From: Kumar Kartikeya Dwivedi <memxor@gmail.com>
To: bpf@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Martin KaFai Lau <martin.lau@kernel.org>,
Joanne Koong <joannelkoong@gmail.com>,
David Vernet <void@manifault.com>
Subject: [PATCH bpf-next v1 11/13] selftests/bpf: Add dynptr var_off tests
Date: Tue, 18 Oct 2022 19:29:18 +0530 [thread overview]
Message-ID: <20221018135920.726360-12-memxor@gmail.com> (raw)
In-Reply-To: <20221018135920.726360-1-memxor@gmail.com>
Ensure that variable offset is handled correctly, and verifier takes
both fixed and variable part into account. Also ensure that only
constant var_off is allowed.
Make sure that unprivileged BPF cannot use var_off for dynptr.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
---
tools/testing/selftests/bpf/verifier/dynptr.c | 38 ++++++++++++++++++-
1 file changed, 36 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/bpf/verifier/dynptr.c b/tools/testing/selftests/bpf/verifier/dynptr.c
index 798f4f7e0c57..1aa7241e8a9e 100644
--- a/tools/testing/selftests/bpf/verifier/dynptr.c
+++ b/tools/testing/selftests/bpf/verifier/dynptr.c
@@ -1,5 +1,5 @@
{
- "dynptr: rewrite dynptr slot",
+ "dynptr: rewrite dynptr slot (pruning)",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_LD_MAP_FD(BPF_REG_6, 0),
@@ -26,7 +26,7 @@
.errstr = "arg 1 is an unacquired reference",
},
{
- "dynptr: type confusion",
+ "dynptr: type confusion (pruning)",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_LD_MAP_FD(BPF_REG_6, 0),
@@ -88,3 +88,37 @@
.result = REJECT,
.errstr = "arg 1 is an unacquired reference",
},
+{
+ "dynptr: rewrite dynptr slot (var_off)",
+ .insns = {
+ BPF_ST_MEM(BPF_W, BPF_REG_10, -4, 16),
+ BPF_LDX_MEM(BPF_W, BPF_REG_8, BPF_REG_10, -4),
+ BPF_JMP_IMM(BPF_JGE, BPF_REG_8, 0, 2),
+ BPF_MOV64_IMM(BPF_REG_0, 1),
+ BPF_EXIT_INSN(),
+ BPF_JMP_IMM(BPF_JLE, BPF_REG_8, 16, 2),
+ BPF_MOV64_IMM(BPF_REG_0, 1),
+ BPF_EXIT_INSN(),
+ BPF_ALU64_IMM(BPF_AND, BPF_REG_8, 16),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_MOV64_IMM(BPF_REG_2, 8),
+ BPF_MOV64_IMM(BPF_REG_3, 0),
+ BPF_MOV64_REG(BPF_REG_4, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, -32),
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_4, BPF_REG_8),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_ringbuf_reserve_dynptr),
+ BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, 0xeB9F),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -32),
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_8),
+ BPF_MOV64_IMM(BPF_REG_2, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_ringbuf_discard_dynptr),
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_8),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map_ringbuf = { 9 },
+ .result_unpriv = REJECT,
+ .errstr_unpriv = "R4 variable stack access prohibited for !root, var_off=(0x0; 0x10) off=-32",
+ .result = REJECT,
+ .errstr = "dynptr has to be at the constant offset",
+},
--
2.38.0
next prev parent reply other threads:[~2022-10-18 14:00 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-18 13:59 [PATCH bpf-next v1 00/13] Fixes for dynptr Kumar Kartikeya Dwivedi
2022-10-18 13:59 ` [PATCH bpf-next v1 01/13] bpf: Refactor ARG_PTR_TO_DYNPTR checks into process_dynptr_func Kumar Kartikeya Dwivedi
2022-10-18 19:45 ` David Vernet
2022-10-19 6:04 ` Kumar Kartikeya Dwivedi
2022-10-19 15:26 ` David Vernet
2022-10-19 22:59 ` Joanne Koong
2022-10-20 0:55 ` Kumar Kartikeya Dwivedi
2022-10-18 13:59 ` [PATCH bpf-next v1 02/13] bpf: Rework process_dynptr_func Kumar Kartikeya Dwivedi
2022-10-18 23:16 ` David Vernet
2022-10-19 6:18 ` Kumar Kartikeya Dwivedi
2022-10-19 16:05 ` David Vernet
2022-10-20 1:09 ` Kumar Kartikeya Dwivedi
2022-10-18 13:59 ` [PATCH bpf-next v1 03/13] bpf: Rename confusingly named RET_PTR_TO_ALLOC_MEM Kumar Kartikeya Dwivedi
2022-10-18 21:38 ` sdf
2022-10-19 6:19 ` Kumar Kartikeya Dwivedi
2022-11-07 22:35 ` Joanne Koong
2022-11-07 23:12 ` Kumar Kartikeya Dwivedi
2022-10-18 13:59 ` [PATCH bpf-next v1 04/13] bpf: Rework check_func_arg_reg_off Kumar Kartikeya Dwivedi
2022-10-18 21:55 ` sdf
2022-10-19 6:24 ` Kumar Kartikeya Dwivedi
2022-11-07 23:17 ` Joanne Koong
2022-11-08 18:22 ` Kumar Kartikeya Dwivedi
2022-10-18 13:59 ` [PATCH bpf-next v1 05/13] bpf: Fix state pruning for STACK_DYNPTR stack slots Kumar Kartikeya Dwivedi
2022-11-08 20:22 ` Joanne Koong
2022-11-09 18:39 ` Kumar Kartikeya Dwivedi
2022-11-10 0:41 ` Joanne Koong
2022-10-18 13:59 ` [PATCH bpf-next v1 06/13] bpf: Fix missing var_off check for ARG_PTR_TO_DYNPTR Kumar Kartikeya Dwivedi
2022-10-19 18:52 ` Alexei Starovoitov
2022-10-20 1:04 ` Kumar Kartikeya Dwivedi
2022-10-20 2:13 ` Alexei Starovoitov
2022-10-20 2:40 ` Kumar Kartikeya Dwivedi
2022-10-20 2:56 ` Alexei Starovoitov
2022-10-20 3:23 ` Kumar Kartikeya Dwivedi
2022-10-21 0:46 ` Alexei Starovoitov
2022-10-21 1:53 ` Kumar Kartikeya Dwivedi
2022-10-18 13:59 ` [PATCH bpf-next v1 07/13] bpf: Fix partial dynptr stack slot reads/writes Kumar Kartikeya Dwivedi
2022-10-21 22:50 ` Joanne Koong
2022-10-21 22:57 ` Joanne Koong
2022-10-22 4:08 ` Kumar Kartikeya Dwivedi
2022-11-03 14:07 ` Joanne Koong
2022-11-04 22:14 ` Andrii Nakryiko
2022-11-04 23:02 ` Kumar Kartikeya Dwivedi
2022-11-04 23:08 ` Andrii Nakryiko
2022-10-18 13:59 ` [PATCH bpf-next v1 08/13] bpf: Use memmove for bpf_dynptr_{read,write} Kumar Kartikeya Dwivedi
2022-10-21 18:12 ` Joanne Koong
2022-10-18 13:59 ` [PATCH bpf-next v1 09/13] selftests/bpf: Add test for dynptr reinit in user_ringbuf callback Kumar Kartikeya Dwivedi
2022-10-19 16:59 ` David Vernet
2022-10-18 13:59 ` [PATCH bpf-next v1 10/13] selftests/bpf: Add dynptr pruning tests Kumar Kartikeya Dwivedi
2022-10-18 13:59 ` Kumar Kartikeya Dwivedi [this message]
2022-10-18 13:59 ` [PATCH bpf-next v1 12/13] selftests/bpf: Add dynptr partial slot overwrite tests Kumar Kartikeya Dwivedi
2022-10-18 13:59 ` [PATCH bpf-next v1 13/13] selftests/bpf: Add dynptr helper tests Kumar Kartikeya Dwivedi
2023-10-31 7:05 ` CVE-2023-39191 - Dynptr fixes - reg Nandhini Rengaraj
2023-10-31 7:13 ` Greg KH
2023-10-31 7:57 ` Shung-Hsi Yu
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