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[PATCH 6/6] test_bpf: add tests checking that JIT/interpreter sets A and X to 0.

From Nicolas Schichan <nschichan@freebox.fr>
Newsgroups linux.kernel
Subject [PATCH 6/6] test_bpf: add tests checking that JIT/interpreter sets A and X to 0.
Date 2015-08-03 16:10 +0200
Message-ID <pToBc-5iK-43@gated-at.bofh.it> (permalink)
References <pToBb-5iK-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

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It is mandatory for the JIT or interpreter to reset the A and X
registers to 0 before running the filter. Check that it is the case on
various ALU and JMP instructions.

Signed-off-by: Nicolas Schichan <nschichan@freebox.fr>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
---
 lib/test_bpf.c | 158 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 158 insertions(+)

diff --git a/lib/test_bpf.c b/lib/test_bpf.c
index a84a875..51f94f9 100644
--- a/lib/test_bpf.c
+++ b/lib/test_bpf.c
@@ -4931,6 +4931,164 @@ static struct bpf_test tests[] = {
 		},
 		{ {0x40, 0x88ee99ff } },
 	},
+	/*
+	 * verify that the interpreter or JIT correctly sets A and X
+	 * to 0.
+	 */
+	{
+		"ADD default X",
+		.u.insns = {
+			/*
+			 * A = 0x42
+			 * A = A + X
+			 * ret A
+			 */
+			BPF_STMT(BPF_LD | BPF_IMM, 0x42),
+			BPF_STMT(BPF_ALU | BPF_ADD | BPF_X, 0),
+			BPF_STMT(BPF_RET | BPF_A, 0x0),
+		},
+		CLASSIC | FLAG_NO_DATA,
+		{},
+		{ {0x1, 0x42 } },
+	},
+	{
+		"ADD default A",
+		.u.insns = {
+			/*
+			 * A = A + 0x42
+			 * ret A
+			 */
+			BPF_STMT(BPF_ALU | BPF_ADD | BPF_K, 0x42),
+			BPF_STMT(BPF_RET | BPF_A, 0x0),
+		},
+		CLASSIC | FLAG_NO_DATA,
+		{},
+		{ {0x1, 0x42 } },
+	},
+	{
+		"SUB default X",
+		.u.insns = {
+			/*
+			 * A = 0x66
+			 * A = A - X
+			 * ret A
+			 */
+			BPF_STMT(BPF_LD | BPF_IMM, 0x66),
+			BPF_STMT(BPF_ALU | BPF_SUB | BPF_X, 0),
+			BPF_STMT(BPF_RET | BPF_A, 0x0),
+		},
+		CLASSIC | FLAG_NO_DATA,
+		{},
+		{ {0x1, 0x66 } },
+	},
+	{
+		"SUB default A",
+		.u.insns = {
+			/*
+			 * A = A - -0x66
+			 * ret A
+			 */
+			BPF_STMT(BPF_ALU | BPF_SUB | BPF_K, -0x66),
+			BPF_STMT(BPF_RET | BPF_A, 0x0),
+		},
+		CLASSIC | FLAG_NO_DATA,
+		{},
+		{ {0x1, 0x66 } },
+	},
+	{
+		"MUL default X",
+		.u.insns = {
+			/*
+			 * A = 0x42
+			 * A = A * X
+			 * ret A
+			 */
+			BPF_STMT(BPF_LD | BPF_IMM, 0x42),
+			BPF_STMT(BPF_ALU | BPF_MUL | BPF_X, 0),
+			BPF_STMT(BPF_RET | BPF_A, 0x0),
+		},
+		CLASSIC | FLAG_NO_DATA,
+		{},
+		{ {0x1, 0x0 } },
+	},
+	{
+		"MUL default A",
+		.u.insns = {
+			/*
+			 * A = A * 0x66
+			 * ret A
+			 */
+			BPF_STMT(BPF_ALU | BPF_MUL | BPF_K, 0x66),
+			BPF_STMT(BPF_RET | BPF_A, 0x0),
+		},
+		CLASSIC | FLAG_NO_DATA,
+		{},
+		{ {0x1, 0x0 } },
+	},
+	{
+		"DIV default X",
+		.u.insns = {
+			/*
+			 * A = 0x42
+			 * A = A / X ; this halt the filter execution if X is 0
+			 * ret 0x42
+			 */
+			BPF_STMT(BPF_LD | BPF_IMM, 0x42),
+			BPF_STMT(BPF_ALU | BPF_DIV | BPF_X, 0),
+			BPF_STMT(BPF_RET | BPF_K, 0x42),
+		},
+		CLASSIC | FLAG_NO_DATA,
+		{},
+		{ {0x1, 0x0 } },
+	},
+	{
+		"DIV default A",
+		.u.insns = {
+			/*
+			 * A = A / 1
+			 * ret A
+			 */
+			BPF_STMT(BPF_ALU | BPF_DIV | BPF_K, 0x1),
+			BPF_STMT(BPF_RET | BPF_A, 0x0),
+		},
+		CLASSIC | FLAG_NO_DATA,
+		{},
+		{ {0x1, 0x0 } },
+	},
+	{
+		"JMP EQ default A",
+		.u.insns = {
+			/*
+			 * cmp A, 0x0, 0, 1
+			 * ret 0x42
+			 * ret 0x66
+			 */
+			BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, 0x0, 0, 1),
+			BPF_STMT(BPF_RET | BPF_K, 0x42),
+			BPF_STMT(BPF_RET | BPF_K, 0x66),
+		},
+		CLASSIC | FLAG_NO_DATA,
+		{},
+		{ {0x1, 0x42 } },
+	},
+	{
+		"JMP EQ default X",
+		.u.insns = {
+			/*
+			 * A = 0x0
+			 * cmp A, X, 0, 1
+			 * ret 0x42
+			 * ret 0x66
+			 */
+			BPF_STMT(BPF_LD | BPF_IMM, 0x0),
+			BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_X, 0x0, 0, 1),
+			BPF_STMT(BPF_RET | BPF_K, 0x42),
+			BPF_STMT(BPF_RET | BPF_K, 0x66),
+		},
+		CLASSIC | FLAG_NO_DATA,
+		{},
+		{ {0x1, 0x42 } },
+	},
 };
 
 static struct net_device dev;
-- 
1.9.1

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Thread

[PATCH 0/6] test_bpf improvements Nicolas Schichan <nschichan@freebox.fr> - 2015-08-03 16:10 +0200
  [PATCH 4/6] test_bpf: add module parameters to filter the tests to run. Nicolas Schichan <nschichan@freebox.fr> - 2015-08-03 16:10 +0200
    Re: [PATCH 4/6] test_bpf: add module parameters to filter the tests  to run. Daniel Borkmann <daniel@iogearbox.net> - 2015-08-03 18:00 +0200
      Re: [PATCH 4/6] test_bpf: add module parameters to filter the tests  to run. Daniel Borkmann <daniel@iogearbox.net> - 2015-08-03 18:40 +0200
      Re: [PATCH 4/6] test_bpf: add module parameters to filter the tests  to run. Nicolas Schichan <nschichan@freebox.fr> - 2015-08-03 18:40 +0200
  [PATCH 3/6] test_bpf: test LD_ABS and LD_IND instructions on fragmented skbs. Nicolas Schichan <nschichan@freebox.fr> - 2015-08-03 16:10 +0200
    Re: [PATCH 3/6] test_bpf: test LD_ABS and LD_IND instructions on  fragmented skbs. Daniel Borkmann <daniel@iogearbox.net> - 2015-08-03 17:10 +0200
  [PATCH 6/6] test_bpf: add tests checking that JIT/interpreter sets A and X to 0. Nicolas Schichan <nschichan@freebox.fr> - 2015-08-03 16:10 +0200
    Re: [PATCH 6/6] test_bpf: add tests checking that JIT/interpreter  sets A and X to 0. Daniel Borkmann <daniel@iogearbox.net> - 2015-08-03 17:10 +0200
  [PATCH 5/6] test_bpf: add more tests for LD_ABS and LD_IND. Nicolas Schichan <nschichan@freebox.fr> - 2015-08-03 16:10 +0200
    Re: [PATCH 5/6] test_bpf: add more tests for LD_ABS and LD_IND. Daniel Borkmann <daniel@iogearbox.net> - 2015-08-03 17:10 +0200
  [PATCH 1/6] test_bpf: avoid oopsing the kernel when generate_test_data() fails. Nicolas Schichan <nschichan@freebox.fr> - 2015-08-03 16:10 +0200
    Re: [PATCH 1/6] test_bpf: avoid oopsing the kernel when generate_test_data()  fails. Daniel Borkmann <daniel@iogearbox.net> - 2015-08-03 16:50 +0200

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