41] random: fix data race on crng_node_pool Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 35/41] random: fix data race on crng init time Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 36/41] random: fix crash on multiple early calls to add_bootloader_randomness() Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 37/41] platform/x86/intel: hid: add quirk to support Surface Go 3 Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 38/41] media: Revert "media: uvcvideo: Set unique vdev name based in type" Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 39/41] staging: wlan-ng: Avoid bitwise vs logical OR warning in hfa384x_usb_throttlefn() Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 40/41] drm/i915: Avoid bitwise vs logical OR warning in snb_wm_latency_quirk() Greg Kroah-Hartman
2022-01-14 8:16 ` [PATCH 5.15 41/41] staging: greybus: fix stack size warning with UBSAN Greg Kroah-Hartman
2022-01-14 17:43 ` [PATCH 5.15 00/41] 5.15.15-rc1 review Naresh Kamboju
2022-01-14 19:59 ` Ron Economos
2022-01-15 8:14 ` Greg Kroah-Hartman
2022-01-15 11:52 ` Ron Economos
2022-01-15 12:15 ` Greg Kroah-Hartman
2022-01-15 12:31 ` Ron Economos
2022-01-14 22:29 ` Florian Fainelli
2022-01-14 23:32 ` Fox Chen
2022-01-15 0:24 ` Shuah Khan
2022-01-15 11:03 ` Sudip Mukherjee
2022-01-15 14:47 ` Andrei Rabusov
2022-01-15 16:39 ` Guenter Roeck
2022-01-15 16:48 ` Jeffrin Jose T
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