test_bpf: test LD_ABS and LD_IND instructions on fragmented skbs.

These new tests exercise various load sizes and offsets crossing the
head/fragment boundary.
Signed-off-by: Nicolas Schichan <nschichan@freebox.fr>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

lib/test_bpf.c

@@ -4493,6 +4493,148 @@ static struct bpf_test tests[] = {
 		{ { 1, 0xbef } },
 		.fill_helper = bpf_fill_ld_abs_vlan_push_pop,
 	},
+	/*
+	 * LD_IND / LD_ABS on fragmented SKBs
+	 */
+	{
+		"LD_IND byte frag",
+		.u.insns = {
+			BPF_STMT(BPF_LDX | BPF_IMM, 0x40),
+			BPF_STMT(BPF_LD | BPF_IND | BPF_B, 0x0),
+			BPF_STMT(BPF_RET | BPF_A, 0x0),
+		},
+		CLASSIC | FLAG_SKB_FRAG,
+		{ },
+		{ {0x40, 0x42} },
+		.frag_data = {
+			0x42, 0x00, 0x00, 0x00,
+			0x43, 0x44, 0x00, 0x00,
+			0x21, 0x07, 0x19, 0x83,
+		},
+	},
+	{
+		"LD_IND halfword frag",
+		.u.insns = {
+			BPF_STMT(BPF_LDX | BPF_IMM, 0x40),
+			BPF_STMT(BPF_LD | BPF_IND | BPF_H, 0x4),
+			BPF_STMT(BPF_RET | BPF_A, 0x0),
+		},
+		CLASSIC | FLAG_SKB_FRAG,
+		{ },
+		{ {0x40, 0x4344} },
+		.frag_data = {
+			0x42, 0x00, 0x00, 0x00,
+			0x43, 0x44, 0x00, 0x00,
+			0x21, 0x07, 0x19, 0x83,
+		},
+	},
+	{
+		"LD_IND word frag",
+		.u.insns = {
+			BPF_STMT(BPF_LDX | BPF_IMM, 0x40),
+			BPF_STMT(BPF_LD | BPF_IND | BPF_W, 0x8),
+			BPF_STMT(BPF_RET | BPF_A, 0x0),
+		},
+		CLASSIC | FLAG_SKB_FRAG,
+		{ },
+		{ {0x40, 0x21071983} },
+		.frag_data = {
+			0x42, 0x00, 0x00, 0x00,
+			0x43, 0x44, 0x00, 0x00,
+			0x21, 0x07, 0x19, 0x83,
+		},
+	},
+	{
+		"LD_IND halfword mixed head/frag",
+		.u.insns = {
+			BPF_STMT(BPF_LDX | BPF_IMM, 0x40),
+			BPF_STMT(BPF_LD | BPF_IND | BPF_H, -0x1),
+			BPF_STMT(BPF_RET | BPF_A, 0x0),
+		},
+		CLASSIC | FLAG_SKB_FRAG,
+		{ [0x3e] = 0x25, [0x3f] = 0x05, },
+		{ {0x40, 0x0519} },
+		.frag_data = { 0x19, 0x82 },
+	},
+	{
+		"LD_IND word mixed head/frag",
+		.u.insns = {
+			BPF_STMT(BPF_LDX | BPF_IMM, 0x40),
+			BPF_STMT(BPF_LD | BPF_IND | BPF_W, -0x2),
+			BPF_STMT(BPF_RET | BPF_A, 0x0),
+		},
+		CLASSIC | FLAG_SKB_FRAG,
+		{ [0x3e] = 0x25, [0x3f] = 0x05, },
+		{ {0x40, 0x25051982} },
+		.frag_data = { 0x19, 0x82 },
+	},
+	{
+		"LD_ABS byte frag",
+		.u.insns = {
+			BPF_STMT(BPF_LD | BPF_ABS | BPF_B, 0x40),
+			BPF_STMT(BPF_RET | BPF_A, 0x0),
+		},
+		CLASSIC | FLAG_SKB_FRAG,
+		{ },
+		{ {0x40, 0x42} },
+		.frag_data = {
+			0x42, 0x00, 0x00, 0x00,
+			0x43, 0x44, 0x00, 0x00,
+			0x21, 0x07, 0x19, 0x83,
+		},
+	},
+	{
+		"LD_ABS halfword frag",
+		.u.insns = {
+			BPF_STMT(BPF_LD | BPF_ABS | BPF_H, 0x44),
+			BPF_STMT(BPF_RET | BPF_A, 0x0),
+		},
+		CLASSIC | FLAG_SKB_FRAG,
+		{ },
+		{ {0x40, 0x4344} },
+		.frag_data = {
+			0x42, 0x00, 0x00, 0x00,
+			0x43, 0x44, 0x00, 0x00,
+			0x21, 0x07, 0x19, 0x83,
+		},
+	},
+	{
+		"LD_ABS word frag",
+		.u.insns = {
+			BPF_STMT(BPF_LD | BPF_ABS | BPF_W, 0x48),
+			BPF_STMT(BPF_RET | BPF_A, 0x0),
+		},
+		CLASSIC | FLAG_SKB_FRAG,
+		{ },
+		{ {0x40, 0x21071983} },
+		.frag_data = {
+			0x42, 0x00, 0x00, 0x00,
+			0x43, 0x44, 0x00, 0x00,
+			0x21, 0x07, 0x19, 0x83,
+		},
+	},
+	{
+		"LD_ABS halfword mixed head/frag",
+		.u.insns = {
+			BPF_STMT(BPF_LD | BPF_ABS | BPF_H, 0x3f),
+			BPF_STMT(BPF_RET | BPF_A, 0x0),
+		},
+		CLASSIC | FLAG_SKB_FRAG,
+		{ [0x3e] = 0x25, [0x3f] = 0x05, },
+		{ {0x40, 0x0519} },
+		.frag_data = { 0x19, 0x82 },
+	},
+	{
+		"LD_ABS word mixed head/frag",
+		.u.insns = {
+			BPF_STMT(BPF_LD | BPF_ABS | BPF_W, 0x3e),
+			BPF_STMT(BPF_RET | BPF_A, 0x0),
+		},
+		CLASSIC | FLAG_SKB_FRAG,
+		{ [0x3e] = 0x25, [0x3f] = 0x05, },
+		{ {0x40, 0x25051982} },
+		.frag_data = { 0x19, 0x82 },
+	},
 };
 
 static struct net_device dev;