From: Maxim Mikityanskiy <maxtram95@gmail.com>
To: Eduard Zingerman <eddyz87@gmail.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Shung-Hsi Yu <shung-hsi.yu@suse.com>
Cc: John Fastabend <john.fastabend@gmail.com>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
Jiri Olsa <jolsa@kernel.org>, Mykola Lysenko <mykolal@fb.com>,
Shuah Khan <shuah@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Jesper Dangaard Brouer <hawk@kernel.org>,
bpf@vger.kernel.org, linux-kselftest@vger.kernel.org,
netdev@vger.kernel.org, Maxim Mikityanskiy <maxim@isovalent.com>
Subject: [PATCH bpf-next v2 05/15] selftests/bpf: Add a test case for 32-bit spill tracking
Date: Mon, 8 Jan 2024 22:51:59 +0200 [thread overview]
Message-ID: <20240108205209.838365-6-maxtram95@gmail.com> (raw)
In-Reply-To: <20240108205209.838365-1-maxtram95@gmail.com>
From: Maxim Mikityanskiy <maxim@isovalent.com>
When a range check is performed on a register that was 32-bit spilled to
the stack, the IDs of the two instances of the register are the same, so
the range should also be the same.
Signed-off-by: Maxim Mikityanskiy <maxim@isovalent.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
---
.../selftests/bpf/progs/verifier_spill_fill.c | 31 +++++++++++++++++++
1 file changed, 31 insertions(+)
diff --git a/tools/testing/selftests/bpf/progs/verifier_spill_fill.c b/tools/testing/selftests/bpf/progs/verifier_spill_fill.c
index 848f2930f599..f303ac19cf41 100644
--- a/tools/testing/selftests/bpf/progs/verifier_spill_fill.c
+++ b/tools/testing/selftests/bpf/progs/verifier_spill_fill.c
@@ -735,4 +735,35 @@ __naked void stack_load_preserves_const_precision_subreg(void)
: __clobber_common);
}
+SEC("xdp")
+__description("32-bit spilled reg range should be tracked")
+__success __retval(0)
+__naked void spill_32bit_range_track(void)
+{
+ asm volatile(" \
+ call %[bpf_ktime_get_ns]; \
+ /* Make r0 bounded. */ \
+ r0 &= 65535; \
+ /* Assign an ID to r0. */ \
+ r1 = r0; \
+ /* 32-bit spill r0 to stack. */ \
+ *(u32*)(r10 - 8) = r0; \
+ /* Boundary check on r0. */ \
+ if r0 < 1 goto l0_%=; \
+ /* 32-bit fill r1 from stack. */ \
+ r1 = *(u32*)(r10 - 8); \
+ /* r1 == r0 => r1 >= 1 always. */ \
+ if r1 >= 1 goto l0_%=; \
+ /* Dead branch: the verifier should prune it. \
+ * Do an invalid memory access if the verifier \
+ * follows it. \
+ */ \
+ r0 = *(u64*)(r9 + 0); \
+l0_%=: r0 = 0; \
+ exit; \
+" :
+ : __imm(bpf_ktime_get_ns)
+ : __clobber_all);
+}
+
char _license[] SEC("license") = "GPL";
--
2.43.0
next prev parent reply other threads:[~2024-01-08 20:52 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-08 20:51 [PATCH bpf-next v2 00/15] Improvements for tracking scalars in the BPF verifier Maxim Mikityanskiy
2024-01-08 20:51 ` [PATCH bpf-next v2 01/15] selftests/bpf: Fix the u64_offset_to_skb_data test Maxim Mikityanskiy
2024-01-08 20:51 ` [PATCH bpf-next v2 02/15] bpf: make infinite loop detection in is_state_visited() exact Maxim Mikityanskiy
2024-01-08 20:51 ` [PATCH bpf-next v2 03/15] selftests/bpf: check if imprecise stack spills confuse infinite loop detection Maxim Mikityanskiy
2024-01-08 20:51 ` [PATCH bpf-next v2 04/15] bpf: Make bpf_for_each_spilled_reg consider narrow spills Maxim Mikityanskiy
2024-01-08 20:51 ` Maxim Mikityanskiy [this message]
2024-01-08 20:52 ` [PATCH bpf-next v2 06/15] bpf: Add the assign_scalar_id_before_mov function Maxim Mikityanskiy
2024-01-08 20:52 ` [PATCH bpf-next v2 07/15] bpf: Add the get_reg_width function Maxim Mikityanskiy
2024-01-08 20:52 ` [PATCH bpf-next v2 08/15] bpf: Assign ID to scalars on spill Maxim Mikityanskiy
2024-01-08 20:52 ` [PATCH bpf-next v2 09/15] selftests/bpf: Test assigning " Maxim Mikityanskiy
2024-01-09 23:34 ` Andrii Nakryiko
2024-01-08 20:52 ` [PATCH bpf-next v2 10/15] bpf: Track spilled unbounded scalars Maxim Mikityanskiy
2024-01-12 19:10 ` Alexei Starovoitov
2024-01-12 20:44 ` Maxim Mikityanskiy
2024-01-12 20:50 ` Alexei Starovoitov
2024-01-08 20:52 ` [PATCH bpf-next v2 11/15] selftests/bpf: Test tracking " Maxim Mikityanskiy
2024-01-08 20:52 ` [PATCH bpf-next v2 12/15] bpf: Preserve boundaries and track scalars on narrowing fill Maxim Mikityanskiy
2024-01-09 23:51 ` Andrii Nakryiko
2024-01-08 20:52 ` [PATCH bpf-next v2 13/15] selftests/bpf: Add test cases for " Maxim Mikityanskiy
2024-01-09 23:55 ` Andrii Nakryiko
2024-01-08 20:52 ` [PATCH bpf-next v2 14/15] bpf: Optimize state pruning for spilled scalars Maxim Mikityanskiy
2024-01-10 0:22 ` Andrii Nakryiko
2024-01-10 21:04 ` Eduard Zingerman
2024-01-10 21:52 ` Andrii Nakryiko
2024-01-08 20:52 ` [PATCH bpf-next v2 15/15] selftests/bpf: states pruning checks for scalar vs STACK_{MISC,ZERO} Maxim Mikityanskiy
2024-01-10 0:27 ` Andrii Nakryiko
2024-01-10 20:27 ` Eduard Zingerman
2024-01-12 3:00 ` [PATCH bpf-next v2 00/15] Improvements for tracking scalars in the BPF verifier patchwork-bot+netdevbpf
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