Commit fa47a16b authored by Daniel Borkmann's avatar Daniel Borkmann Committed by Alexei Starovoitov
Browse files

bpf: test case to check whether src/dst regs got mangled by xadd 



We currently do not have such a test case in test_verifier selftests
but it's important to test under bpf_jit_enable=1 to make sure JIT
implementations do not mistakenly mess with src/dst reg for xadd/{w,dw}.

Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent b9c1e60e

tools/testing/selftests/bpf/test_verifier.c

+40 −0
Original line number Diff line number Diff line
@@ -12004,6 +12004,46 @@ static struct bpf_test tests[] = { 
		.errstr = "BPF_XADD stores into R2 packet",

		.prog_type = BPF_PROG_TYPE_XDP,

	},

	{

		"xadd/w check whether src/dst got mangled, 1",

		.insns = {

			BPF_MOV64_IMM(BPF_REG_0, 1),

			BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),

			BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),

			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),

			BPF_STX_XADD(BPF_DW, BPF_REG_10, BPF_REG_0, -8),

			BPF_STX_XADD(BPF_DW, BPF_REG_10, BPF_REG_0, -8),

			BPF_JMP_REG(BPF_JNE, BPF_REG_6, BPF_REG_0, 3),

			BPF_JMP_REG(BPF_JNE, BPF_REG_7, BPF_REG_10, 2),

			BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -8),

			BPF_EXIT_INSN(),

			BPF_MOV64_IMM(BPF_REG_0, 42),

			BPF_EXIT_INSN(),

		},

		.result = ACCEPT,

		.prog_type = BPF_PROG_TYPE_SCHED_CLS,

		.retval = 3,

	},

	{

		"xadd/w check whether src/dst got mangled, 2",

		.insns = {

			BPF_MOV64_IMM(BPF_REG_0, 1),

			BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),

			BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),

			BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -8),

			BPF_STX_XADD(BPF_W, BPF_REG_10, BPF_REG_0, -8),

			BPF_STX_XADD(BPF_W, BPF_REG_10, BPF_REG_0, -8),

			BPF_JMP_REG(BPF_JNE, BPF_REG_6, BPF_REG_0, 3),

			BPF_JMP_REG(BPF_JNE, BPF_REG_7, BPF_REG_10, 2),

			BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_10, -8),

			BPF_EXIT_INSN(),

			BPF_MOV64_IMM(BPF_REG_0, 42),

			BPF_EXIT_INSN(),

		},

		.result = ACCEPT,

		.prog_type = BPF_PROG_TYPE_SCHED_CLS,

		.retval = 3,

	},

	{

		"bpf_get_stack return R0 within range",

		.insns = {

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