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[129.132.31.88]) by smtp.gmail.com with ESMTPSA id fk15-20020a05600c0ccf00b0040849ce7116sm1453505wmb.43.2023.11.01.05.34.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 01 Nov 2023 05:34:00 -0700 (PDT) From: Hao Sun Date: Wed, 01 Nov 2023 13:33:52 +0100 Subject: [PATCH bpf v3 2/2] selftests/bpf: Add test for immediate spilled to stack Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20231101-fix-check-stack-write-v3-2-f05c2b1473d5@gmail.com> References: <20231101-fix-check-stack-write-v3-0-f05c2b1473d5@gmail.com> In-Reply-To: <20231101-fix-check-stack-write-v3-0-f05c2b1473d5@gmail.com> To: Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Mykola Lysenko , Shuah Khan , Eduard Zingerman , Shung-Hsi Yu Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Hao Sun X-Mailer: b4 0.12.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1698842036; l=1559; i=sunhao.th@gmail.com; s=20231009; h=from:subject:message-id; bh=X708/twj4ALP3sH/UCKpd3VcD0BtAnZ51P5Y+lRiPRs=; b=++oeE46PI1J1crf5k1aYBSJFGizoKfdmleJvtvCppmRPIRWoLkWYWOgFnuBuvRm0LbN0LU73p 3GjqBRHyVTzB9WCDwWMoEWvY2xJsO31BC3cO6OBZh0tFUue4GzS0CxR X-Developer-Key: i=sunhao.th@gmail.com; a=ed25519; pk=AHFxrImGtyqXOuw4f5xTNh4PGReb7hzD86ayyTZCXd4= X-Patchwork-Delegate: bpf@iogearbox.net Add a test to check if the verifier correctly reason about the sign of an immediate spilled to stack by BPF_ST instruction. Signed-off-by: Hao Sun --- tools/testing/selftests/bpf/verifier/bpf_st_mem.c | 32 +++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/tools/testing/selftests/bpf/verifier/bpf_st_mem.c b/tools/testing/selftests/bpf/verifier/bpf_st_mem.c index 3af2501082b2..b616575c3b00 100644 --- a/tools/testing/selftests/bpf/verifier/bpf_st_mem.c +++ b/tools/testing/selftests/bpf/verifier/bpf_st_mem.c @@ -65,3 +65,35 @@ .expected_attach_type = BPF_SK_LOOKUP, .runs = -1, }, +{ + "BPF_ST_MEM stack imm sign", + /* Check if verifier correctly reasons about sign of an + * immediate spilled to stack by BPF_ST instruction. + * + * fp[-8] = -44; + * r0 = fp[-8]; + * if r0 s< 0 goto ret0; + * r0 = -1; + * exit; + * ret0: + * r0 = 0; + * exit; + */ + .insns = { + BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, -44), + BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -8), + BPF_JMP_IMM(BPF_JSLT, BPF_REG_0, 0, 2), + BPF_MOV64_IMM(BPF_REG_0, -1), + BPF_EXIT_INSN(), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + /* Use prog type that requires return value in range [0, 1] */ + .prog_type = BPF_PROG_TYPE_SK_LOOKUP, + .expected_attach_type = BPF_SK_LOOKUP, + .result = VERBOSE_ACCEPT, + .runs = -1, + .errstr = "0: (7a) *(u64 *)(r10 -8) = -44 ; R10=fp0 fp-8_w=-44\ + 2: (c5) if r0 s< 0x0 goto pc+2\ + R0_w=-44", +},