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Commit 29200c19 authored by Josef Bacik's avatar Josef Bacik Committed by David S. Miller
Browse files

bpf: test for AND edge cases 



These two tests are based on the work done for f23cc643.  The first test is
just a basic one to make sure we don't allow AND'ing negative values, even if it
would result in a valid index for the array.  The second is a cleaned up version
of the original testcase provided by Jann Horn that resulted in the commit.

Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9172d2a0

tools/testing/selftests/bpf/test_verifier.c

+55 −0
Original line number Diff line number Diff line
@@ -4370,6 +4370,61 @@ static struct bpf_test tests[] = { 
		.result = ACCEPT,

		.prog_type = BPF_PROG_TYPE_TRACEPOINT,

	},

	{

		"invalid and of negative number",

		.insns = {

			BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),

			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),

			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),

			BPF_LD_MAP_FD(BPF_REG_1, 0),

			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,

				     BPF_FUNC_map_lookup_elem),

			BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4),

			BPF_MOV64_IMM(BPF_REG_1, 6),

			BPF_ALU64_IMM(BPF_AND, BPF_REG_1, -4),

			BPF_ALU64_IMM(BPF_LSH, BPF_REG_1, 2),

			BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),

			BPF_ST_MEM(BPF_DW, BPF_REG_0, 0,

				   offsetof(struct test_val, foo)),

			BPF_EXIT_INSN(),

		},

		.fixup_map2 = { 3 },

		.errstr_unpriv = "R0 pointer arithmetic prohibited",

		.errstr = "R0 min value is negative, either use unsigned index or do a if (index >=0) check.",

		.result = REJECT,

		.result_unpriv = REJECT,

	},

	{

		"invalid range check",

		.insns = {

			BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),

			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),

			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),

			BPF_LD_MAP_FD(BPF_REG_1, 0),

			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,

				     BPF_FUNC_map_lookup_elem),

			BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 12),

			BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_0, 0),

			BPF_MOV64_IMM(BPF_REG_9, 1),

			BPF_ALU32_IMM(BPF_MOD, BPF_REG_1, 2),

			BPF_ALU32_IMM(BPF_ADD, BPF_REG_1, 1),

			BPF_ALU32_REG(BPF_AND, BPF_REG_9, BPF_REG_1),

			BPF_ALU32_IMM(BPF_ADD, BPF_REG_9, 1),

			BPF_ALU32_IMM(BPF_RSH, BPF_REG_9, 1),

			BPF_MOV32_IMM(BPF_REG_3, 1),

			BPF_ALU32_REG(BPF_SUB, BPF_REG_3, BPF_REG_9),

			BPF_ALU32_IMM(BPF_MUL, BPF_REG_3, 0x10000000),

			BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_3),

			BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_3, 0),

			BPF_MOV64_REG(BPF_REG_0, 0),

			BPF_EXIT_INSN(),

		},

		.fixup_map2 = { 3 },

		.errstr_unpriv = "R0 pointer arithmetic prohibited",

		.errstr = "R0 min value is negative, either use unsigned index or do a if (index >=0) check.",

		.result = REJECT,

		.result_unpriv = REJECT,

	}

};



static int probe_filter_length(const struct bpf_insn *fp)